Marine Sanctuaries Conservation Series ONMS-13-05

The Natural Resources of Monterey Bay 

National Marine Sanctuary:

A Focus on Federal Waters

Final Report

June 2013

U.S. Department of Commerce

National Oceanic and Atmospheric Administration

National Ocean Service

Office of National Marine Sanctuaries June 2013
About the Marine Sanctuaries Conservation Series

The National Oceanic and Atmospheric Administration’s National Ocean Service (NOS) 

administers the Office of National Marine Sanctuaries (ONMS). Its mission is to identify, 

designate, protect and manage the ecological, recreational, research, educational, historical, 

and aesthetic resources and qualities of nationally significant coastal and marine areas. The 

existing marine sanctuaries differ widely in their natural and historical resources and include 

nearshore and open ocean areas ranging in size from less than one to over 5,000 square miles. 

Protected habitats include rocky coasts, kelp forests, coral reefs, sea grass beds, estuarine 

habitats, hard and soft bottom habitats, segments of whale migration routes, and shipwrecks.

Because of considerable differences in settings, resources, and threats, each marine sanctuary 

has a tailored management plan. Conservation, education, research, monitoring and 

enforcement programs vary accordingly. The integration of these programs is fundamental to 

marine protected area management. The Marine Sanctuaries Conservation Series reflects and 

supports this integration by providing a forum for publication and discussion of the complex 

issues currently facing the sanctuary system. Topics of published reports vary substantially and 

may include descriptions of educational programs, discussions on resource management issues, 

and results of scientific research and monitoring projects. The series facilitates integration of 

natural sciences, socioeconomic and cultural sciences, education, and policy development to 

accomplish the diverse needs of NOAA’s resource protection mandate.
The Natural Resources of Monterey Bay 

National Marine Sanctuary: 

A Focus on Federal Waters

Final Report

June 2013

Jennifer A. Brown, Erica Burton, Sophie De Beukelaer

Monterey Bay National Marine Sanctuary

Silver Spring, Maryland

June 2013

U.S. Department of Commerce

Cameron Kerry, Acting Secretary

National Ocean and Atmospheric Administration

Kathryn Sullivan, Ph.D.

Acting Under Secretary of Commerce for Oceans and Atmosphere

National Ocean Service

Holly Bamford, Ph.D., Acting Assistant Administrator

Office of National Marine Sanctuaries

Daniel J. Basta, Director
Disclaimer

Report content does not necessarily reflect the views and policies of the Office of National 

Marine Sanctuaries or the National Oceanic and Atmospheric Administration, nor does the 

mention of trade names or commercial products constitute endorsement or recommendation for 

use.

Report Availability

Electronic copies of this report may be downloaded from the Office of National Marine 

Sanctuaries web site at http://sanctuaries.noaa.gov. Hard copies may be available from the 

following address:

National Oceanic and Atmospheric Administration

Office of National Marine Sanctuaries

SSMC4, N/ORM62

1305 East-West Highway

Silver Spring, MD 20910

Cover

Top Left: Pacific white-sided dolphins (Lagenorhynchus obliquidens), Chad King/MBNMS

Top Right: Spotted ratfish (Hydrolagus colliei) and sun star (Rathbunaster californicus), Jean 

deMarignac/MBNMS

Bottom Left: Canary rockfish (Sebastes pinniger), bocaccio (S. paucispinis), yelloweye rockfish 

(S. ruberrimus), feather stars (Florometra serratissima) and sponges, Rick 

Starr/MBNMS

Bottom Right: “Mystery Mollusk” (Order Nudibranchia), NOAA/MBARI

Suggested Citation

Brown, Jennifer A., Erica J. Burton, Sophie De Beukelaer. (2013). The Natural Resources of 

Monterey Bay National Marine Sanctuary: A Focus on Federal Waters. Marine Sanctuaries 

Conservation Series ONMS-13-05. U.S. Department of Commerce, National Oceanic and 

Atmospheric Administration, Office of National Marine Sanctuaries, Silver Spring, MD. 264 pp. 

Contact

Jennifer A. Brown

SIMoN Ecosystem Scientist

Monterey Bay National Marine Sanctuary

99 Pacific Street, Bldg 455A

Monterey, CA 93940

(415) 310-6764

jennifer.brown@noaa.gov
Abstract

This natural resources assessment synthesizes the current scientific knowledge of the physical 

and biological resources in the offshore habitats of Monterey Bay National Marine Sanctuary

(MBNMS). The main body of this report is organized into sections by offshore habitat category.

Benthic habitats categories were defined by substrate type (hard and soft) and depth: shelf I (30-

100 m), shelf II (100-200 m), slope (200-3,000 m), and rise (>3,000 m). Additional offshore 

habitat categories included in this report are open ocean, submarine canyon, seamount, oxygen 

minimum zone, chemosynthetic biological communities, and macrophyte detritus. For each of 

these habitat categories, information was compiled on topics spanning many levels of ecological 

organization (e.g., population, species, community) and various ecological processes (e.g., 

productivity, dispersal). Information sources included primary literature, unpublished data, and 

expert interviews. The purpose of this document is to identify sources of regional information, 

and describe natural resources and processes in federal waters of Monterey Bay National Marine 

Sanctuary .

Key Words

Monterey Bay National Marine Sanctuary, natural resources, site characterization, continental 

shelf, continental slope, continental rise, open water, submarine canyon, seamount, oxygen 

minimum zone, plankton, algae, invertebrates, fishes, seabirds, marine mammals, sea turtles, 

species diversity, species richness, species composition, sensitive species

Acknowledgements

The authors acknowledge important contributions from the following colleagues. Mark Carr 

provided guidance on the search topics for the literature review. Jim Barry, Elizabeth Becker, 

Scott Benson, Dan Dorfman, David Foley, Karin Forney, John Guinotte, Julie Howar, Jaime 

Jahncke, Linda Kuhnz, Matt Merrifield, John Oliver, Charlie Paull, Steve Ralston, Bruce 

Robison, Brian Schlining, Mary Silver, Rob Sherlock, Heather Spalding, Rick Starr, Robert 

Vrijenhoek, Curt Whitmire, and Mary Yoklavich provided important information, such as 

unpublished data, relevant literature, and help drafting and reviewing figures. Andrew 

DeVogelaere, Oren Frey, Steve Lonhart, and Lisa Wooninck reviewed all or portions of this 

document and provided helpful comments. The following regional scientific experts reviewed 

two or more sections of the report during the external review process: Jim Barry, John Field, 

Karin Forney, Chris Harrold, Linda Kuhnz, James Lindholm, Lonny Lundsten, John Pearse, Paul 

Reilly, Curt Storlazzi, and Brian Tissot.

i
Table of Contents

Topic Page

Abstract............................................................................................................................................ i

Key Words....................................................................................................................................... i

Acknowledgements.......................................................................................................................... i

Table of Contents............................................................................................................................ ii

List of Figures................................................................................................................................iii

List of Tables ................................................................................................................................. iv

Introduction..................................................................................................................................... 1

Background................................................................................................................................. 1

MBNMS and Defined Study Area.............................................................................................. 1

Methods........................................................................................................................................... 2

Organization of Report ............................................................................................................... 4

Species of Special Interest .......................................................................................................... 4

Spatial Data Layers and Maps .................................................................................................... 6

Shelf I (30-100 m) and Shelf II (100-200 m) – Hard Substrate...................................................... 7

Shelf I (30-100 m) and Shelf II (100-200 m) – Soft Substrate ..................................................... 23

Slope (200-3,000 m) – Hard Substrate ......................................................................................... 42

Slope (200-3,000 m) – Soft Substrate........................................................................................... 52

Rise (>3,000 m) – Soft Substrate.................................................................................................. 72

Open Water................................................................................................................................... 79

Submarine Canyon...................................................................................................................... 101

Seamount..................................................................................................................................... 115

Oxygen Minimum Zone.............................................................................................................. 123

Chemosynthetic Biological Communities.................................................................................. 132

Macrophyte Detritus ................................................................................................................... 137

Literature Cited ........................................................................................................................... 142

Appendix I. Catalogue of Research Studies ............................................................................... 241

Appendix II. Catalogue of GIS Data........................................................................................... 249

Appendix III. Benthic-Pelagic Coupling .................................................................................... 257

Appendix IV. Definition of Terms.............................................................................................. 259

Appendix V. List of Acronyms................................................................................................... 262

Appendix VI. List of Persons Providing Personal Communication ........................................... 264

ii
List of Figures

Figure Number and Title Page

Figure 1. Benthic habitat categories in Monterey Bay National Marine Sanctuary. .................. 159

Figure 2. Submarine canyons in Monterey Bay National Marine Sanctuary. ............................ 160

Figure 3. Seamounts in and adjacent to Monterey Bay National Marine Sanctuary.................. 161

Figure 4. Oxygen Minimum Zone in Monterey Bay National Marine Sanctuary...................... 162

Figure 5. Three dimensional view of the Oxygen Minimum Zone in MBNMS. ....................... 163

Figure 6. Observations of Chemosynthetic Biological Communities in MBNMS. ................... 164

Figure 7. Depth distribution and relative abundance of deep-water algae along the central 

California coast........................................................................................................... 165

Figure 8. Observations of structure-forming invertebrates associated with hard substrate........ 166

Figure 9. Corals collected in National Marine Fisheries Service groundfish trawl surveys....... 167

Figure 10. Predicted habitat suitability for six taxa of deep-sea coral........................................ 168

Figure 11. Groundfish abundance and diversity at Point Pinos and Point Sur........................... 169

Figure 12. Location of eight zones for pelagic species off central California............................ 170

Figure 13. Observations of invertebrates associated with soft substrate. ................................... 171

Figure 14. Number and abundance of infaunal taxa along a submarine cable in MBNMS. ...... 172

Figure 15. Species richness of demersal rockfishes.................................................................... 173

Figure 16. Species richness of demersal fishes........................................................................... 174

Figure 17. Species diversity of demersal fishes.......................................................................... 175

Figure 18. Depth range of groundfishes collected from slope trawl surveys. ............................ 176

Figure 19. Depth distribution of continental slope species in MBNMS..................................... 177

Figure 20. Hotspots, principal foraging area, and critical habitat for the leatherback sea turtle.178

Figure 21. Hotspots for seabirds in MBNMS. ............................................................................ 179

Figure 22. Hotspots for marine mammals in MBNMS............................................................... 180

Figure 23. Persistent upwelling zones in MBNMS .................................................................... 181

Figure 24. CoastWatch Oceanic Front Probability Index by season. ......................................... 182

Figure 25. Modeled multispecies seabird hotspots in MBNMS................................................. 183

Figure 26. Modeled densities of whales in the California Current Ecosystem........................... 184

Figure 27. Stratified estimates of harbor porpoise density in MBNMS. .................................... 186

iii
List of Tables

Table Number and Title Page

Table 1. Search topics, definitions and search questions..............................................187

Table 2. Area of benthic habitats in Monterey Bay National Marine Sanctuary...................190

Table 3. Invertebrate species of special interest in MBNMS......................................... 191

Table 4. Fish species of special interest in MBNMS...................................................193

Table 5. Reptile species of special interest in MBNMS...............................................201

Table 6. Seabird species of special interest in MBNMS............................................... 202

Table 7. Marine mammal species of special interest in MBNMS....................................204

Table 8. The relative abundance of megafaunal invertebrates at three sites on the shelf.........206

Table 9. Smmary of baseline characterization data for eight marine protected areas............. 208

Table 10. Typical rockfish assemblage in each of five habitat categories........................... 211

Table 11. Fish species assemblages from "A Biogeographic Assessment of North/Central 

California"..................................................................................... 213

Table 12. Relative abundance and seasonal occurrence of sea turtles, seabirds, and marine 

mammals off central California............................................................. 216

Table 13. Fish species associated with soft-bottom habitats in central California.................219

Table 14. Epipelagic and mesopelagic organisms observed by MBARI in MBNMS............ 222

Table 15. Ichthyoplankton assemblage along the U.S. West Coast................................. 224

Table 16. Epipelagic, mesopelagic and bathypelagic fish assemblages in MBNMS............. 225

Table 17. Taxa observed at Davidson Seamount and their listing categories....................... 228

Table 18. Dominant invertebrate phyla observed at Davidson and Pioneer Seamounts........... 235

Table 19. Dominant fish families observed at Davidson and Pioneer Seamounts................. 236

Table 20. Sea-surface species observed within Davidson Seamount Management Zone.........237

Table 21. Species observed at four CBCs in Monterey Bay.......................................... 239

iv
Introduction

Background

Monterey Bay National Marine Sanctuary (MBNMS) is one of 13 national marine sanctuaries in 

U.S. waters. The National Marine Sanctuary System is mandated to “maintain for future 

generations the habitat and ecological services of the natural assemblages of living resources that 

inhabit these areas.”1 In order to accomplish this mandate for MBNMS, we need a thorough 

understanding of the natural resources occurring inside the sanctuary’s boundaries.

The “Monterey Bay National Marine Sanctuary Site Characterization”, completed in 1996, 

provided a summary of the existing information on the sanctuary’s physical and biological 

features as well as human influences (Guerrero and Kvitek 1996). The site characterization 

provided the most current information on the status of MBNMS natural resources.

With more than 30 education and marine research institutions located in close proximity to the 

sanctuary, a substantial amount of new information has been collected on the status of natural 

resources in the sanctuary since the release of the site characterization. However, for that 

information to be used effectively in the management of sanctuary resources, it must be collected 

and synthesized. This natural resources assessment, which is focused on the habitats and 

resources in offshore waters, provides an updated compilation of scientific knowledge of the 

physical and biological resources in the offshore portions of the sanctuary. This report combines 

information from the site characterization with more recent studies to provide a more current and 

detailed understanding of offshore resources.

There are several reasons for the focus on offshore resources. First, there has already been a 

significant effort, led by the state of California as part of the California State Marine Life 

Protection Act process, to understand, protect, and monitor marine resources within state waters 

(< 3 nautical miles from shore). Second, improvements in sampling techniques and technologies, 

such as submersibles, satellites, and animal tags, have facilitated exploration and monitoring in 

the more remote portions of MBNMS. Third, these evolving technologies also change the 

landscape of current and potential human uses of sanctuary resources, including submerged 

cables, offshore aquaculture, and green energy development. An updated and expanded 

understanding of the physical and biological resources in the offshore habitats is critical to 

managing these resources in response to ever changing human influences.

MBNMS and Defined Study Area

Monterey Bay National Marine Sanctuary was established in 1992 by the Office of National 

Marine Sanctuaries. The sanctuary extends along the coast from Rocky Point (Marin County) to 

Cambria Rock (San Luis Obispo County), encompassing nearly 450 km of shoreline (Figure 1). 

As originally designated in 1992, MBNMS encompassed 13,780 km2 of ocean, extended 91.5 

km offshore at its widest point, and reached a depth of 3,250 m at its deepest point. On March 9, 

2009, MBNMS was expanded by 2,007 km2 to include the Davidson Seamount Management 

Zone (DSMZ). Davidson Seamount is one of the largest known underwater mountains in U.S. 

1 Title 16 United States Code, Chapter 32, §1431(a)(4)(C)

1 Introduction

 
coastal waters; it is 2,280 m tall, 42 km long and 13 km wide. The shallowest point is 1,250 m 

below the ocean’s surface and the deepest part of the DSMZ is 3,875 m.

The northern portion of MBNMS, extending along the coast of San Mateo and Santa Cruz 

Counties, consists of long stretches of sandstone cliffs with a few small beaches and estuaries 

created by coastal streams. This section of the sanctuary has a relatively wide and shallow 

continental shelf bisected by four submarine canyons: Pioneer, Ascension, Año Nuevo, and 

Cabrillo Canyons (Figure 2). Due to the broad continental shelf, the heads of these submarine 

canyons are located far from shore.

The central portion of MBNMS is dominated by Monterey Bay, which extends between Point 

Santa Cruz to the north and a prominent granite headland, Point Pinos, to the south. Monterey 

Bay covers an area of about 550 km2

. The northern coastline of Monterey Bay consists of sand 

bluffs, mudstone terraces, rocky intertidal benches, sand beaches, and cliffs. Two major rivers, 

the San Lorenzo and Pajaro, enter Monterey Bay along its north shore. Elkhorn Slough, the only 

large estuary in MBNMS, connects to the ocean at Moss Landing. The Salinas River, which is 

the major drainage system for the extensive Salinas Valley watershed, enters Monterey Bay to 

the south of Elkhorn Slough. Sandy beaches and dunes characterize the coastline extending 

between Moss Landing and the granite headlands of the Monterey peninsula. The broad, shallow 

continental shelf found in Monterey Bay is bisected by Monterey Canyon, the largest submarine 

canyon in the sanctuary. This canyon extends from the shore near Moss Landing to a depth of 

over 3,200 m. There are two main branches of Monterey Canyon: Soquel Canyon to the north 

and Carmel Canyon to the south (Figure 2).

South of the Monterey Peninsula, are Carmel Bay and the Big Sur coast. Big Sur is characterized 

by steep cliffs and rocky headlands interspersed with small pocket beaches. The watersheds of 

the Santa Lucia Range drain to the ocean through many streams and creeks that cut the steep 

western face of the mountain range. This steep topography continues below the ocean surface, 

resulting in a relatively narrow continental shelf incised by many submarine canyons, including 

Sur, Partington, and Lucia Canyons.

The Davidson Seamount is a pristine, volcanic undersea mountain habitat 129 km to the 

southwest of Monterey and 121 km west of San Simeon. The vertical nature and rocky substrate 

on the seamount creates habitat that is vastly different from the surrounding soft-sediments on 

the seafloor. The seamount hosts large coral forests, vast sponge fields, crabs, deep-sea fishes, 

shrimp, basket stars, and large numbers of rare and unidentified benthic species.

The study area for this natural resources assessment includes the portions of MBNMS to the 

south of Pigeon Point (San Mateo County) and to the west of the state waters boundary, 

including the DSMZ (hereafter referred to as the “federal study area”; Figure 1). Habitats and 

ecosystems that only occur in state waters (e.g., estuaries, intertidal zone, nearshore sandy 

seafloor) are not considered here.

2 Introduction
Methods

The purpose of this natural resources assessment is to identify and describe the biological 

resources and ecological processes in the offshore habitats of the federal study area. A benthic 

habitat was defined as encompassing the seafloor and associated benthic and benthopelagic 

fauna. Benthic fauna include the epifauna (active, crawling, or attached organisms living on the 

surface of the seafloor) and infauna (organisms living buried in the sediments). Benthopelagic 

fauna are organisms swimming or drifting in the waters immediately over the seafloor.

Primary benthic habitats were identified according to substrate type and depth zone. The two 

major substrate types, soft bottom and hard bottom, were selected because very different 

biological communities are associated with each and coarse-scale substrate data are available for 

the entire MBNMS. Five benthic depth zones were identified (based on Airamé et al. 2003, 

Allen 2006, and Greene et al. 1999):

• Nearshore: 0-30 m

• Shelf I: 30-100 m

• Shelf II: 100-200 m

• Slope: 200-3,000 m

• Rise: >3,000 m

Figure 1 shows the spatial distribution of the primary benthic habitats in MBNMS and their 

overlap with the federal study area. Table 2 provides the area (km2

) in each primary benthic 

habitat and shows the percentage of the entire MBNMS and the federal study area in each 

habitat. The nearshore depth zone does not occur in the federal study area so it was excluded 

from this natural resources assessment.

The open water habitat was identified as an additional primary habitat. The open water habitat

encompasses the entire water column, from the surface to just above the seafloor. Fauna in the 

open water habitat includes nektonic (strong swimmers) and planktonic (weak swimmers and 

drifters) organisms that rarely or never interact with benthic habitats.

In addition to the primary habitats, we identified features in the offshore waters of MBNMS that 

modify the biological communities and ecological processes typically associated with a given 

habitat. These features, hereafter referred to as secondary habitats, are:

• Submarine Canyon

• Seamount

• Oxygen Minimum Zone (OMZ)

• Chemosynthetic Biological Communities (CBCs)

• Macrophyte Detritus

Submarine canyons and seamounts are large geological features with substantially different 

topography than the surrounding shelf, slope and rise habitats. The spatial distribution of 

submarine canyon and seamount habitats are shown in Figure 2 and Figure 3, respectively. The 

oxygen minimum zone - a layer of the water column with reduced levels of dissolved oxygen - is 

an oceanographic feature that strongly influences the distribution and abundance of fauna where 

it intersects with the seafloor (Figure 4) and the water column (Figure 5). Table 2 provides the 

area (km2

) of seafloor (in MBNMS and in the federal study area) covered by submarine canyon, 

2 Methods
seamount, and oxygen minimum zone habitats. Chemosynthetic biological communities (Figure 

6) and macrophyte detritus are features that provide primary production and biogenic structure to 

habitats with little to no other sources of energy and physical structure.

The main focus of the literature review for the secondary habitats was to identify the biological 

communities and ecological processes associated with these features and to describe how these 

features modify the processes and communities typically associated with a given depth and 

substrate type (i.e., primary habitats).

Literature Review and Data Gathering

In order to identify and describe the biological resources and ecological processes in the offshore 

habitats of the federal study area, we identified search topics spanning many levels of ecological 

organization (e.g., population, species, community) and various ecological processes (e.g., 

productivity, dispersal). The search topics were grouped under four themes: habitat function, 

habitat structure, movement and dispersal, and species of special interest (Table 1). These search 

topics were the target of information gathering efforts for each primary and secondary habitat.

The habitat information presented in this report was compiled in two phases. The first phase, 

which occurred from March-August 2006, consisted of a review of published papers and, to the 

extent that we could find them, unpublished reports and unpublished data through 2005.

Research studies conducted in MBNMS (Figure 1) were the primary focus of the literature 

review and data gathering effort. However, if little to no information was found on a specific 

topic in the sanctuary, we broadened the search to include studies conducted along the California 

coast between Point Arena and Point Conception. When necessary, we further expanded our 

search to studies along western North America.

Information was gathered using library and internet resources, as well as personal 

communication with regional scientists. To search for information in the published literature, two 

electronic databases were accessed: Aquatic Sciences and Fisheries Abstracts (ASFA; 1971-

2005) and BIOSIS Previews (1969-2005). In addition, broad searches on the internet were 

performed using web-based search engines (e.g., Google, Google Scholar). Appendix I provides

a catalogue of the research studies used in this natural resources assessment. For each study, the 

following information was included in the appendix: timing of the study, location of the study, 

habitat category, and sampling method. Appendix VI lists regional scientist that provided 

personal communication including published studies, technical reports, and unpublished reports 

and data.

Relevant geo-referenced data layers were requested or constructed and assimilated in

Geographical Information Systems (GIS). We focused on identifying and gathering the most 

complete, up-to-date, and reliable spatial data from authoritative sources that would help 

illustrate the spatial distribution of geological, oceanographic, and biological resources in 

offshore habitats. Appendix II provides a catalogue of the GIS data layers used in this natural 

resources assessment. For each data layer, the following information was included in the 

appendix: figure number, data type, data developer, a description of the how the data layer was 

developed and how it should be used, and a website where data can be downloaded (if available).

3 Methods
The second phase (2006-July 2012) consisted of a targeted updating of geo-referenced data 

layers and inclusion of more recent studies for specific topics related to on-going resource 

management concerns and actions. New information was added to the habitat summaries and 

many of the GIS data layers were supplemented or replaced with more recently available data. 

When geo-referenced data were not available, we worked with experts to create GIS layers such 

as the leatherback sea turtle layer. Much of the new information was obtained because of its 

relevance to resource management actions or concerns in MBNMS. In spite of our best efforts, it 

is likely that some sections of this report do not contain all the most recent information available 

in the scientific literature.

Organization of Report

The main body of this report is divided into sections by habitat; primary habitat sections are 

presented first, followed by secondary habitat sections. The 11 primary habitat categories 

originally identified as occurring in MBNMS resulted in only 6 primary habitat sections because: 

nearshore habitats were excluded (not in the federal study area); shelf I and shelf II were 

combined due to substantial overlap in the information found for this depth range; and no 

information was found for hard substrate in the rise (except on seamounts).

Each habitat section begins with a Habitat Overview - a brief description of the focal habitat. 

Next, a Search Topic Table provides an overview of the information found during the literature 

review for the focal habitat. The table lists the search topics as organized in Table 1. When 

information was found for a search topic in the focal habitat, the page number where that 

information is located in the habitat summary is provided. If little or no information was found, 

then a brief summary is provided or related information available in other habitat sections is 

noted. The remainder of the section is the Habitat Summary, which contains a detailed 

description of the information found for the focal habitat organized by search topic. Search 

topics without substantial information (as noted in the Search Topic Table) are omitted from the 

habitat summary.

Species of Special Interest

Some species in MBNMS are the focus of a higher level of interest and attention from resource 

managers. This interest may be due to a variety of factors, including ecological role in the 

ecosystem, sensitivity to disturbance, low population size, or economic value. The following 

three categories were used to help identify species of special interest to resource management in 

the offshore habitats of MBNMS: 

 Species landed in MBNMS2

 Endangered and Threatened Species

 Other At-Risk Species

2 The listing category, “Species Landed in the MBNMS” only applies to invertebrates and fishes. Seabirds, marine 

mammals, and reptiles are protected from take by one or more of the following laws: the Migratory Bird Treaty Act, 

the Marine Mammals Protection Act, and the Endangered Species Act.

4 Methods

 
Appendix A in Starr et al. (2002a) was used to identify species landed in MBNMS. Endangered 

and threatened species includes species listed under the federal Endangered Species Act (ESA) 

and the California Endangered Species Act (CESA). Other at-risk species includes species listed 

as "Critically Endangered", "Endangered" or "Threatened" on the International Union for 

Conservation of Nature (IUCN) Red List, species listed as “Candidate Species” or "Species of 

Special Concern” under the ESA or CESA, and fish stocks listed as "Overfished" by the National 

Marine Fisheries Service (NMFS).

In addition, MBNMS staff identified species that do not appear on these lists, but have been the 

focus of resource management interest in the sanctuary. For example, both the state of California 

and the National Marine Fisheries Service recently created prohibitions on the harvest of krill in

the waters off California to assure the protection of this resource for the marine mammals, 

seabirds, and fishes that rely on krill as a primary food source.

The species of special interest list is presented in a series of tables with each table representing a 

major taxonomic group: invertebrates (Table 3); fishes (Table 4); reptiles (Table 5); seabirds 

(Table 6) and marine mammals (Table 7). These tables show only a subset of all the species that 

occur in MBNMS because the tables include only species that are of special interest to resource 

management and occur in one, or more, offshore habitats (species only found in nearshore 

habitats were excluded).

Many of these species are of special interest to resource management because their abundance is 

reduced compared to historic levels. Population status information, including biomass levels 

compared to historically high levels (e.g., 50%) and recent trend in abundance (e.g., increasing, 

decreasing), is provided when available (Table 3-7). Listing status and population status 

information was updated in May of 2012. Data sources for population status information are

footnoted in the tables.

Habitat distribution in the benthic, open water and submarine canyon habitats is provided for all 

species of special interest. Though most species are either benthic or pelagic, some species are 

associated with both the open water and benthic habitats. For example, some pelagic predators 

(e.g., California sea lions) also forage on benthic organisms and some fishes (e.g., blue rockfish) 

with a benthic adult phase have a pelagic juvenile phase. Species were indicated as being 

associated with submarine canyon habitat if they have been observed in submarine canyons or 

their distribution in the water column appears to be influenced by features associated with 

submarine canyons. For example, blue whales are commonly observed foraging on prey 

aggregations in canyon heads.

For invertebrates and fishes (Tables 3 and 4, respectively), habitat distribution information is

provided for both juvenile and adult phases when available. We used the following references to 

compile habitat distribution information (e.g., substrate preferences, depth zones) for 

invertebrates and fishes: Miller and Lea 1972, Morris et al. 1980, Eschmeyer et al. 1983, Love 

1996, Cailliet et al. 2000, Leet et al. 2001, Warner et al. 2001, Love et al. 2002, Starr et al. 

2002a, Ebert 2003, Animal Diversity Web 2005, CDFG 2005, Fishbase 2005, NCCOS 2005.

5 Methods
For sea turtles, seabirds, and marine mammals (Tables 5-7, respectively), a species was only 

indicated as occurring in a benthic habitat category if it interacts with the benthos, such as 

foraging on benthic or benthopelagic organisms. We used the following references to compile 

habitat distribution information for turtles, seabirds, and mammals: Keitt et al. 2000, Folkens 

2002, Roberson 2002, NCCOS 2003, Birds of North America Online 2005, CDFG 2005, 

NCCOS 2005.

Spatial Data Layers and Maps

Geo-referenced data layers were gathered during literature searches and expert interviews and 

assimilated in GIS. We focused on assimilating the most recent, complete and comprehensive 

data from authoritative sources and data that could provide broad overviews of the distribution of 

the resources in the offshore habitats of MBNMS.

A variety of data layers were compiled in this natural resources assessment including:

• Geological features such as hard substrate, seamounts and submarine canyons;

• Oceanographic features such as upwelling zones, the oxygen minimum zone, and fronts;

• Biological resources such as structure-forming species (e.g., deep-sea corals, CBCs) and 

species of special interest (e.g., seabirds, marine mammals, groundfish).

Some data are based on field observations (e.g., ROV surveys, trawl surveys), some are based on 

the outputs of models (habitat suitability for deep-sea corals, densities of cetaceans), and some 

are based on expert opinion informed by field observations and models (e.g., leatherback turtle, 

seabird, and marine mammal hotspots). A table cataloging the source, availability for web 

download and metadata is available in Appendix II.

In order to display the data layers in the natural resources assessment, we created a bathymetric 

base map including national marine sanctuary boundaries, state waters3

, well-known land points, 

a latitude-longitude grid, depth zones, and substrate type (Figure 1). This map served as the base 

map for the majority of the figures, allowing the viewer to easily compare the distribution of 

resources to the benthic habitat categories and to cross-reference the data illustrated in the 

different maps.

3 “State waters” are defined as shoreline to 3 nautical miles offshore and includes Monterey Bay.

6 Methods

 
Shelf I (30-100 m) and Shelf II (100-200 m) – Hard Substrate

HABITAT OVERVIEW

Subtidal rocky reefs in MBNMS are most often associated with dense kelp forests visible from 

shore and popular among SCUBA divers. However, canopy-forming kelp species are generally 

found on reefs that are shallower than 30 m water depth because not enough sunlight penetrates 

deeper waters to support the high growth rates of large kelps (e.g., giant and bull kelps). Hard 

bottom habitat on the shelf (between 30 and 200 m) is rare, constituting only 1.68% of the benthic 

habitat in MBNMS (Figure 1). Within the federal study area, hard bottom habitats on the shelf 

comprise approximately 75 km2, which is 0.68% of the study area (Table 2).

Though canopy-forming kelps are absent from hard bottom habitats deeper than 30 m, smaller 

forms of brown and red algae grow on hard substrate down to a depth of between 60 and 75 m 

depending on local environmental conditions. Rocky reefs on the shelf provide habitat for many 

species of invertebrates that require hard substrate for attachment (e.g., corals, sponges). The 

complex physical structure created by boulders, caves, pinnacles, and outcrops are a favorite 

habitat of many species of fish. The marcoalgae and large, erect invertebrates that grow on the 

surface of these rocks create biogenic structure that enhances the diversity of microhabitats and 

provides food, shelter and surface area for settlement and retention of other organisms. Pelagic 

predators, including large fishes, seabirds, and marine mammals, hunt for fish and invertebrate 

prey along the benthos.

Much less is known about the hard bottom communities on the shelf than is known about coastal 

kelp forests because most researchers using SCUBA equipment are limited to waters less than 30 

m deep. Until recently, Remotely Operated Vehicles (ROVs) used to study deep-sea habitats 

tended to be used in waters deeper than 200 m. Thus, there has been an information gap from 30 to 

200 m. This gap is slowly being filed by research using ROVs and other technologies including 

camera sleds and human-occupied submersibles.

SEARCH TOPIC TABLE

HABITAT FUNCTION

Functional Habitats:

Nursery Habitat: See page 8

Feeding Ground:

Piscivores, such as adult rockfishes, salmon, lingcod and wolfeels, prey on YOY rockfishes that school around rocky outcrops 

on the shelf (Cascorbi 1999a). Various seabirds, such as Common 

Murre and Brandt’s Cormorant, rely on juvenile rockfishes for 

food (Airamé et al. 2003).

Spawning Ground:

The fish and invertebrate species that are resident on the rocky 

shelf use this habitat for spawning. No specific information was 

found on species that migrate to the hard-bottom shelf habitat to 

spawn.

7 Shelf I & II – Hard
Migratory Corridor:

See “Movement and Dispersal” section below for information on 

species that move through the hard-bottom shelf habitat during 

ontogenetic shifts and seasonal migrations.

Biogenic Habitat: See page 9

Energy Flow:

Primary Production: See page 11

Benthic-Pelagic Coupling: See page 11

Key Trophic Interactions: See page 11

Key Trophic Cascades: No specific information was found on this topic.

Productivity Hotspots: No specific information was found on this topic.

HABITAT STRUCTURE

Species Composition: See page 12

Species Composition Shifts: See page 17

Species Diversity and Richness: See page 18

Biomass: See page 19

Key Species Interactions No specific information was found on this topic.

MOVEMENT AND DISPERSAL See page 20

SPECIES OF SPECIAL INTEREST See page 21

HABITAT SUMMARY

HABITAT FUNCTION

Functional Habitats

Nursery Habitat: Many fish and invertebrate species inhabit rocky reef on the shelf as juveniles 

and move to deeper reef or soft-bottom shelf and slope habitats as they mature. This pattern of 

movement, called ontogenetic migration, is common in rockfishes. In a review of 48 species of 

rockfish, Love et al. (1991) found that juveniles of 40 species recruited to water shallower than 

adult depth, or at least in the shallowest part of the adult range. Less is known about invertebrates. 

Giant octopuses find shelter in the cracks and crevices of rocky reefs on the shelf as juveniles, but 

adults tend to be found in deeper water (Cascorbi 1999a).

 Rockfishes. Shallow, high-relief rock habitat inside and adjacent to Big Creek Ecological 

Reserve in central California appeared to serve as a nursery habitat for young-of-the-year 

(YOY) rockfish (Yoklavich et al. 2002). The density of YOY rockfishes on rock outcrops 

between 20-90 m ranged from 27 to 857 fish/m2 and represented 38-93% of all fishes on 

the outcrops (YOY rockfishes accounted for only 0.7-1.9% of the total fish at depths >100 

m). A survey of recruitment habitat for YOY rockfishes in Monterey Bay identified two 

areas of high density in south Monterey Bay associated with low relief granite/ sedimentary 

8 Shelf I & II – Hard
rock outcrops in 80-90 m (Johnson et al. 2001). Laidig et al. (2009) found that fishes less 

than 20 cm accounted for over 80% of all fishes observed on low relief rocky outcrops 

between 65-110 m on the Davenport Shelf. The abundance of immature fishes may indicate 

that this area of the shelf is a nursery for younger fishes. Specifically the outer shelf may be 

an intermediate staging area between the shallow, nearshore YOY habitats and deeper, 

adult habitats.

Biogenic Habitat: Macroalgae and structure-forming invertebrates attach to hard substrates on the 

shelf creating biogenic habitats. Structure-forming species contribute significantly to benthic 

habitat structure and function by adding vertical relief, increasing the diversity of microhabitats, 

and increasing the surface area for settlement and retention of other organisms.

 Deep-water Algae in Central California (Spalding et al. 2003). Deep-water algae are a 

biogenic habitat on hard bottom from 30-75 m deep (Figure 7). Macroalgae can have 

profound effects on the local abundances of fishes by providing shelter for juveniles and 

adults and by providing a habitat for small invertebrate prey.

 Structure-forming Invertebrates. Sessile, erect megafaunal invertebrates contribute 

significantly to benthic habitat structure and function through large size, complex 

morphology or the ability to form high density aggregations (Tissot et al. 2006). These 

invertebrates add vertical relief, increase the diversity of microhabitats, and increase the 

surface area for settlement and retention of other organisms. Biogenic habitat may be 

especially important where the physical habitat lacks large structural relief or complexity.

Managed fish species associated with structure-forming invertebrates include: lingcod, 

longspine and shortspine thornyhead, sablefish, spotted ratfish, and rockfishes (e.g., 

bocaccio, cowcod, flag, greenspotted, quillback, rosethorn, sharpchin, starry, tiger, 

vermillion, yelloweye, and yellowtail) (NMFS 2005, Tissot et al. 2006). Structure-forming 

invertebrates are susceptible to damage from physical structures dragged across the 

seafloor including anchor lines and fishing gear. Growth rates for many of these 

invertebrate species are low, extending the time to recovery if these communities are 

damaged.

 Structure-forming Invertebrates in MBNMS (MBARI VARS database 2011). The 

locations where Monterey Bay Aquarium Research Institute (MBARI) scientists have 

observed structure-forming invertebrates associated with hard substrates are shown in

Figure 8. These observations of soft corals, stony corals, black corals, hydrocorals, 

crinoids and sponges were made during ROV surveys in 1989-2009. Each data point 

represents a sighting regardless of the abundance of the organisms in the video frame. It 

is important to note that these organisms are likely to occur in portions of MBNMS that 

have not been sampled by MBARI.

 Deep-sea Corals Collected in Bottom Trawls in MBNMS (Curt Whitmire, pers.

comm.). The locations where deep-sea corals were collected incidentally in bottom 

trawl surveys by the National Marine Fisheries Service (1980-2010) are shown in 

Figure 9. Records represent the presence of a given taxonomic group in the area swept 

by trawl gear; exact location, species, and abundance information is not available.

Corals from the following taxa likely were associated with hard substrate: Antipatharia 

(black corals), Alcyonacea (soft corals), Anthoathecata, Scleractinia (stony corals), and 

Gorgonacea (gorgonians). It is important to note that these trawl surveys were designed 

9 Shelf I & II – Hard
to monitor groundfish populations (not corals) and the surveys occurred mostly over 

low-relief, soft bottom. Trawl gear is not designed to sample the habitats in which 

many coral taxa reside, particularly those habitats characterized by rocky substrate and 

high relief.

 Structure-forming Invertebrates Observed in MBNMS Shelf Characterization 

Surveys (IfAME and MBNMS 2011). Video transects using a remotely operated 

vehicle (ROV) and a towed camera sled were made to characterize the distribution of 

fishes, invertebrates, and seafloor habitats on the continental shelf (50-200 m) and 

upper slope (200-400 m) at five locations in MBNMS: Ascension and Año Nuevo 

Canyons; North Monterey Bay; Carmel Bay and Point Lobos; Point Sur Shelf; and La 

Cruz Canyon and Point Piedras Blancas. Transects covered a varied of substrate types 

including rock ridges, bolder, and cobble. Structure-forming species commonly 

observed in this study include brachiopod beds, plumose anemones (Metridium 

farcimen), sponges, basket stars, crinoids, and gorgonians. Specific locations where 

structure-forming invertebrates were observed along the transects are available through 

the Shelf Characterization and Image Display website 

(http://sep.csumb.edu/ifame/scid).

 Structure-forming Invertebrates in Central California MLPA MPAs (Starr and 

Yoklavich 2008). A manned submersible was used to characterize the benthic habitat 

and associated invertebrates in the deep portion (24-365 m) of eight of the new central 

California Marine Life Protection Act marine protected areas and associated reference 

sites. Structure-forming species associated with hard bottom (e.g., corals, sponges, 

crinoids, gorgonians) were observed at all sites. See Table 9 for a summary of locations 

where structure-forming species were part of the dominant megafaunal invertebrate 

assemblage.

 Deep-sea Coral Habitat Suitability (Guinotte and Davies 2012). The potential 

distribution of deep-sea corals was modeled for the U.S. West Coast Exclusive 

Economic Zone. Predicted habitat suitability in MBNMS is shown separately for 6 

deep-sea coral taxa (Figure 10). Habitat suitability probabilities and areal extent of 

predicted habitat were highest in the sanctuary for Suborders Alcyoniina, Calcaxonia, 

Holaxonia, and Order Scleractinia. In contrast, suitability probabilities and areal extent 

were lower in these areas for Order Antipatharia (except at Davison Seamount) and 

Suborder Scleraxonia. The models used a variety of physical, chemical and 

environmental variables known or thought to influence the distribution of deep-sea 

corals. However, the model will likely overpredict the amount of suitable habitat in 

some areas (e.g., indicate suitable coral habitat in areas that are known soft bottom 

regions) because fine-scale bathymetric features (10’s of meters), substrate, and current 

data were not available for the entire study area.

 Brachiopod Beds as Fish Habitat. Dense brachiopod beds have been observed at 

many locations on the continental shelf in MBNMS (Starr and Yoklavich 2008 and 

IfAME and MBNMS 2011). Laidig and colleagues (2009) examined brachiopod beds 

as a benthic fish habitat by manned-submersible transects at depths between 65 and 110 

m on the shelf offshore of Davenport. This biogenic habitat type had the lowest 

abundance and diversity of fishes, and only two species (greenspotted and greenstriped 

rockfishes) were commonly observed in and around brachiopods. A few other species, 

10 Shelf I & II – Hard
such as small flatfishes and lingcod, were occasionally seen. It may be that brachiopod 

beds are not associated with suitable prey or perhaps the beds are an ephemeral habitat 

that is periodically covered by the surrounding sediment and not consistently available 

as shelter for fishes. In a separate study, small finfish (e.g., rockfish, combfish), were 

observed swimming above an extensive brachiopod bed while flatfishes were observed

in the sandy patches between brachiopod beds (IfAME and MBNMS 2011).

Energy Flow

Primary Production: There are two main sources of primary production in rocky reef shelf 

habitat: deep-water algae attached to the substrate, which is only found in waters less than 75 m 

deep, and phytoplankton in the water column. 

 Deep-water Algae in Central California (Spalding et al. 2003). Deep-water algae are a 

source of primary production on rocky reefs from 30-75 m deep. Surveys of deep-water 

algal communities between Point Pinos and Point Sur found that algae were present at 

fairly high densities from 30-45 m and beyond this depth range algal density declined with 

increasing depth (Figure 7). The maximum depth of algae occurrence was approximately 

75 m at a site off of Point Sur where water clarity was the highest.

 Iron Availability and Phytoplankton Productivity (Hutchins et al. 1998; Firme et al. 

2003). In MBNMS, waters over the shelf tend to be iron-replete and waters offshore of the 

shelf tend to be iron-limited. Iron-replete waters tend to have higher primary productivity 

than Fe-limited waters. See ‘Open Water’ habitat summary for additional information.

Benthic-Pelagic Coupling: The flux of material between the water column and benthos occurs 

through sinking of non-living organic matter and the active movement of organisms. Falling 

plankton, fecal pellets, animal carcasses, and drift algae may be deposited on rocky reefs and 

utilized by scavenging herbivores and detritivores. See Appendix III for more general information 

about this process.

 Drift Algae: Fronds shed by kelp growing on the rocky reef in waters <30 m may be 

transported by water currents and gravity to deeper sections of the reef. Spalding et al. 

(2003) observed a few pieces of drift kelp (Pleurophycus gardneri and Eisenia arborea) 

with an ROV from 60 to 80 m in central California, suggesting that drift from deep-water 

algal beds is transported down the reef. See ‘Macrophyte Detritus’ habitat summary for 

additional information.

 Spawning of Pelagic Eggs/ Larvae: The majority of invertebrates (e.g., sea urchins, sea 

stars) and fishes (e.g., rockfish, Hexagrammids) living associated with the rocky shelf have 

eggs and/or larvae that are pelagic. Therefore, reproduction is a major source of upward 

flux of organic matter to the pelagic compartment.

 Settlement/Recruitment of Juveniles: Some species, such as sessile invertebrates, have 

larval or juvenile phases that settle back onto the rocky shelf, while the juveniles of other 

species (e.g., rockfish) will settle into shallow nearshore habitats and then move at an older 

age to the rocky shelf.

Key Trophic Interactions: Many of the invertebrates living on the rocky shelf are either 

detritivores or planktivores. These organisms play an important role in the shelf food web by 

converting nutrients, phytoplankton, and sinking organic matter into reef-associated biomass.

11 Shelf I & II – Hard
 Detritivores: Large pieces of organic matter, such as macrophyte detritus and animal 

carcasses, that sink to the reef are consumed by scavengers such as crabs and shrimp. 

Smaller sinking organic particles, such as phytoplankton shells and fecal pellets, coat the 

surface of the reef and are consumed by deposit feeders (such as sea cucumbers).

 Planktivores (Cascorbi 1999a). Filter-feeders (such as encrusting sponges and tunicates) 

and suspension feeders (such as anemones and corals) catch and consume phytoplankton, 

small zooplankton, and other suspended organic matter that is carried over the reef by 

water currents.

HABITAT STRUCTURE

Species Composition: Hard substrates are suitable habitat for attachment of algae (down to 75 m) 

and a rich fauna of sessile and mobile invertebrates, including sponges, corals, brachiopods, 

crinoids, sea anemones, sea stars and sea urchins. Shale reefs, because of their softer composition, 

support a large abundance of rock-boring organisms, such as clams, and a variety of fish and 

invertebrates that use the bored holes for shelter.

Rockfishes are by far the most numerous group of fishes associated with hard bottom on the shelf, 

though many other fish species can be found living on and near hard bottom (especially in Shelf I). 

Vertical relief and rugosity of the hard substrate alters species composition, since species 

differentially associate with boulders, flat rock, and cobble. A high diversity of seabirds and 

marine mammals are observed in the waters over the shelf. All of the marine mammals and some 

of the seabirds are strong divers that may feed on benthic fishes and invertebrate prey on or just 

above the rocky reefs of the shelf.

 Deep-water Algae in Central California (Spalding et al. 2003). In a study of multiple 

sites between Point Pinos and Point Sur, 48 macroalgal taxa were found attached to hard 

substrate in depths exceeding 30 m. These taxa were distributed in three broadly 

overlapping zones (Figure 7):

 An upper “Pleurophycus zone” of stipitate kelps and Desmarestia spp. with a high 

percent cover of corallines, low cover of uncalcified red algae, and rare green algae;

 A middle “Maripelta zone” with common uncalcified red algae and infrequent 

corallines and green algae;

 A zone of infrequent patches of nongeniculate coralline algae.

NOTE: Many of the species identified in this study also occur in the hard-bottom nearshore 

(<30 m) habitat.

 Epifaunal Invertebrates in Northern Monterey Bay (CSLC & MBNMS 2005). 

Epifaunal macro-invertebrates were surveyed on hard-bottom habitats of the shelf in 

northern Monterey Bay. The species assemblage was characterized as follows: 

 Inner shelf (30-150 m): cup corals (e.g., Paracyathus, Balanophyllia), encrusting 

sponges, tunicates, gorgonians, anemones (Metridium and Urticina), and brittlestars;

 Outer shelf (150-300 m): erect sponges, anemones (e.g., Stomphia, Amphianthus, 

Metridium), decapods, brittlestars, and sea stars;

12 Shelf I & II – Hard
 Many echinoderm genera (e.g., Florometra, Gorgonocephalus, Strongylocentrotus) 

were distributed over a broad depth range (100-500 m or more);

 High relief (>1 m) rocky habitat: suspension feeding cnidarians (e.g., Lophelia, cup 

corals, anemones, zoanthids), erect sponges, crinoids (e.g., Florometra), basket stars 

(e.g., Gorgonocephalus), and bryozoans;

 Low relief rocky habitat: species that can survive episodic sediment burial, and high 

loads of suspended particles in the water column. Species include anemones (e.g., 

Metridium), cup corals, and brittlestars.

 Megafaunal Invertebrates in the MBNMS (Graiff 2008). The abundance and distribution 

of megafaunal invertebrates on the continental shelf and upper slope was surveyed at three 

sites in the MBNMS using a manned submersible. See Table 8 for the relative abundance 

of megafaunal invertebrates at Portuguese Ledge (71-252 m), Point Sur (72-126 m), and 

Big Creek (19-249 m).

 Megafaunal Invertebrates and Fishes in central California MLPA MPAs (Starr and 

Yoklavich 2008). A manned submersible was used to characterize the benthic habitat and 

associated megafaunal invertebrate and fish assemblages in the deep portion (24-365 m) of 

eight of the new central California Marine Life Protection Act marine protected areas and 

associated reference sites. See Table 9 for a summary of the dominant megafaunal 

invertebrates and the relative abundance of common groups of demersal fishes at each site.

 Megafaunal Invertebrates (Cascorbi 1999a, Airamé et al. 2003). Rocky reefs beyond 30 

m support a rich turf of encrusting animals including: sponges (e.g., orange puffball sponge 

Tethya aurantia, cobalt sponge Acanthancora cyanocrypta), anemones (e.g., strawberry 

anemone Corynactis californica, Metridium spp., rose anemones Urticina lofotensis, 

swimming anemone Stomphia didemon), cup corals (e.g., orange cup coral Balanophyllia 

elegans), hydrocorals (e.g., California hydrocoral Stylaster californicus), sea fans (e.g., red 

gorgonian Lophogorgia chilensis), and tube worms (e.g., feather duster worm Eudistylia 

polymorpha). Mobile invertebrates include sea cucumbers (e.g., Parastichopus spp.), 

shrimp and prawns (e.g., spot prawn Pandalus platyceros), and octopus. On shale reefs, 

rock-boring clams and date mussels bore into the reef and create holes that are inhabited by 

small invertebrates such as polychaete worms, snails, sea stars, small octopuses, porcelain 

crabs (Petrolisthes spp.), peanut worms, nestling clams, baby hermit crabs and gumboot 

chitons (Cryptochiton stelleri).

 Fish at Davenport Shelf (Laidig et al. 2009). Two species, pygmy rockfish and blackeye 

goby, accounted for 41% of all fishes identified between 65-110 m on the shelf offshore of

Davenport. The fish assemblages were identified based on bottom habitat. Two general 

assemblages were observed over boulder habitat: one in which pygmy rockfish dominated 

(19–22% contribution), and the other without pygmy rockfish. Rosy, yellowtail, and starry 

rockfishes, other Sebastomus spp., and blackeye gobies were consistent members of both 

types of assemblage on boulder habitat. Other species observed in boulder habitat include 

boccacio, canary, greenstriped, greenspotted, squarespot, and vermilion rockfishes, kelp 

greenling, pink surfperch, Northern ronquil, lingcod, sculpins, and flatfishes.

 Fishes at Point Lobos (Anderson and Yoklavich 2007). Demersal fishes and benthic 

habitats were surveyed from a manned submersible in southern Monterey Bay near Point 

13 Shelf I & II – Hard
Lobos (60-260 m). Three habitat types (hard, soft, mixed) were classified from acoustic 

maps. Habitat type was a strong predictor of fish assemblage composition:

 Hard (high relief outcrops, 60−100 m): fish assemblage characterized by schools of 

small-bodied rockfish species (e.g., squarespot, pygmy, and young-of-the-year), a suite 

of large-bodied rockfishes (e.g., bocaccio, yellowtail, flag, rosy, and Sebastomus spp.), 

and a few non-rockfish species (e.g., blackeyed goby and lingcod).

 Mixed (low relief outcrops, 90−150 m): fish assemblage characterized by schools of 

small-bodied rockfish species, halfbanded rockfish, two large-bodied rockfishes 

(greenspotted and greenstriped), and a variety of non-rockfish species (e.g., sanddabs, 

pink seaperch, combfishes, Pacific argentine, and lingcod). This habitat type had the 

highest species diversity, which resulted from a combination of species unique to the 

mixed stratum and species characteristic of both the hard and soft strata.

 Fishes In and Around Big Creek Marine Ecological Reserve (Yoklavich et al. 2002). At 

least 36 of the 82 species of fishes identified in and around Big Creek Ecological Reserve 

were rockfishes; 95% of all fishes surveyed at water depths of 35-100 m were rockfishes, 

and 64% of fishes at depths 100-250 m were rockfishes. Four distinct fish assemblages 

were identified between 20-250 m and two of these were associated with hard bottom:

 Boulders and biogenic habitats (e.g., algae) on rock in shallow water (<100 m): blue, 

copper, gopher, halfbanded, olive, rosy and vermilion rockfishes, painted greenling, 

blackeye goby, sharpnose seaperch, and señorita;

 Bedrock with uneven surface in deep water (100-250 m): bank, darkblotched, 

greenspotted, pygmy, rosethorn, squarespot, and yelloweye rockfish.

 Fishes at Point Pinos and Point Sur (Starr et al. 2006). The relative abundance of fishes 

was determined for shallow water (70-90 m) high-relief habitats and deep water (90-130 m) 

high-relief and low-relief habitats at Point Pinos and Point Sur in central California (Figure 

11). Rockfishes (Sebastes spp.) were the most common fish observed at all sites.

 Shallow, high relief habitats: Approximately 50% of the fish identified at both sites 

were pygmy and squarespot rockfish. Also observed in decreasing order of abundance 

were blackeye goby, rosy rockfish, species of the Sebastomus group, and yellowtail 

rockfish;

 Deep high-relief habitats: Between 40-50% of the fishes identified at both sites were 

pygmy rockfish. Other species observed commonly at both sites were unidentified 

Sebastes spp. (small fish, usually young-of-the-year), members of the Sebastomus

species complex, squarespot rockfish, and yellowtail rockfish. Point Pinos had higher 

abundance of lingcod and blackeyed gobies while Point Sur had high abundance of 

bocaccio and halfbanded rockfish;

 Deep low-relief habitats: the species composition was quite different for this habitat at 

the two sites. At Point Pinos, halfbanded and pygmy rockfishes were observed most 

frequently. Also observed in decreasing order of abundance were: Sebastomus species 

complex, squarespot rockfish, blackeye goby, unidentified Sebastes spp., and 

greenstriped rockfish. At Point Sur, approximately 50% of the fish observed were 

pygmy rockfish. Also observed in decreasing order of abundance were: Sebastomus

14 Shelf I & II – Hard
species complex, unidentified Sebastes spp., squarespot rockfish, greenstriped rockfish, 

greenspotted rockfish and bank rockfish.

 Fish at Cordell Bank (Pirtle 2005). Cordell Bank has a diversity of habitats that includes

high-relief rock pinnacles, flat rock, boulders, cobble, sand, and mud. Rockfishes were the 

most abundant fishes observed on Cordell Bank, accounting for over 90 percent of the 

recorded fish. Young-of-year rockfishes were the most numerous and most frequently 

occurring group of fishes observed on rocky regions of the bank. Pygmy rockfish, the 

numerically dominant adult fish, were most abundant in low relief rock and boulder 

habitats. Species common in shallow (40-80 m) high-relief rock habitats were rockfishes of 

the Sebastomus group, with rosy rockfish in close proximity to the substrate and yellowtail 

rockfish and widow rockfish primarily occupying the water column. Greenspotted rockfish, 

yellowtail rockfish, rosy rockfish, lingcod, painted greenling, and blackeye goby were often 

associated with flat rock and boulder habitats. 

 Fish-Habitat Associations at Cordell Bank (Anderson et al. 2009). Habitat type and the 

associated fish fauna were surveyed between 52-365 m depth using a manned submersible. 

An abundant and diverse fish fauna (87,078 individuals from 70 species/ taxa in 21 

families) was recorded on and around Cordell Bank and was dominated by the genus 

Sebastes (27 species, 95% of individuals). Five broad-scale habitat zones (three of which 

contain hard bottom shelf habitat) were characterized by distinct fish faunas, with depth 

and habitat composition strong predictors of fish assemblages:

 Slope-bank transition zone (interwoven mud and patchy reef, 120-130 m):

characterized by an array of species found in both mud (e.g., flatfishes and poachers) 

and patchy mud-reef habitats (e.g., shortspined combfish, sculpins, and sharpchin 

greenspotted, and greenstriped rockfishes);

 Bank (rock–boulder–sand; 52–110 m): characterized by a diverse and abundant array 

of fish species that varied over its depth range: 

 Upper bank: characterized by schooling species (e.g., pygmy and yellowtail 

rockfishes) and more solitary species (e.g., rosy rockfish and lingcod);

 Middle bank: characterized by a variety of schooling species (e.g., squarespot, 

widow, and speckled rockfishes) and solitary species (e.g., painted greenling and 

blackeyed goby); 

 Deep bank: characterized by the presence (in low numbers) of large-bodied 

commercial species such as bocaccio, yelloweye, canary, and vermilion rockfishes, 

along with small-bodied rockfishes such as swordspine rockfish. 

 Shelf–bank transition zone (reef–sand, 80–110 m): similar fish assemblage to that of 

the slope–bank transition (except in lower densities), with the addition of sanddabs and 

pricklebacks.

 Fish over Hard Substrate (Love and Yoklavich 2006). In central and northern California 

the following species make up the typical adult fish assemblage over rocky substrate on the 

shelf:

 Mid-Shelf (30-100 m): Rockfishes (black, blue, bocaccio, canary, chilipepper, china, 

copper, cowcod, flag, halfbanded, olive, pygmy, quillback, squarespot, starry, 

15 Shelf I & II – Hard
vermilion, widow, yelloweye, yellowtail), lingcod, kelp and painted greenling, cabezon, 

blackeye goby, pile perch, sharpnose seaperch, white seaperch, and wolf eel;

 Deep Shelf (100-200 m): Lingcod and rockfishes (bank, bocaccio, canary, chilipepper, 

cowcod, darkblotched, halfbanded, greenblotched, greenspotted, pygmy, redbanded, 

rosethorn, sharpchin, swordspine, splitnose, vermilion, widow, yelloweye, yellowtail).

 Rockfishes (Love et al. 2002). The typical rockfish assemblages along the coast of central 

and northern California were identified for five depth categories (Table 10). The species 

included in the table occur over hard and soft-bottom, but the majority of the species are 

primarily found over hard bottom. Shelf I and II were the depth categories with the highest 

species richness - 23 and 22 species, respectively.

 Groundfish Assemblages in Central and Northern California. Using CDFG 

recreational hook-and-line catch data, NCCOS (2003) identified 5 depth-stratified species 

assemblages between 13 and 157 m (Table 11). Because rockfishes were the target of the 

hook-and-line recreational fishery, hard-bottom shelf was the habitat most likely sampled 

in this data set.

 CPFV fishing locations based on similarities in species composition (Sullivan 1995). 

Purpose of this study was to evaluate cluster analysis as a method of grouping northern and 

central California Commercial Passenger Fishing Vessel (CPFV) fishing locations based on 

similarities in species composition. Most of the fishes included in analyses were rockfishes 

(RF); other species included lingcod, Pacific hake, sablefish, Pacific sanddab, and petrale 

sole. Fishing locations ranged from Pescadero Point to Point Sur. Data set was separated 

into two species groups: midwater schooling species, and benthic species. For the benthic 

species, four location groups were geographically and bathymetrically distinct:

 South Shallow: rosy and starry RF, and lingcod

 North Shallow: lingcod and gopher RF

 Canyon Ledge: greenstriped and greenspotted RF, sablefish, and lingcod

 Shelf Flats: greenspotted, rosy, greenstriped, and starry RF, and lingcod

 Seabirds and Marine Mammals (Research Planning Inc. 2006). Table 12 provides a list 

of the seabird and marine mammals species typically observed along the central California 

coast and their relative abundance and seasonality in eight pelagic zones off of central 

California (Figure 12):

 Seabirds: Of the seabird species found over the shelf, only the deepest diving seabirds, 

such as shearwaters and auks (e.g., murres, auklets), are capable of feeding at or near 

the bottom in shelf habitats;

 Marine Mammals: The species most commonly observed in waters over the shelf that 

may feed at or near the bottom in MBNMS are northern elephant seals, harbor seals, 

California sea lion, Dall’s porpoise, harbor porpoise, Risso’s dolphin, and bottlenose 

dolphin. Sea otters tend to be found in waters less than 30 meters deep, but they are 

occasionally found out to a depth of 100 m.

16 Shelf I & II – Hard
Species Composition Shifts: 

 Natural Changes: Significant natural changes in water temperature and current patterns, 

such as El Niño/La Niña events and the Pacific Decadal Oscillation, can cause shifts in 

species composition of the rocky shelf.

 Pacific Decadal Oscillation: Beginning in mid-1970s, >20 years of a warm and 

plankton-depleted oceanographic regime was at least partially responsible for poor 

reproductive success of many fish species and may have contributed to fisheries 

depletion of some large rockfish species (Love and Yoklavich 2006).

 Fish Species Composition Shifts in Central and Southern California (Love and 

Yoklavich 2006). Fish assemblages on deep (30-200 m) rock habitats off central and 

southern California substantially changed over the last century. Fish assemblages are 

now dominated by small rockfish species (e.g., halfbanded, pygmy, squarespot, 

swordspine) that perhaps are more productive and able to avoid capture. Many of the 

previously dominant, larger-sized species (e.g., canary, darkblotched, widow, bocaccio, 

cowcod, lingcod) are virtually absent from many areas. The authors attribute this 

pattern to the combination of intense recreational and commercial fishing beginning in

the 1940s in combination with more than two decades (beginning in mid-1970s) of poor 

reproductive success of many targeted species. The low reproductive output was caused 

at least in part by an oceanographic regime of warm and plankton-depleted waters (i.e., 

the warm phase of the Pacific Decadal Oscillation or PDO)

 Human-Induced Changes: Humans can alter species composition on the shelf through 

various activities. Studies have examined the potential impacts of fishing, (including the 

use of bottom-tending fishing gear), laying cables, and deposition of marine debris.

 Fishing Effects on Megafaunal Invertebrates (Graiff 2008). Underwater video 

surveys at three sites in central California were used to assess the effects of fishing on 

the abundance of megafaunal invertebrates categorized as slow-growing, sessile species

(e.g., sponges, gorgonians) and fast-growing, mobile species (e.g., crinoids). The three 

sites (Portuguese Ledge, Point Sur, and Big Creek) have been subjected to varying 

levels of fishing intensity and gear use. Fishing intensities were calculated for

recreational hook and line and five bottom-contact commercial gear types: bottom 

trawl, traps, bottom-set gillnet, bottom-set longline, and hook and line. Overall, there 

were little to no detected effects on invertebrates due to fishing. Environmental 

variables were most likely influencing invertebrate abundance and distribution patterns. 

One of the most challenging aspects of determining the impacts of fishing intensity on 

megafaunal invertebrates was the lack of high-resolution data on the distribution of 

fishing effort.

 Structure-forming Invertebrates: Structure-forming invertebrates are very 

susceptible to damage from gear contacting the seafloor including anchors, chains, nets, 

pots/traps, bottom trawls and other types of fishing gear (NRC 2002, Chuenpagdee et 

al. 2003). Morgan et al. (2005) compared the distribution of deep-sea coral records 

along the west coast of North America and the distribution of groundfish landings in 

2000 to determine areas of potential conflict. Groundfish landings in 2000 were

confined mostly to the shelf, while deep-sea coral occurrences were greatest along the 

shelf break and in Monterey Canyon. This pattern suggests that either there is limited 

17 Shelf I & II – Hard
overlap between fishery operations and deep-sea corals, or that fishing has already had 

substantial negative impact on coral occurrences.

 Relative Impacts of Recreational and Commercial Fishing on Size Structure and 

Species Composition of Rockfishes (Southern California Bight; Schroeder and Love 

2002). In southern California, the area open to all fishing had the highest density of 

rockfishes (7,212 fish/ha), but the size structure and species composition were 

dominated by small fishes. The area open only to recreational fishing had the lowest 

rockfish density (423 fish/ha) and a size structure also dominated by small fishes. In 

contrast, the de facto protected area possessed high fish density (5,635 fish/ha) and the 

size structure and species composition shifted toward larger fishes. Cowcod and 

bocaccio had 32-fold and 408-fold higher densities in the de facto reserve than inside 

the recreational fishing area, and 9-fold and 18-fold higher densities than in the area 

open to all fishing. Recreational fishing was found to have a strong impact on species 

composition, size structure, and density.

 Effects of Demersal Marine Debris (Watters et al. 2010). Video surveys in central 

California of the seafloor at depths of 20-365 m observed various type of debris 

including monofilament line, longlines, nets, traps, beverage cans, bottles, anchors, 

cables, household items, and construction items. By providing artificial habitat to 

demersal organisms, debris can alter seafloor habitat and species assemblages. The 

majority of debris (e.g., 99% of 815 items surveyed in 2007) was colonized moderately 

to heavily by encrusting invertebrates. In surveys during the 1990s, 13% of debris items 

had fishes associated with them, and 38% were associated with large, structure-forming 

invertebrates. In 2007, less than 10% of debris items had fishes associated with them, 

and 30% were associated with large, structure-forming invertebrates. Fishes only 

associated with types of debris that could provide structure and cover; they did not 

associate with monofilament line. Debris occurred disproportionately in rock compared 

to soft sediment habitats likely due to concentrated recreational fishing effort for 

rockfishes (Sebastes spp.), which occur in complex rock habitat where monofilament

line can be snagged.

Species Diversity and Species Richness: Species diversity and species richness of deep-water 

algae declines with increasing depth and decreasing light levels. The diversity and richness of the 

fish assemblage on the rocky shelf appears to increase with depth.

 Deep-water Algae in Central California (Spalding et al. 2003). Forty-seven species of 

algae occur on rocky habitats between 30 and 75 m depth. Species diversity declined with 

increasing water depth. Taxonomic diversity was highest for the non-coralline red algae (28 

species) and brown algae (11 species) and lowest for the green algae (4 species) and 

coralline red algae (4 species).

 Fishes of California (Allen and Pondella 2006). The authors provided H' (diversity) and S 

(species richness) for 36 marine habitat types and for 14 major marine habitats in 

California. The mid-depth reef (Shelf I & II) in the central region had 7th highest species 

diversity recorded in the comparison (H` = ~2.8) and was the highest diversity habitat type 

in the central and northern regions. Species richness was not determined for mid-depth reef 

in the central region, but as a major habitat type (across all regions), mid-depth reef, with 

18 Shelf I & II – Hard
~64 species, fell into the middle of the distribution of values for all major habitats 

examined.

 Demersal Fishes at Point Lobos (Anderson and Yoklavich 2007). Sixty-two species of 

demersal fishes (from 21 families) totaling 21,184 fishes were recorded during surveys 

from a manned submersible in southern Monterey Bay near Point Lobos (60-260 m). 

Species richness was determined for three habitat strata: 41 species in the hard stratum, 44 

species in the mixed stratum, and 19 species in the soft mud stratum. The high diversity in 

the mixed stratum resulted from a combination of species unique to the mixed stratum and 

species characteristic of both hard and soft strata.

 Demersal Fishes at Big Creek Ecological Reserve (Yoklavich et al. 2002). In general, 

shallow-water (<100 m) fish assemblages were found to be more diverse over rock 

outcrops than over sand. In addition, the deeper reef (100-250 m) fish assemblage was 

more diverse than the shallow water assemblage.

 Demersal Fishes at Davenport Shelf (Laidig et al. 2009). During submersible surveys of 

112 transects covering 32 km of habitat (including bolder, cobble, mud, and brachiopod 

beds), fishes were identified to 62 taxa, including 49 species, 7 genera and subgenera, and 6 

families. Thirty-four of these taxa comprised at least 5% of the total number of fishes 

observed on a given transect.

 Demersal Fishes at Cordell Bank (Anderson et al. 2009). An abundant and diverse fish 

fauna (87,078 individuals from 70 species/ taxa in 21 families) was recorded on and around 

Cordell Bank and was dominated by the genus Sebastes (27 species, 95% of individuals). 

Mean and total species richness was determined for the five major habitat types:

 Mean species richness: slope-bank transition (16 spp.) ≈ shelf-bank transition (16 spp.) 

≈ bank (15 spp.) ≈ slope (14 spp.) > shelf (6 spp.)

 Total species richness: slope (~55 spp.) > bank (~38 spp.) ≈ slope-bank transition (~35 

spp.) > shelf-bank transition (~30 spp.) > shelf (~12 spp.)

Biomass: 

 Deep-water Algae in Central California (Spalding et al. 2003). Biomass was highest 

from 30-40 m and decreased with increasing water depth to 75 m. 

 Demersal Fishes at Point Lobos (Anderson and Yoklavich 2007). Biomass was not 

calculated for this study, but density of demersal fishes was provided for three different 

benthic habitat strata. The hard stratum appears to have the highest demersal fish biomass 

based on density estimates for both all demersal fishes (1,357 fishes/1000 m2) and largebodied (>20 cm) fishes (27 fishes/1000 m2

). The mixed stratum (862 fishes/1000 m2) had 

substantially higher density of all demersal fish compared to the soft stratum (130 

fishes/1000 m2

), although the density of large-bodied fish was higher in the soft stratum (21 

fishes/1000 m2) compared to mixed (4 fishes/1000 m2).

 Harvested Species: Recreational and commercial harvest removes biomass of targeted fish 

and invertebrate populations. For some targeted species, biomass is substantially reduced 

compared to unfished biomass levels (Tables 3 and 4). Though extraction is the primary 

reason for a reduction in biomass for many species, changing oceanographic and ecological 

conditions are an important contributing factor for some harvested species. For the majority 

19 Shelf I & II – Hard
of the 10 invertebrate and 156 fish stocks commonly landed in MBNMS, the status of the 

stock has not been assessed (Tables 3 and 4).

MOVEMENT AND DISPERSAL

Lowe and Bray (2006) reviewed the general movement patterns for reef-associated fish. Many 

small, benthic, reef-associated fishes (e.g., gobies) tend to exhibit small home ranges due to the 

availability of high-quality habitat and resources. For territorial species, home range size may be 

large for juveniles that are too small to effectively defend a territory and get repeatedly displaced 

by other territorial individuals. The home range may decrease when an individual becomes large 

enough to hold a small territory, and then the territory may expand as the fish gets larger. In nonterritorial species, home range size often increases with body size as energetic requirements 

increase and risk of predation decreases. Also species with stronger associations with benthic 

habitat tend to have smaller home ranges than species that are weakly associated with the bottom 

(mid-water species may have territories that are more 3-dimensional as well). Individuals living in 

high-quality habitat often have smaller territories than those living in lower quality habitat - thus 

fish density is higher in the high-quality habitat.

Some species of fish that are found on the hard-bottom shelf during one or more life stages move 

to adjacent habitats such as the kelp forest or deep reef on the slope. These movements may be 

ontogenetic (age-related), or they may be seasonal (e.g., spawning migrations). Ontogenetic 

movement from shallow reef to deep reef is common in rockfishes (Table 10; Love et al. 2002). 

For example canary rockfish and cowcod juveniles recruit to hard and soft-bottom on the inner 

shelf and then over time move to deeper hard-bottom habitats on the outer shelf and upper slope.

Other examples of species-specific movement patterns include:

 Juvenile Rockfishes: Of the 48 species of rockfish for which data were available, juveniles 

of 40 of these species recruit to water shallower than adult depth, or at least in the 

shallowest part of the adult range; individuals then move at an older stage to the depth 

range inhabited by adults (Love et al. 1991). Laidig et al. (2009) found that fishes less than 

20 cm accounted for over 80% of all fish observed on low relief rocky outcrops between 

65-110 m on the Davenport Shelf. The abundance of immature fishes may indicate that the 

outer shelf is an intermediate staging area between the shallow, nearshore juvenile habitats 

and deeper, adult habitats.

 Rockfishes in Central California (Lea et al. 1999). Twenty-one species of rockfish (RF) 

and 8 additional species of fish, including cabezon, kelp greenling, and lingcod, were 

tagged and released to study patterns of movement at various dive and fishing sites along in 

central California. Of 7332 tagged fish, 197 (3%) representing 15 species, were recaptured. 

Most nearshore and shelf rockfishes appear to be highly residential, though a few exhibited 

substantial movement. The following general movement patterns were observed for each 

species (number of observations included in parentheses when available):

 No movement (recaptured at the same general locality as release): black RF (4), blackand-yellow RF (10), blue RF (18), bocaccio (3), brown RF (1), China RF (1), copper 

RF, gopher RF, kelp RF (11), olive RF, vermillion RF (4), yellowtail RF (4), cabezon 

(3), lingcod (31);

20 Shelf I & II – Hard
 Limited movement (up to 1.5 nm over same reef system as release): copper RF, 

gopher RF, olive RF, lingcod (1);

 Substantial movement (more than 1.5 nm): canary RF (3), yellowtail RF (5), lingcod

(7).

 Rockfishes on Cordell Bank (Anderson et al. 2009). High densities of young-of-the year 

(YOY) rockfishes were observed on the upper reaches of Cordell Bank (2,081 YOYs/1000 

m

2

) and moderate densities of juvenile and adult rockfishes were observed on the lower 

bank and transition zones. While many commercial fish species were recorded, only 7% of 

the fish assemblage was of harvestable size. These large adult rockfishes occurred mainly 

around boulders and overhangs in deep sections and transition zones, whereas YOY 

rockfishes occurred in highest densities in the shallowest regions of the bank, indicating 

that for some species ontogenetic shifts may be important.

 Blue Rockfish (Miller and Geibel 1973). Of the tagged blue rockfish that were recaptured

inside kelp beds in Monterey Bay over a 3-year period, 95% were recaptured at the release 

site. Of the recaptured adult blue rockfish from tagging outside kelp beds, 85% moved <1.6 

km.

SPECIES OF SPECIAL INTEREST

Many species of special resource management interest are found in the hard-bottom shelf habitat

of MBNMS (Tables 3-7).

• Species Landed in MBNMS: Of the 10 invertebrate and 156 fish taxa that are commonly 

caught and sold in the commercial and/or recreational fisheries of MBNMS (Starr et al. 

2002a), 7 invertebrates and 82 fishes taxa occur in hard-bottom, shelf habitats. More landed 

fish and invertebrates occur in the shallower habitats of Shelf I than Shelf II.

• Endangered and Threatened Species: There are no known endangered or threatened 

invertebrate or fish species associated with hard-bottom, shelf habitat. Of the 3 listed 

seabirds and 10 listed marine mammals, only Steller sea lions and sea otters are likely to 

interact strongly with benthic resources on the shelf.

• Other At-Risk Species: None of the invertebrate taxa in the federal waters of MBNMS are 

listed as “At-Risk”. Five at-risk fishes occur in hard-bottom, shelf habitats. Of the 11 atrisk seabirds and 9 at-risk marine mammals, only the deepest diving seabird (Pink-footed

Shearwater) and marine mammals (sea otters and Steller sea lion) are likely to interact 

strongly with benthic resources on the shelf.

Additional species of special resource management interest in the hard-bottom shelf habitat

include: 

• Structure-forming invertebrates, such as corals and sponges, due to their important 

ecological role in creating habitat structure and their vulnerability to disturbance from 

human activities;

• Sooty Shearwaters which reach extremely high densities during the summer, when 

hundreds of thousands of adults forage for fishes and squid in sanctuary waters after 

migrating from the southern hemisphere;

21 Shelf I & II – Hard
• Seabirds (e.g., Common Murres, Rhinoceros Auklets, Brandt’s Cormorants) and marine 

mammals (e.g., harbor seals, harbor porpoise, elephant seals, sea otters) vulnerable to 

disturbance, injury or death from human activities in the sanctuary such as oil spills and 

entanglement in fishing gear.

22 Shelf I & II – Hard
Shelf I (30-100 m) and Shelf II (100-200 m) – Soft Substrate

HABITAT OVERVIEW

The continental shelf is the gradually sloping submerged margin of a continent that extends from 

shore to the shelf break. Beyond the shelf break the continental slope descends more steeply to 

the ocean floor. In the sanctuary, the continental shelf is relatively broad from the northern 

boundary to southern Monterey Bay. The shelf narrows considerably south of Monterey Bay and 

remains narrow throughout most of the southern portion of the sanctuary, except around Point 

Sur and near the southern boundary in Cambria. The shelf edge is marked by the abrupt break in 

slope that occurs at a depth of 100-140 m (Greene et al. 2002). The vast majority (~ 93%) of the 

shelf in Monterey Bay National Marine Sanctuary is composed of soft bottom habitats (Figure 

1). Within the federal study area, soft bottom habitats on the shelf comprise approximately 957

km2, which is 8.7% of the study area (Table 2).

Water motion, such as waves, surge and currents, organize soft sediment particles into different 

group sizes. Sandy bottom is generally found in shallow waters of the shelf (<40 m depth). The 

shelf is a prominent feature of the northern part of the sanctuary. There, the sediments on the 

outer shelf are generally coarser than those on the upper slope and on the middle of the 

continental shelf (mid-shelf "mud belt"; Storlazzi and Reid 2010). This is likely due to large 

internal waves breaking at the shelf break winnowing out the finer-grained material that 

dominates the middle of the shelf and the continental slope (Curt Storlazzi, pers. comm.).

The lack of hard substrate for attachment prevents algae and some invertebrates from colonizing 

soft bottom habitats. Soft-bottom associated species live either on the surface or buried in the 

sediments. Some of these animals, such as the burrowing tube anemone, build somewhat 

permanent tubes and burrows. The burrowing activities of fishes and invertebrates mix the 

surface sediments and also add some structural relief to a relatively flat habitat. Large sessile and 

sedentary invertebrates, such as sea pens, create structural relief also.

SEARCH TOPIC TABLE

HABITAT FUNCTION

Functional Habitats:

Nursery Habitat: See page 24

Feeding Ground: See page 25

Spawning Ground: See page 25

Migratory Corridor:

See “Movement and Dispersal” section below for information 

on species that move through the soft-bottom shelf habitat 

during ontogenetic and seasonal migrations.

Biogenic Habitat: See page 26

Energy Flow:

23 Shelf I & II – Soft
Primary Production: See page 27

Benthic-Pelagic Coupling: See page 27

Key Trophic Interactions: See page 28

Key Trophic Cascades: No specific information was found on this topic.

Productivity Hotspots: No specific information was found on this topic.

HABITAT STRUCTURE

Species Composition: See page 28

Species Composition Shifts: See page 34

Species Diversity and Richness: See page 37

Biomass: See page 39

Key Species Interactions No specific information was found on this topic.

MOVEMENT AND DISPERSAL See page 40

SPECIES OF SPECIAL INTEREST See page 41

HABITAT SUMMARY

HABITAT FUNCTION

Functional Habitats

Nursery Habitat: The soft-sediments of the continental shelf are used as a nursery habitat by a 

number of fish and mobile invertebrates species. All of these species show a similar life history 

pattern; after a pelagic larval phase, the juvenile phase recruits to the relatively shallow and 

warmer waters of the continental shelf. Then, as they grow and mature, individuals gradually 

migrate to the colder, darker, and deeper waters of the outer shelf, slope, and submarine canyons.

 Spot Prawn. Based on a shallow water trap survey for juvenile spot prawn in Howe 

Sound (British Columbia), catch of juveniles was highest at depths of 46-60 m (Sloan 

1987). Although juvenile size did not vary in a depth-related pattern, mean size of mature 

males increased with depth. A similar trend of male size increasing with depth was found 

in a study of spot prawn catches in and around the Carmel Bay Ecological Reserve in 

central California (Schlining and Spratt 2000). The authors of this study suspected that 

juvenile prawns were using shallow waters as a nursery ground.

 Stripetail Rockfish (Yoklavich et al. 2002). Based on ROV surveys in and around Big 

Creek Ecological Reserve, low relief fields of coarse sand and sea pens in about 70 m of 

water appeared to be a nursery ground for stripetail rockfish.

 Rockfishes (Johnson et al. 2001). The soft-bottom shelf in the Monterey Bay was 

recruitment habitat for 15 species of rockfish in 1995 and 1996. Greenstriped, stripetail, 

and cowcod were most abundant, followed by chilipepper, halfbanded, darkblotched, and 

splitnose. The highest densities were collected from 60-100 m. Peaks in birth dates 

24 Shelf I & II – Soft
corresponded to periods of increased upwelling; peaks in settlement followed upwelling. 

Growth rates declined during months of highest sea-surface temperature. Juveniles 

ontogenetically moved toward adult depths and most left the area during the onset of 

winter storms.

 Sablefish and Shortspine Thornyhead (Jacobson et al. 2001). In benthic surveys 

between central California and Washington at depths of 183-1280 m, the smallest 

sablefish were collected at 183-364 m and the smallest shortspine thornyheads at 183-547 

m. Large individuals occupied the entire range of depths, but they were relatively rare in 

the shallowest part of the range. The shallow areas appeared to be primarily juvenile 

habitat for these two species.

 Rex and Dover Sole. Juvenile rex sole were commonly found on the outer edge of the 

California continental shelf at depths of 150-200 m, which may be a nursery area for this 

species (Leet et al. 2001). Repeated surveys of the shelf and upper slope off Oregon, 

indicated that the nursery area for age-2 to -5 juvenile Dover sole was found at 80-119 m

(Toole et al. 1997). This preferred nursery habitat was found to have elevated prey 

biomass. Earlier beam trawl surveys in Oregon indicated that rex and Dover sole may use 

the outer continental shelf-upper slope region (150-260 m) as a nursery during early 

benthic life (Pearcy et al. 1977).

Feeding Ground: The continental shelf is a feeding ground for a number of species, particularly 

during the summer months, when high productivity in the waters over the continental shelf may 

support an increase in biomass of prey species, such small crustaceans, krill and copepods. The 

spawning activities of large schools of market squid draw predators and scavengers to sandy 

shelf habitats.

 Squid Predators and Scavengers (Cascorbi 1999b). During spawning season, actively 

spawning adults, benthic egg masses, and the sinking carcasses of dying adult squid 

provide large amounts of food for predators and scavengers including rockfishes, sharks, 

seals, sea lions, Dungeness crab, bat stars, and sea urchins.

 Pacific Hake (Baily et al. 1982). The most abundant age classes in the Monterey area are 

age 2-4 (though some age 5-9 individuals are also present). Hake show an inshoreoffshore movement pattern (spring and early summer over the slope, summer to <100 m 

depth, and offshore again in early August). The food of juvenile hake is mainly copepods 

and krill. Smaller adults eat mostly krill and large adults eat mostly other fish and shrimp.

 Juvenile Dover Sole (Toole et al. 1997). Food for juvenile Dover sole less than 100 mm 

total length consists of 90% crustaceans and polychaete worms and 10% mollusks. Off 

Oregon, the edible biomass of this prey was greatest at 100-102 m, a depth that coincided 

with the highest density of age-2 to -5 juvenile Dover sole (80-119 m).

 Herring (Hay and McCarter 1997). Pacific herring (Clupea pallasi) life history is closely 

associated with the continental shelf (<200 m) and adjacent coastal areas. The shelf area 

appears to be the summer feeding habitat for Pacific herring.

Spawning Ground: The fish and invertebrate species that are residents of the soft-bottom shelf 

use this habitat to spawn. In addition, some species, such as flatfishes and market squid, also 

move to specific depth zones on the shelf to spawn.

25 Shelf I & II – Soft
 Market Squid (Forsythe et al. 2004). In 2000 and 2001, market squid spawning grounds 

were located on open, sandy substrate in depths of 20-60 m in southern Monterey Bay 

(just beyond the kelp beds). Small groups of squids (20-200 individuals) generally 

descended during the day and laid eggs for several hours before rejoining schools in the 

water column (there was no evidence of death immediately after mating). 

 English Sole (Lassuy and Moran 1989). English sole most likely spawn over sand and 

sand-mud bottoms at depths of 60-110 m. Spawning is usually most intense during 

winter, but is known to occur in all seasons. These suggested spawning times and 

locations are inferred from the spatial and temporal distribution of either turgid or spent 

females or the egg and larval stages from studies along the west coast.

Biogenic Habitats: Structure-forming invertebrates primarily associated with soft sediments

include sea pens, sea whips, and brittle stars. In general, these invertebrates provide some of the 

only emergent structural relief to the surface of soft-bottom habitats, especially when they 

aggregate in high numbers. Aggregations may provide significant structural relief for fishes in 

mud- and sand-dominated habitats (Tissot et al. 2006). Structure-forming invertebrates are 

susceptible to damage from physical structures dragged across the seafloor including anchor lines 

and fishing gear. Growth rates for many of these invertebrate species are low, extending the time 

to recovery if these communities are damaged.

 Sea Pens. Sea pens were some of the most abundant epifaunal invertebrates observed in

soft-bottom habitats of the shelf (40-140 m) in northern Monterey Bay (CSLC &

MBNMS 2005). Low relief fields of coarse sand and sea pens in about 70 m of water in 

and adjacent to Big Creek Ecological Reserve appeared to be a nursery ground for 

stripetail rockfish (Yoklavich et al. 2002).

 Sea Pen Observations in MBNMS (MBARI VARS database 2011). The locations 

where Monterey Bay Aquarium Research Institute (MBARI) scientists have observed sea 

pens (Order Pennatulacea) are shown in Figure 13. These observations were made during 

ROV surveys 1989-2009. Each data point represents a sighting regardless of the 

abundance of the organisms in the video frame. Sea pens can be fairly abundant on the 

seabed, so the map generally reflects where sampling has occurred. It is important to note 

that sea pens are likely to occur in portions of MBNMS that have not been sampled by

MBARI.

 Structure-forming Invertebrates Observed in MBNMS Shelf Characterization 

Surveys (IfAME and MBNMS 2011). Video transects using a remotely operated vehicle 

(ROV) and a towed camera sled were made to characterize the distribution of fishes, 

invertebrates, and seafloor habitats on the continental shelf (50-200 m) and upper slope 

(200-400 m) at five locations in MBNMS: Ascension and Año Nuevo Canyons; North 

Monterey Bay; Carmel Bay and Point Lobos; Point Sur Shelf; and La Cruz Canyon and 

Point Piedras Blancas. Transects covered a varied of substrate types including mud and 

sand. Structure-forming invertebrates commonly observed in soft-bottom habitat include 

sea pens, sea whips, and brittle starts. Specific locations where structure-forming 

invertebrates were observed along the transects are available through the Shelf 

Characterization and Image Display website (http://sep.csumb.edu/ifame/scid).

 Deep-sea Corals Collected in Bottom Trawls in MBNMS (Curt Whitmire, pers. comm.).

The locations where deep-sea corals were collected incidentally in bottom trawl surveys by 

26 Shelf I & II – Soft
the National Marine Fisheries Service (1980-2010) are shown in Figure 9. Records 

represent the presence of a given taxonomic group in the area swept by trawl gear; exact 

location, species, and abundance information is not available. Of the 6 coral taxa collected, 

sea pens (Order Pennatulacea) are the only taxa associated with soft sediments. Sea pens 

were the most frequently collected taxa, which is likely due to the fact that the trawl 

surveys were targeting groundfish in low-relief, soft bottom habitats.

 Structure-forming Invertebrates in Central California MLPA MPAs (Starr and 

Yoklavich 2008). A manned submersible was used to characterize the benthic habitat and 

associated invertebrates in the deep portion (24-365 m) of eight of the new central 

California Marine Life Protection Act marine protected areas and associated reference 

sites. Structure-forming species associated with soft bottom (e.g., sea pens, sea whips, 

brittle stars) were observed at most sites. See Table 9 for a summary of locations where 

structure-forming species were part of the dominant megafaunal invertebrate assemblage.

Energy Flow

Primary Production: Phytoplankton is the only source of primary production in the waters over 

the soft-bottom shelf. In some portions of the open ocean there is sufficient sunlight to support 

photosynthesis down to 200 m. However, high turbidity in coastal waters decreases the depth at 

which photosynthesis can occur.

The photosynthetic rate of phytoplankton is influenced by the availability of iron. In MBNMS, 

the primary source of iron during upwelling season consists of sediments re-suspended from the 

continental shelf. In areas with a wider continental shelf, such as the area between Monterey Bay 

and San Francisco Bay, upwelled waters interact extensively with shelf sediments and carry high 

amounts of iron into surface waters (Firme et al. 2003). In areas with a narrower shelf, such as 

the coast of Big Sur, upwelled waters have a more limited interaction with shelf sediments, and 

the surface waters in these areas tend to be more iron limited (Firme et al. 2003). Thus, rates of 

photosynthesis tend to be higher in areas with wider continental shelves. See ‘Open Water’ 

habitat summary for additional information.

Benthic-Pelagic Coupling: The flux of material between the benthos and the overlying water 

column occurs through the sinking of non-living organic matter and the active movement of 

organisms. Falling animal carcasses and drift algae may be deposited on the seafloor and utilized 

by scavenging herbivores and detritivores. See Appendix III for more general information about 

this process.

 Drift Algae: Drift algae settling to the seafloor is a source of organic matter for benthic 

organisms. Drift algae may not accumulate as readily on the soft-bottom shelf as it does 

in other habitats, such as submarine canyons. In central California, lower biomass of drift 

algae was observed at sites on the shelf and slope near Point Joe (87-357 m) as compared 

to shallow and deep sites in Carmel Canyon (Harrold et al. 1998). This lower biomass 

may have been due to lower flux and/or higher consumption by resident herbivores (e.g., 

urchins), which were at higher density on the shelf. Vetter and Dayton (1998) reported 

similar results – lower biomass of drift algae at sites on the shelf and slope than in La 

Jolla Canyon. See the “Macrophyte Detritus” habitat section for additional information.

27 Shelf I & II – Soft
 Spawning of Pelagic Eggs/ Larvae: The majority of infaunal and epifaunal invertebrates 

(e.g., tube worms, brittle stars) and demersal fishes (e.g., flatfishes) living in soft-bottom 

shelf habitats release eggs and/or larvae that are pelagic. Therefore, reproduction 

contributes significantly to the upward flux of organic matter from the seafloor to the 

pelagic compartment.

 Squid Egg Beds. The deposition of benthic eggs by pelagic organisms can be a 

significant downward flux of organic matter to the seafloor. Foote et al. (2006) surveyed 

benthic egg masses of market squid (Doryteuthis opalescens) on the sandy shelf of 

southern Monterey Bay. In a selected quadrat, the estimated density of eggs was 47,720 

eggs/m2.

 Settlement/Recruitment of Juveniles: Some species (e.g., sea pens) have juvenile 

phases that settle back into the adult habitat, while the juvenile of other species (e.g., 

Dungeness crabs, flatfishes) settle into shallow nearshore and estuarine habitats and then 

move at an older stage to the soft-bottom shelf. 

Key Trophic Interactions: Many of the invertebrates living on the soft-bottom shelf are either 

detritivores or planktivores. These organisms play an important role in the shelf food web by 

converting phytoplankton, sinking organic matter and nutrients into shelf-associated biomass.

 Planktivores (Cascorbi 1999b). Brittle stars carpet the soft-bottom shelf in some areas. 

While buried beneath the surface they use their long arms to catch plankton in the water 

column. Sea pens, sea whips, and tube anemones are examples of suspension feeders that 

use either stinging cells or sticky mucous to capture phytoplankton, small zooplankton, 

and other suspended organic matter in the water column.

 Detritivores (Hyland 1991). The macroinfaunal communities of the continental shelf and 

slope in Santa Maria Basin were studied for 2.5 years. The majority of the species found 

in this study were deposit feeders and relied on ingestion and absorption of organic 

matter in the sediments for nourishment.

HABITAT STRUCTURE

Species Composition: The infaunal invertebrate assemblage in MBNMS has a high level of 

species richness and tends to be dominated by polychaete worms. Other abundant taxa include 

gammarid amphipods, bivalves, nemertean worms, and ostracods. Large epifaunal invertebrates, 

such as brittle stars, sea stars, sea pens, gastropods, anemones, and sea cucumbers are commonly 

observed on the soft sediments of the shelf beyond 30 m. The fish fauna is diverse, with 

flatfishes being among the most common group of fishes observed in this habitat. A high 

diversity of seabirds and marine mammals are observed in the waters over the shelf. All of the 

marine mammals and some of the seabirds are strong divers that may feed on benthic fishes and 

invertebrate prey.

 Infauna in Northern Monterey Bay (CSLC & MBNMS 2005). Infauna was sampled at 

multiple stations between 25 and 90 m on the shelf in northern Monterey Bay. Polychaete 

worms showed the highest abundance and species richness at most depths. Gammarid 

amphipods were relatively abundant at all stations. Some of the most abundant taxa by 

depth were:

28 Shelf I & II – Soft
 25 m = polychaete worms (Magelona hartmanae, M. sacculata, and Scoletoma luti);

 44-47 m = polychaete worms (Chaetozone lunula, Aricidae (Acmira) catherinae, and 

Mediomastus spp.), bivalves, nemertean worms, ostracods;

 60 m = polychaete worms (Sternaspis nr. fossor), bivalves, brittlestars;

 90 m = polychaete worms (Mediomastus spp. and Spiophanes berkeleyorum), 

bivalves, brittlestars.

 Infauna near Davenport (John Oliver, MLML, unpubl. data). In northern Monterey Bay 

and off Davenport, sediment cores along transects between 10 m and 2,000 m have 

shown distinct infaunal species assemblages that vary by depth. For the two species 

assemblages identified on the shelf, the ten most abundant species are listed in decreasing 

abundance below:

 Mid/Outer Shelf Group (50-90 m): Mediomastus spp. (polychaete), Nephtys cornuta 

(polychaete), Spiophanes berkeleyorum (polychaete), Cossura pygodactylata 

(polychaete), Gadila spp. (toothshell), Sternaspis fossor (polychaete), Pholoe glabra 

(polychaete), Allia ramosa (polychaete), Mediomastus californiensis (polychaete), 

Euclymeninae spp. (polychaete);

 Shelf Break Group (109-150 m): Photis spp. (amphipod), Mediomastus spp. 

(polychaete), Spiophanes berkeleyorum (polychaete), Cirratulidae spp. (polychaete), 

Decamastus gracilis (polychaete), Photis californica (amphipod), Rutiderma lomae 

(ostracod), Pleurogonium californiense (isopod), Nemertea (ribbon worm), 

Euclymeninae spp. (polychaete).

 Infauna Northern Monterey Bay and Off San Francisco (Nybakken 1996). The 

infaunas north of Monterey Canyon (16-60 m) and off San Francisco (40-600 m) were

dominated by polychaete worms. The polychaete fauna had the highest species richness 

and this group comprised at least 50% of the total number of individuals at each site. 

Mollusks comprised 20-25% and crustaceans comprised 13-25% of individual organisms. 

Brittlestars were the only echinoderm with notable abundance

 Infauna on the Shelf in California (Nelson et al. 2008). Sediment grabs were used to 

sample the invertebrate assemblage on the shelf at 50 sites in California, including 14 

sites in MBNMS. Sites ranged in depth from 28-138 m (46-112 m for MBNMS sites). 

Polychaetes, crustaceans and mollusks were the dominant taxa, both by percent 

abundance (59%, 17%, 12%, respectively) and percent species (44%, 25%, 17%, 

respectively). The 10 most abundant taxa were the polychaetes Mediomastus spp., 

Spiophanes duplex, Spiophanes berkeleyorum, Chloeia pinnata, Myriochele striolata, 

Prionospio jubata, and Spiophanes bombyx, the ophiuroid Amphiodia urtica, the decapod 

Pinnixa occidentalis, and the ostracod Euphilomedes carcharodonta.

 Infaunal and Epifaunal Invertebrates off Pillar Point (Kogan et al. 2006). The infauna 

and epifauna was surveyed on the shelf and slope between Pillar Point and Pioneer 

Seamount in northern MBNMS. The species assemblages at shelf sites (43, 67, 75, 140 

m) were summarized as follows:

 Infauna: Of the 24 infaunal taxonomic groups identified in this study, polychaete 

worms, nematodes, and amphipod crustaceans accounted for the majority of infaunal 

29 Shelf I & II – Soft
abundance along the survey route (Figure 14). Polychaete worms were the most 

diverse taxonomic group with up to 33 taxa per station;

 Epifauna: Brittle stars (Ophiuroidea), anemones (Actiniaria), sea pens 

(Pennatulacea), Anthomastus ritteri and gorgonians (Alcyonaria), and sponges 

(Porifera) were the most abundant epifaunal groups, accounting for 84.2% of total 

epifaunal abundance. Brittle stars were the most abundant group at two shelf sites 

(67, 75 m) while the sea pen (Halipteris californica) dominated the shelf/slope break 

site (140 m). 

 Infaunal and Epifaunal Invertebrates in Central California (de Marignac et al. 2009). 

ROV surveys and sediment samples were used to study infauna and epifauna on the shelf 

between 113 and 152 m in June 2006. Both recently trawled and recovering sites were 

surveyed. The taxa observed in all surveys combined were:

 Infauna: Thyasirid bivalve (Axinopsida serricata), polychaete worms (Myriochele 

gracilis, Myriochele olgae, Spiophanes duplex, Spiophanes bombyx, Prionospio spp., 

Scoloplos armiger, Decamastus gracilis, and members of families Terebellidae, 

Cirratulidae, and Maldanidae), and juvenile brittle stars (Ophiuroidea);

 Epifauna: Brittle stars (Ophiothrix spp.), sea whips (Halipteris cf.), and fan worms 

(Sabellidae) were the most abundant epifaunal groups. A brachyuran crab (Cancer

sp.) and an anomuran crab (possibly Lopholithodes spp.) were observed. Three 

distinct species of gastropod were recorded, the most common a Conus species. In 

addition, one moon snail (unknown species) and two cowries (possibly Cypraea 

spadicea) were observed.

 Epifaunal Invertebrates in Northern Monterey Bay (CSLC & MBNMS 2005). 

Epifauna were surveyed from 25-200 m in northern Monterey Bay. Sea pens, anemones, 

crabs and sea stars were common at most stations. The characteristic species assemblages 

by depth were:

 25-39 m = gastropods (most abundant), sea pens, and sea stars;

 40-59 m = cerianthaid anemones, sea stars (Luidia foliolata), sea pens, gastropods;

 60-139 m = sea stars (Rathbunaster californicus), sea pens (Ptilosarcus gurneyi, 

Pennatula spp.);

 90-139 m (adjacent to hard substrate) = sea urchins (Strongylocentrotus fragilis), sea 

cucumbers (Parastichopus leukothele), sea stars (R. californicus);

 140-200 m (dense shell hash) = dominated by the sea star (R. californicus).

 Epifaunal Invertebrates in MBNMS (Nybakken 1996, Cascorbi 1999b, Airamé et al. 

2003). Common large epifaunal invertebrates found on soft sediments on the shelf 

(deeper than 30 m) in Monterey Bay include sea pens, notaspidean opisthobranchs, 

octopus (e.g., Octopus rubescens), squid (e.g., Rossia), sea stars (e.g., Luidia), tube 

worms, and amphipods. Some species are most often seen at night, such as brittle stars, 

polychaete worms, basket stars, sand stars, and short-spined sea stars. Dungeness crabs 

(Cancer magister) are concentrated on sandy to sandy-mud bottoms from the intertidal to 

approximately 100 m. Yellow rock crabs (Cancer anthonyi) inhabit open sand or softbottom habitats. Concentrations of ocean shrimp (Pandalus jordani) are found on green 

mud and mud-sand bottoms at depths of 50-400 m, whereas ridgeback prawn (Sicyconia 

30 Shelf I & II – Soft
ingentis) are found on bottoms composed of sand, shell, and green mud at depths of 50-

175 m.

 Megafaunal Invertebrates in the MBNMS (Graiff 2008). The abundance and distribution 

of megafaunal invertebrates on the continental shelf and upper slope was surveyed at three 

sites in the MBNMS using a manned submersible. See Table 8 for the relative abundance 

of megafaunal invertebrates at Portuguese Ledge (71-252 m), Point Sur (72-126 m), and 

Big Creek (19-249 m).

 Megafaunal Invertebrates and Fishes in central California MLPA MPAs (Starr and 

Yoklavich 2008). A manned submersible was used to characterize the benthic habitat and 

associated megafaunal invertebrate and fish assemblages in the deep portion (24-365 m) of 

eight of the new central California Marine Life Protect Act marine protected areas and 

associated reference sites. See Table 9 for a summary of the dominant megafaunal 

invertebrates and the relative abundance of common groups of demersal fishes at each site.

 Megafaunal Invertebrates and Fishes in the Gulf of the Farallones (SAIC and MLML 

1992). In 1991, fishes and megafaunal invertebrates were sampled at depths of 72-1800 

m using bottom trawls in GFNMS. Benthic communities were distributed primarily by 

depth and the faunal community on the shelf was characterized as follows:

 Invertebrates: Megafauna in the shelf community (~72-200 m) were sparse, but 

included the following species: sea stars (Luidia foliolata, Astropecten verrilli, 

Hippasteria californica, Hippasteria spinosa, Rathbunaster californicus), sea pens 

(Stylatula spp.), anemones (Metridium spp.), octopus (Octopus rubescens), brittlestars 

(Asteronyx loveni, Ophuiura lutkeni, Gorgonocephalus euchnemis), crabs (Cancer 

magister), opisthobranchs (Pleurobranchaea californicus, Tritonia diomedia), and 

sea cucumbers (Parastichopus spp.);

 Fishes: The shelf community (~72-200 m) was dominated by fishes including Pacific 

sanddab, Dover sole, English sole, rex sole, slender sole, rockfishes (including 

chilipepper, shortbelly, and stripetail), pink seaperch, Pacific pompano, white 

croakers, plainfin midshipman, and big skate.

 Megafaunal Invertebrates and Fishes at Cordell Bank (Pirtle 2005). The species that 

were observed in different soft-bottom habitats over the depths range 55-250 m include:

 Muddy, Low or No Vertical Relief: sea pens (Ptilosarcus sp. and suborder 

Subsellaflorae), snails (subclass Prosobranchia), box crabs (Lopholithodes

foraminatus), urchins (Strongylocentrotus fragilis), Dover sole (Microstomus 

pacificus), unknown flatfishes, poachers (Agonidae), combfish (Zaniolepis spp.), and 

spotted ratfish (Hydrolagus colliei);

 Deeper Mud (160-250 m): galatheid crabs (Munida quadrispina), spot prawns 

(Pandalus platyceros), Pacific hagfish (Eptatretus stoutii), and deep-water rockfishes 

including splitnose, stripetail, sharpchin, and greenstriped;

 Sandy, Low-Relief (less diverse): sea star (Luidia foliolata), sanddabs (Citharichthys

spp.), sea pens (Ptilosarcus spp.), and brittle stars.

 Fishes at Point Lobos (Anderson and Yoklavich 2007). Demersal fishes and benthic 

habitats were surveyed from a manned submersible in southern Monterey Bay near Point. 

31 Shelf I & II – Soft
Lobos (60-260 m). Three habitat types (hard, soft, mixed) were classified from acoustic 

maps. Habitat type was a strong predictor of fish assemblage composition:

 Soft (homogeneous mud, 80−260 m): fish assemblage characterized by non-rockfishes 

(e.g., flatfishes and poachers); non-rockfishes dominated this assemblage (63% of 

observed fishes).

 Mixed (low relief outcrops, 90−150 m): fish assemblage characterized by schools of 

small-bodied rockfishes, halfbanded rockfish, two large-bodied rockfishes 

(greenspotted and greenstriped), and a variety of non-rockfish species (e.g., sanddabs, 

pink seaperch, combfishes, Pacific argentine, and lingcod). This habitat stratum had the 

highest species diversity, which resulted from a combination of species unique to the 

mixed stratum and species characteristic of both the hard and soft strata.

 Fishes In and Around Big Creek Marine Ecological Reserve (Yoklavich et al. 2002). 

Using ROV surveys during 1997 and 1998, four distinct fish assemblages were identified 

between 20-250 m (two of which were associated with soft bottom)

 Sand waves and shell hash in shallow water (<100 m): speckled and Pacific sanddabs, 

and sculpins. 

 Fine, smooth sediment in deep water (>100 m): Dover, rex, and slender soles, 

poachers, and Pacific hake. 

 Fish at Davenport Shelf (Laidig et al. 2009). Two species, pygmy rockfish and blackeye 

goby, accounted for 41% of all fishes identified between 65-110 m on the shelf off 

Davenport. The fish assemblage was examined based on bottom habitat. Flatfishes, 

poachers, sanddabs, and greenstriped rockfishes characterized the species assemblages on 

mud-dominated habitat. Other species observed in mud-dominated habitat include rex 

sole, English sole, rock sole, greenspotted rockfish, lingcod, pink surfperch and blackeye 

goby.

 Fish-Habitat Associations at Cordell Bank (Anderson et al. 2009). Habitat type and the 

associated fish fauna were surveyed between 52-365 m depth using a manned 

submersible. An abundant and diverse fish fauna (87,078 individuals from 70 species/ 

taxa in 21 families) was recorded on and around Cordell Bank and was dominated by the 

genus Sebastes (27 species, 95% of individuals). Five broad-scale habitat zones (four of 

which contain soft bottom shelf habitat) were characterized by distinct fish faunas, with 

depth and habitat composition strong predictors of fish assemblages:

 Continental slope (deep mud, 107–298 m): characterized by flatfishes, poachers, 

spotted ratfish, hagfishes, longspined combfish, and a few Sebastes species (stripetail, 

splitnose, and sharpchin rockfishes);

 Slope-bank transition zone (interwoven mud and patchy reef, 120-130 m):

characterized by an array of species found in both mud (e.g., flatfishes and poachers) 

and patchy mud-reef habitats (e.g., shortspined combfish, sculpins, and sharpchin 

greenspotted, and greenstriped rockfishes);

 Shelf–bank transition zone (reef–sand, 80–110 m): similar fish assemblage to that 

of the slope–bank transition (except in lower densities), with the addition of sanddabs 

and pricklebacks.

32 Shelf I & II – Soft
 Continental shelf (homogenous sand, 98–114 m): was depauperate compared to 

other zones and characterized only by sanddabs.

 Rockfishes. Williams and Ralston (2002) examined rockfish assemblages from southern 

Oregon to Point Conception using data from NMFS shelf and slope trawls over primarily 

soft bottom. Rockfish richness was highest at a depth of 200-250 m, where the shelf and 

slope meet. Depth and latitude were the main determinants of rockfish assemblages. 

There were four suggested species assemblages based on distribution, ordination, and 

partitioning analyses and three of these included shelf habitat:

 Nearshore (50-150 m): copper, vermilion, brown, and halfbanded rockfishes;

 Southern shelf (100-250 m; 34°N to the Mendocino Escarpment): bocaccio, 

chilipepper, cowcod, greenspotted, greenstriped, shortbelly, and stripetail rockfishes;

 Northern shelf (150-250 m; 43°N to Monterey Canyon): canary, redstripe, rosethorn, 

sharpchin, widow, yelloweye, and yellowtail rockfishes.

 Deepwater slope (200-500 m): aurora, bank, blackgill, darkblotched, Pacific Ocean 

perch, redbanded, shortspine, and splitnose rockfishes.

NOTE: there was overlap in species assemblages between the Monterey Canyon and 

Mendocino Escarpment.

 Benthic Fish and Invertebrate Assemblages (Zimmerman 2006). Using the NMFS US 

west coast bottom trawl survey (55-500 m) data during 1995, 1998, and 2001, three 

biologically distinct assemblages occurred along the US west coast; shallow, middle, and 

deep assemblages. Within the MBNMS, the shallow (55-183 m) and deep (367-500 m) 

assemblages were prominent. A distinct middle assemblage was lacking; there was a 

mixing of shallow, deep, or uncertain assemblages occurring between 184-366 m.

 Groundfish Assemblages in Central and Northern California. Using NMFS 

groundfish shelf trawl data, NCCOS (2003) identified 10 depth-stratified species 

assemblages between 62 and 463 m (Table 11). Assemblages identified species that 

tended to be caught together and were named for the most influential species. Four of the 

assemblages (Pacific herring assemblage, halfbanded rockfish assemblage, Pacific 

sanddab assemblage and big skate assemblage) occurred primarily on the shelf, two 

occurred primarily on the upper slope, and four (chilipepper rockfish assemblage, rex 

sole assemblage and Pacific hake assemblage) occurred in both the shelf and upper slope 

area. Sampling targeted gently sloping soft bottom on the shelf and shelf break, but some 

gently sloping hard bottom was probably encountered (highly sloped rocky bottom was 

not sampled). 

 Fishes on the California Shelf. Allen (2006) identified ‘ecologically important’ species 

in middle shelf (31-100 m) and outer shelf (101-200 m) habitats off north-central 

California (Cape Mendocino to San Simeon) (Table 13). Ecologically important species 

were defined as those occurring frequently within a depth zone and likely to play 

important ecological roles (generally with regard to feeding) in the soft-bottom 

community. 

 General Classification of California Marine Fishes. Allen and Pondella (2006) used 

cluster analysis of species assemblages to determine which species occur together in 

33 Shelf I & II – Soft
particular habitats (by substrate type, depth, and latitude). The following species 

assemblages occur in soft bottom shelf habitats in central California: 

 Mid-Shelf Generalists: longspine combfish, pink seaperch, pixie poacher, calico 

rockfish, spotted cuskeel, curlfin turbot, English sole; 

 Mid- to Outer Shelf Generalists: plainfin midshipman, hundred-fathom codling, 

blackbelly eelpout, blacktip poacher, Pacific sanddab, slender sole; 

 Outer Shelf and Slope: Dover sole, California slickhead, longspine thornyhead, giant 

grenadier, black hagfish, California rattail.

 Seabirds and Marine Mammals (Research Planning Inc. 2006). Table 12 provides a list 

of the seabird and marine mammals species typically observed along the central 

California coast and their relative abundance and seasonality in eight pelagic zones off of 

central California (Figure 12):

 Seabirds: Of the seabird species found over the shelf, only the deep diving seabirds, 

such as shearwaters and auks (e.g., murres, auklets), are capable of feeding at or near 

the bottom in shelf habitats;

 Marine Mammals: The species most commonly observed in waters over the shelf 

that may feed at or near the bottom in MBNMS are northern elephant seals, harbor 

seals, California sea lion, Dall’s porpoise, harbor porpoise, Risso’s dolphin, and 

bottlenose dolphin. Sea otters tend to be found in waters less than 30 meters deep, but 

they are occasionally found out to a depth of 100 m.

Species Composition Shifts: 

 Natural Changes: Significant natural changes in water temperature and current patterns, 

such as El Niño/La Niña events and the Pacific Decadal Oscillation, may lead to changes 

in the species composition on the soft-bottom shelf. However, no specific information 

was found on this topic in this habitat category during the literature review.

 Human Induced Changes: Human activities can alter species composition on the shelf. 

Studies in MBNMS have investigated the potential impacts of submerged cables, fishing, 

disposal of dredge material, and deposition of marine debris.

 Effects of a Submarine Cable on the Benthic Fauna in Northern MBNMS 

(Kogan et al. 2006). The potential impacts of a submarine cable on the distribution

and abundance of 17 megafaunal groups and 19 infaunal taxa were investigated using 

video observations and sediment cores. No cable-related changes in distribution or 

abundance were detected for most faunal groups. Three megafaunal groups exhibited 

cable-related changes at one or more stations. Sea anemones colonized the cable 

when it was exposed on the seafloor, and were therefore generally more abundant on 

the cable than in surrounding, sediment-dominated seafloor habitats. Some fishes, 

such as flatfishes, were more abundant near the cable, apparently due to the higher 

habitat complexity provided by the cable. Sea cucumbers, a minor element of the 

seafloor fauna, were less abundant near the cable than along the control transect at 

one (1700 m station) of the six stations inhabited by this group. These results suggest

that the biological impacts of the cable were minor.

34 Shelf I & II – Soft
 Effects of Submarine Cable on Seabed and Benthic Faunal Assemblages (Kuhnz 

et al. 2011). A geological and biological sampling program was performed to assess 

the condition of the Monterey Accelerated Research System (MARS) cable and its 

potential effects on seabed geology and biology. The major conclusion of the study is 

that the MARS cable has had little detectable impact on seabed geomorphology, 

sediment conditions, or biological assemblages. Specific conclusions include the 

following:

 Changes in mean grain size were undetectable in relation to the MARS cable.

 The percent organic carbon content of sediments increased near the MARS cable 

at some locations, possibly due to natural variation or the effects of the cable or 

both.

 Local variation in benthic megafaunal communities near (within 50-100 m) the 

MARS cable is minor or undetectable.

 The MARS cable has little or no detectable effect on the distribution and 

abundance of macrofaunal and megafaunal assemblages on a regional scale (e.g. 

kilometers).

 Effects of Bottom Trawling on Benthic Invertebrates in MBNMS. Engel and 

Kvitek (1998) compared highly trawled (HT; trawled 4 times per year) and lightly 

trawled (LT; trawled once every 3 years) areas. The substrate was less heterogeneous 

in HT areas. In LT areas, detritus was more common on the surface of the substrate, 

large epifaunal invertebrates (e.g., sea pens, sea stars, sea anemones, and sea slugs) 

were more dense and infaunal polychaetes had higher species richness. Oligochaetes, 

nematodes, and ophiuroids were more dense in the HT area. These organisms were 

either opportunistic or not damaged/collected by the nets. There was no measurable 

difference in crustaceans, urochordates, sipunculids, other echinoderms, and 

echiurans between HT and LT areas. Overall, high-intensity trawling reduced habitat 

complexity and biodiversity while increasing opportunistic infauna and certain prey 

important in the diet of some commercial fish species.

 Fishing Effects on Megafaunal Invertebrates (Graiff 2008). Underwater video 

surveys at three sites in central California were used to assess the effects of fishing on 

the abundance of megafaunal invertebrates categorized as slow-growing, sessile species

(e.g., sea pens) and fast-growing, mobile species. The three sites (Portuguese Ledge, 

Point Sur, and Big Creek) have been subjected to varying levels of fishing intensity and 

gear use. Fishing intensities were calculated for recreational hook and line and five 

bottom-contact commercial gear types: bottom trawl, traps, bottom-set gillnet, bottomset longline, and hook and line. Overall, there were little to no detected effects on 

invertebrates due to fishing. Environmental variables were most likely influencing 

invertebrate abundance and distribution patterns. One of the most challenging aspects 

of determining the impacts of fishing intensity on megafaunal invertebrates was the 

lack of high-resolution data on the distribution of fishing effort.

 Effects of Bottom Trawling on Benthic Invertebrates in Central California (de

Marignac et al. 2009). ROV surveys and sediment samples were used to compare 

infauna and epifauna at recently trawled sites and recovering sites on the shelf 

35 Shelf I & II – Soft
between 113 and 152 m. Some minor, but distinct differences in faunal assemblages 

were observed:

 Infauna: There were no major differences in measures of species richness for 

benthic infauna, diversity (H′), or evenness (J′) between trawled vs. recovering 

site groups. There was a clear difference between benthic infaunal communities in 

the recovering vs. trawled areas due to differences in the relative abundances of 

component species. The two oweniid polychaetes, Myriochele gracilis and M. 

olgae, and the polychaete family Terebellidae all had significantly lower densities 

at trawled sites. The thyasirid bivalve Axinopsida serricata and the polychaetes 

Spiophanes spp., Prionospio spp., and Scoloplos armiger all had significantly to 

near-significantly higher abundances at trawled sites.

 Epifauna: Trawled transects were populated by sea whips and gastropods whereas 

transects within the recovering transects were dominated by patchily distributed 

ophiuroids (brittle stars). Macrofaunal species richness was very low for both 

actively trawled and recovering sites. The trawled site contained only six distinct 

species and the recovering site only three.

 Effects of Exploitation on the West Coast Groundfish Assemblage (Levin et al. 

2006). Data from fishery-independent trawls on the soft bottom shelf and slope (55 to 

366 m) conducted by NMFS from 1980-2001 along the U.S. west coast (WA, OR, 

CA combined), indicate that there have been fundamental changes in the fish 

assemblage. Populations of flatfishes, cartilaginous fishes, and small rockfishes have 

increased, while populations of large rockfishes have decreased. In 1977, rockfishes 

were more than 60% and flatfishes were 34% of the fish captured in the survey. In 

2001, rockfishes were 17% of the fish captured in the survey and flatfishes were 

nearly 80%. The species that now dominate the assemblage have vastly different 

trophic roles and life-history strategies than the species they replaced.

 Effects of Dredge Material Disposal (Oliver and Slattery 1976). The effects of 

disposal of dredged material on the benthic invertebrate assemblage and subsequent 

recovery of the fauna was studied near the Monterey Canyon head at Moss Landing. 

Sediment cores contained 60% fewer individuals after disposal of dredge material.

After 1.5 years, the number of individuals in sediment cores remained low, but the 

species diversity and evenness indices were higher than before disposal. Organisms 

adapted to unstable bottom conditions survived burial better than those adapted to 

more stable benthic conditions.

 Effects of Demersal Marine Debris (Watters et al. 2010). Video surveys in central 

California of the seafloor at depths of 20-365 m observed various type of debris

including monofilament line, longlines, nets, traps, beverage cans, bottles, anchors, 

cables, household items, and construction items. By providing artificial habitat to 

demersal organisms, debris can alter seafloor habitat and species assemblages. In 

surveys during the 1990s, 13% of debris items had fishes associated with them, and 

38% of items were associated with large, structure-forming invertebrates. In 2007, 

less than 10% of debris items had fishes associated with them, and 30% were 

associated with large, structure-forming invertebrates. The majority of debris (e.g.,

99% of 815 items surveyed in 2007) was colonized moderately to heavily by 

36 Shelf I & II – Soft
encrusting invertebrates. Fishes only associated with types of debris that could 

provide structure and cover; they did not associate with monofilament line. Though 

debris occurred disproportionately in rocky habitats, ~40% of debris was observed on 

soft sediments.

Species Diversity and Species Richness: 

Species richness of the infaunal and the demersal fish assemblages on the shelf tends to increase 

with depth and peak near the shelf break. Species diversity of the fish assemblage associated 

with soft-bottom habitats appears to be lower than that found associated with hard-bottom 

habitats.

 Infauna in MBNMS (Nelson et al. 2008). Sediment grabs were used to sample the 

invertebrate assemblage on the shelf at 14 sites in MBNMS. Sites ranged in depth from 

46 to 112 m. Species richness (mean number of taxa per grab) at these sites ranged from 

52 to 119, with 6 of the sites having over 100 taxa. Mean H’ diversity per grab ranged 

from 4.233 to 5.776.

 Infauna Near Davenport (John Oliver, MLML, unpubl. data). In northern Monterey 

Bay and off Davenport, the mean number of species in sediment cores increased along 

the shelf, peaking at 109 and 150 m (at the shelf break), and then declining along the 

slope to 700 m. The mean number of species per sample was similar from 700-2000 m. 

The number of species of crustaceans followed a similar pattern.

 Infauna off Pillar Point (Kogan et al. 2006). A total of 24 infaunal taxonomic groups 

were identified along a submarine cable between Pillar Point and Pioneer Seamount in 

the northern portion of MBNMS. Polychaetes were the most species rich group with up 

to 33 taxa per station. Species richness increased with depth along shelf and peaked at the 

shelf break (Figure 14).

 Infauna from Northern Monterey Bay and off San Francisco (Nybakken 1996). The 

total number of infaunal invertebrate species reported in a study in northern Monterey 

Bay (16-60 m) was 383 while in a study off San Francisco (40-600 m) a total 309 species 

was reported.

 Infaunal and Epifaunal Invertebrates in Central California (de Marignac et al. 2009). 

Infauna and epifauna on the shelf between 113 and 152 m were surveyed using an ROV 

in recently trawled and recovering sites. Macrofaunal species richness was very low for 

both actively trawled and recovering sites. The trawled site contained only six distinct 

species and the recovering site only three. Diversity of the macrofaunal assemblage was 

low in both actively trawled and recovering sites, with significant differences in mean 

diversity between the two sites. No major differences in measures of infaunal species 

richness, diversity (H′) or evenness (J′), were observed between trawled vs. recovering 

site groups. Mean number of taxa per sediment grab was 62 and 65 and mean H’ 

diversity was 3.4 and 4.0 for recovering and trawled sites, respectively.

 Megafaunal Invertebrates Inside and Outside Monterey Bay (Oliver et al. 2011). 

Estimates of soft-bottom species density were obtained by sampling benthic megafaunal 

invertebrate communities in four major sampling programs along the coast of Central and 

Northern California. Three of these programs were focused around the Monterey Bay 

area. Samples from 30 to 2,000 m depths were analyzed. The Monterey Bay shelf was a 

37 Shelf I & II – Soft
local hot spot for species density, peaking at 449 species/m2 at the shelf break (100-150 

m). This species density is just slightly less than the highest species densities measured 

worldwide (436 species/0.81 m2

). There were 337 species/m2 in the mid-shelf mud zone 

(80 m). Species densities were lower on the slope. Species density was highest inside the 

bay (328-446 species/m

2

) compared to outside (336-339 species/m

2

) when comparing 

samples from the same water depths. The authors speculate that the highest species 

densities occur where ocean water exchanges energy with shoaling topography at the 

continental margin, bringing more food to the benthos.

 Fish and Megafaunal Invertebrates in the Gulf of the Farallones (SAIC and MLML 

1992). Fish and megafaunal invertebrates were sampled using bottom trawls in the Gulf 

of the Farallones. The number of fish species collected by trawl was highest on the shelf 

and peaked at 85 m. The number of benthic megafaunal invertebrate species was lowest 

on the shelf and increased with depth.

 Demersal Fishes at Point Lobos (Anderson and Yoklavich 2007). Nineteen species of 

demersal fishes were recorded during surveys of soft mud habitat from a manned 

submersible in southern Monterey Bay near Point Lobos (60-260 m). Higher species 

richness of 41 and 44 species was observed in hard-bottom and mixed-substrate habitats, 

respectively. The high richness in the mixed habitat resulted from a combination of species 

unique to the mixed habitat and species characteristic of both soft and hard-bottom habitats.

 Demersal Fish at Big Creek Ecological Reserve (Yoklavich et al. 2002). Shallow-water 

(<100 m) assemblages were more diverse over rock outcrops than over sand. Species 

diversity was generally higher in deep-water habitats (100-250 m) than in shallow water 

(20-100 m).

 Demersal Fishes at Cordell Bank (Anderson et al. 2009). An abundant and diverse fish 

fauna (87,078 individuals from 70 species/ taxa in 21 families) was recorded on and 

around Cordell Bank and was dominated by the genus Sebastes (27 species, 95% of 

individuals). Mean and total species richness was determined for the five major habitat 

types:

 Mean species richness: slope-bank transition (16 spp.) ≈ shelf-bank transition (16 

spp.) ≈ bank (15 spp.) ≈ slope (14 spp.) > shelf (6 spp.)

 Total species richness: slope (~55 spp.) > bank (~38 spp.) ≈ slope-bank transition 

(~35 spp.) > shelf-bank transition (~30 spp.) > shelf (~12 spp.)

 Demersal Fishes in Central California (NCCOS 2003). Rockfish species richness 

tended to be highest along the edge of the continental shelf (Figure 15). Areas with high 

species richness (for all demersal fish species) tended to be in water less than 200 m 

(Figure 16). Areas with high species diversity (for all demersal fish species) tended to be 

on the slope in waters deeper than 300 m (Figure 17).

 General Classification of California Marine Fishes. Allen and Pondella (2006) 

provided H' (diversity) for 36 marine habitat types and for 14 major marine habitats in 

California. The middle shelf (Shelf I & II) in the central region had the lowest species 

diversity recorded in the comparison (H` = ~0.6). The outer shelf (Shelf II) in the central 

region had a higher diversity of ~1.75, though this value is much lower than most habitats 

in the study.

38 Shelf I & II – Soft
 Flatfish (Vetter et al. 1994). Flatfish diversity was greatest on the outer shelf (12 species, 

100-200 m). After the shelf-slope transition, flatfish diversity decreased rapidly.

 Demersal Rockfishes off California (Williams and Ralston 2002). Rockfish richness 

was highest at a depth of 200-250 meters, where shelf and slope faunal groups overlap. 

The area between Monterey Canyon and the Mendocino Escarpment - an area of overlap 

of southern and northern assemblages - was found to have the highest species richness. 

For southern latitudes (34.0–38.0°N), the ridge of high diversity veered well offshore to a 

depth of 450 m, and there was some indication of a secondary increase in diversity at 150 

m for the most southerly latitudes 34.0–36.0°N.

Biomass: The biomass of infaunal invertebrates appears to be elevated at mid-shelf depths. 

Biomass of megafaunal invertebrates and fishes appears to be lower on the shelf than on the 

slope. The biomass of many species of invertebrates and fishes has been reduced, dramatically 

for some species, by commercial and/or recreational harvest.

 Infauna near Davenport (John Oliver, MLML, unpubl. data). In northern Monterey Bay 

and off Davenport, the mean biomass per sample was highest at 60 m. Mean biomass was 

elevated at 60-109 m and at 325, 700, and 1500 m.

 Infauna off Pillar Point (Kogan et al. 2006). Infauna were surveyed along a submarine 

cable between Pillar Point and Pioneer Seamount in the northern portion of MBNMS. 

Biomass was not reported in this study, but estimates of abundance (the average number 

of infauna per sample) show that infaunal species were more abundant at three (43, 67, 

140 m) of the four stations on the shelf (Figure 14). Infauna was less abundant at 75 m 

and at all the stations on the slope.

 Fish and Megafaunal Invertebrates in the Gulf of the Farallones (SAIC and MLML 

1992). The highest density of fishes was collected on a mid-depth transect (128m), due 

primarily to the presence of flatfishes and shortbelly rockfish. Shelf depths had lower 

biomass than upper and middle slope depths. Megafaunal invertebrate densities were 

more variable than fishes; middle slope depths had the highest densities, associated 

primarily with echinoderms.

 Demersal Fishes at Point Lobos (Anderson and Yoklavich 2007). Biomass was not 

calculated for this study, but density of demersal fishes was provided for three different 

benthic habitat strata (hard, mixed, soft). The mixed stratum (862 fishes/1000 m2

) had

substantially higher density of all demersal fish compared to the soft stratum (130 

fishes/1000 m2), although the density of large-bodied (>20 cm) fish was higher in the soft 

stratum (21 fishes/1000 m2) compared to mixed (4 fishes/1000 m2). The hard stratum 

appears to have the highest demersal fish biomass based on density estimates for both all 

demersal fishes (1,357 fishes/1000 m2

) and large-bodied fishes (27 fishes/1000 m2).

 Herring (Hay and McCarter 1997). The Pacific herring life history is closely associated 

with the continental shelf (<200 m) and adjacent coastal areas. In general, throughout the 

Northern Hemisphere, areas with large herring populations have broad continental 

shelves, and areas with small populations have narrow shelves. The density-independent 

maximal biomass of each stock was estimated based on the availability of shelf area. The 

maximal average density of herring on the shelf was estimated to be about 10 g/m2

.

39 Shelf I & II – Soft
 Harvested Species: Recreational and commercial harvest removes biomass of targeted fish 

and invertebrate populations. For some targeted species, biomass is substantially reduced 

compared to unfished biomass levels (Tables 3 and 4). Though extraction is the primary 

reason for a reduction in biomass for many species, changing oceanographic and ecological 

conditions are an important contributing factor for some harvested species. For the majority 

of the 10 invertebrate and 156 fish stocks landed in MBNMS, the status of the stock has not 

been assessed (Tables 3 and 4).

MOVEMENT AND DISPERSAL

Due to the lower habitat complexity and patchier food availability in soft bottom habitats, many 

species commonly found in this habitat may have to move more to find food and avoid predation 

than species living in rocky habitats (Lowe and Bray 2006). Many species of fish that are found 

on the sandy shelf during one (or more) life stage(s) also use adjacent habitats during another life 

stage or during certain times of year. Some examples of these ontogenetic and seasonal 

movement patterns were summarized by Cailliet et al. (2000):

 Plainfin Midshipman: Males migrate inshore in winter to make nests on hard substrates 

in nearshore (<30 m) and intertidal habitats. Females follow soon after. Both sexes return 

to deep-water soft-bottom habitats in fall.

 Flatfish (e.g., California halibut, starry flounder, rock sole and sand sole): Adults of 

many species of flatfish move inshore in late winter-early spring to spawn and then move 

back offshore into deeper water in the summer or early fall.

 Elasmobranchs (e.g., leopard sharks, bat rays, round stingray): Some elasmobranchs 

exhibit seasonal inshore-offshore movements, congregating in shallow waters, such as 

estuaries and bays, during the breeding season. Many species of elasmobranchs also 

exhibit along shore movement patterns over soft bottoms.

 Flatfish and Elasmobranchs (e.g., California halibut, English sole, speckled sanddab, 

leopard sharks, bat rays, round stingray): Juveniles are found in nearshore habitats, 

including estuaries, and move into deeper water as they mature. 

 Petrale Sole: Adults move offshore to deeper water in fall and winter to spawn.

 Dover Sole: age-1 to age-5 fish move inshore during the summer and fall and return 

offshore by late fall or winter. 

 Shiner surfperch and pile perch: Move to shallow waters to mate in spring and deeper 

waters in the fall/winter.

 Juvenile Rockfish (Johnson et al. 2001). Juvenile rockfish that recruited to the soft 

bottom shelf in Monterey Bay underwent ontogenetic movements to deeper waters, with 

density and size of fishes increasing with depth over the course of the study.

 English Sole in Monterey Bay (Brown 2006). Ontogenetic movement from estuaries to 

the soft-bottom shelf appears to be an important process for supplying new recruits into 

the offshore, harvested adult population. In a sample of 47 sub-adult and adult English 

sole collected from the soft-bottom shelf in Monterey Bay, approximately half were 

identified as having previously resided in estuaries. This level of estuarine contribution to 

40 Shelf I & II – Soft
offshore adult population is much higher than would be expected based on the relative 

area of estuarine and nearshore sandy habitats in the region.

SPECIES OF SPECIAL INTEREST

Many of species of special resource management interest are found in the soft-bottom shelf 

habitats of MBNMS Tables 3-7.

• Species Landed in the MBNMS: Of the 10 invertebrate and 156 fish taxa that are 

commonly caught and sold in the commercial and/or recreational fisheries of MBNMS 

(Starr et al. 2002a), 7 invertebrates and 79 fishes taxa occur in soft-bottom, shelf habitats. 

More landed fish and invertebrates occur in the shallower habitats of Shelf I than Shelf II.

• Endangered and Threatened Species: There are no known endangered or threatened 

invertebrate species associated with soft-bottom, shelf habitat. Green sturgeon, which is 

listed as threatened, is the only endangered or threatened fish species in this habitat. Of 

the 3 listed seabirds and 10 listed marine mammals, Steller sea lions and sea otters are the 

only species likely to interact strongly with benthic resources on the shelf

• Other At-Risk Species: None of invertebrate in the federal waters of MBNMS are listed 

as ‘at-risk’. Four at risk fishes occur in soft-bottom shelf habitats. Of the 11 at-risk 

seabirds and 9 at-risk marine mammals, only the deepest diving seabird (Pink-footed 

Shearwater) and marine mammals (sea otters and Steller sea lion) are likely to interact 

strongly with benthic resources on the shelf.

Additional species of special resource management interest in the soft-bottom shelf habitat 

include: 

• Structure-forming invertebrates, such as sea pens, due to their important ecological role in 

creating habitat structure and their vulnerability to disturbance from human activities;

• Sooty Shearwaters which reach extremely high densities during the summer, when 

hundreds of thousands of adults forage for fishes and squid in sanctuary waters after 

migrating from the southern hemisphere;

• Seabirds (e.g., Common Murres, Rhinoceros Auklets, Brandt’s Cormorants) and marine 

mammals (e.g., harbor seals, harbor porpoise, elephant seals, sea otters) vulnerable to 

disturbance, injury or death from human activities in the sanctuary such as oil spills and 

entanglement in fishing gear.

41 Shelf I & II – Soft
Slope (200-3,000 m) – Hard Substrate

HABITAT OVERVIEW

The seafloor between the continental shelf break (~200 m) and 3,000 m is considered slope 

habitat. A small portion (3.2%) of the slope in MBNMS is composed of hard bottom habitats 

(Figure 1). Within the federal study area, hard bottom habitats on the slope comprise 

approximately 466 km2, which is 4.24% of the study area (Table 2).

Productivity, biomass, and physical energy in the deep sea (>1000 m) are relatively low, 

increasing the potential sensitivity of this habitat to human impacts. In addition, diversity is 

relatively high in the deep sea, making the habitat more sensitive to human impacts (Glover and 

Smith 2003).

Species that live on the continental slope depend on the downward flux of primary production 

from surface waters. Organic matter produced on the surface sinks to the seafloor where it is 

consumed by organisms, decomposed, or buried in sediments. As the decomposing detritus sinks 

through the water column, it creates a zone of relatively low dissolved oxygen at about 700 m 

known as the oxygen minimum zone (OMZ; see Oxygen Minimum Zone habitat summary for 

more information). Below the OMZ, the dissolved oxygen and nutrient content of the water is 

higher. See Figure 4 for general location of the OMZ in MBNMS.

Organisms that associate with deep, complex habitats are difficult to survey. It is only during the 

past three decades that species-habitat associations in deep rock habitats have been quantitatively 

surveyed off central and southern California using occupied research submersibles. 

SEARCH TOPIC TABLE

HABITAT FUNCTION

Functional Habitats:

Nursery Habitat: No specific Information was found on this topic.

Feeding Ground:

The slope off Point Sur between 600-1,200 m (soft and hard 

bottom) was identified as an important feeding and spawning 

ground for a diverse group of fishes, many of which utilize 

shallower nursery grounds on the shelf (Wakefield 1990).

Spawning Ground: See page 43

Migratory Corridor: See “Movement and Dispersal” section below for information 

on species that move to the slope during ontogenetic migrations.

Biogenic Habitat: See page 44

Energy Flow:

Primary Production: See page 46

Benthic-Pelagic Coupling: See page 46

Key Trophic Interactions: No specific Information was found on this topic. See “Shelf I & 

42 Slope – Hard
II – Hard Bottom” habitat summary for information on the role 

of detritivores and planktivores on deep reef habitats.

Key Trophic Cascades: No specific Information was found on this topic.

Productivity Hotspots: See page 46

HABITAT STRUCTURE

Species Composition: See page 47

Species Composition Shifts: See page 48

Species Diversity and Richness: See page 49

Biomass: See page 50

Key Species Interactions See page 50

MOVEMENT AND DISPERSAL See page 51

SPECIES OF SPECIAL INTEREST See page 51

HABITAT SUMMARY

HABITAT FUNCTION

Functional Habitats

Spawning Ground: Slope habitats (soft and hard) in central California are important spawning 

areas for groundfishes, including those of commercial importance. Rocky outcrops between 

1,300-3,000 m (north of the study area) are spawning grounds for blob sculpin and octopus. 

Similar habitats within the study area may be equally important to these species.

• Groundfish (Wakefield 1990). The slope off Point Sur (600-1,200 m) was identified as 

an important feeding and spawning ground for a diverse group of fishes, many of which 

utilize shallower nursery grounds on the shelf.

• Longspine Thornyhead (Wakefield 1990; Wakefield unpubl. data). Off Point Sur, 93% 

of the longspine thornyhead spawning stock inhabit 500-1,100 m.

• Thornyheads (Jacobson and Vetter 1996). Peak spawning biomass for both thornyhead 

species off Oregon and central California (Point Sur to Point Conception) occurs between 

600-1,000 m. Small shortspine thornyheads are found on the shallow slope (200-600 m), 

but migrate to deeper water with growth. Longspine thornyhead of all size classes were 

found between 600-1,400 m.

• Blob Sculpin and Octopus. Off northern California (Gorda Escarpment) between 1300-

3000 m, Drazen et al. (2003) observed concentrations of blob sculpin (Psychrolutes 

phrictus) and octopus (Graneledone spp.) at the crest of steep, rocky outcrops and near 

cold seeps. Observations were only made during summer months. Biomass of blob 

sculpin at one site was equivalent to the average total biomass of fishes on the slope. 

Likewise, density of Graneledone was considerably greater than previous estimates. The 

authors hypothesized that local topography interacting with physical and geological

43 Slope – Hard
settings create a localized reproductive hot spot in the deep sea used by at least two very 

different animals. In a separate study at Cascadia Basin (2,600 m), Voight and Grehan 

(2000) document that the octopuses Graneledone and Benthoctopus attached their eggs to 

basalt outcrops and apparently brood them through development. The dense aggregations 

of Graneledone and Benthoctopus may be due to the availability of rocky substrate for 

egg attachment and bivalve prey from nearby cold seeps. 

Biogenic Habitat: Various types of structure-forming invertebrates attach to hard substrates on 

the slope creating biogenic habitat. Structure-forming organisms contribute significantly to

benthic habitat structure and function by adding vertical relief, increasing the diversity of 

microhabitats, and increasing the surface area for settlement and retention of other organisms. 

Managed fish species associated with structure-forming invertebrates include: lingcod, longspine 

and shortspine thornyhead, sablefish, spotted ratfish, and rockfishes (e.g., bocaccio, cowcod, 

flag, greenspotted, quillback, rosethorn, sharpchin, starry, tiger, vermillion, yelloweye, and 

yellowtail) (NMFS 2005, Tissot et al. 2006). Structure-forming invertebrates are susceptible to 

damage from physical structures dragged across the seafloor including anchor lines and fishing 

gear. Growth rates for many of these invertebrate species are low, extending the time to recovery 

if these communities are damaged.

• Structure-forming Invertebrates in MBNMS (MBARI VARS database 2011). The 

locations where Monterey Bay Aquarium Research Institute (MBARI) scientists have 

observed structure-forming invertebrates associated with hard substrates are shown in

Figure 8. These observations of gorgonians, stony corals, black corals, hydrocorals, 

crinoids and sponges were made during ROV surveys in 1989-2009. Each data point 

represents a sighting regardless of the abundance of the organisms in the video frame. It is 

important to note that these organisms are likely to occur in portions of MBNMS that have 

not been sampled by MBARI.

• Structure-forming Invertebrates Observed in MBNMS Shelf Characterization 

Surveys (IfAME and MBNMS 2011). Video transects using a remotely operated vehicle 

(ROV) and a towed camera sled were made to characterize the distribution of fishes, 

invertebrates, and seafloor habitats on the continental shelf (50-200 m) and upper slope 

(200-400 m) at five locations in MBNMS: Ascension and Año Nuevo Canyons; North 

Monterey Bay; Carmel Bay and Point Lobos; Point Sur Shelf; and La Cruz Canyon and 

Point Piedras Blancas. Transects covered a varied of substrate types including rock ridges, 

bolder, and cobble. Structure-forming species commonly observed in this study include 

brachiopod beds, plumose anemones (Metridium farcimen), sponges, basket stars, crinoids, 

and gorgonians. Specific locations where structure-forming invertebrates were observed 

along the transects are available through the Shelf Characterization and Image Display 

website (http://sep.csumb.edu/ifame/scid).

• Structure-forming Invertebrates in Central California MLPA MPAs (Starr and 

Yoklavich 2008). A manned submersible was used to characterize the benthic habitat and 

associated invertebrates in the deep portion (24-365 m) of eight of the new central 

California Marine Life Protection Act marine protected areas and associated reference 

sites. Structure-forming species associated with hard bottom (e.g., corals, sponges, crinoids, 

gorgonians) were observed at all sites. See Table 9 for a summary of locations where 

structure-forming species were part of the dominant megafaunal invertebrate assemblage.

44 Slope – Hard
• Deep-sea Corals Collected in Bottom Trawls in MBNMS (Curt Whitmire, pers. 

comm.). The locations where deep-sea corals were collected incidentally in bottom trawl 

surveys by the National Marine Fisheries Service (1980-2010) are shown in Figure 9. 

Records represent the presence of a given taxonomic group in the area swept by trawl 

gear; exact location, species, and abundance information is not available. Corals from the 

following taxa likely were associated with hard substrate: Antipatharia (black corals), 

Alcyonacea (soft corals), Anthoathecata, Scleractinia (stony corals), and Gorgonacea 

(gorgonians). It is important to note that these trawl surveys were designed to monitor 

groundfish populations (not corals) and the surveys occurred mostly over low-relief, soft 

bottom. Trawl gear is not designed to sample the habitats in which many coral taxa 

reside, particularly those habitats characterized by rocky substrate and high relief.

• Deep-sea Coral Distribution (Etnoyer and Morgan 2003, Morgan et al. 2005). Records 

on 8 habitat forming deep-sea coral families from 10 different institutions were gathered 

to create a dataset of range and distribution of corals along the west coast of North

America. Habitat-forming deep-sea corals (octocorals, hexacorals, hydrocorals in the 

Phylum Cnidaria) were defined as those families with a majority of species exhibiting a 

complex branching morphology and sufficient size to provide substrate or refuge to 

associated species. The shelf break along the west coast and Monterey Canyon were

identified as areas of highest occurrence of deep-sea corals. Examples of species

associated with corals include: crabs and fishes (resting/refuge), fish egg cases 

(attachment substrate in well-aerated water column), and crinoids, basket stars, and 

anemones (suspension feeding).

• Deep-sea Coral Habitat Suitability (Guinotte and Davies 2012). The potential 

distribution of deep-sea corals was modeled for the U.S. West Coast Exclusive Economic 

Zone. Predicted habitat suitability in MBNMS is shown separately for 6 deep-sea coral 

taxa (Figure 10). Habitat suitability probabilities and areal extent of predicted habitat 

were highest in the sanctuary for Suborders Alcyoniina, Calcaxonia, Holaxonia, and 

Order Scleractinia. In contrast, suitability probabilities and areal extent were lower in 

these areas for Order Antipatharia (except at Davison Seamount) and Suborder 

Scleraxonia. The models used a variety of physical, chemical and environmental 

variables known or thought to influence the distribution of deep-sea corals. However, the 

model will likely overpredict the amount of suitable habitat in some areas (e.g., indicate 

suitable coral habitat in areas that are known soft bottom regions) because fine-scale 

bathymetric features (10’s of meters), substrate, and current data were not available for 

the entire study area.

• Megafaunal Invertebrates on Cordell Bank (Pirtle 2005). Megafaunal invertebrates 

and demersal fishes were surveyed at depths between 52 and 365 m at Cordell Bank in 

2002 using a submersible. Nineteen species of megafaunal invertebrates, such as sponges, 

gorgonian corals, crinoids, and large anemones, were identified as structure-forming 

based on large size, complex morphology, or the ability to form high density 

aggregations. Several species of fish were observed in close proximity to structureforming invertebrates. These associations appeared to be especially important in habitats 

lacking large structural relief or complexity, and were presumably important to smaller 

fishes in exposed habitats.

45 Slope – Hard
Energy Flow

Primary Production: The amount of sunlight needed to support primary production through 

photosynthesis only penetrates the top 30-50 m of the water column in MBNMS (Rigsby 1999a). 

Therefore, phytoplankton are a source of primary production in the surface waters over the slope, 

but photosynthesis cannot occur in the benthic habitats of the slope. In areas where there is 

seepage of sulfide- and methane-rich fluids, some organisms fix carbon through chemosynthesis. 

These areas, called “Cold Seeps” or “Chemosynthetic Biological Communities” (CBCs), are the 

only sources of primary production in the deep-sea habitats of MBNMS and act as oases in an 

otherwise low productivity area. See “Chemosynthetic Biological Communities” habitat 

summary for additional information.

Benthic-Pelagic Coupling: Deep-sea benthic processes are often tightly linked, or coupled, to 

particulate-organic flux from the pelagic realm. Coupling occurs because the deep sea is highly 

dependent on sinking food material (Glover and Smith 2003). The quality and quantity of 

sinking food materials varies spatially and temporally across the ocean surface on seasonal, 

interannual, and decadal time scales (Glover and Smith 2003). The buoyant eggs of demersal 

fishes and invertebrates provide one form of upward flux of particulate organic carbon (POC). 

Most of the research on measuring flux of organic matter to the benthos occurs in areas with soft 

bottom; see “Slope – Soft Bottom” and “Submarine Canyon” habitat summaries for specific 

information on these studies. See “Appendix III - Benthic-Pelagic Coupling” for more general 

information.

Productivity Hot Spots: Productive areas in slope habitats tend to be dynamic in space and time 

and, although they can last for decades, they are considered temporary and sometimes 

unpredictable.

• Steep Rocky Outcrops and Cold Seep Habitats. Drazen et al. (2003) observed some of 

the highest fish and octopus densities ever reported in the deep sea (Gorda Escarpment, N 

California; 1,300-3,000 m), with most individuals of both species observed brooding 

eggs. The blob sculpin (Psychrolutes phrictus) and octopus (Graneledone spp.) were 

concentrated at the crest of the local topography and near cold seeps where they may 

benefit from enhanced current flow and local productivity. The authors hypothesize that

local topography interacting with physical and geological settings create a localized 

reproductive hot spot in the deep sea used by at least two very different animals. These 

findings provide new information on the reproductive behaviors of deep-sea animals. 

More importantly, they highlight how physical and bathymetric heterogeneity in the 

environment can result in reproductive hot spots, which may provide a critical resource 

for reproductive success in some deep-sea species.

• Edges of the Oxygen Minimum Zone (Mullins et al. 1985, Thompson et al. 1985). Off 

central California, the edges of the OMZ may be sites of increased biological activity 

because of greater nutrient concentrations plus larger food supplies in the form of 

bacteria. See “Oxygen Minimum Zone” habitat summary for details and Figure 4 for the 

general location of the OMZ in central California.

46 Slope – Hard
• Whale Falls (Smith and Baco 2003, Lundsten et al. 2010). Dead whale carcasses that 

sink to the deep seafloor introduce a massive pulse of energy capable of hosting dynamic 

communities of organisms in an otherwise food-limited environment. Carcass 

degradation occurs sub-decadally.

HABITAT STRUCTURE

Species Composition: Invertebrates and fishes are the numerically dominant animal groups on 

the slope. Few species composition studies have been conducted in deep, rocky habitats. 

Invertebrates and fishes tend to be distributed by depth, substrate type, and degree of relief.

• Epifaunal Invertebrates in Northern Monterey Bay (CSLC & MBNMS 2005). 

Epifauna were surveyed on hard-bottom habitats 150-1,000 m deep in northern Monterey 

Bay. The species assemblages were characterized as follows: 

o Outer shelf/upper slope (150-300 m): erect sponges, anemones (e.g., Stomphia, 

Amphianthus, Metridium), decapods, brittlestars, and sea stars;

o Middle slope (300-1,000 m): the typical species assemblage has a greater 

diversity and size of sponges and echinoderms than that observed on the shelf;

o Many echinoderm genera (e.g., Florometra, Gorgonocephalus, 

Strongylocentrotus) were distributed over a broad depth range (100-500 m or 

more);

o High relief (>1m) rocky habitat: suspension feeding cnidarians (e.g., Allopora, 

cup corals, anemones, zoanthids), erect sponges, crinoids (e.g., Florometra), 

basket stars (e.g., Gorgonocephalus), and bryozoans;

o Low relief rocky habitat: species that can survive episodic sediment burial and 

high suspended particle loads in the water column. Species include anemones 

(e.g., Metridium), cup corals, and brittlestars.

• Deep-sea Corals (Etnoyer and Morgan 2003, 2005): Five families of habitat-forming 

deep-sea corals have been observed in MBNMS: Antipathidae, Paragorgiidae, 

Primnoidae, Stylasteridae, and Isididae.

• Megafaunal Invertebrates in the MBNMS (Graiff 2008). The abundance and 

distribution of megafaunal invertebrates on the upper slope was surveyed at two sites in 

the MBNMS using a manned submersible. See Table 8 for the relative abundance of 

megafaunal invertebrates at Portuguese Ledge (71-252 m) and Big Creek (19-249 m).

• Megafaunal Invertebrates and Fishes in central California MLPA MPAs (Starr and 

Yoklavich 2008). A manned submersible was used to characterize the benthic habitat and 

associated megafaunal invertebrate and fish assemblages in the deep portion (24-365 m) 

of eight of the new central California Marine Life Protect Act marine protected areas and 

associated reference sites. See Table 9 for a summary of the dominant megafaunal 

invertebrates and the relative abundance of common groups of demersal fishes at each 

site.

47 Slope – Hard
• Fishes over Hard Substrate (Love and Yoklavich 2006). In central and northern 

California the following species make up the typical adult fish assemblage over rocky 

substrate on the upper slope (201-500 m): aurora, bank, blackgill, bocaccio, chilipepper, 

cowcod, darkblotched, greenblotched, greenspotted, Pacific Ocean Perch, rosethorn, 

sharpchin, and splitnose rockfishes and lingcod.

• General Classification of California Marine Fishes (Allen and Pondella 2006). The 

authors used cluster analysis of species assemblages to determine which species occur 

together and in what habitat (by substrate type, depth, and latitude). The following 

species assemblages occur over hard bottom slope habitats in central California:

o Deep shelf, bank and slope (>200 m): spiny dogfish, Pacific hake, spotted 

ratfish, splitnose rockfish, Pacific hagfish, rex sole, longnose skate; 

o Deep bank and shelf (>200 m): sablefish, aurora rockfish, blackgill rockfish, 

brown cat shark, shortspine thornyhead, filetail catshark;

o Deep-water generalists: shortspine thornyhead, spotted ratfish, bank rockfish, 

shortspine combfish, Pacific hake, swordspine rockfish, greenstriped rockfish, 

greenblotched rockfish, stripetail rockfish, splitnose rockfish, bocaccio, lingcod. 

These generalists tended to be equally represented in deep-water habitats with 

both rocky and soft substrate.

• Rockfishes (Love et al. 2002). The typical rockfish assemblages along the coast of 

central and northern California were identified for five depth categories (Table 10). The 

species included occur over hard and soft bottom, but the majority of the species are 

primarily found over hard bottom. Fifteen rockfish species typically occur in slope 

habitats. Shelf I and Shelf II were the depth categories with the highest species richness -

23 and 22, respectively. 

• Seabirds and Marine Mammals (Research Planning Inc. 2006). Table 12 provides a list 

of the seabird and mammal species typically observed along the central California coast 

and their relative abundance and seasonality in eight pelagic zones off of central 

California (Figure 12). None of the seabird species dive deep enough to forage on benthic 

resources on the slope. However, deep diving mammals (e.g., sperm whales, northern 

elephant seal) can exceed depths of 1,000 m to forage on demersal fishes and 

invertebrates on the slope.

Species Composition Shifts: 

• Natural Changes: Significant natural changes in water temperature and current patterns, 

such as El Niño/La Niña events and the Pacific Decadal Oscillation, can cause shifts in 

species composition of the rocky slope. Food falls and periods of high productivity in 

surface waters deliver natural supplies of food to the slope, which in turn can rapidly 

change the species compositions at these depths.

o Whale Falls (Smith and Baco 2003, Lundsten et al. 2010). Falls of large whales are a 

sporadic source of large-volume labile organic matter to the deep seafloor. Whale 

carcasses in the deep ocean off California may pass through three to four overlapping 

successional stages. In Monterey Canyon, this successional process occurs rapidly; 

less than 10 years. The majority of species observed at Monterey Canyon whale falls 

48 Slope – Hard
are common deep-sea inhabitants of Monterey Canyon, nearby seamounts, and the 

continental slope. See “Slope – Soft Bottom” habitat summary for additional 

information.

• Human-induced Changes: Human activities, such as high levels of fishing, bottomtending fishing gears, and deposition of marine debris, can influence species composition 

on in slope habitats.

o Fishing Impacts on Fishes. Intense recreational and commercial fishing can lead to

changes in fish assemblages. Levin et al. (2006) found that the fish assemblage on the 

shelf and upper slope has changed from rockfish dominated in 1977 to flatfish 

dominated in 2001.

o Marine Debris (Watters et al. 2010). Video surveys in central California found that 

demersal marine debris altered seafloor habitat and species assemblages by providing 

artificial habitat to demersal organisms. In surveys during the 1990s, 13% of debris 

items had fishes associated with them, and 38% were associated with large, structureforming invertebrates. In 2007, less than 10% of debris items had fishes associated 

with them, and 30% were associated with large, structure-forming invertebrates. The 

majority of debris (e.g., 99% of 815 items surveyed in 2007) was colonized 

moderately to heavily by encrusting invertebrates. Fishes associated with debris that 

could provide structure and cover; they did not associate with monofilament line. 

Debris occurred disproportionately in rock compared to soft sediment habitats.

o Structure-forming Invertebrates: Structure-forming invertebrates are very 

susceptible to damage from gear contacting the seafloor including anchors, chains, 

nets, pots/traps, trawls and other types of fishing gear (NRC 2002, Chuenpagdee et al. 

2003). Due to low growth rates for some structure-forming species (e.g., corals, 

sponges), these communities can take decades to recover if damaged.

Species Diversity and Species Richness: Species diversity in the deep sea is greater than once 

thought. Small patches (mm to m) of biogenic disturbance and food input, separated on spatial 

scales of meters to km, are important in maintaining high diversity in deep-sea communities. 

Low productivity, reduced broad-scale disturbance, and the large surface area of the deep sea are 

relevant to the maintenance of diversity. Because of the large surface area and the many 

undescribed species, diversity in the deep sea may rival that found in tropical rain forests 

(reviewed in Grassle 1989). High diversity makes this habitat sensitive to human impacts 

(reviewed in Glover and Smith 2003).

Species diversity of macro- and megafauna in the deep sea follows a parabolic pattern along 

depth gradients, increasing with depth below the continental shelf to a maximum at mid to lower 

bathyal regions and then decreasing with increasing distance seaward on the abyssal plain (Rex 

1981). The level of diversity in the deep sea may be related to productivity, competition, and 

predation, and the relative importance of these factors varies with depth. 

• Demersal Fishes off Central California (NCCOS 2003). Rockfish species richness 

tended to be highest along the edge of the continental shelf (Figure 15). Areas with high 

species richness (for all demersal fish species) tended to be in water less than 200 m 

(Figure 16). Areas with high species diversity (for all demersal fish species) tended to be 

on the slope in waters deeper than 300 m (Figure 17).

49 Slope – Hard
• Whale Falls. Local species diversity (mean of 185 macrofaunal species) on large whale 

skeletons during the sulphophilic stage is higher than in any other deep-sea hard 

substratum community (Smith and Baco 2003). Global species richness on whale falls 

(407 species) is also high compared with cold seeps and rivals that of hydrothermal vents 

(469 species worldwide). The majority of species at Monterey Canyon whale fall 

communities are common deep-sea inhabitants of Monterey Canyon, nearby seamounts, 

and the continental slope (Lundsten et al. 2010). Upon initial arrival, whale carcasses 

host a relatively low-diversity community of mobile scavengers. Through time, diversity 

increases; however, most of the increases in species richness come from background taxa 

that exploit abundant nutrients provided by the carcass.

Biomass: Productivity, biomass, and physical energy in the deep sea (>1,000 m) are relatively 

low, increasing the potential sensitivity to human impacts (Glover and Smith 2003). 

Unfortunately, we know of no slope station off California where the biomass distribution of the 

total benthic community (megafauna, macrofauna, and meiofauna) has been measured (Smith 

and Demopoulos 2003). Very little is known about the biomass on hard bottom slope habitats.

• Longspine Thornyhead off Central California (Wakefield unpubl. data, Wakefield and 

Smith 1990). Sebastolobus altivelis (longspine thornyhead) represents 25% of the slopewide standing stock (biomass) of all demersal fishes (Monterey to Point Sur, 400-1,600 

m).

• Harvested Species: Recreational and commercial harvest removes biomass of targeted fish 

and invertebrate populations. For some targeted species, biomass is substantially reduced 

compared to unfished biomass levels (Tables 3 and 4). Though extraction is the primary 

reason for a reduction in biomass for many species, changing oceanographic and ecological 

conditions is an important contributing factor for some harvested species. For the majority 

of the 10 invertebrate and 156 fish stocks landed in MBNMS, the status of the stock has not 

been assessed (Tables 3 and 4).

Key Species Interactions: Predation is a species interaction for which we have some information 

specific to the slope habitat. Much is yet to be learned in deep-water habitats.

• Predation (Drazen et al. 2001). Macrourid fishes are among the dominant fishes in the 

deep sea. Many species are large and, in combination with their abundance, are 

potentially important apex predators in the deep-sea environment. Apex predators play a 

vital role in many communities by controlling prey populations, exerting selective 

pressure, and influencing general community dynamics. The two dominant slope 

dwelling macrourids (Coryphaenoides acrolepis, Albatrossia pectoralis) are at the top of 

the food web on the upper continental slope, and because of their abundance, may exert 

significant pressure on their prey populations.

• Competition and Predation. The intensity of competition varies inversely to predation 

pressure in the deep sea (reviewed by Rex 1981). Predation becomes less important as a 

structuring agent on the upper reaches of the slope. Competition among benthic infauna 

increases with depth on the slope.

50 Slope – Hard
MOVEMENT AND DISPERSAL

Many fishes exhibit some degree of ontogenetic shift in space utilization as they mature and the 

degree of movement or area used by adults may vary depending on species and location. This is 

particularly true of demersal species of fishes, such as flatfishes, some rockfishes, and wrasses 

(Lowe and Bray 2006). Most movement studies have been done on shallower water species. 

Ontogenetic migration (movement to deep water as fish grow and age) occurs in sablefish, Dover 

sole, shortspine thornyhead, and weakly in longspine thornyhead (see also Hunter et al. 1990; 

Jacobson and Vetter 1996). See “Movement and Dispersal” in the soft bottom slope section for 

more specific information.

SPECIES OF SPECIAL INTEREST

Many species of special resource management interest are found in the hard-bottom slope habitat

of MBNMS Tables 3-7.

• Species Landed in MBNMS: Of the 10 invertebrate and 156 fish species that are 

commonly caught and sold in the commercial and/or recreational fisheries of MBNMS 

(Starr et al. 2002a), 2 invertebrates and 46 fishes are associated with hard-bottom, slope 

habitats.

• Endangered and Threatened Species: None of invertebrate species in the offshore

habitats of MBNMS are listed as endangered or threatened. None of the 6 endangered or 

threatened fish species in MBNMS are associated with hard-bottom, slope habitat. Of the 

3 listed seabirds and 10 listed marine mammals, Steller sea lions and sperm whales are 

the only species that have the potential to interact strongly with benthic resources on the 

slope.

• Other At-Risk Species: None of invertebrate species in the offshore habitats of MBNMS

are considered to be at-risk. Of the 10 known fishes at-risk, 5 are associated with hardbottom, slope habitat. Of the 11 at-risk seabirds and 9 at-risk marine mammals, Steller 

sea lions and sperm whales are the only species that have the potential to interact strongly 

with benthic resources on the slope.

Additional species of special resource management interest associated with the hard-bottom slope 

habitat are:

• Structure-forming invertebrates, such as corals and sponges, due to their important 

ecological role in creating habitat structure and their vulnerability to disturbance from 

human activities.

51 Slope – Hard
Slope (200-3,000 m) – Soft Substrate

HABITAT OVERVIEW

The seafloor between the continental shelf break (~200 m) and 3,000 m is considered the slope 

habitat. A large portion (94.5%) of the slope in MBNMS is composed of soft bottom habitats 

(Figure 1). Within the federal study area, soft bottom slope habitats comprise approximately 7,598

km2, which is 69.1% of the study area (Table 2).

North of Point Conception, the slope descends gently from the shelf to a depth of 600 m, forming a 

plateau (Neighbors and Wilson 2006). The predominant habitat of the upper slope consists of 

sandy and muddy sediments (Allen 2006). The soft bottom habitat is relatively flat, although there 

is some micro-relief resulting from water movement (waves, currents) or biological activity (e.g. 

excavations, burrows, protruding tubes; Allen 2006). The lack of hard substrate for attachment 

prevents some invertebrates from colonizing soft bottom habitats. In areas with soft bottom, 

animals live either on the surface or buried in the sediments. Animals may build somewhat 

permanent tubes and burrows.

The seafloor between approximately 600-1,000 m intersects a portion of the water column where 

the oxygen concentration is below 0.5 ml/l. The distribution and abundance of benthic fauna are 

influenced by dissolved oxygen levels, which fluctuate throughout this oxygen minimum zone (see 

“Oxygen Minimum Zone” habitat section for more information).

SEARCH TOPIC TABLE

HABITAT FUNCTION

Functional Habitats:

Nursery Habitat:

No information was found indicating that slope habitats off 

California serve as nursery areas. One study (Pearcy et al. 1977) 

suggested that Dover and rex sole may use the upper slope 

region (off Oregon) as a nursery area during early benthic life.

Feeding Ground: See page 53

Spawning Ground: See page 53

Migratory Corridor:

See “Movement and Dispersal” section below for information 

on species that move to the soft bottom slope during 

ontogenetic migrations.

Biogenic Habitat: See page 54

Energy Flow:

Primary Production: See page 55

Benthic-Pelagic Coupling: See page 55

Key Trophic Interactions: See page 57

Key Trophic Cascades: No specific information was found on this topic.

52 Slope – Soft
Productivity Hotspots: See page 57

HABITAT STRUCTURE

Species Composition: See page 57

Species Composition Shifts: See page 63

Species Diversity and Richness: See page 66

Biomass: See page 67

Key Species Interactions See page 69

MOVEMENT AND DISPERSAL See page 70

SPECIES OF SPECIAL INTEREST See page 71

HABITAT SUMMARY

HABITAT FUNCTION

Functional Habitats

Feeding Ground: The slope habitat off Point Sur is an important feeding ground for a diverse 

group of demersal fishes (Wakefield 1990). Whale falls provide significant sources of organic 

material for mobile scavengers in deep-sea habitats. These falls, however, are unpredictable in 

space and time.

• Whale Falls (Smith et al. 1989; Goffredi et al. 2004; Lundsten et al. 2010). It is estimated 

that hundreds of gray whales sink to the seafloor annually within a 8x105 km2 area of the 

North Pacific (along the migration route). This estimate suggests that large animal falls are 

a significant source of organic enrichment to deep-sea habitats and act as important feeding 

grounds for mobile scavengers. Carcass degradation at Monterey Canyon occurs subdecadally. 

Spawning Ground: The soft slope between 300-1,200 m has been identified as an important 

spawning area for a variety of groundfish species.

• Groundfish (Wakefield 1990). The slope off Point Sur (600-1,200 m) was identified as an 

important feeding and spawning ground for a diverse group of fishes, many of which utilize 

shallower nursery grounds on the shelf.

• Longspine Thornyhead (Wakefield 1990; Wakefield unpubl. data). Off Point Sur, 93% of 

the longspine thornyhead spawning stock inhabit 500-1,100 m.

• Thornyheads (Jacobson and Vetter 1996). Peak spawning biomass for both thornyhead 

species off Oregon and central California (Point Sur to Point Conception) occurs between 

600-1,000 m. Small shortspine thornyheads are found on the shallow slope (200-600 m), 

but migrated to deeper water with growth. Longspine thornyhead of all size classes were 

found between 600-1,400 m.

53 Slope – Soft
• Dover Sole (Hunter et al. 1990). Ninety-eight percent of the spawning biomass of Dover 

sole (Microstomus pacificus) in central California waters live on the soft-bottom slope 

between 640-1,005 m. Dover sole spawn at these depths and the eggs rise to the surface 

layers.

• Petrale Sole (Airamé et al. 2003). Spawning aggregations of petrale sole occur at depths of 

300-400 m off Cape Mendocino, Point Delgado, Point Montara, and Point Sal.

• Giant Grenadier (Novikov 1970). Male and female giant grenadier (Albatrossia 

pectoralis) live separately (females prefer ~300-700 m; and males prefer >~700 m). This 

separation is rarely disturbed. During spawning, females migrate to deeper depths (depths 

may be specific to the North Pacific). The spawning period for giant grenadier is prolonged 

and not confined to definite dates.

Biogenic Habitat: Though structure-forming invertebrates tend to be more abundant on hard 

substrate, some species (such as sea pens, sea whips, and brittle stars) are found primarily in soft 

sediments. In general, these invertebrates provide some of the only emergent structural relief to the 

surface of soft-bottom habitats, especially when they aggregate in high numbers. Aggregations 

may provide significant structural relief for fishes in mud- and sand-dominated habitats (Tissot et 

al. 2006). Structure-forming invertebrates are susceptible to damage from physical structures 

dragged across the seafloor including anchor lines and fishing gear. Growth rates for many of these 

invertebrate species are low, extending the time to recovery if these communities are damaged.

• Sea Pen Observations in MBNMS (MBARI VARS database 2011). The locations where 

Monterey Bay Aquarium Research Institute (MBARI) scientists have observed sea pens

(Order Pennatulacea) are shown in Figure 13. These observations were made during ROV 

surveys 1989-2009. Each data point represents a sighting regardless of the abundance of 

the organisms in the video frame. Sea pens can be fairly abundant on the seabed, so the 

map generally reflects where sampling has occurred. It is important to note that these 

organisms are likely to occur in portions of MBNMS that have not been sampled by

MBARI.

• Deep-sea Corals Collected in Bottom Trawls in MBNMS (Curt Whitmire, pers. comm.). 

The locations where deep-sea corals were collected incidentally in bottom trawl surveys by 

the National Marine Fisheries Service (1980-2010) are shown in Figure 9. Records 

represent the presence of a given taxonomic group in the area swept by trawl gear; exact 

location, species, and abundance information is not available. Of the 6 coral taxa collected, 

sea pens (Order Pennatulacea) are the only taxa associated with soft sediments. Sea pens 

were the most frequently collected taxa, which is likely due to the fact that the trawl 

surveys were targeting groundfish in low-relief, soft bottom habitats.

• Structure-forming Invertebrates Observed in MBNMS Shelf Characterization 

Surveys (IfAME and MBNMS 2011). Video transects using a remotely operated vehicle 

(ROV) and a towed camera sled were made to characterize the distribution of fishes, 

invertebrates, and seafloor habitats on the continental shelf (50-200 m) and upper slope 

(200-400 m) at five locations in MBNMS: Ascension and Año Nuevo Canyons; North 

Monterey Bay; Carmel Bay and Point Lobos; Point Sur Shelf; and La Cruz Canyon and 

Point Piedras Blancas. Transects covered a varied of substrate types including mud and 

sand. Structure-forming invertebrates commonly observed in soft-bottom habitat include 

54 Slope – Soft
sea pens, sea whips, and brittle starts. Specific locations where structure-forming 

invertebrates were observed along the transects are available through the Shelf 

Characterization and Image Display website (http://sep.csumb.edu/ifame/scid).

• Structure-forming Invertebrates in Central California MLPA MPAs (Starr and 

Yoklavich 2008). A manned submersible was used to characterize the benthic habitat and 

associated invertebrates in the deep portion (24-365 m) of eight of the new central 

California Marine Life Protection Act marine protected areas and associated reference 

sites. Structure-forming species associated with soft bottom (e.g., sea pens, sea whips, 

brittle stars) were observed at most sites. See Table 9 for a summary of locations where 

structure-forming species were part of the dominant megafaunal invertebrate assemblage.

• Chemosynthetic Biological Communities (CBCs): Structure-forming invertebrates found 

at CBCs are used by other sessile organisms as hard substrate for attachment, and by 

mobile organisms for shelter and food. CBCs in Monterey Bay have been found most 

frequently on steep slopes at depths exceeding 550 m (Figure 6). More detailed information 

can be found in the “Chemosynthetic Biological Communities” habitat section.

Energy Flow

Primary Production: The amount of sunlight needed to support primary production through 

photosynthesis only penetrates the top 30-50 m of the water column in MBNMS (Rigsby 1999a). 

Therefore, phytoplankton are a source of primary production in the surface waters over the slope, 

but photosynthesis cannot occur in the benthic habitats of the slope. In areas where there is seepage 

of sulfide- and methane-rich fluids, some organisms fix carbon through chemosynthesis. These 

areas, called “Cold Seeps” or “Chemosynthetic Biological Communities” (CBCs), are the only 

sources of primary production in the deep-sea habitats of MBNMS and act as oases in an otherwise 

low productivity area. See the “Chemosynthetic Biological Communities” habitat section for more 

information.

Benthic-Pelagic Coupling: Deep-sea benthic processes are often tightly linked, or coupled, to 

particulate-organic flux from the pelagic realm. Coupling occurs because the deep sea is highly 

dependent on sinking food material (Glover and Smith 2003). The quality and quantity of sinking 

food materials varies spatially and temporally across the ocean surface on seasonal, interannual, 

and decadal time scales (Glover and Smith 2003). The buoyant eggs of demersal fishes and 

invertebrates provide one form of upward flux of particulate organic carbon (POC).

• Sources of Downward Flux:

o Marine Snow (Rigsby 1999b). Food flows to the deep sea in the form of sinking 

remains and waste from organisms at the sea surface and in the water column. The 

amount and type of snow varies with the seasons. Peaks of marine snow follow 

upwelling productivity in spring and summer; during mass molts of krill; and 

following nightly surface feeding of vertical migrators (in the form of fecal pellets). 

For addition information, see “Submarine Canyon” habitat summary.

o Particulate Organic Carbon (POC) (Smith and Demopoulos 2003). Upwelling off 

California causes high flux of particulate organic carbon (POC) to the slope (~10 g 

C/m2

/yr); shelf and slope waters beneath these upwelling zones frequently are 

depleted of oxygen as a result of high rates of degradation of POC, and the underlying 

sediments typically are organic rich. Beneath coastal upwelling sites and within the 

55 Slope – Soft
OMZ, such sediments may contain 2-18% organic carbon by weight (much higher 

than continental margins; 1-2%). The primary source of organic matter for California 

slope assemblages include 1) very small sinking particles, 2) phytodetrital aggregates, 

3) sinking carcasses of nekton, and 4) sinking parcels of macroalgae such as kelp). 

Flux of POC appears to play a dominant role in controlling regional variations in 

biotic structure, much as temperature and rainfall control ecosystem structure in 

terrestrial habitats.

o Sinking Larvacean Houses: The abandoned mucous houses of the giant larvacean 

Bathychordaeus are a significant source of rapid carbon transport through the water 

column to the deep seafloor. Robison et al. (2005) estimated the production rate of 1 

sinking Bathychordaeus house per day in Monterey Bay to be approximately 5.4 mg 

of total organic carbon. This number is an underestimate of total flux of giant

larvacean houses because there are at least two other species found in Monterey Bay. 

See “Submarine Canyon” habitat summary for additional information.

o Macrophyte Detritus (Harrold et al. 1998). Macrophyte detritus sinking to the 

benthos is a source of nutrition for benthic organisms living on the slope. See 

“Macrophyte Detritus” habitat summary for more information.

o Whale Falls (Lundsten et al. 2010). Dead whale carcasses that sink to the deep 

seafloor introduce a massive pulse of energy capable of hosting dynamic 

communities of organisms in an otherwise food-limited environment. Carcass 

degradation occurs sub-decadally. The majority of species in these communities are 

background deep-sea taxa.

o Downward Transport of Domoic Acid (Sekula-Wood et al. 2009). The 

concentration of domoic acid (DA) in surface waters and sediment traps - between 

550 and 800 m in depth - were measured off the coast of southern California to study 

vertical fluxes of DA. This study detected rapid vertical transport of DA-containing 

Pseudo-nitzschia cells to sediments on the soft bottom slope. DA-containing particles 

appear to persist in the sediments and are available for consumption by bottom 

feeders and incorporation into benthic food webs.

o Vertical Ontogenetic Migration (VOM) by Longspine Thornyhead (Wakefield 

and Smith 1990). Longspine thornyheads inhabiting the continental slope off central 

California (Monterey to Point Sur) were studied as a mechanism for coupling 

transport of particulate matter between surface waters and the bathyal seafloor (400-

1,600 m). At bathyal depths it is unlikely that VOM contributes >1% to the POC flux 

reaching the deep seafloor.

• Sources of Upward Flux: The vast majority of marine organisms (including infaunal and 

epifaunal invertebrates and demersal fish) release eggs and/or larvae that are pelagic.

o Longspine Thornyhead Eggs (Wakefield and Smith 1990). The upward flux of POC 

as buoyant eggs of demersal fishes (e.g., thornyheads) could represent a significant 

portion of the total upward flux.

• Diel Vertical Migration (reviewed in Raffaellia et al. 2003). Animals that undertake a diel 

vertical migration feed in surface waters at night and then carry the food (in their guts) 

down to depths, usually exceeding 200 m, during the day. These organisms greatly increase 

56 Slope – Soft
the food supply in mid- and deep-waters. Also, fecal pellets that are voided at depth during 

the day greatly increase the flux of carbon from the surface to the seafloor. In the Pacific, 

some 43% of the individuals and 47% of the biomass migrate from below 400 m by day to 

above this depth at night. It has been estimated that there may be a vertical translocation of 

almost 109 tons/day throughout the world’s oceans. 

Key Trophic Interactions: Many of the invertebrates living on the soft bottom slope are either 

detritivores or planktivores. These organisms play an important role in the slope food web by 

converting phytoplankton, sinking organic matter and nutrients into slope-associated biomass.

Brittle stars act as major links in local food chains.

• Detritivores (Hyland 1991). The macroinfaunal communities of the continental shelf and 

slope in Santa Maria Basin were studied for 2.5 years. The majority of the species found in 

this study were deposit feeders and relied on ingestion and absorption of organic matter in 

the sediments for nourishment.

• Brittle Stars Impact Community Energetics (Summers and Nybakken 2000). Because of 

their abundance, feeding behavior, and high activity levels, ophiuroids (brittle stars) are 

thought to significantly impact energetics and ecology of bathyal soft-bottom communities 

through the utilization, processing, and redistribution of organic matter at the seafloor. 

Brittle stars increase bioturbation rates and act as major links in local food chains. 

Compared to sites on the Farallon slope (1,010 - 3,085 m) and Pioneer Canyon (3,090 –

3,300 m), Monterey Canyon sites (2,300 - 3,300 m) had the highest mean abundance of 

ophiuroids.

Productivity Hotspots: Productive areas in slope habitats tend to be dynamic in space and time

and, although they can last for decades, they are considered temporary and sometimes 

unpredictable.

• Whale Falls (Lundsten et al. 2010). Dead whale carcasses that sink to the deep seafloor 

introduce a massive pulse of energy capable of hosting dynamic communities of organisms 

in an otherwise food-limited environment. Carcass degradation at Monterey Canyon occurs 

sub-decadally.

• Chemosynthetic Biological Communities are productivity hotspots in slope, rise, and 

canyon habitats (Paull et al. 2005a). See “’Chemosynthetic Biological Communities” 

habitat summary for details and Figure 6 for locations where CBCs have been observed in 

the Monterey Bay area.

• Edges of the Oxygen Minimum Zone (Mullins et al. 1985, Thompson et al. 1985). Off 

central California, the edges of the OMZ may be sites of increased biological activity 

because of greater nutrient concentrations plus larger food supplies in the form of bacteria.

See “Oxygen Minimum Zone” habitat summary for details and Figure 4 for the general 

location of the OMZ in central California.

HABITAT STRUCTURE

Species Composition: Invertebrates and fishes are the numerically dominant animal groups on the 

slope. Species distributions appear to be influenced by many factors including depth, sediment 

57 Slope – Soft
composition, and dissolved oxygen levels. The unique faunal assemblage found in Chemosynthetic 

Biological Communities is described in the CBC habitat summary.

• Infauna in Northern Monterey Bay (CSLC & MBNMS 2005). More than 1,000 infaunal 

species inhabit soft-substrate shelf and slope areas off central California. Infauna were 

sampled at multiple stations between 325 and 885 m in northern Monterey Bay. Polychaete 

worms showed the highest abundance and species richness at most depths. Gammarid 

amphipods were relatively abundant at all stations and were the most abundant taxa at 640, 

770, and 795 m. Oligochaete worms were the most abundant taxa at 885 m. Some of the 

most abundant taxa by depth were:

 325 m: polychaete worms (Sphaerosyllis ranunculus), ostracods, caprellid 

amphipods;

 450 m: polychaete worms (Onuphidae spp., Protodorvillea gracilis, and S. 

ranunculus), brittlestars;

 640 m: gammarid amphipods (Ampelisca unsocalae, Lepidepecreum serraculum, 

and Tiron biocellata), bivalves;

 770 m: gammarid amphipods (Ampelisca unsocalae, Photis typhlops, and Byblis 

barbarensi);

 795 m: gammarid amphipods (Lepidepecreum serraculum and Ampelisca 

unsocalae);

 885 m: Oligochaete worms, polychaete worms (Cossura pygodactylata).

• Infauna near Davenport (John Oliver, MLML, unpubl. data). In northern Monterey Bay 

and off Davenport, sediment cores along transects have shown distinct infaunal species 

assemblages that vary by depth: 

o Upper Slope Group (325-450 m): Chloeia pinnata, Onuphidae spp., Oligochaetes, 

Tellina carpenteri, Decamastus gracilis, Cirratulidae spp., Euclymeninae spp., 

Mediomastus spp., Huxleyia munita, Polycirrus spp.;

o Oxygen Minimum Zone Group (700 m): Byblis barbarensis, Ampelisca unsocalae, 

Myriochele gracilis, Gammaropsis ocellata, Phyllochaetopterus limicolus, 

Lepidepecreum kasatka, Photis typhlops, Scoloura phillipsi, Nemertea, 

Harpiniopsis epistomata;

o Deep-sea Zone Group (1,000-2,000 m): Aricidea (Acmira) simplex, Cirratulidae 

spp., Ampharetidae spp., Euclymeninae spp., Nephtys cornuta, Lumbrineridae spp., 

Actiniaria, Aricidea spp., Cossura candida, Neomediomastus glabrus.

• Epifaunal Invertebrates in Northern Monterey Bay (CSLC & MBNMS 2005). More 

than several hundred epifaunal species inhabit soft-substrate shelf and slope areas off 

central California. Epifauna were surveyed from 200 to 885 m in northern Monterey Bay. 

Sea pens, anemones, crabs and sea stars were common at most stations. The species 

assemblages were characterized as follows: 

o 280-449 m (adjacent to hard substrate): sea urchin (Strongylocentrotus fragilis), sea 

cucumber (Parastichopus leukothele), sea star (R. californicus);

o 450-599 m: dominated by sea pen (Halipteris californica), also gastropods, 

cerianthaid anemones, and anemone (Liponema brevicornis);

58 Slope – Soft
o > 600 m: dominated by sea pens (H. californica and Umbellula magniflora), also 

Tanner crab (Chionoecetes tanneri), gastropods, mesomyarian anemones, 

cerianthaid anemones, and sea cucumber (Pannychia moseleyi).

• Epifauna and Infauna west of Pillar Point (Kogan et al. 2006). Quantitative comparisons 

of biological communities between cable (ATOC) and control sites were made in soft 

bottom habitats from 43-1,940 m. Differences in abundance between cable and control sites

were minor. General changes in the benthos across the central California continental 

margin were documented. 

o Epifauna: Slope sites characterized by large numbers of Actiniaria (anemones), 

especially on hard substrate (cable);

o Infauna: Primary taxonomic groups at slope sites were polychaetes, crustaceans, 

and mollusks (Figure 14 illustrates the taxonomic diversity and abundance of 

infauna).

• Benthic Invertebrates 300-1,400 m (Thompson et al. 1985). The distribution of both 

infaunal and epifaunal invertebrates off central California (Point Lobos to Point Sur) was 

examined. A distinct depth zonation in relation to dissolved oxygen levels was observed. 

See “Oxygen Minimum Zone” habitat summary for more information.

• Megafaunal Invertebrates in the MBNMS (Graiff 2008). The abundance and distribution 

of megafaunal invertebrates on the upper slope was surveyed at two sites in the MBNMS 

using a manned submersible. See Table 8 for the relative abundance of megafaunal 

invertebrates at Portuguese Ledge (71-252 m) and Big Creek (19-249 m).

• Benthic Megafauna west of the Farallones (Nybakken 1996, Nybakken et al. 1998). 

Benthic megafaunal invertebrates were sampled on the soft bottom slope (2,300-3,075 m) 

west of the Farallones and in Pioneer Canyon (Monterey Canyon was not adequately 

sampled). The benthic invertebrate megafauna were dominated by echinoderms (mostly 

burrowers) with holothurians (cucumbers), ophiuroids (brittle stars), and asteroids (sea 

stars) in the upper three ranks. Distribution of megafaunal organisms is highly patchy, 

especially among surface-dwelling forms. Quantitative analysis of differences between 

sites and between survey years indicated that the megafaunal associations at the same depth 

in MBNMS are really quite different at different sites. Results also suggest that there are 

strong seasonal and yearly differences within the same site.

• Megafaunal Invertebrates and Fishes in central California MLPA MPAs (Starr and 

Yoklavich 2008). A manned submersible was used to characterize the benthic habitat and 

associated megafaunal invertebrate and fish assemblages in the deep portion (24-365 m) of 

eight of the new central California Marine Life Protect Act marine protected areas and 

associated reference sites. See Table 9 for a summary of the dominant megafaunal 

invertebrates and the relative abundance of common groups of demersal fishes at each site.

• Invertebrates and Fishes in Abyssal Habitats (Barry et al. 2004). The typical megafaunal 

assemblage of abyssal deep-sea communities in the eastern Pacific includes moderate 

densities of macrourid (Coryphaenoides armatus) and zoarcid fishes (Pachychara sp.), 

octopus (Benthoctopus sp.), holothurians (Peniogone spp., Staurocucumis abyssorum, 

Scotoplanes globosa), echinoids (Cystechinus loveni, Aporocidaris milleri), gastropod 

mollusks (Mohina vernalis), ophiuroids (brittle stars), and a variety of less abundant 

59 Slope – Soft
species. The infaunal macrofauna assemblage is dominated by tube-dwelling ampeliscid 

amphipods (Haploops lodo), but also includes numerous other crustaceans, polychaetes, 

mollusks, and cnidarians. Sediment-dwelling meiofauna are abundant, and are dominated 

by nematodes, flagellates, and amoebae, with lesser densities of ciliates, foraminifera, and 

other groups.

• Benthic Fishes and Megafaunal Invertebrates West of Half Moon Bay (SAIC and 

MLML 1992). Results of cluster analysis based on density and histogram summaries based 

on species numbers, density, and biomass, indicated that benthic fish and megafaunal 

invertebrate communities are distributed primarily by depth, and are independent of study 

area boundaries. Three communities on the slope were determined:

o Upper Slope (200-500 m): Fish were common and included Dover sole, rex sole, 

rockfishes and thornyheads. Megafauna abundances were moderate and included 

sea stars, brittlestars, and sea cucumbers;

o Mid-Slope (500-1,200 m): Fishes were common and included thornyheads, Dover 

sole, rattails, and finescale codling. Megafaunal abundance was high and included 

Tanner crabs, sea stars, brittlestars, snails, and sea cucumbers;

o Lower Slope (1,200- >1,800 m): Lower slope fishes were sparse and included 

rattails, finescale codling, and eelpouts. Megafauna were also sparse and included 

sea cucumbers, brittlestars, sea stars, and cnidarians.

• Fishes in Northern Monterey Bay (CSLC & MBNMS 2005). Less than 100 fish species 

were observed on soft substrate in the upper and middle slope areas (200-1,000 m) off 

central California. These include: Dover sole, California halibut, rockfishes (Sebastes spp.), 

Pacific hake, sablefish, and skates.

• Fish-Habitat Associations at Cordell Bank (Anderson et al. 2009). Habitat type and the 

associated fish fauna were surveyed between 52-365 m depth using a manned submersible. 

Five broad-scale habitat zones were characterized by distinct fish faunas, with depth and 

habitat composition strong predictors of fish assemblage. The continental slope habitat 

zone (deep mud, 107–298 m) was characterized by flatfishes, poachers, spotted ratfish, 

hagfishes, longspined combfish, and a few Sebastes species (stripetail, splitnose, and 

sharpchin rockfishes). The total number of species recorded per habitat zone was highest 

on the slope due to the occurrences of rare species.

• Demersal Fishes West of the Farallones (Cailliet et al. 1992, 1999). The deep-sea 

demersal fish fauna on the soft bottom slope (2,000-3,300 m) west of the Farallones 

appeared similar in species composition to the fauna of the eastern Pacific and other deepwater sites around the world. The fish fauna was dominated by families Macrouridae, 

Zoarcidae, Moridae, and Rajidae and included the following species: skate (Bathyraja 

trachura), spiny eel (Notacanthus chemnitzii), lizardfish (Bathysaurus mollis), snailfishes 

(Paraliparis spp., Paraliparis rosaceus, Careproctus melanurus, Careproctus ovigerum), 

cuskeel (Spectrunculus grandis), codling (Antimora microlepis), grenadier 

(Coryphaenoides acrolepis, C. armatus, C. filifer, C. leptolepis), eelpouts (Lycenchelys

spp., Pachycara lepinium, Bothrocara spp.).

• Rockfishes, Williams and Ralston (2002) examined rockfish assemblages from southern 

Oregon to Point Conception using data from NMFS shelf and slope trawls over primarily 

60 Slope – Soft
soft bottom. Rockfish richness was highest at a depth of 200-250 m, where the shelf and 

slope meet. Depth and latitude were the main determinants of rockfish assemblages. There 

were four suggested species assemblages based on distribution, ordination, and partitioning 

analyses and three of these included slope habitat:

o Nearshore (50-150 m): copper, vermilion, brown, and halfbanded rockfishes;

o Southern shelf (100-250 m; 34°N to the Mendocino Escarpment): bocaccio, 

chilipepper, cowcod, greenspotted, greenstriped, shortbelly, and stripetail 

rockfishes;

o Northern shelf (150-250 m; 43°N to Monterey Canyon): canary, redstripe, 

rosethorn, sharpchin, widow, yelloweye, and yellowtail rockfishes.

o Deepwater slope (200-500 m): aurora, bank, blackgill, darkblotched, Pacific Ocean 

perch, redbanded, shortspine, and splitnose rockfishes.

NOTE: there was overlap in species assemblages between the Monterey Canyon and 

Mendocino Escarpment.

• Flatfishes on Smooth Ridge (Vetter et al. 1994). Flatfishes undergo species replacements 

with increasing depth along a transect from 100 m on the shelf down to a depth of 1,400 m 

on the slope. Flatfish diversity was greatest on the outer shelf with 12 species at 100-200 

m. After the shelf-slope transition, flatfish diversity decreased rapidly to ~3 species. At 600 

m, Dover sole was the only flatfish. Dover sole and deep-sea sole co-occurred at 800-1,200 

m with both species common at the 1,000 m site.

• Demersal Fishes off Point Sur (Wakefield 1990). A study of the fish fauna for seven 200-

m depth intervals from 400 to 1,600 m at Point Sur found that the upper slope habitat 

between 600 and 1,200 m contains a diverse array of fishes. Faunal break at 400-600 m, 

corresponds to a transition between shelf- and slope-dwelling species. The depth 

distribution of the adult population of a number of fishes (e.g., thornyheads, Dover sole, 

and sablefish) is centered within the OMZ. See “Oxygen Minimum Zone” habitat summary 

for more information.

• Fishes on the California Slope (Allen 2006, Neighbors and Wilson 2006). Common 

species of the upper, middle, and lower slope were identified (Table 13).

• Groundfish Assemblages off U.S. West Coast Slope (Tolimieri and Levin 2006). Data 

from trawl surveys along the U.S. west coast at 100 m intervals between 200-1,200 m 

revealed a strong shift in fish assemblage structure at approximately 500-600 m and a 

second, more minor shift at 900-1,000 m. These shifts are likely due to temperature 

changes and are possibly a response to the oxygen minimum zone at 600-1,000 m. Five 

assemblages were identified based on depth and latitude (Figure 18).

• Fishes on the Slope in the MBNMS (Steve Ralston, pers. comm.). The depth distributions 

of 15 fish species/groups were determined using data from NWFSC slope trawl survey in 

the years 1999-2006 at sites in the MBNMS. Each species or genus generally fell into one 

of the following groups (Figure19):

o Common above OMZ (200-600 m): chilipepper, shortbelly, stripetail, splitnose 

and aurora rockfishes, spotted ratfish, rex sole, and bigfin eelpout;

61 Slope – Soft
o Common above and inside OMZ (200-1,000 m): cat sharks, Dover sole, sablefish, 

shortspine thornyhead

o Common inside and below OMZ (600->1,000 m): longspine thornyhead, 

California slickhead, grenadier

• Benthic Fish and Invertebrate Assemblages (Zimmerman 2006). Using the NMFS US

west coast bottom trawl survey (55-500 m) data during 1995, 1998, and 2001, three 

biologically distinct assemblages occurred along the US west coast; shallow, middle, and 

deep assemblages. Within the MBNMS, the shallow (55-183 m) and deep (367-500 m) 

assemblages were prominent. The middle depth (184-366 m) was lacking a distinct 

assemblage; there was a mixing of shallow, deep, or uncertain assemblages.

• Groundfish Assemblages in Central and Northern California. Using NMFS groundfish 

shelf trawl data, NCCOS (2003) identified 10 depth-stratified species assemblages between 

62 and 463 m (Table 11). Sampling targeted gently sloping soft bottom on the shelf and 

shelf break, but some hard bottom was probably encountered (highly sloped rocky bottom 

was not sampled).

• General Classification of California Marine Fishes (Allen and Pondella 2006). The 

authors used cluster analysis of species assemblages to determine which species occur 

together and in what habitat (by substrate type, depth, and latitude). The following species 

assemblage was identified for the soft bottom outer shelf and slope in central California: 

Dover sole, California slickhead, longspine thornyhead, giant grenadier, black hagfish, 

California rattail.

• Benthic Fishes off Oregon, Washington, and central N. Pacific (Pearcy et al. 1982). 

Families represented by the most species were Scorpaenidae, Liparidae, Zoarcidae on the 

slope (400-2,600 m) and Liparididae, Zoarcidae, Macrouridae on the abyssal plains (2,600-

3,050 m). The bathymetric ranges of most species began or ended in three zones of rapid 

faunal change: 400-900 m, 1,900-2,200 m, 2,800-3,100 m. Species assemblages were 

characterized as follows:

o The three species assemblages on the upper-slope (515-2,100 m, 800-2,500 m, 860-

1,143 m) were dominated by thornyhead (Sebastolobus spp.);

o The one species assemblage on the mid-slope (800-2,300 m) was dominated by 

Pacific grenadier (Coryphaenoides acrolepis);

o The two species assemblages on the lower slope-abyssal plain (840-3,900 m, 2,100-

5,180 m) were dominated by abyssal grenadier (Coryphaenoides armatus).

• Seabirds and Marine Mammals (Research Planning Inc. 2006). Table 12 provides a list 

of the seabird and mammal species typically observed along the central California coast 

and their relative abundance and seasonality in eight pelagic zones off of central California 

(Figure 12). None of the seabird species dive deep enough to forage on benthic resources 

on the slope. However, deep diving mammals (e.g., sperm whales, northern elephant seal) 

can exceed depths of 1,000 m to forage on demersal fishes and invertebrates on the slope.

62 Slope – Soft
Species Composition Shifts:

• Natural Changes: Significant natural changes in water temperature and current patterns, 

such as El Niño/La Niña events and the Pacific Decadal Oscillation, can cause shifts in 

species composition of the rocky slope. Food falls and periods of high productivity in 

surface waters deliver natural supplies of food to the slope, which in turn can rapidly 

change the species compositions at these depths.

o Whale Falls (Smith and Baco 2003, Lundsten et al. 2010). Falls of large whales are a 

sporadic source of large-volume labile organic matter to the deep seafloor. Whale 

carcasses in the deep ocean off California may pass through three to four overlapping

successional stages: 

 A “necrophage” or mobile-scavenger stage: aggregations of sleeper sharks, 

hagfish, rattails and invertebrate scavengers;

 An “enrichment opportunist” stage: organically enriched sediments and exposed 

bones are colonized by dense assemblages of opportunistic polychaetes and 

crustaceans; 

 A “sulphophilic” stage: a large, species-rich, trophically complex assemblage 

lives on the skeleton as it emits sulphide from anaerobic breakdown of bone 

lipids; this stage includes a chemoautotrophic component deriving nutrition from 

sulphur-oxidizing bacteria;

 A “reef” stage: inhabited by suspension feeders exploiting the remaining nutrientdepleted hard substrate.

In Monterey Canyon, this successional process (without “reef” stage) occurs rapidly; 

less than 10 years (Lundsten et al. 2010). The majority of species at Monterey Canyon 

whale fall communities are common deep-sea inhabitants of Monterey Canyon, nearby 

seamounts, and the continental slope. Bone specialists are abundant and include many 

species of bone-eating worms Osedax sp., and two bone-eating gastropods. The 

abundance of these bone-eating worms at whale falls suggests they might play a 

substantial role in the cycling of large organic inputs into the surrounding deep-sea 

communities (Monterey Bay, 2,891 m). Sub-decadal degradation of whale skeletons 

appears to be largely driven by Osedax. Lundsten et al. 2010 suggest Osedax be 

considered a foundation species that controls whale-fall community structure and 

longevity.

• Human-Induced Changes: A variety of human activities, including the use of bottomtending fishing gear, laying of submerged cables, disposal of dredge material, deposition of 

marine debris, and sunken vessels, can alter species composition in slope habitats.

 Effects of a Submarine Cable on the Benthic Fauna in Northern MBNMS (Kogan 

et al. 2006). The potential impacts of a submarine cable on the distribution and 

abundance of 17 megafaunal groups and 19 infaunal taxa were investigated using video 

observations and sediment cores. No cable-related changes in distribution or abundance 

were detected for most faunal groups. Three megafaunal groups exhibited cable-related 

changes at one or more stations. Sea anemones colonized the cable when it was

exposed on the seafloor, and were therefore generally more abundant on the cable than 

63 Slope – Soft
in surrounding, sediment-dominated seafloor habitats. Some fishes, such as flatfishes, 

were more abundant near the cable, apparently due to the higher habitat complexity

provided by the cable. Sea cucumbers, a minor element of the seafloor fauna, were less 

abundant near the cable than along the control transect at one (1700 m station) of the 

six stations inhabited by this group. These results suggest that the biological impacts of 

the cable were minor.

 Effects of Submarine Cable on Seabed and Benthic Faunal Assemblages (Kuhnz et 

al. 2011). A geological and biological sampling program was performed to assess the 

condition of the Monterey Accelerated Research System (MARS) cable and its 

potential effects on seabed geology and biology. The major conclusion of the study is 

that the MARS cable has had little detectable impact on seabed geomorphology, 

sediment conditions, or biological assemblages. Specific conclusions include the 

following:

 Changes in mean grain size were undetectable in relation to the MARS cable.

 The percent organic carbon content of sediments increased near the MARS cable at 

some locations, possibly due to natural variation or the effects of the cable or both.

 Local variation in benthic megafaunal communities near (within 50-100 m) the 

MARS cable is minor or undetectable.

 The MARS cable has little or no detectable effect on the distribution and abundance 

of macrofaunal and megafaunal assemblages on a regional scale (e.g. kilometers).

 Effects of Exploitation on the West Coast Groundfish Assemblage (Levin et al. 

2006). Data from fishery-independent trawls on the soft bottom shelf and slope (55 to 

366 m) conducted by NMFS from 1980-2001 along the U.S. west coast (WA, OR, CA 

combined), indicate that there have been fundamental changes in the fish assemblage. 

Populations of flatfishes, cartilaginous fishes, and small rockfishes have increased, 

while populations of large rockfishes have decreased. In 1977, rockfishes were more 

than 60% and flatfishes were 34% of the fish captured in the survey. In 2001, 

rockfishes were 17% of the fish captured in the survey and flatfishes were nearly 80%. 

The species that now dominate the assemblage have vastly different trophic roles and 

life-history strategies than the species they replaced.

 Effects of Bottom Trawling on Seafloor Assemblages in Oregon (Hixon and Tissot 

2007). Visual transects over mud seafloors (183-361 m depth) at Coquille Bank, 

Oregon were used to compare the seafloor assemblages in trawled and untrawled areas. 

Untrawled seafloors had 23% more fish and 6 times greater density of benthic 

invertebrates than trawled seafloors. Untrawled seafloors had 27 fish species and 6 taxa 

of benthic invertebrates compared to 19 species of fish and 11 taxa of benthic 

invertebrates on trawled seafloors. The seafloor assemblages were characterized as 

follows:

 Untrawled assemblage: sea pens, ratfish, sablefish, ronquil, slender sole, and 

poacher. Sea pens, which dominated untrawled bottoms, are sessile, slow-growing, 

long-lived species that are likely to recover slowly from physical disturbance;

64 Slope – Soft
 Trawled assemblage: sea stars, hermit crabs, bigfin eelpout, Dover sole, hagfish, 

and shortspine thornyhead. These species are known mobile scavengers that may 

aggregate along trawl-door tracks.

 Effects of Demersal Marine Debris (Watters et al. 2010). Video surveys in central 

California of the seafloor at depths of 20-365 m observed various type of debris 

including monofilament line, longlines, nets, traps, beverage cans, bottles, anchors, 

cables, household items, and construction items. By providing artificial habitat to 

demersal organisms, debris can alter seafloor habitat and species assemblages. In 

surveys during the 1990s, 13% of debris items had fishes associated with them, and 

38% of items were associated with large, structure-forming invertebrates. In 2007, less 

than 10% of debris items had fishes associated with them, and 30% were associated 

with large, structure-forming invertebrates. The majority of debris (e.g., 99% of 815 

items surveyed in 2007) was colonized moderately to heavily by encrusting 

invertebrates. Fishes only associated with types of debris that could provide structure 

and cover; they did not associate with monofilament line. Though debris occurred 

disproportionately in rocky habitats, ~40% of debris was observed on soft sediments.

 Species Associated with Sunken Vessels in MBNMS. When a vessel sinks and settles 

on the soft-bottom slope, they introduce hard substrate into the local area. This hard 

substrate is colonized over time by a fauna that is more similar to the fauna associated 

with the hard-bottom slope habitat.

 Macrofaunal Invertebrates and Fishes Associated with the Shipwreck of the 

Oil Tanker Montebello (de Marignac and Burton 2003). The shipwreck of the oil 

tanker Montebello lies on the soft-bottom slope at approximately 275 meters off 

Cambria (adjacent to the southern border of MBNMS). The wreck is an artificial 

reef that is teeming with fishes and invertebrates. Sixteen species of fishes and 29 

species of macrofaunal invertebrates were identified. The high relief and hard 

substrate provided by the Montebello created habitat for different species 

assemblages than that of the surrounding low-relief, soft bottom habitat.

 Fishes: Rockfishes were very common. Large schools of bank, bocaccio, 

chilipepper, and widow rockfish aggregated at the upper part of the shipwreck. 

Splitnose and greenstriped rockfish were observed at the base of the hull and 

around the vicinity of the shipwreck. Redbanded and greenblotched/pinkrose 

rockfish were distributed throughout the shipwreck. The other fish species 

identified (Pacific hagfish, spotted ratfish, Pacific Argentine, eelpouts, poachers, 

and Dover sole) were typically observed on the seafloor at the base of the hull 

and in the vicinity of the shipwreck. The occurrence and abundance of these 

species were representative for the area, with the possible exception of the

higher number of Pacific hagfish.

 Macrofaunal Invertebrates: The white plumed anemone (Metridium farcimen) 

was abundant, especially on the upper area of the shipwreck. Other sessile 

invertebrates on the shipwreck included vase and encrusting sponges, hydroids, 

anemones (Actinostola sp.), brown cup coral (Paracyathus stearnsii) and 

tunicates (Clavelina sp.). Mobile invertebrates observed on and around the 

shipwreck included at least six species of crustaceans (e.g., Cancer crab, 

65 Slope – Soft
California king crab, and red galatheid crab, spot prawn), at least five species of 

sea star, and four species of sea cucumber. Dense patches of a polynoid 

polychaete (Chloeia sp.) and low numbers of white sea pen (Stylatula elongata) 

and California sea slug (Pleurobranchaea californica) were recorded on the 

seafloor around the shipwreck. The abundant fishing gear entangled on the 

Montebello was still catching fish; king crabs and an octopus were feeding on 

fish caught in the nets.

 Macrofaunal Invertebrates and Fishes Associated with the Shipwreck of the 

USS Macon (Burton and Lundsten 2006). The USS Macon is located on the softbottom continental slope off Point Sur at approximately 430 meters. The wreckage 

provides hard-bottom habitat for sessile invertebrates, mobile invertebrates, and 

fishes, serving as an artificial reef in the deep sea. At least 90 taxa were observed at 

the Macon wreck site and surrounding area. Organisms typically found in deep, 

hard-bottom habitats were observed at the wreck site, and those typically found in 

soft-bottom habitats were found in the surrounding areas. There was overlap in 

species composition at the interface of hard- and soft-bottom habitats (mixed 

habitats). Four fish taxa were the most abundant organisms at the wreck site: 

sablefish, Pacific hake, blackgill rockfish, and thornyheads. Common taxa 

associated with the wreck included anemones, basket stars, and rockfishes. Other 

common taxa associated with the interface of the wreck and soft-bottom habitats 

included sea stars, brittle stars, hagfishes, and flatfishes.

Species Diversity and Species Richness: Species diversity in the deep sea is greater than once 

thought. Small patches (mm to m) of biogenic disturbance and food input, separated on spatial 

scales of meters to km, are important in maintaining high diversity in deep-sea communities. Low 

productivity, reduced broad-scale disturbance, and large surface area of the deep sea are relevant to 

maintenance of diversity. Because of the large surface area and the many undescribed species, 

diversity in the deep sea may rival that found in tropical rain forests (reviewed in Grassle 1989). 

High diversity makes this habitat sensitive to human impacts (reviewed in Glover and Smith 

2003).

• Infauna Near Davenport (John Oliver, pers. comm.). In northern Monterey Bay and off 

Davenport, the mean number of species in sediment cores increased along the shelf, 

peaking at 109 and 150 m (at the shelf break), and then declined along the slope to 700 m. 

The mean number of species per sample was similar from 700-2,000 m. The number of 

species of crustaceans followed a similar pattern.

• Megafaunal Invertebrates Inside and Outside Monterey Bay (Oliver et al. 2011). 

Estimates of soft-bottom species density were obtained by sampling benthic megafaunal 

invertebrate communities in four major sampling programs along the coast of Central and 

Northern California. Three of these programs were focused around the Monterey Bay area. 

Samples from 30 to 2,000 m depths were analyzed. There were fewer species along the 

slope – 335 species/m2 on the upper slope (250-750 m) and 205 species/m2 from the lower 

slope (950-2000 m) – as compared to the shelf-slope break (446 species/m2 ). Species 

density was higher inside the bay (328-446 species/m

2

) compared to outside (336-339 

species/m

2

) when comparing samples from the same water depths.

66 Slope – Soft
• Whale Falls. Local species diversity (mean of 185 macrofaunal species) on large whale 

skeletons during the sulphophilic stage is higher than in any other deep-sea hard substratum 

community (Smith and Baco 2003). Global species richness on whale falls (407 species) is 

also high compared with cold seeps and rivals that of hydrothermal vents (469 species 

worldwide). The majority of species at Monterey Canyon whale fall communities are 

common deep-sea inhabitants of Monterey Canyon, nearby seamounts, and the continental

slope (Lundsten et al. 2010). Upon initial arrival, whale carcasses host a relatively lowdiversity community of mobile scavengers. Through time, diversity increases; however, 

most of the increase in species richness comes from background taxa that exploit abundant 

nutrients provided by the carcass.

• Marine Fishes off California (Allen and Pondella 2006). Species diversity (H’) and 

species richness (S) are provided for 14 major habitat types in California waters. The 

deepest major habitats (Deep Slope, Deep Bank and Deep Reef) had some of the lowest 

species richness (~15, ~16, and ~35 species, respectively). Deep Slope, Deep Bank and 

Deep Reef varied in their species diversity; ~1.5, ~1.9, and ~2.6, respectively.

• Demersal Fishes in Central California (NCCOS 2003). Rockfish species richness tended 

to be highest along the edge of the continental shelf (Figure 15). Areas with high species 

richness (for all demersal fish species) tended to be in water less than 200 m (Figure 16). 

Areas with high species diversity (for all demersal fish species) tended to be on the slope in 

waters deeper than 300 m (Figure 17).

• Demersal Fish Species Richness (Wakefield 1990). A study of the fish fauna on the slope 

at Point Sur found that the number of species identified from trawls was relatively constant 

at ~20 species for four 200-m depth intervals from 400 to 1,000 m. Richness decreased 

below 1,000 m to a minimum at 1,600 m.

• Flatfish Diversity (Vetter et al. 1994). Flatfish diversity is greatest (12 species) at the outer 

shelf (100-200 m). After the shelf-slope transition, flatfish diversity decreases rapidly to 

approximately 3 species. At 600 m, Dover sole is the only flatfish. Dover and deep-sea sole 

co-occur at 1,000-1,200 m. At 1,400 m, deep-sea sole abundance declines and no flatfishes 

occur at deeper depth.

• Species Diversity in Groundfish Assemblages off U.S. West Coast Slope (Tolimieri 

2007). Patterns of diversity (species richness, species diversity, and evenness) in 

groundfish assemblages were investigated in relation to depth (100-1200 m) and latitude 

(33-47°N). Data (pooled across depths) from trawl surveys along the U.S. west coast at 100 

m intervals between 200-1,200 m revealed species density and evenness declined with 

latitude. Latitudinal gradients were examined within four depth zones (200-300 m, 400-500 

m, 600-900 m, and 1000-1200 m). At deeper depths (1000-1200 m), species richness and 

evenness were inversely correlated with latitude. In two shallower categories, species 

richness and evenness were positively correlated with latitude.

Biomass: Productivity, biomass, and physical energy in deep sea (>1,000 m) are relatively low, 

increasing the potential sensitivity to human impacts (Glover and Smith 2003). Unfortunately, we 

know of no slope station off California where the biomass distribution of the total benthic 

community (megafauna, macrofauna, and meiofauna) has been measured (Smith and Demopoulos 

2003).

67 Slope – Soft
 Infauna near Davenport (John Oliver, pers. comm.). In northern Monterey Bay and off 

Davenport, the mean biomass per sample was highest at 60 m. Mean biomass was elevated 

at 60-109, 325, 700, and 1,500 m.

 Invertebrates off Central California (Thompson et al. 1985). Polychaetes were the most 

abundant invertebrate throughout the depth range 300-1,400 m between Point Lobos and 

Point. Sur. Though populations of large epifauna are rare relative to small infauna, they 

locally comprise a significant portion of the invertebrate biomass. Specifically, 

echinoderms constitute >90% of biomass (57 g/m2

) at the upper (500-600 m) and lower 

(900 m) edges of the oxygen minimum zone. See “Oxygen Minimum Zone” habitat section 

for additional information.

 Invertebrates and Fishes (Smith and Demopoulos 2003). The California slopes and basins 

harbor rich benthic assemblages:

o Epibenthic megafauna (>2 cm) often are abundant (densities: 0.3-17 indiv/m2). 

Echinoderms are particularly common with brittle stars and holothuroids 

dominating the megafauna, and at times attaining high biomasses (67+/- 30 g wet 

wt/m2

). Other taxa include gastropods, hexactinellid sponges, fishes (macrourids, 

zoarcids, hagfish), decapods and galatheids;

o Macrobenthos (2 cm-300 μm) consist of a high diversity of taxa, especially 

polychaetes, agglutinating foraminifera, bivalves, cumaceans, tanaids, and 

enteropneusts, with biomass of 4-8 g wet wt/m2 and abundances of 5,000-10,000 

individuals/m2;

o Meiobenthos (300 μm-42 μm) are an abundant but relatively poorly studied 

component of the slope benthos. Nematodes, calcareous and agglutinating 

foraminifera, and harpacticoid copepods abound in this size class, with forams and 

nematodes probably the most abundant. A small number of core samples (620-

3,700 m) found foram biomass ranging from 2.6-1,700 g wet wt/m2; foram biomass 

may approach and even substantially exceed that found in the macrofaunal and 

megafaunal size categories from similar depths;

o Nanobenthos (<42 μm, including bacteria, Archaea, yeasts, ciliates, flagellates, and 

amoebae) constitute an important but poorly evaluated component of the slope 

benthos. Limited studies suggest that California slope sediments harbor microbial 

biomasses that are high by the standards of both the deep sea and shallower waters.

 Groundfish off Central California (Butler et al. 1989, Wakefield unpubl. data). Eight 

species of demersal fishes (shortspine thornyhead, longspine thornyhead, Dover sole, rex 

sole, deep-sea sole, sablefish, Pacific grenadier, giant grenadier) dominate the slope in 

terms of biomass off central California (Half Moon Bay to Purisima Point).

 Groundfish off Point Sur (Wakefield 1990). Total fish biomass is constant between 600-

800 m (average 24 mt/km2

). Biomass decreased below 1,000 m to a minimum at 1,600 m 

(4 mt/km2). Estimates of abundance and biomass for the entire upper slope between 300-

1,700 m were 102,700/km2 and 16.1 mt/km2, respectively.

 Longspine Thornyhead off Central California (Wakefield unpubl. data; Wakefield and 

Smith 1990). Sebastolobus altivelis (longspine thornyhead) represents 25% of the slopewide standing stock (biomass) of all demersal fishes (Monterey to Point Sur, 400-1,600 m).

68 Slope – Soft
 Thornyheads in Central California (Jacobson and Vetter 1996). Biomass for both 

thornyhead species off central California (Point Sur to Point Conception) was determined 

from trawl survey data. The biomass of shortspine thornyhead was relatively constant 

across depth strata (400-1,000 m) whereas that of longspine thornyhead peaked sharply at 

800–1000 m. Average biomass (kg/km2) by depth stratum (m) were:

o Shortspine thornyhead: 

 200–400 m = 44 kg/km2

 400–600 m = 714 kg/km2

 600–800 m = 531 kg/km2

 800–1000 m = 772 kg/km2

 1000–1200 m = 176 kg/km2

 1200–1400 m = 57 kg/km2

o Longspine thornyhead:

 200–400 m = 2 kg/km2

 400–600 m = 692 kg/km2

 600–800 m = 1,736 kg/km2

 800–1000 m = 2,775 kg/km2

 1000–1200 m = 216 kg/km2

 1200–1400 m = 81 kg/km2

 Groundfish in Eastern North Pacific (Pearcy et al. 1982). The benthic fish fauna was 

examined from beam and otter trawl surveys from the slope and abyssal plains off Oregon, 

Washington, and the central North Pacific (400-5180 m). Abundance and biomass were

highest at the slope North Station (515-805 m; 10.7/1000 m2 and 2.9 g/m2

, respectively) 

and lowest on the Tufts Abyssal Plain (2,780-2,820 m; 0.6/1000m2 and 0.2 g/m2

, 

respectively).

 Harvested Species: Recreational and commercial harvest removes biomass of targeted fish 

and invertebrate populations. For some targeted species, biomass is substantially reduced 

compared to unfished biomass levels (Tables 3 and 4). Though extraction is the primary 

reason for a reduction in biomass for many species, changing oceanographic and ecological 

conditions are an important contributing factor for some harvested species. For the majority 

of the 10 invertebrate and 156 fish stocks landed in MBNMS, the status of the stock has not 

been assessed (Tables 3 and 4).

Key Species Interactions: Predation and facilitation are two species interactions for which we have 

some information specific to the soft bottom slope habitat. Much is yet to be learned in deep-water 

habitats.

 Predation (Drazen et al. 2001). Macrourid fishes are among the dominant fishes in the 

deep sea. Many species are large and, in combination with their abundance, are potentially 

important apex predators in the deep-sea environment. Apex predators play a vital role in 

many communities by controlling prey populations, exerting selective pressure, and 

influencing general community dynamics. The two dominant slope dwelling macrourids 

(Coryphaenoides acrolepis, Albatrossia pectoralis) are at the top of the food web on the 

upper continental slope and, because of their abundance, may exert significant pressure on 

their prey populations.

69 Slope – Soft
 Facilitation

o Brittle Stars Impact Community Energetics (Summers and Nybakken 2000). 

Because of their abundance, feeding behavior, and high activity levels, ophiuroids 

(brittle stars) are thought to significantly impact energetics and ecology of bathyal

soft-bottom communities through utilizing, processing, and redistributing organic 

matter at the seafloor. Brittle stars increase bioturbation rates and act as major links 

in local food chains. Compared to two other sites (Farallon slope 1,010-3,085 m and 

Pioneer Canyon 3,090-3,300 m), Monterey Canyon (2,300-3,300 m) had the highest 

mean abundance of ophiuroids.

o Bioturbation (Smith and Demopoulos 2003). Bioturbation, or the movement of 

sediment particles by animals, is a key ecosystem process in low-energy, 

depositional environments, such as much of the deep sea. Bioturbation results from 

the sum of deposit-feeding, locomotion and home-building activities of the benthos; 

rates of bioturbation thus provide an integrative measure of the physical activity of 

sediment assemblages (Pacific Ocean with reference to California slope).

o Black hagfish (Wakefield 1990). The numeric and gravimetric importance of 

Eptatretus deani (black hagfish) in the upper-slope fish assemblage was 

unexpected. This hagfish represented 25% of the total fish abundance between 300-

1,600 m. Due to the abundance and size of burrows excavated by E. deani, this 

scavenger may play an important role in resuspending and reworking sediments and 

it may have a major influence on the community structure within a portion of the 

upper slope off central California (Point Sur).

MOVEMENT AND DISPERSAL

Almost all fishes exhibit some degree of ontogenetic shift in space utilization as they mature and 

the degree of movement or area used by adults may vary depending on species and location. This 

is particularly true of demersal species of fishes, such as flatfishes, some rockfishes, and wrasses 

(Lowe and Bray 2006). Most movement studies have been done on shallower water species. 

Ontogenetic migration (movement to deep water as fish grow and age) occurs in sablefish, Dover 

sole, shortspine thornyhead, and weakly in longspine thornyhead (see also Hunter et al 1990; 

Jacobson and Vetter 1996).

• Sablefish (Jacobson et al. 2001). Depth range of the smallest individuals was 183-364 m. 

The largest individuals occurred in the entire depth range, but were relatively rare in the 

shallowest water and relatively abundant in the deepest water (survey to 1,280 m).

• Dover Sole and Shortspine Thornyhead (Jacobson et al. 2001). Depth range of the 

smallest Dover sole and shortspine thornyhead was 183-547 m. The largest individuals 

occurred in the entire depth range, but were relatively rare in the shallowest water and 

relatively abundant in the deepest water (survey to 1,280 m).

• Dover Sole (Hunter et al. 1990). Dover sole migrate to deeper depths as they grow, mature, 

and age. Ontogenetic movement down the shelf to the slope is gradual and occurs over 

decades.

70 Slope – Soft
SPECIES OF SPECIAL INTEREST

Many species of special resource management interest are found in the soft-bottom slope habitats 

of MBNMS Tables 3-7.

• Species Landed in MBNMS: Of the 10 invertebrate and 156 fish species that are 

commonly caught and sold in the commercial and/or recreational fisheries of MBNMS 

(Starr et al. 2002a), one invertebrate (Dungeness crab) and 47 fishes are associated with the 

soft-bottom slope.

• Endangered and Threatened Species: There are no known endangered or threatened 

invertebrate or fish species associated with the soft-bottom slope. Of the 3 listed seabirds 

and 10 listed marine mammals, Steller sea lions and sperm whales are the only species that 

potentially interact with benthic resources on the slope.

• Other At-Risk Species: None of the invertebrate taxa in the federal waters of MBNMS are 

considered to be at-risk. Shortspine thornyhead is the only at-risk fish associated with softbottom, slope habitat. Of the 11 at-risk seabirds and 9 at-risk marine mammals, Steller sea 

lions and sperm whales are the only species that potentially to interact with benthic 

resources on the slope.

Additional species of special resource management interest associated with the soft-bottom slope 

habitat are:

• Structure-forming invertebrates, such sea pens, due to their important ecological role in 

creating habitat structure and their vulnerability to disturbance from human activities.

71 Slope – Soft
Rise (>3,000 m) – Soft Substrate

HABITAT OVERVIEW

One must dive over 3,000 meters before landing on the seafloor in the central western portion of 

Monterey Bay National Marine Sanctuary and in portions of the Davidson Seamount 

Management Zone. The vast majority (~91%) of the seafloor habitat in Monterey Bay National 

Marine Sanctuary that is deeper than 3,000 m, also known as the rise, is composed of soft bottom 

habitats (Figure 1). Within the federal study area, soft bottom habitats of the rise comprise 

approximately 1,720 km2, which is 15.6% of the study area (Table 2). 

The Davidson Seamount is the only known hard-bottom feature in the rise habitat of MBNMS. 

This inactive volcano is approximately 42 km long and rises 2,300 m off the seafloor. The base 

is in the rise and the summit is in the slope depth zones. Due to its uniqueness and because it 

occurs in two benthic habitat zones, the Davidson Seamount is discussed in the “Seamounts”

habitat section. Other than the seamount, the rise habitat in the sanctuary is almost entirely soft 

bottom. Very little is known about the rise habitat and communities.

SEARCH TOPIC TABLE

HABITAT FUNCTION

Functional Habitats:

Nursery Habitat: No specific information was found on this topic.

Feeding Ground: No specific information was found on this topic.

Spawning Ground: No specific information was found on this topic.

Migratory Corridor: No specific information was found on this topic.

Biogenic Habitat:

Structure-forming invertebrates found in Chemosynthetic 

Biological Communities are used by other sessile organisms as 

a hard surface for attachment, and by mobile organisms for 

shelter or food. See “Chemosynthetic Biological Communities” 

habitat summary for additional information.

Energy Flow:

Primary Production:

In areas where there is seepage of sulfide- and methane-rich 

fluids, some organisms fix carbon through chemosynthesis. 

These areas, called “Cold Seeps” or “Chemosynthetic 

Biological Communities” (CBCs), are the only source of 

primary production in the deep-sea habitats of MBNMS. See 

the “Chemosynthetic Biological Communities” habitat 

summary for additional information.

Benthic-Pelagic Coupling: See page 73

Key Trophic Interactions: See page 74

Key Trophic Cascades: No specific information was found on this topic.

72 Rise – Soft
Productivity Hotspots: See page 74

HABITAT STRUCTURE

Species Composition: See page 74

Species Composition Shifts: See page 75

Species Diversity and Richness: See page 76

Biomass: See page 77

Key Species Interactions See page 77

MOVEMENT AND DISPERSAL No specific information was found on this topic.

SPECIES OF SPECIAL INTEREST

There are no species of special resource management interest 

associated with the rise habitat in MBNMS (Tables 3-7). Some 

deep-water fish species (e.g., grenadiers) might be targeted by 

fisheries in the future.

HABITAT SUMMARY

HABITAT FUNCTION

Energy Flow

Benthic-Pelagic Coupling (reviewed by Raffaellia et al. 2003). There is a two-way exchange, or 

flux of matter, between the benthos and the overlying water body, which is important for both 

benthic and pelagic compartments. This flux occurs through sinking of non-living organic matter 

(e.g., falling plankton, fecal pellets, animal carcasses, and drift algae) and the active movement 

of organisms. 

• Particulate Organic Carbon (POC) and Particulate Total Nitrogen (PTN) (Smith et 

al. 2001). Fluxes of POC and PTN measured over an and 8-year period via sediment traps 

600 m and 50 m above the seafloor at Station M (4,100 m, west of California) declined 

significantly from October 1989-1996 and then increased in 1998. These flux 

measurements, when compared to the sediment community oxygen consumption, suggest 

that there is a food deficit in the deep sea. Sediment traps may have under-sampled flux 

from lateral advection of organic matter from the slope and shelf and from dissolved 

organic matter. These sources may explain the discrepancy between supply and demand 

in the abyssal Pacific. Decadal-scale climate variations influencing marine primary 

production and terrestrial discharges into the ocean may be extremely important in 

understanding biogeochemical processes in the deep sea.

• Whale Falls (Lundsten et al. 2010). Dead whale carcasses that sink to the deep seafloor 

introduce a massive pulse of energy capable of hosting dynamic communities of 

organisms in an otherwise food-limited environment. Carcass degradation occurs subdecadally. The majority of species in these communities are background deep-sea taxa.

• Sinking Larvacean Houses: The abandoned mucous houses of the giant larvacean 

Bathychordaeus are a significant source of rapid carbon transport through the water 

73 Rise – Soft
column to the deep seafloor. Robison et al. (2005) estimated the production rate of 1 

sinking Bathychordaeus house per day in Monterey Bay to be approximately 5.4 mg of 

total organic carbon. This number is an underestimate of total flux of giant larvacean 

houses because there are at least two other species found in Monterey Bay. See

“Submarine Canyon” habitat summary for additional information.

Key Trophic Interactions: Many of the invertebrates living on the rise are either detritivores or 

planktivores. These organisms play an important role in the food web by converting sinking 

organic matter and nutrients into benthic-associated biomass. Brittle stars act as major links in 

local food chains.

• Brittle Stars Impact Community Energetics (Summers and Nybakken 2000). Because 

of their abundance, feeding behavior, and high activity levels, ophiuroids (brittle stars) 

are thought to significantly impact energetics and ecology of bathyal soft-bottom 

communities through the utilization, processing, and redistribution of organic matter at 

the seafloor, increasing bioturbation rates, and act as major links in local food chains. 

Compared to sites on the Farallon slope (1,010 - 3,085 m) and Pioneer Canyon (3,090 –

3,300 m), Monterey Canyon sites (2,300 - 3,300 m) had the highest mean abundance of 

ophiuroids.

Productivity Hotspots: Productive areas in rise habitats tend to be dynamic in space and time

and, although they can last for decades, they are considered temporary and sometimes 

unpredictable.

• Whale Falls (Lundsten et al. 2010). Dead whale carcasses that sink to the deep seafloor 

introduce a massive pulse of energy capable of hosting dynamic communities of 

organisms in an otherwise food-limited environment. Carcass degradation at Monterey 

Canyon occurs sub-decadally.

• Chemosynthetic Biological Communities are productivity hotspots in slope, rise, and 

canyon habitats. See “Chemosynthetic Biological Communities” habitat summary for 

details. See Figure 6 for locations where CBCs have been observed in the Monterey Bay 

area.

HABITAT STRUCTURE

Species Composition: Invertebrates and fishes are the major animal groups on the rise. Few 

studies have been conducted at these deeper depths. The unique faunal assemblage found in

Chemosynthetic Biological Communities is described in the CBC habitat summary.

• Benthic Megafauna West of the Farallones (Nybakken 1996, Nybakken et al. 1998). 

Benthic megafaunal invertebrates was sampled on the soft bottom slope (2,300-3,075 m) 

west of Farallones and in Pioneer Canyon (Monterey Canyon was not adequately 

sampled). The benthic invertebrate megafauna were dominated by echinoderms (mostly 

burrowers) with holothurians (cucumbers), ophiuroids (brittle stars), and asteroids (sea 

stars) in the upper three ranks. Distribution of megafaunal organisms is highly patchy, 

especially among surface-dwelling forms. Quantitative analysis of differences between 

sites and between survey years indicated that the megafauna associations at the same 

74 Rise – Soft
depth in MBNMS are really quite different at different sites. Results also suggest that 

there are strong seasonal and yearly differences within the same site.

• Fishes on the California Rise (Allen 2006; Neighbors and Wilson 2006). Common 

species of the rise are identified (Table 13). 

• Demersal Fishes West of the Farallones (Cailliet et al. 1992, 1999). The deep-sea 

demersal fish fauna on the soft bottom slope and rise (2,000-3,300 m) west of Farallones 

appeared similar in species composition to the fauna of the eastern Pacific and other 

deep-water sites around the world. The fish fauna was dominated by families 

Macrouridae, Zoarcidae, Moridae, and Rajidae and included the following species: skate 

(Bathyraja trachura), spiny eel (Notacanthus chemnitzii), lizardfish (Bathysaurus mollis), 

snailfishes (Paraliparis spp., Paraliparis rosaceus, Careproctus melanurus, Careproctus 

ovigerum), cuskeel (Spectrunculus grandis), codling (Antimora microlepis), grenadier 

(Coryphaenoides acrolepis, C. armatus, C. filifer, C. leptolepis), eelpouts (Lycenchelys

spp., Pachycara lepinium, Bothrocara spp.).

• Benthic Fishes off Oregon, Washington, and Central North Pacific (Pearcy et al. 

1982). Families represented by the most species were Scorpaenidae, Liparidae, Zoarcidae 

on the slope (400-2,600 m) and Liparididae, Zoarcidae, Macrouridae on the abyssal 

plains (2,600-3,050 m). The bathymetric ranges of most species began or ended in three 

zones of rapid faunal change: 400-900 m, 1,900-2,200 m, 2,800-3,100 m. Species 

assemblages were characterized as follows:

o Three species assemblages were recognized on the upper-slope (515-2,100 m, 

800-2,500 m, 860-1,143 m; all dominated by thornyhead (Sebastolobus spp.);

o One on the mid-slope (800-2,300 m; dominated by Pacific grenadier 

(Coryphaenoides acrolepis);

o Two on the lower slope-abyssal plains (840-3,900 m, 2,100-5,180 m; dominated 

by abyssal grenadier (Coryphaenoides armatus).

• Marine Mammals: Even the deepest diving cetaceans (e.g., sperm whales and beaked 

whales) do not dive deep enough to forage on the benthic organisms in the rise habitat.

Species Composition Shifts: Long time-series data are lacking for most of the deep sea making it 

difficult to detect shifts in species composition and to understand the cause of those shift.

• Natural Changes: Significant natural changes in water temperature and current patterns, 

such as El Niño/La Niña events, can cause shifts in species composition of the benthic 

community. Food falls and periods of high productivity in surface waters deliver natural 

supplies of food to the seafloor, which in turn can rapidly change the species 

compositions at these depths.

o Whale Falls (Smith and Baco 2003, Lundsten et al. 2010). Falls of large whales 

are a sporadic source of large-volume labile organic matter to the deep seafloor. 

Whale carcasses in the deep ocean off California may pass through three to four 

overlapping successional stages and this successional process may occur rapidly, 

in less than 10 years. The majority of species at Monterey Canyon whale fall 

communities are common deep-sea inhabitants of Monterey Canyon, nearby 

75 Rise – Soft
seamounts, and the continental slope. See “Slope – Soft Bottom” habitat summary 

for additional information.

o Major El Niño/La Niña Event (Ruhl and Smith 2004). A major change in the 

community structure of the dominant epibenthic megafauna was observed at 

4,100 meters (Station M) in the northeast Pacific and was synchronous to a major 

El Niño/La Niña event that occurred between 1997 and 1999. Photographic 

abundance estimates of epibenthic megafauna from 1989 to 2002 show that two 

taxa (cucumbers) decreased in abundance after 1998 by 2 to 3 orders of 

magnitude, whereas several other species (4 cucumbers, 1 urchin, brittlestar 

group) increased in abundance by 1 to 2 orders of magnitude. These faunal 

changes are correlated to climate fluctuations dominated by El Niño/La Niña. 

Correlations between food supply and megafauna abundance over the 14 year 

time period suggest that some taxa increase in abundance during periods of high 

food supply, whereas others may be favored during deficits.

• Human-induced Changes: Productivity, biomass, and physical energy are all relatively 

low in the deep sea, increasing the potential sensitivity to human impacts (Glover and 

Smith 2003). In addition, species diversity is relatively high in the deep sea, making the 

habitat more sensitive to human impacts.

• Carbon Dioxide Sequestration. CO2 injection at 3,600 m in Monterey Bay caused 

high rates of mortality in meiofauna (Barry et al. 2004). Hagfish (Eptatretus stouti) 

were more affected by respiratory stress associated with the high partial pressure of 

CO2 than by the lowered pH (Tamburri et al. 2000). Liquid CO2 introduced onto the 

seafloor at 3,250 m depth killed significantly greater numbers of representative 

infauna at the experimental site than at areas a distance away (Thistle et al. 2005). 

This demonstration that sequestered CO2 can adversely affect the deep-sea infauna 

brings CO2 sequestration in the deep sea into conflict with the preservation of deepsea biodiversity. The principal impact to general benthic ecosystems is likely to be 

reduced pH, and for those organisms directly in the path of the CO2 plume, 

physiological stress caused by an elevated partial pressure of CO2 (Glover and Smith 

2003).

Species Diversity and Species Richness: Species diversity in the deep sea is greater than once 

thought. Small patches (mm to m) of biogenic disturbance and food input (e.g., food falls), 

separated on spatial scales of meters to km, are important in maintaining high diversity in deepsea communities. Low productivity, reduced broad-scale disturbance, and large surface area of 

the deep sea are relevant to maintenance of diversity. Because of the large surface area and the 

many undescribed species, diversity in the deep sea may rival that found in tropical rain forests 

(reviewed in Grassle 1989). High diversity makes this habitat sensitive to human impacts 

(reviewed in Glover and Smith 2003).

• Whale Falls. Local species diversity (mean of 185 macrofaunal species) on large whale 

skeletons during the sulphophilic stage is higher than in any other deep-sea hard 

substratum community (Smith and Baco 2003). Global species richness on whale falls 

(407 species) is also high compared with cold seeps and rivals that of hydrothermal vents 

(469 species worldwide). The majority of species at Monterey Canyon whale fall 

communities are common deep-sea inhabitants of Monterey Canyon, nearby seamounts, 

76 Rise – Soft
and the continental slope (Lundsten et al. 2010). Upon initial arrival, whale carcasses 

host a relatively low-diversity community of mobile scavengers. Through time, diversity 

increases; however, most of the increases in species richness come from background taxa 

that exploit abundant nutrients provided by the carcass.

Biomass: Productivity, biomass, and physical energy in deep sea (>1,000 m) are relatively low, 

increasing the potential sensitivity to human impacts (Glover and Smith 2003). Very little is 

known of the biomass in the soft-bottom rise habitat.

 Invertebrates and Fishes (Smith and Demopoulos 2003). The California slopes and

basins harbor rich benthic assemblages:

o Epibenthic megafauna (>2 cm) often are abundant (densities: 0.3-17 indiv/m2). 

Echinoderms are particularly common with brittle stars and holothuroids 

dominating the megafauna, and at times attaining high biomasses (67+/- 30 g wet 

wt/m2). Other taxa include gastropods, hexactinellid sponges, fishes (macrourids, 

zoarcids, hagfish), decapods and galatheids;

o Macrobenthos (2 cm-300 μm) consist of a high diversity of taxa, especially 

polychaetes, agglutinating foraminifera, bivalves, cumaceans, tanaids, and 

enteropneusts, with biomass of 4-8 g wet wt/m2 and abundances of 5,000-10,000 

individuals/m2;

o Meiobenthos (300 μm-42 μm) are an abundant, but relatively poorly studied 

component of the slope benthos. Nematodes, calcareous and agglutinating 

foraminifera, and harpacticoid copepods abound in this size class, with forams 

and nematodes probably the most abundant. A small number of core samples 

(620-3,700 m) found foram biomass ranging from 2.6-1,700 g wet wt/m2; foram 

biomass may approach and even substantially exceed that found in the 

macrofaunal and megafaunal size categories from similar depths;

o Nanobenthos (<42 μm, including bacteria, Archaea, yeasts, ciliates, flagellates, 

and amoebae) constitute an important, but poorly evaluated component of the 

slope benthos. Limited studies suggest that California slope sediments harbor 

microbial biomasses high by the standards of the deep sea, and even shallow 

water.

 Groundfish in Eastern North Pacific (Pearcy et al. 1982). The benthic fish fauna was 

examined from beam and otter trawl surveys from the slope and abyssal plains off 

Oregon, Washington, and the central N. Pacific (400-5180m). Abundance and biomass 

was highest at the slope (North station: 515-805 m; 10.7/1000 m2 and 2.9 g/m2

, 

respectively) and lowest on the Tufts Abyssal Plain (2,780-2,820 m; 0.6/1000m2 and 0.2 

g/m2, respectively).

Key Species Interactions: Facilitation is one species interaction for which we have some 

information specific to the rise habitat. Much is yet to be learned in deep-water habitats.

 Facilitation

o Bioturbation (Smith and Demopoulos 2003). Bioturbation, or the movement of 

sediment particles by animals, is a key ecosystem process in low-energy, 

depositional environments, such as much of the deep sea. Bioturbation results 

77 Rise – Soft
from the sum of deposit-feeding, locomotion and home-building activities of 

benthos; rates of bioturbation thus provide an integrative measure of the physical 

activity of sediment assemblages (Pacific Ocean with reference to California 

slope).

o Brittle Stars Impact Community Energetics (Summers and Nybakken 2000). 

Because of their abundance, feeding behavior, and high activity levels, ophiuroids 

(brittle stars) are thought to significantly impact energetics and ecology of bathyal

soft-bottom communities through utilizing, processing, and redistributing organic 

matter at the seafloor, increasing bioturbation rates, and acting as major links in 

local food chains. Compared to two other sites (Farallon slope 1,010-3,085 m and 

Pioneer Canyon 3,090-3,300 m), Monterey Canyon (2,300-3,300 m) had the 

highest mean abundance of ophiuroids.

78 Rise – Soft
Open Water

HABITAT OVERVIEW

All of the water in the 15,787 km2 of Monterey Bay National Marine Sanctuary that is not 

associated with the seafloor is part of the open water habitat. The open water habitat has a total 

volume of approximately 18,670 km3. This habitat is constantly moving and comprises a portion 

of the California Current system. The California Current is a southward flowing current that 

extends from shore to several hundred miles offshore and from the surface to depths of about 100 

m. This current brings cooler, northern waters into the sanctuary. In deeper waters over the lower 

shelf and slope, the northward flowing California Undercurrent brings warmer southern waters

into the sanctuary. In winter, this undercurrent often surfaces to become the northward flowing 

Davidson Current, inshore of the California Current. These currents vary in intensity and 

location, both seasonally and from year to year. MBNMS contains a mix of waters from these 

different currents.

The major currents are greatly influenced by a number of variables including the strength and 

direction of winds, ocean temperatures and salinity, the topography of the coastline, and the 

shape of the ocean bottom. Primarily during the spring and summer months, northwest winds 

drive nearshore surface waters up to 50 km offshore in a process called upwelling. The nearshore 

waters are replaced from below by colder, nutrient-rich waters. The surface waters off central 

California may be pushed even further offshore by numerous jets, filaments, and eddies. Some 

oceanographic features, such as upwelling shadows, do not move waters offshore, but instead 

retain waters in an area for a period of time. Many oceanographic features have somewhat 

predictable locations especially those tied to key features such as point and headlands. Features 

and processes that modify the flow of currents also influence dispersal of planktonic organisms 

and the spatial distribution of nektonic organisms.

Generally, the open water habitat can be divided into three depth zones: the epi-, meso-, and 

bathypelagic zones. The epipelagic zone includes the upper 200 m of the water column and has a 

total volume in MBNMS of 2,569 km3

. This zone receives high levels of light and is subjected to 

seasonal variations in temperature and salinity. The epipelagic zone supports a diverse and 

complex food web of plankton, invertebrates, fishes, turtles, seabirds, and mammals. The 

mesopelagic zone (200–1,000 m) and the bathypelagic zone (below 1,000 m) have total volumes

of 7,250 and 8,854 km3

, respectively. The waters of these zones are characterized by low or no 

light, lower temperature and food availability, slower currents, and higher salinity and pressure. 

Organisms that live under these conditions require specialized adaptations for locating food and 

mates.

SEARCH TOPIC TABLE

HABITAT FUNCTION

Functional Habitats:

Nursery Habitat: See page 80

Feeding Ground: See page 81

79 Open Water
Spawning/Breeding Ground: See page 83

Migratory Corridor: See page 84

Biogenic Habitat: See page 84

Energy Flow:

Primary Production: See page 85

Benthic-Pelagic Coupling: See page 86

Key Trophic Interactions: See page 87

Key Trophic Cascades: No specific information was found on this topic.

Productivity Hotspots: See page 88

HABITAT STRUCTURE

Species Composition: See page 89

Species Composition Shifts: See page 93

Species Diversity and Richness: See page 97

Biomass: See page 97

Key Species Interactions No specific information was found on this topic.

MOVEMENT AND DISPERSAL 

The movements of most open ocean fish appear to be correlated 

with movements of water masses, which can vary with season, 

current, and decadal weather pattern (Lowe and Bray 2006). 

Highly mobile species tend to search for environmental 

conditions most likely to contain prey patches. Young stages of 

larval fish tend to drift passively in the water column while 

older-stage larvae of some species (e.g., flatfishes and rockfish) 

exhibit diel vertical migration (Lowe and Bray 2006).

SPECIES OF SPECIAL INTEREST See page 100

HABITAT SUMMARY

HABITAT FUNCTION

Functional Habitats

Nursery Habitat: Oceanographic features that concentrate planktonic organisms, such as 

retention zones and frontal zones, may serve as good nursery habitat for pelagic larval fish and 

invertebrates. By concentrating prey resources, including phytoplankton and small zooplankton, 

these features may support higher growth rates of larval fish and invertebrates than the 

surrounding waters.

 Retention Zones (reviewed in Morgan and Botsford 1998). Along the central California 

coast, plumes of upwelled water are usually found jetting to the southwest of 

promontories. These waters may then be retained in upwelling shadows or upwelling 

fronts. Localized retention zones hold and concentrate primary production and make it 

80 Open Water
available for higher trophic levels. Planktonic consumers of this primary production, such 

as the pelagic larvae of fish and invertebrates, are also concentrated and retained in these 

zones. During upwelling relaxation events, water and entrained larvae can flow back 

toward shore leading to pulses of settlement in nearshore habitats (Wing et al. 2003). 

 Upwelling Shadow in Northern Monterey Bay (Graham and Largier 1997). When 

upwelling occurs to the north of Monterey Bay, an upwelling shadow occurs in the 

northern portion of Monterey Bay. The water mass in the upwelling shadow exhibits 

cyclonic (counter-clockwise) circulation and strong thermal stratification with warm 

surface waters. Residence time is estimated to be 8 days. This feature should retain 

shelf-derived primary production so that it is available for higher trophic levels. The 

feature breaks down during prolonged (>7 days) relaxation events. Larvae with short 

planktonic stages (<10 days) released north of Monterey Bay during upwelling 

periods may be entrained in the northern part of the bay and remain available for 

settlement there. Positive buoyancy or upward movement of eggs and larval 

organisms will enhance their accumulation within the surface waters of the upwelling 

shadow.

 Frontal Zones off Central California (Bjorkstedt et al. 1997). Along the central 

California coast during the upwelling season, ichthyoplankton were abundant at 

upwelling fronts. Ichthyoplankton were distributed deeper offshore of the surface 

front. This pattern of distribution suggests that upwelling fronts may reduce crossshelf transport of fish larvae (and increase retention of larvae near the front) by 

removing larvae from the surface Ekman layer.

 Central California. Larson et al. (1994) analyzed NMFS midwater trawl results to 

find recurrent patterns in the distribution of pelagic juvenile rockfish just prior to 

settlement. They found clear gradients in fish size. The smallest pelagic juveniles 

were often located offshore beyond the upwelling front while larger pelagic juveniles 

were found close to shore, even during active upwelling. This pattern is probably 

caused by passive offshore transport of smaller juveniles during upwelling and 

ontogenetic changes that allow larger fish to be less susceptible to offshore transport 

or actively engage in onshore transport. Pelagic juveniles of all sizes appeared to be 

advected closer to shore during relaxation events. 

 Frontal Zone off Point Reyes (Wing et al. 1998, 2003). Cancrid crab larvae, 

particularly rock crabs (Cancer antennarius, C. productus) and Dungeness crab (C. 

magister), were found in the frontal waters off of Point Reyes between newly 

upwelled water and the relatively warmer water directly south of Point Reyes in the 

Gulf of the Farallones. Larvae in this group exhibit strong vertical migratory 

behavior, which resulted in local concentration in the cross-shelf front. Onshore 

movement of the larvae to juvenile habitat appeared to rely on upwelling relaxation 

events and alongshore flows. Seasonal rates of settlement to coastal habitats at 

Bodega Head were highest during wind relaxations.

Feeding Ground: Many species of marine mammals, seabirds, and predatory fish travel to 

MBNMS during part of the year to forage on locally abundant prey species, including jellies, 

krill, squid, anchovy, and sardine. Some of these predators do not reproduce in MBNMS, but 

forage here during the non-breeding season. Species that are observed in higher abundance in 

81 Open Water
northern Monterey Bay (e.g., leatherback turtles, harbor porpoise, Sooty Shearwaters) may be 

attracted to a concentration of prey items associated with this retention zone.

 Pelagic Fish (Love 1996, Leet et al. 2001). A number of pelagic fish species travel to 

MBNMS to forage during the highly productive upwelling season. Examples include 

Pacific hake, Pacific bonito, basking shark, blue shark, albacore, and yellowfin tuna.

 White Shark (Pyle et al. 1996, Klimley et al. 2001, Kelly and Klimley 2003,Weng et al. 

2007, Jorgensen et al. 2009). Tracking of white sharks using acoustic tags has revealed a 

regular presence/absence pattern in North American coastal habitats with presence 

peaking during the months of August through February followed by near-complete 

absence between mid-April and mid-July. The peak in shark abundance coincides with 

the peak occurrence of northern elephant seal pups (1-3 years of age), which are the 

preferred prey of adult white sharks. White sharks appear to have a preference for certain 

foraging hotspots including Año Nuevo Island, which is a primary elephant seal rookery

in central California. In general, while near pinniped rookeries in autumn and winter, 

white sharks avoid the surface and use water to 50 m depth, consistent with a silhouettebased hunting strategy.

 Leatherback Turtle (Benson et al. 2007, 2011). A principal foraging area for 

leatherback sea turtles (Dermochelys coriacea) within the California Current includes the 

area between Point Sur and Point Arena extending offshore to the 200 m isobath (Figure 

20). The preferred prey of leatherback sea turtles, brown sea nettles (Chrysaora 

fuscescens), are observed in high densities in the principle foraging area particularly 

within upwelling shadows and retention areas.

 Seabirds (Roberson 2002, NCCOS 2003, 2007). Many seabirds are not year-round 

residents in MBNMS, but forage in sanctuary waters during the non-breeding season. 

Species that breed at higher latitudes (e.g., Alaska) during the summer and have highest 

densities in the sanctuary from late-fall to early spring include: loons, grebes, Northern 

Fulmars, scoters, Herring Gulls, Glaucous-winged Gulls, Black-legged Kittiwakes, and 

Rhinoceros Auklets. Species that migrate to the sanctuary after breeding at lower 

latitudes (during the winter) or in the southern hemisphere and have highest abundance in 

MBNMS during the summer and fall include: Black-footed Albatross, Sooty 

Shearwaters, Leach’s Storm-Petrels, Buller’s Shearwaters, Brown Pelicans, and Xantus’s 

Murrelets. 

 Seabird Foraging Hotspots (Research Planning Inc. 2006). Locations of concentrations, 

or ‘hotspots’, of seabirds were identified by USGS, NOAA, and MLML seabird, marine 

mammal, and sea turtle experts (Figure 21). Hotspots tend to be areas with elevated 

abundance of prey or located adjacent to nesting habitats during the breeding season.

 Storm-Petrel: A seasonal (August-November) hotspot for Ashy and other StormPetrels was identified between the 200 and 1,000 m isobaths from Pescadero Point to 

Cypress Point.

 Cassin’s Auklet: A seasonal (May-July) hotspots for Cassin’s Auklet was identified

between the 200 and 1,000 m isobaths from Cypress Point to Pfeiffer Point.

 Sooty Shearwater: Seasonal (June-September) hotspots for Sooty Shearwater were

identified from the coast to 5 km offshore from Pleasure Point to Moss Landing 

82 Open Water
(northern Monterey Bay) and along the central California coast from Lopez Point to 

Mill Creek, and from Point Piedras Blancas to San Simeon. 

 Marbled Murrelet: A year-round hotspot for Marbled Murrelet was identified from 

the coast to 2 km offshore from Pillar Point to Moss Landing.

 Diving Birds, Gulls, and Seabirds: Seasonal hotspots for diving birds (grebe, loons, 

cormorants), gulls, and/or seabirds (auks, storm-petrels, shearwaters, albatrosses) 

were identified for the waters around Devil’s Slide Rock (February-August), Año 

Nuevo Island (February-August), Bird Rock (April-August), and Castle Rocks 

(February-August).

 Blue Whale (Croll et al. 2005). Blue whales are found in Monterey Bay during summer 

months when euphausiid densities are high. Whale foraging effort is concentrated on 

dense schools associated with the edge of the submarine canyon. The whales appear to 

concentrate their foraging activity on deeper layers of euphausiid schools (typically 

between 150 and 200 m) where adult euphausiids tend to be found.

 Marine Mammal Foraging Hotspots (Research Planning Inc. 2006). Locations of 

concentrations, or ‘hotspots’, of marine mammals were identified by USGS, NOAA, and 

MLML seabird, marine mammal, and sea turtle experts (Figure 22). Hotspots tend to be 

areas with elevated abundance of prey.

 Blue whale, humpback whale, Dall’s porpoise, dolphin, and California sea lion:

Central Monterey Bay over the submarine canyon and from the Monterey Peninsula 

south to Partington Point from the coast out to the 1,000 m isobath was identified as a 

year-round hotspot for Dall’s porpoise, dolphins, and California sea lions and a 

seasonal hotspot for humpback whales (March-November) and blue whales (March 

and November).

 Blue whale and humpback whale: A seasonal hotspot for humpback whales 

(March-November) and blue whales (June-November) was identified between the 50 

and 200 m isobaths from San Pedro Point to Point Año Nuevo.

 Harbor Porpoise: Hotspots for harbor porpoise were identified over the shelf out to 

the 100 m isobath from Duxbury Point to Pescadero Point, Davenport to Moss 

Landing, and Purisima Point to Estero Point.

Spawning/Breeding Ground: Many species of seabirds, marine mammals, fish, and 

invertebrates (e.g., market squid, krill) are year-round residents in MBNMS and complete their 

life cycle in sanctuary waters. Some species (e.g., northern elephant seal) travel to MBNMS for 

the purpose of reproduction. A number of migratory fish species migrate to lower latitudes (e.g., 

the Southern California Bight and southern Baja California) to spawn. These species may avoid 

spawning off central California because of the vigorous upwelling in this region, which can 

advect spawned eggs and larvae far offshore (Allen and Cross 2006).

 Seabirds (Roberson 2002, NCCOS 2003, Research Planning Inc. 2006, NCCOS 2007). 

In general, the seabirds that nest along the coast or on offshore islands in MBNMS are 

resident species that are also present in the sanctuary during the non-breeding season 

(though relative abundance may vary by season). These species include: Ashy StormPetrel, Brandt’s Cormorant, Pelagic Cormorant, Heermann’s Gull, Western Gull, Caspian 

Tern, Forster’s Tern, Common Murre, Cassin’s Auklet, Pigeon Guillemot, Marbled 

83 Open Water
Murrelet, and Rhinoceros Auklet. The need to return frequently to the nest during the 

breeding season results in higher densities of these seabirds in the waters adjacent to 

nesting areas. For example:

 Rhinoceros and Cassin’s Auklets in the waters surrounding Año Nuevo Island 

during the breeding season (spring and summer). This area includes the heads of Año 

Nuevo and Ascension Canyons;

 Marbled Murrelets in the waters near Point Año Nuevo during the breeding season 

(April-July);

 Common Murres in the waters around the Devil’s Slide/Point San Pedro breeding 

colony;

 Brandt’s Cormorant (April to August) in the waters around the breeding colonies at 

Devil’s Slide/Point San Pedro, Año Nuevo Island, Bird Rock, and Point Lobos.

 Marine Mammals (NCCOS 2003, Research Planning Inc. 2006). In general, the marine 

mammals that reproduce in MBNMS are resident in sanctuary waters year-round (though 

relative abundance may vary by season). These species include: sea otter, harbor seal, 

northern elephant seal, harbor porpoise, Dall’s porpoise, and bottlenose dolphin. Steller 

sea lion density is elevated near the rookery at Año Nuevo Island, especially during the 

breeding season (May-July). The density of northern elephant seals is elevated 

throughout much of the year near the breeding and molting beaches at Año Nuevo Island, 

Piedras Blancas and Cape San Martin/Gorda. 

Migratory Corridor:

 Gray Whale (Rice and Wolman 1971, NCCOS 2003). The coastal waters over the 

continental shelf in MBNMS are part of a migratory corridor for gray whales. Gray 

whales are seen migrating southward through MBNMS between mid-December and midFebruary with abundance typically peaking in January. Some pregnant females give birth 

in MBNMS waters during the southward migration (Karin Forney, per. comm.). The 

northward return migration primarily occurs between February and May with abundance 

typically peaking in March. Gray whales tend to be observed in shallow coastal waters 

often within 1-3 nautical miles (1.8-5.6 km) of shore except in Monterey Bay where they 

may travel across the mouth of the bay through very deep water (Figure 22).

Biogenic Habitat: Habitat created by plants or animals is generally lacking in the open water 

environment. However, there are a few examples of smaller organisms living in close association 

with larger organisms or drifting kelp mats, which likely provide benefits such as food, shelter 

from predation, or improved dispersal.

 Marine Snow (Silver et al. 1998, Mary Silver, pers. comm.). Many different types of 

micro-organisms and small zooplankton (e.g., copepods) live on or in association with 

sinking particles of marine snow and with larger zooplankton-derived aggregates, such as 

abandoned larvacean mucous houses.

 Floating Kelp Mats (Cascorbi 1999c, Allen and Cross 2006). Ocean-going mats of kelp 

provide shelter to many species that otherwise find little shelter in the open ocean, 

including juvenile sea turtles, swimming crabs, and the young of important sport and 

commercial fishes such as jacks, sablefish, rockfishes, and yellowtail.

84 Open Water
 Gelatinous Organisms: Medusafish (Icichthys lockingtoni), bluefin driftfish (Psenes 

pellucidus), and smalleye squaretail (Tetragonurus cuvieri) associate with medusa, 

siphonophores, and salps (Allen and Cross 2006). Graham (1994) found that megalops 

and juveniles of the slender crab (Cancer gracilis) commonly cling to large 

scyphomedusae (Chrysaora fuscescens) in central California waters. This association 

may help to enhance growth, survival, cross-shelf transport and dispersal of the crabs.

Energy Flow

Primary Production: Phytoplankton are the only source of primary production in the open 

water habitat. Sufficient sunlight to support photosynthesis only penetrates the waters of the 

epipelagic zone. Primary production shows high temporal and spatial variability in sanctuary 

waters. This variability is driven by many factors including:

 Iron Availability (Hutchins et al. 1998, Firme et al. 2003). Varying degrees of ironlimitation are found in the coastal upwelling region of central California during the 

summer. Iron-limitation is most common and severe in regions removed from continental 

shelf sources of iron. Thus, areas with a wide continental shelf (e.g., Monterey Bay and 

the shelf to the north) tend to have waters that are iron-replete compared to areas with a 

narrow shelf (south of Monterey Bay). Iron-limitation tends to be more severe during 

upwelling relaxation events because the phytoplankton community rapidly depletes the 

amount of dissolved iron in an upwelled water mass as it ages during the relaxation event. 

In iron-replete waters, ample iron allows for unrestricted growth of large phytoplankton 

(primary productivity is limited instead by the amount of nutrients, light, and grazing) 

and results in high production of particulate organic nitrogen and carbon. In contrast, in 

iron-limited waters, the growth rate of phytoplankton is low. Small phytoplankton and 

bacterioplankton dominate the plankton community leading to reduced production of 

particulate organic nitrogen and carbon.

 Upwelling (Chavez 1996, Pilskaln et al. 1996). Upwelled waters - the deep, cool, 

nutrient-rich waters that replace nearshore surface waters - support rapid growth of

phytoplankton populations. For example, primary production in Monterey Bay exhibits a 

strong seasonal pattern, with lower rates of approximately 500 mg C/m2

/day from 

October to February (non-upwelling season), and higher, more variable rates on the order 

of 1,500 mg C/m2

/day during the upwelling season of March-July/August. There is 

considerable interannual variation in the timing and intensity of upwelling.

 El Niño Events (Chavez 1996, Pilskaln et al. 1996, Chavez et al. 2002). Phytoplankton 

production usually decreases during El Niño events. During the 1992-93 El Niño, total 

phytoplankton abundance and primary production rates measured in March 1992 were 

reduced by factors of three to four compared to March 1990. March 1992 primary 

productivity levels were on the order of only 500 mg C/m2

/day whereas productivity 

values exceeded 1,000 mg C/m2

/day in both March 1990 and 1991. The reduction in 

coastal California primary productivity associated with the strong 1997–1998 El Niño 

was estimated to be 50 million metric tons of carbon (5 × 1013 g C). Chlorophyll was 

reduced on average to less than 50% of normal and was down to 20% of normal during 

the late 1998 upwelling season. This reduction certainly had deleterious effects on 

zooplankton and higher trophic levels.

85 Open Water
Benthic-Pelagic Coupling: There is a two-way exchange, or flux of matter, between the benthos 

and the overlying water body, which is important for both benthic and pelagic compartments. 

This flux occurs through the sinking of non-living organic matter and the active movement of 

organisms.

 Sources of downward flux:

 Particulate Organic Carbon (Pilskaln et al. 1996). Flux rates of small particle flux 

to the deep-sea are coupled to surface productivity. POC flux to midwater sediment 

traps deployed at 450 m varied from a minimum of 10 mg C/m2

/d in December to 120 

mg C/m2/d in May. The mean annual POC flux at 450 m was estimated to be 14.4 g 

C/m2/yr for Monterey Bay.

 Larvacean Houses: The abandoned mucous houses of the giant larvacean 

Bathychordaeus are a significant source of rapid carbon transport through the water 

column and to the deep seafloor. Flux calculations in Monterey Bay, based on an 

average abundance of approximately 1 house per 100 ml, indicate that abandoned 

houses may seasonally account for 15% of overall carbon flux at 500 m (Silver et al. 

1998). More recently, Robison et al. (2005) estimated the production rate of 1 sinking 

Bathychordaeus house per day in Monterey Bay to be approximately 5.4 mg of total 

organic carbon. This number is an underestimate of total flux of giant larvacean 

houses because there are at least two other species found in Monterey Bay.

 Whale Falls (Smith and Baco 2003, Lundsten et al. 2010). Falls of large whales are a 

sporadic source of large-volume labile organic matter to the deep seafloor.

 Settlement of pelagic larvae or juveniles: Flux to the benthos of live organisms 

occurs during settlement of pelagic larval and juvenile stages. The majority of benthic 

invertebrates and fish release pelagic eggs or larvae.

 Deposition of benthic eggs: Some pelagic species (e.g., market squid, grunion) 

deposit eggs on the seafloor. (See “Shelf I & II - Soft Bottom” habitat summary for 

an estimate of the density of benthic eggs laid by market squid in southern Monterey 

Bay).

 Sources of Upward Flux:

 Macrophytes, including large kelps, smaller algae, and seagrasses, are major primary 

producers in the marine environment, but only grow in relatively shallow nearshore 

habitats. Periodically large storms and other disturbances cause parts of the 

macrophytes to break loose and these floating rafts are a source of food and shelter in 

offshore surface waters.

 Many marine organisms (including infaunal and epifaunal invertebrates and demersal 

fish) release eggs and/or larvae that are pelagic.

 Benthic Feeding by Pelagic Organisms: Many pelagic species consume benthic 

organisms living in the soft and hard bottom habitats of the shelf, slope and rise. For 

example, northern elephant seals and sperm whales dive hundreds of meters to 

capture demersal fish. In addition, during ROV surveys of deep-sea habitats in 

Monterey Bay, pelagic organisms, such as medusae and isopods, have been observed 

86 Open Water
grabbing detritus on the seafloor and taking it up into the water column (Bruce 

Robison, pers. comm.).

 Diel Vertical Migration: Nocturnal diel vertical migration is a behavior in which 

organisms residing at deeper depths during the day rise to the surface or near-surface 

waters at night. This behavior enables organisms to feed in the relatively productive 

surface waters at night while avoiding visual predators during the day. Vertical migration 

occurs in almost all of dominant taxa in the Monterey Bay zooplankton community, 

including copepods, krill, crab larvae, cladocerans, polychaetes, chaetognaths, 

siphonophores, ctenophores, larvaceans, and bryozoan larvae (Carr et al. 2008). The 

families Myctophidae (lanternfishes), Gonostomatidae (bristlemouths), Stomiidae 

(dragonfishes), and Gempylidae (snake mackerels) are representative of the types of fish 

species that undergo diel vertical migration (Allen and Cross 2006).

Key Trophic Interactions: Phytoplankton is the primary source of primary production in the 

oceans and forms the base of the open water food web. Zooplankton and small, schooling fishes 

comprise the principal linkage between phytoplankton and higher trophic levels. Sinking 

particulate organic matter (POM) and larger detritus is a primary source of food for pelagic 

organisms in deeper waters.

 Planktivores in the Epipelagic Zone: Planktivory is the base of the pelagic food web in 

the epipelagic zone. Zooplankton (e.g., copepods, krill, jellies, and larval fish and 

invertebrates) and filter feeding fish (e.g., anchovy, sardine, herring) are some of the 

major consumers of phytoplankton.

 Suspension Feeders in the Mesopelagic Zone: Gelatinous zooplankton, including 

pteropods, salps, and appendicularians, are suspension feeders that capture sinking POM 

using mucous sheets, nets, strands, and filters. These organisms play a significant role in 

processing and transporting nutrients throughout the oceans.

 Predation on Schooling Zooplankton and Small Fishes

 Examples of predators of euphausiids (krill): 

 Marine Mammals: blue whale, humpback whale, fin whale, minke whale, gray 

whale.

 Seabirds: Sooty Shearwaters, Common Murres, Rhinoceros Auklet, Cassin's 

Auklet, Ashy Storm-Petrel, Leach's Storm-Petrel, Fork-tailed Storm-Petrel, 

Western Gull, Sabine's Gull, Red Phalaropes.

 Fish: salmon, juvenile rockfish, Pacific butterfish, speckled and Pacific sanddabs, 

Pacific hake, anchovy, blue sharks, Pacific herring, juvenile rockfishes.

 Invertebrates: Humboldt squid, brown sea nettles.

 Examples of predators of market squid: 

 Marine Mammals: California sea lion, Steller sea lion, harbor seal, northern 

elephant seal, northern fur seal, Dall's porpoise, harbor porpoise, Pacific whitesided dolphin, bottlenose dolphin, Risso’s dolphin, short-beaked common 

dolphin, northern right whale dolphin, short-finned pilot whale, killer whale, 

bottlenose whale, beaked whales, sperm whale, humpback whale, fin whale. 

87 Open Water
 Seabirds: Black-footed Albatross, Laysan's Albatross, Sooty Shearwater, Pinkfooted Shearwater, Short-tailed Shearwater, Northern Fulmar, Ashy Storm-Petrel, 

Black Storm-Petrel, Fork-tailed Storm-Petrel. Pelagic Cormorant, Brandt's 

Cormorant, Common Murre, Pigeon Guillemot, Rhinoceros Auklet, Marbled 

Murrelet, California Gull, Mew Gull, Glaucous-winged Gull, Heermann's Gull, 

Black-legged Kittiwake.

 Fish: croakers, plainfin midshipman, curlfin turbot, Pacific sanddab, lingcod, 

petrale sole, California halibut, Pacific bonito, salmon, yellowtail, California 

barracuda, blue shark, common thresher shark, albacore, and blue, bocaccio, 

chilipepper, copper, cowcod, greenblotched, greenstriped, olive, and vermillion 

rockfish.

 Examples of predators of anchovy and sardines: 

 Marine Mammals: California sea lion, Steller sea lion, harbor seal, northern 

elephant seal, northern fur seal, Dall's porpoise, harbor porpoise, Pacific whitesided dolphin, bottlenose dolphin, short-beaked common dolphin, northern right 

whale dolphin, humpback whale, minke whale.

 Seabirds: Western and Clark's Grebes, Brown Pelican, Brandt's Cormorant, 

Pelagic Cormorant, Arctic Loon, Sooty Shearwater, Pink-footed Shearwater, 

Short-tailed Shearwater, Buller's Shearwater, Western Gull, California Gull, Mew 

Gull, Glaucous-winged Gull, Heermann's Gull, Bonaparte's Gull, Black-legged 

Kittiwake, Pomarine Jaeger, Common Murre, Rhinoceros Auklet, Pigeon 

Guillemot, Marbled Murrelet, Xantus's Murrelet, Craveri's Murrelet, Tufted 

Puffin.

 Fish: common thresher shark, blue shark, marlin, yellowtail, albacore, barracuda, 

bonito, mackerel, hake, salmon, California halibut, jacksmelt, topsmelt, plainfin 

midshipman, and bocaccio, canary, chilipepper and vermillion rockfish.

 Invertebrates: Humboldt squid, large jellies (e.g., sea nettle Chrysaora fuscescens)

Productivity Hotspots: The process of upwelling brings iron-replete, nutrient-rich waters into 

the photic zone over the continental shelf. Areas with high rates of upwelling, or where upwelled 

waters are retained, tend to be hotspots of primary productivity.

 Upwelling Centers (Broenkow 1996). Two coastal upwelling centers are present in 

MBNMS: one near Point Año Nuevo and a stronger one south of Point Sur. 

 Upwelling Zones (TNC 2006). Recurring patterns of cold surface water were used to 

identify upwelling zones in northern and central California (Figure 23). Average sea 

surface temperature (based on AVHRR data compiled by NOAA Coast Watch) during 

the upwelling season (March - September) was determined for the years 2000-2003. In 

general, most of the upwelling zones were defined as having May-June temperatures 

between 9-12 oC. The strongest upwelling centers in central California were identified at 

Point Reyes, Davenport, Big Sur and Point Conception; these are areas where upwelling 

is persistent and strong and probably enhanced by coastal headlands. Upwelling of cold 

nutrient-rich waters occurs in early spring and summer and generally peaks in May and 

June; however, there is significant variability in upwelling between years and with 

latitude.

88 Open Water
 Persistent Fronts (CoastWatch 2007, unpubl. data). The CoastWatch Oceanic Front 

Probability Index (FPI) measures the probability of sea surface temperature front 

formation based on data from NOAA's GOES satellites (Nearshore areas are not 

surveyed by the GOES data). Daily average SST is generated from the GOES data. 

Fronts are identified by applying an edge detection algorithm to this daily averaged SST 

field (Breaker et al. 2005). Pixels with gradients greater than 0.375 °C are classified as a 

front. The frontal probability index is then calculated as the number of times a pixel is 

classified as a front divided by the number of cloud-free days per month. Pixels with a 

monthly FPI of 20% or greater are selected and averaged for all months within a given 

season, for the entire duration of the data set (2001-2006). Figure 24 shows the FPI in 

MBNMS by season

 Frontal Zones (Ryan et al. 2005). A transitory frontal zone was identified in northern 

Monterey Bay over the sloping inner shelf in waters ~20- 50 m deep. High concentrations 

of phytoplankton were measured in association with this front.

 Iron-replete Waters (Firme et al. 2003). Iron-replete waters support higher primary 

productivity. In MBNMS, iron-replete waters tend to be found over the continental shelf 

and near upwelling centers. Iron-replete waters occur further from shore in areas with a 

wide continental shelf, such as Monterey Bay and along the coast to the north of 

Monterey Bay, than in areas with a narrow continental shelf, such as the Big Sur coast 

south of Monterey Bay.

HABITAT STRUCTURE

Species Composition: Phytoplankton and zooplankton are very abundant in the surface waters of 

the open water habitat. Crustaceans (copepods, krill, larvae of macro-crustaceans) and larvae of 

pelagic fish constitute a large portion of the zooplankton. The composition of the larval fish 

assemblage varies throughout the year since the timing of spawning and larval duration varies for 

different species, and from year to year with environmental fluctuations. A small number of 

coastal pelagic species, including market squid, northern anchovy, Pacific sardine, Pacific hake, 

and jack mackerel, provide important linkages in the marine food web, supporting a wide variety 

of higher-level predators, including other fishes, seabirds, and marine mammals. Gelatinous 

zooplankton are abundant in both the epi- and mesopelagic zones. Seabirds, marine mammals, 

and leatherback turtles are important predators in the epipelagic waters of MBNMS. Only a few 

species of deep-diving mammals are important predators in the mesopelagic zone.

 Phytoplankton (summarized in Sliver et al. 1996). Netplankton (>20 microns) are 

responsible for seasonal blooms during the upwelling season. The phytoplankton smaller 

than 20 microns (the 2-20 micron nanoplankton and the <2 micron picoplankton) can 

contribute the largest proportion of the phytoplankton biomass and production during 

non-upwelling periods.

 Epipelagic Zooplankton (Silver et al. 1996). Dominant groups are crustacean larvae, 

copepods, euphausiids (krill), ctenophores (comb jellies), hydrozoan medusae, 

siphonophores, and chaetognaths (arrow worms).

 Copepods: Epipelagic zooplankton is often dominated by copepods, including 

Acartia, Paracalanus, Calanus pacificus, Metridia pacifica, Pleuromamma, and 

89 Open Water
Oithona. Copepods appear to be separated to some extent into niches that are 

onshore-offshore, depth and migration related.

 Euphausiids: Net samples collected in Monterey Bay revealed that euphausiid 

schools are highly variable in species and size structure (Croll et al. 2005). On 

average a school consisted of 68.32 (±34.75)% Euphausia pacifica, 30.17 (±34.95)% 

Thysanoessa spinifera, and 1.51 (± 2.56)% other species.

 Gelatinous Organisms: The epipelagic zone contains numerous small hydrozoan 

medusae and larger scyphozoan medusae (e.g., purple striped jelly Chrysaora

colorata, sea nettle Chrysaora fuscescens, moon jelly Aurelia spp., and egg yolk jelly 

Phacellophora camtschatica), siphonophores (e.g., Muggiaea), comb jellies (e.g., 

Pleurobrachia, Leucothea), by-the-wind-sailor (Velella velella), larvaceans (e.g., 

Oikopleura longicauda), salps, doliolids, and pteropods (e.g., Corolla, Clione).

 Meso- and Bathypelagic Zooplankton (Silver et al. 1996). Below the epipelagic zone, 

the zooplankton fauna is much less well known. Recently, observations from ROVs and 

submersibles have allowed study of this group. The invertebrate fauna is dominated by 

eight phyla: 

 Ctenophora (comb jellies): a number of species including Kiyohime usagi;

 Cnidaria: hydrozoans (e.g., Solmissus), the red/purple medusa (Atolla), the black 

medusa (Vampyrocrossota childressi), and siphonophores (Apolemia spp., Praya 

dubia, Nanomia spp.);

 Nemertea (ribbon worms): pelagic worms including Nectonemertes spp.;

 Annelida (segmented worms): mesopelagic worms including Tomopterus, Alciopina, 

Poebius and Vanadus;

 Chaetognatha (arrow worms): at least 15 species in three families, including 

Caecosagitta macrocephala, Flaccisagitta hexaptera, Parasagitta euneritica, 

Pseudosagitta lyra, Pseudosagitta maxima, and Solidosagitta zetesios;

 Arthropoda (mainly Crustacea): ostracods (e.g., Conchoecia spp., Gigantocypris), 

copepods (e.g., the black copepod, Gaussia princeps, and numerous types of red 

copepods), mysid shrimp (e.g., Gnathophausia ingens, Boreomysis spp., Eucopia

spp.), amphipods (over a dozen species including the genera Hyperia, Paraphronima, 

Vibilia, Paracallisoma, Phronima, Scina, Orchomenella, Primno, Cystisoma, 

Streetsia, Cyphocaris, and many species in the family Gammaridea), krill (Euphausia 

pacifica, Nematoscelis difficilis, Thysanoessa spinifera), adult shrimp (Sergestes 

similis, Pasiphaea pacifica, P. emarginata, P. chacei, Parapasiphaea sulcatifrons, 

Gennadas propinquus), and the larvae of galatheid crabs;

 Mollusca: The nektonic mollusks include at least 23 species in 14 families. The most 

common cephalopods in the water column are Doryteuthis (=Loligo) opalescens, 

Histioteuthis heteropsis, Gonatus spp., and Chiroteuthis calyx;

 Chordata: larvaceans including the "giant larvaceans" Bathochordaeus.

 Epipelagic and Mesopelagic Organisms (Bruce Robison, pers. comm.). The upper 

1,000 m of the water column over the Monterey Canyon has been studied by Bruce 

90 Open Water
Robison’s lab at MBARI since 1992. Table 14 provides a preliminary evaluation of the 

relative frequency of sightings of the most commonly observed organisms in 100 m depth 

strata based on data collected between 2000-2002.

 Ichthyoplankton in Central California (Bjorkstedt et al. 1997, 2002). Ichthyoplankton 

were sampled at night from two depth layers (0-27 and 27-55 m depth) at 3 km intervals 

at upwelling fronts along the central California coast during the upwelling season of 1993 

and 1994. Common taxa captured included rockfishes, lanternfishes (Stenobrachius 

leucopsarus, Diaphus theta, and Tarletonbeania crenularis), deep-sea smelts (Bathylagus

spp. and Leuroglossus spp.), sanddabs, and Pacific sardines.

 Ichthyoplankton in Central California (Lenarz et al. 1991). The abundance and 

distribution of late larvae and pelagic juvenile fishes were surveyed at three depths (13, 

37, and 117 m) along the central California coast. The following species were captured: 

rockfish (bocaccio, darkblotched, bank, black, shortbelly, squarespot, canary, stripetail, 

chilipepper, halfbanded, yellowtail, brown, widow, blue, pygmy), Dover sole, rex sole, 

northern anchovy, Pacific hake, speckled sanddab, and Pacific sanddab.

 Ichthyoplankton Assemblages Along the U.S. West Coast (Doyle et al. 2002). The 

ichthyoplankton assemblages prevailing along the U.S. West Coast during spring are 

mainly structured according to water depth and reflect the distribution and habitat 

preference of the adults. They include a coastal/shelf assemblage, a slope assemblage, 

and an oceanic assemblage (Table 15). The slope assemblage represents a transition 

between the shelf and oceanic assemblages, containing some species from both. 

 Epipelagic Nekton (Silver et al. 1996; see Table 16 for a more extensive list of species 

found in central California). The nektonic (strong swimmers) assemblage in the upper 

200 m of the water column of MBNMS is characterized by:

 Cephalopods: The most important squid species along the California coast is the 

market squid (Doryteuthis opalescens). Two large relatively common squid are the 

boreal clubhook squid (Onychoteuthis borealijaponicus) and the robust clubhook 

squid (Moroteuthis robustus). Historically, the Humboldt squid (Dosidicus gigas) had 

been an occasional visitor to central California, but it has been observed in Monterey 

Bay year-round since 2002 (Zeidberg and Robison 2007);

 Cartilaginous Fish: Common species include blue shark, common thresher shark, 

shortfin mako shark, basking shark, and spiny dogfish. Less common species include 

the bigeye thresher shark, salmon shark, soupfin shark, white shark and pelagic 

stingray;

 Bony Fish: The epipelagic bony fishes are very diverse and commonly include 

anadromous fishes (e.g., Chinook salmon), anchovies, sardines, Pacific saury, tunas 

(e.g., albacore, Pacific bonito), jacks and jack mackerels (e.g., Pacific mackerel, jack 

mackerel), swordfish, Pacific hake, Pacific butterfish, yellowtail, North Pacific 

frostfish, opah, louvar, ocean sunfish, and medusafish. Rarer pelagic species include 

the prowfish, oilfish, oxeye oreo, and lancetfish.

 Mesopelagic and Bathypelagic Nekton (Silver et al. 1996; see Table 16 for a more 

extensive list of species found in central California). The meso- and bathypelagic fishes 

are quite diverse, including lanternfishes (Myctophidae), bristlemouths 

91 Open Water
(Gonostomatidae), hatchetfishes (Sternoptychidae), slickheads (Alepocephalidae), 

deepsea smelts (Bathylagidae), spookfishes and barreleyes (Opisthoproctidae), barbeled 

dragonfishes (Stomiidae), snailfishes (Liparidae), eelpouts (Zoarcidae), bigscales 

(Melamphaidae), fangtooths (Anoplogastrodae), dreamers (Oneirodidae), and 

ribbonfishes (Trachipteridae) as well as pelagic juvenile flatfishes and rockfishes.

 General Classification of California Marine Fishes: Allen and Pondella (2006) used 

cluster analysis to identify fish species assemblages in different habitats (by depth and 

latitude). The following species assemblages occur in open water habitats of central 

California: 

 Open Ocean Pelagics (rarely over continental shelf): sharks (soupfin, white, salmon, 

common thresher, blue, shortfin mako, bigeye thresher, smooth hammerhead), ocean 

sunfish, tunas (albacore, bluefin, bigeye, skipjack, yellowfin), opah, swordfish, 

striped marlin, dolphinfish;

 Migratory Coastal Pelagics (migrate northward in summer and southward in winter): 

Pacific bonito, yellowtail;

 California Coastal Pelagics (common over continental shelf): northern anchovy, 

Pacific sardine, Pacific pompano;

 Southern Coastal Pelagics (more abundant off southern California, but also found off 

central California): Pacific and jack mackerel, California barracuda and white 

seabass.

 Epipelagic Assemblages in Central and Northern California: NCCOS (2003) used 

data collected from NMFS midwater trawl surveys to identify seven assemblages of 

pelagic fish and invertebrate species that tended to be collected together off northern and 

central California (Table 11). Assemblages differed to some extent by depth, but all occur 

in epipelagic waters. 

 Midwater Fish Species Composition in Central and Northern California (Sullivan 

1995). Cluster analysis was used to group northern and central California Commercial 

Passenger Fishing Vessel (CPFV) fishing locations based on similarities in species 

composition. Most of the fishes included in the analyses were rockfishes (RF); other 

species included lingcod, Pacific hake, sablefish, Pacific sanddab, and petrale sole. Fishing 

locations ranged from Pescadero Point to Point Sur. The data set was separated into two 

species groups: midwater schooling species, and benthic species. For the midwater 

schooling species, six location groups were geographically and bathymetrically distinct: 

 Canyon Ledge (edge of Monterey Canyon and edge of Carmel Canyon): chilipepper 

with Pacific hake;

 North Shelf (shelf near shelf edge starting west of Monterey Canyon and extending 

northwest along coastline to Davenport): chilipepper with yellowtail and bocaccio RF;

 South Depth Transition (mid-depth areas between Monterey and Point Sur): 

chilipepper with yellowtail, blue and widow RF;

 Monterey Flats (mid-depth locations, south side of Monterey Bay, with few mid-depth 

nearshore locations adjacent to North Shelf area): widow, yellowtail, bocaccio RF;

92 Open Water
 South Shallow (all shallow locations from Monterey to Point Lobos): blue and 

yellowtail RF;

 North Shallow (shallow locations from Davenport north to Pescadero Point); blue and 

black RF, with yellowtail RF.

 Seabirds and Mammals (Harvey 1996, Research Planning Inc. 2006). The spatial and 

temporal patterns of seabird and marine mammal abundance in MBNMS determine 

species composition at any given location (Table 12). Many of the species that occur in 

MBNMS are highly transitory; some species migrate through MBNMS while others 

move into the sanctuary seasonally to feed on locally abundant prey. Some species are 

most common in the sanctuary during the breeding season and others tend to be resident 

year-round. The movements of many species appear to be associated with patterns in prey 

abundance and oceanographic conditions.

 Marine Mammals (Keiper et al. 2005). In a study of marine mammal occurrence 

patterns along the central California coast (Bodega Bay to Monterey Bay) during spring 

and summer from 1986-1994 and 1997-1999, 23 species were observed; 54% of all 

sightings were pinnipeds (seals and sea lions), 36% odontocetes (toothed whales, 

dolphins and porpoise), 9% mysticetes (baleen whales) and 1% sea otters. 

 Species sighted most frequently: California sea lion, northern fur seal, Pacific whitesided dolphin, Dall’s porpoise, harbor porpoise, and humpback whale.

 Species sighted infrequently or seasonally: gray whale, minke whale, sei whale, shortbeaked and long-beaked common dolphins, Risso’s dolphin, northern right whale 

dolphin, killer whale, Cuvier’s beaked whale, Steller sea lion, and northern elephant 

seal.

Species Composition Shifts: 

 Natural Changes: Changes in the physical and chemical properties of surface waters, 

such as iron availability and temperature, may have substantial impacts on the abundance 

of phytoplankton as well as the species composition of the phytoplankton community. 

Reductions in phytoplankton biomass may lead to changes in the abundance of organisms 

at higher trophic levels. These changes may occur over short time periods, such as 

relaxation events during the upwelling season, or they may persist for years (e.g., El Niño 

events) or even decades (e.g., PDO).

 Harmful Algal Blooms (Scholin et al. 2000). In May 1998, a harmful algal bloom 

was observed in Monterey Bay. During the HAB event, the dominant diatom species 

switched from primarily Chaetoceros spp. to Pseudo-nitzschia australis. P. australis

produces domoic acid, a neurotoxin, which was found in high levels in anchovy, 

sardines and California sea lions in central California.

 Iron Availability (Hutchins et al. 1998, Firme et al. 2003). Iron in surface waters 

tends to be more available during upwelling and more limited during upwelling 

relaxation events. Iron-replete and iron-limited waters tend to differ in the associated 

phytoplankton communities and relative biomass at many trophic levels:

93 Open Water
 Characteristics of Iron-replete Waters: Ample iron allows for unrestricted 

growth of large diatoms and dinoflagellates. The community growth rate is high 

and supports increased biomass at upper trophic levels.

 Characteristics of Iron-limited Waters: Pico and nanoplankton dominate the 

plankton community. Large diatoms and dinoflagellates are rare. Biomass at 

upper trophic levels is reduced.

 Upwelling (Silver et al. 1996). Species composition of plankton (>20 microns) 

changes under different oceanographic conditions. During the upwelling season 

(generally spring and summer), colony-forming diatoms, particularly species of 

Chaetoceros, Rhizosolenia, Skeletonema, and Pseudo-nitzschia are dominant. In the 

fall and occasionally during interludes in the upwelling season, dinoflagellates tend to 

dominate (especially during warming intervals). Aggregations of dinoflagellates, such 

as Prorocentrum, Ceratium, and Gonyaulax, sometimes produce red tides during this 

period.

 El Niño Events: El Niño events off central California affect the composition and 

structure of biological communities. Some of the changes appear to be related to 

reduced upwelling-associated primary production and a subsequent reduction in 

zooplankton and forage fish biomass. In addition, changes in current patterns and 

increased water temperature are related to an increase in the abundance of warmwater associated pelagic species and a decrease of cold-water associated pelagic 

species off central California.

 Phytoplankton in Monterey Bay (Silver et al.1996). During the 1982-83 El 

Niño event (the strongest in a century) dramatic changes in the phytoplankton 

composition of Monterey Bay were documented, including increased relative 

abundance of dinoflagellates and tropical species, decreased abundance of 

diatoms, and a significant increase in species diversity of plankton (>20 microns).

 Zooplankton in Monterey Bay (Marinovic et al. 2002). Zooplankton abundance 

and euphausiid community composition were sampled seasonally (spring, 

summer, fall) within Monterey Bay, California, between 1997 and 1999. During 

the 1997-98 El Niño, both total zooplankton and krill abundance dramatically 

declined coincident with a rapid increase in SST and mixed layer depth. The 

composition of the euphausiid community also changed; the relative abundance of 

the southern species Nyctiphanes simplex increased while the abundance of cold 

temperate Euphausia pacifica and northern Thysanoessa spinifera declined. 

Zooplankton abundance, euphausiid community composition, and physical 

oceanographic parameters gradually returned to a more typical upwellingdominated state in the spring and summer of 1998. By the spring and summer of 

1999, both zooplankton and euphausiid abundance had increased to the highest 

levels recorded during the 3-year study. Both E. pacifica and T. spinifera

abundance increased while N. simplex was absent. These changes reflected the 

cooler, highly productive environmental conditions associated with the 1998/1999 

La Niña.

 Humboldt Squid in Monterey Bay (Zeidberg and Robison 2007). Humboldt 

squid recently expanded its perennial range into Monterey Bay. Based on monthly 

94 Open Water
ROV surveys of the water column (0-1,000 m) in Monterey Canyon, this species 

was not observed in Monterey Bay from 1989 to 1997. Humboldt squid first 

appeared during the onset of the strong 1997–1998 El Niño and persisted through 

most of 1998. In 2002 Humboldt squid returned in abundance, associated with a 

small El Niño event, and have been present in Monterey Bay year-round ever 

since. The numbers of Pacific hake, a prey items of Humboldt squid, have been 

significantly lower during periods when the squid was present and the seasonal 

pattern of hake abundance also has been altered. The authors found that the

sustained range expansion of Humboldt squid coincided with changes in climatelinked oceanographic conditions and a reduction in competing top predators (such 

as billfish and tuna).

 Migratory Fish: Species of migratory fish with a distribution centered south of 

Point Conception (e.g., young thresher sharks, louvar, skipjack tuna, striped 

marlin, Pacific mackerel, and jack mackerel) may increase in relative abundance 

off of central California during warm water events (Leet et al. 2001, Starr et al. 

2002a). Southern species with elevated abundance in MBNMS during El Niño 

events include kelp bass, Pacific barracuda, and bluefin tuna.

 Seabirds (Roberson 2002). Species that migrate to MBNMS primarily during 

warm-water events include: Black-Vented Shearwater, Least Storm-Petrel, 

boobies, tropicbirds, frigatebirds, and Craveri’s Murrelet. 

 Cetaceans in Monterey Bay (Benson et al. 2002). The assemblage of 

odontocetes (toothed cetaceans) in Monterey Bay became more diverse during the 

1997-98 El Niño, with a temporary influx of warm-water species (e.g., common 

dolphins) and decreased abundance of cold-water species (e.g., Dall’s porpoise). 

A dramatic reduction in zooplankton (e.g., krill) biomass offshore during the El 

Niño appears to have concentrated baleen whales (e.g., humpback whales, blue 

whales) in the remaining productive coastal upwelling areas, including Monterey 

Bay. 

 Pacific Decadal Oscillation (PDO): The PDO is a long-term pattern of North Pacific 

climate variability with phases that persist from 20-30 years. The positive (warm) 

phase of the PDO is characterized by cooler than average sea surface temperatures 

and air pressure near the Aleutian Islands and warmer than average sea surface 

temperatures near the California coast. The negative (cool) phase tends to reverse 

these climatic patterns. A full cycle of the PDO - a warm phase and a cool phase -

appears to take approximately 50 years. Instrumental data provide evidence for two 

full cycles: cool phases from about 1900 to 1925 and 1950 to 1975 and warm phases 

from about 1925 to 1950 and 1975 to the mid-1990s (Chavez et al. 2003).

 Salmon (PFEL Climate Variability and Marine Fisheries 2005). Salmon stocks

off California, Oregon, and Washington increase during the cool phase and 

decrease during the warm phase of the PDO. Salmon stocks in Alaska show the 

opposite pattern. This "reciprocal oscillation" has been observed over the 70 years 

of available records.

 Sardine vs. Anchovy (Chavez et al. 2003). Off central California, landings of 

anchovies and sardines appear to vary with the PDO. Anchovy abundance is 

95 Open Water
highest during cool phases and sardine abundance is highest during warm phases 

of the PDO. In the mid-1970s, the Pacific changed from a cool "anchovy regime" 

to a warm "sardine regime". A shift back to an “anchovy regime” appears to have 

occurred in the middle to late 1990s.

 Human-Induced Changes: A variety of human activities have alter species composition 

in the open water habitat. Whaling, seal and otter hunting, and collection of seabirds and 

their eggs led to the drastic reduction of some marine mammals and seabird populations 

in the 1800s and 1900s; many of these populations are still recovering (Tables 6 and 7).

Though seabirds and marine mammals are protected from directed take, oil spills, ship 

strikes, and bycatch in fisheries can result in significant mortality events. Strong fishing

pressure on some pelagic species, such as sardines, basking sharks and large tunas, has 

contributed to reduced abundance of some fish populatins in the open water habitat

(Table 4).

 Bycatch of Sensitive Species in Gillnets (Forney et al. 2001). During the 1980s and 

1990s, there appeared to be extensive bycatch of seabirds and marine mammals in 

central California's set gillnet fishery. Species observed entangled in gillnets during 

1990-1994 include two Double-crested Cormorants (Phalacrocorax auritus), one 

Pacific Loon (Gavia pacifica), six unidentified alcids, three unidentified cormorants, 

101 California sea lions (Zalophus californianus), 44 harbor seals (Phoca vitulina), 

and 18 northern elephant seals (Mirounga angustirostris). Historical entanglement 

rates for three sensitive species (sea otters, harbor porpoise, and Common Murres) 

were combined with estimated fishing effort in 1995-1998 to create mortality 

estimates of 5,918-13,060 Common Murres (S.E. 477-1,252), 144-662 harbor 

porpoises (S.E. 18-53), and 17-125 sea otters (S.E. 4-25). In 2002 the California 

Department of Fish and Game implemented a prohibition on the use of set gillnets in 

waters shallower than 60 fathoms (approximately 110 meters) in central California to 

reduced the risk of entanglement of seabirds and marine mammals, including sea 

otters, harbor porpoise, and Common Murres. 

 Oiling of Sensitive Species (Luckenbach Trustee Council 2006). In 2001, extensive 

tarball deposits along the coastline of MBNMS were estimated to have killed 

thousands of seabirds, including grebes, cormorants and Common Murres. The source 

of these tarballs remained unknown for several months, but was ultimately tracked to 

the SS Jacob Luckenbach which sank off San Francisco in 1953 (currently located in 

the Gulf of the Farallones National Marine Sanctuary). Subsequent investigative work 

matching the oil samples indicated this vessel was the likely source of a number of 

tarball and oiled bird incidents dating back to at least 1992. During the period of spills 

linked to the SS Jacob Luckenbach, over 51,000 birds and eight sea otters were estimated to have been killed from north of Bodega to Point Lobos. The remaining oil 

and fuel were removed from this sunken ship removing threat of further spills.

 Long-term Changes in Trophic Level of Marbled Murrelet: Becker and 

Beissinger (2006) compared the stable isotope composition of feathers from Marbled 

Murrelets living along the central California coast in the last decade with those 

collected over 100 years ago. Nitrogen isotope ratios indicated that during the prebreeding season murrelets were foraging on prey one-half a trophic level lower than 

they were 100 years ago. Carbon isotope ratios suggest that this trophic shift is caused 

96 Open Water
by murrelets now eating less anchovy, sardine, and squid (high-trophic level), and 

more juvenile rockfish (mid-trophic level) and krill (low-trophic level). The authors 

suggest that high-trophic level prey (anchovy, sardine and squid) are now less 

available to Marbled Murrelets because of human extraction of these prey species.

Species Diversity and Species Richness: The central California coast is an area where the ranges 

of subtropical species and temperate species overlap. The transitional nature of the area 

contributes to both the high species richness and the diversity observed at all trophic levels. 

Processes, such as El Niño, that alter the location and physical features of water masses have 

measurable influences on species diversity in the sanctuary (see “Species Composition Shifts –

Natural Changes” section above for more details).

 Deep-sea Fishes (Neighbors and Wilson 2006). Species diversity of the deep sea fish 

fauna in the eastern and central Pacific tends to increase with distance offshore. The 

nutrient-rich waters closer to shore support fewer, but more abundant species than 

offshore waters, which support a higher diversity of species that are less abundant.

 Seabirds (NCCOS 2003, 2007). Areas in MBNMS with the highest species diversity of

seabirds were Pioneer Canyon, Año Nuevo/Ascension/Cabrillo Canyon, inner Monterey 

Bay, inner Monterey Canyon, Carmel Canyon and the slope off Point Sur. The seabird 

fauna is the least diverse during the upwelling season (March – August) and the most 

diverse during the Davidson Current season (November – March).

 Marine Mammals.. The marine mammal fauna is the most diverse in the fall because 

this is a time when summer migrants (e.g., blue, humpback and minke whales) are still 

present and winter migrants (e.g., many species of dolphin) begin to arrive (Harvey 

1996).

Biomass: Generally, zooplankton biomass in the California Current is highest in the upwelling 

season (late spring-early fall). This high biomass at lower trophic levels supports seasonally 

elevated biomass at higher trophic levels, such as pelagic predatory fishes, seabirds, and marine 

mammals. Both phytoplankton and zooplankton production varies with physical factors, 

including oceanographic conditions, temperature, currents, and eddies.

 Zooplankton (summarized in Silver et al. 1996). In MBNMS, zooplankton are usually 

more abundant in waters over the continental shelf compared to waters in the offshore 

California Current. Zooplankton abundance generally declines from the epipelagic to the 

mesopelagic and bathypelagic zones. A strong seasonal pattern is evident in zooplankton 

biomass, with the highest amounts observed in spring and summer. Spawning of pelagic 

larvae by shallow benthic invertebrates may be timed to coincide with phytoplankton 

blooms. Some circulation features can concentrate zooplankton biomass. In a study of 

epipelagic zooplankton biomass at three stations offshore of Monterey Bay, the annual 

mean zooplankton biomass ranged from 216.7 to 726.4 mg/m2 (Little 2003).

 Jellies (Graham et al. 2010). Acoustic-sampling techniques, in combination with net 

sampling, was used to estimate the abundance and distribution of scyphozoan jellies

(Aurelia spp., Chrysaora colorata, Chrysaora fuscescens, and Phacellophora 

camtschatica) off central California. Echo-integration methods applied to regions where 

97 Open Water
net catches contained jellyfish resulted in an estimate of a mean density of 251,522 jellies

per square nautical mile and a mean concentration of 0.003 jellies/m3.

 Euphausiids (Croll et al. 2005). Topographic breaks in the continental shelf located 

down-current from upwelling centers work in concert with the diel vertical migratory

behavior of euphausiids to collect and maintain large concentrations of euphausiids. For 

example, dense schools of euphausiids aggregate between 80 and 180 m on the offshore 

edge of the Monterey Canyon. High euphausiid densities are supported by high primary 

production between April and August and a submarine canyon that provides deep water 

down-current from an upwelling region. Mean euphausiid densities in Monterey Bay are 

1.3 g/m3 (39 individuals per m3). Peak euphausiid densities occur in late summer/early 

fall, lagging the seasonal increase in primary production by 3 to 4 mo.

 Harvested Species: Harvest removes biomass of targeted fish and invertebrate

populations. For some targeted species, biomass is substantially reduced compared to 

unfished biomass levels (Tables 3 and 4). However, the size of some of these 

populations, such as anchovy and sardine, is affected strongly by environmental 

conditions (e.g., El Niño events, PDO).

 Deep-sea Fishes (Neighbors and Wilson 2006). Biomass of the deep-sea fish fauna in the 

eastern and central Pacific tends to decrease with distance offshore. The nutrient-rich, 

cooler coastal waters support higher abundance and biomass than the warmer waters of 

the central Pacific.

 Leatherback Turtles Population Estimate (Benson et al. 2007). Aerial surveys over 

waters <92 m in depth off central and northern California during 1990−2003 were used to 

determine foraging population estimates for leatherback turtles. The greatest proportion 

of turtles was encountered within the two central California strata (Monterey Bay and 

Gulf of the Farallones), accounting for an average of 72% of the total abundance. For all 

years combined, estimated leatherback turtle abundance averaged 140 within the central 

California strata and 178 for the entire study area. Average density estimates were 3.6 

and 1.3 turtles/km2 for the Gulf of the Farallones and the Monterey Bay strata, 

respectively.

 Leatherback Turtle Hotspots (Benson et al. 2007, 2011). Hotspots, areas where 

leatherback sea turtles have been encountered most frequently, were identified in central 

California by the offshore Environmental Sensitivity Analysis (RPI 2006) and updated 

based on personal communication with Scott Benson (March 2012). In summer and fall 

leatherbacks are most frequently encountered over the shelf in northern Monterey Bay, 

between Pigeon Point and Pillar Point, and between Half Moon Bay and San Francisco 

(Figure 20). These hotspots are part of the principle foraging area - Area 1 identified in 

Title 50 Code of Federal Regulations, Part 226.207 (77 Federal Register 4170). Brown 

sea nettles (Chrysaora fuscescens), the preferred prey of leatherback sea turtles, are 

observed in high densities in the principle foraging area, particularly within upwelling 

shadows and retention areas. Critical habitat for leatherback sea turtles also includes 

offshore waters utilized by leatherbacks when gelatinous prey availability in the principal 

foraging area is poor (Figure 20).

 Seabirds (NCCOS 2003, 2007). Sooty Shearwaters and Common Murres dominate 

seabird biomass along the central California coast. In MBNMS, high seabird biomass 

98 Open Water
densities occur off Half Moon Bay, just south of Point Año Nuevo, and in inner 

Monterey Bay. Biomass densities are especially high over the continental shelf and slope.

 Seabirds (Research Planning Inc. 2006). Areas of high seabird biomass often are close to 

breeding colonies, along migration routes, or in areas where prey tends to be seasonally 

abundant. Figure 21 shows the location of hotspots for some species of seabirds. 

Additional information is available in ‘Feeding Ground' and ‘Spawning/Breeding 

Ground’ sections above.

 Seabird Hotspots in the California Current (Nur et al. 2011). Data from at-sea surveys 

of seabirds over an 11-year period (1997-2008) were combined with information on 

habitat features (bathymetry and oceanography) to predict hotspots for seabirds in the 

California Current Ecosystem. Single species model predictions for 16 species were 

combined to identify potential hotspots of multispecies seabird aggregation using three 

criteria: overall abundance among species, importance of specific areas to individual 

species, and predicted persistence of hotspots across years (Figure 25). Areas of high 

overall abundance and high species importance were associated with the Farallon Islands

and Monterey Bay. There was substantial overlap between areas identified as highly 

persistent and those identified as having high summed abundance and/or high species

importance. No hotspots were apparent more than 90 km offshore. Bathymetric variables 

were found to be important predictive variables of seabird hotspots, whereas 

oceanographic variables derived from remotely sensed data were generally less 

important. 

 Marine Mammals (NCCOS 2003, Research Planning Inc. 2006). Areas of high biomass 

of marine mammals often are close to breeding colonies (e.g., pinnipeds), along 

migration routes (e.g., gray whales), or where prey tends to be seasonally abundant. 

Figure 22 shows the location of hotspots for some species of marine mammals.

Additional information is available in ‘Feeding Ground' and ‘Spawning/Breeding 

Ground’ sections above.

 Blue Whales (Croll et al. 2005). Blue whale sightings from whale watching trips 

between 1992 and 1996 indicate that blue whales were seasonally present in Monterey 

Bay between June and November. Blue whale density during the time period of peak 

abundance (August) was 0.034 whales km2. Blue whales were concentrated along the 

edge of the Monterey Canyon.

 Cetaceans in the California Current Ecosystem (Barlow et al. 2009, Forney et al. 

2012, Becker et al. in review, Karin Forney, pers. comm.). Data from 15 large-scale 

shipboard cetacean and ecosystem assessment surveys conducted in the temperate and 

tropical eastern Pacific during the period from 1986 to 2008 were combined with 

environmental predictors (e.g., bathymetry, salinity, sea surface temperature) to model 

finer scale cetacean densities within the California Current Ecosystem. The models were 

developed and validated for individuals species or species groups. Modeled densities for 

7 toothed whales and 3 baleen whales are shown in Figure 26. The highest predicted 

densities occurred in MBNMS for blue whales and humpback whales, to the west of 

MBNMS for offshore species (e.g., fin whales, sperm whales, beaked whales, striped 

dolphins), to the north of MBNMS for northern species (Dall’s porpoise, northern right 

99 Open Water
whale dolphin, Pacific white-sided dolphin), and to the south for warm-temperate species 

(short-beaked common dolphin).

 Harbor Porpoise (Carretta et al. 2009). Two sets of aerial survey transects, one inshore 

(out to the 90 m isobath) and one offshore (between the 90 and 200 m isobath), 

conducted between 2002-2007 were used to estimate density and abundance of harbor 

porpoise between the CA/OR border and Pt. Conception. In MBNMS, harbor porpoise 

density was highest in the inshore area and lowest in the offshore area south of Pt. Sur 

(Figure 27).

SPECIES OF SPECIAL INTEREST

Many species of special resource management interest occur in the open water habitat of MBNMS 

Tables 3-7. Most of these species are wide-ranging and not affiliated closely with benthic habitats.

• Species Landed in MBNMS: Of the 10 invertebrate and 156 fish species that are 

commonly caught and sold in the commercial and/or recreational fisheries of MBNMS 

(Starr et al. 2002a), one invertebrate (market squid) and 55 fishes occur in the open water 

habitat. 

• Endangered and Threatened Species: There are no known endangered or threatened 

invertebrate species in the open water habitat. Three threatened and two endangered fish 

taxa occur in open water during a portion of their life, but they also rely on coastal 

habitats that are negatively impacted by human activities. The leatherback turtle is the 

only endangered reptile to occur regularly in the open waters of the sanctuary. All of the 

3 listed seabirds and 10 listed marine mammals occur in open water.

• Other At-Risk Species: None of invertebrate taxa in the federal waters of MBNMS are 

considered to be at-risk. Five at-risk fishes occur in open water. The leatherback turtle, 

along with all 11 at-risk birds and 9 at-risk mammals, occur in open water.

Additional species of special resource management interest in the open water habitat include:

• Krill due to their important ecological role as a primary food source for seabirds, marine 

mammals and fishes;

• Sooty Shearwaters which reach extremely high densities during the summer, when 

hundreds of thousands of adults forage for fishes and squid in sanctuary waters after 

migrating from the southern hemisphere;

• Seabirds (e.g., Common Murres, Rhinoceros Auklets, Brandt’s Cormorants, loons, grebes) 

and marine mammals (e.g., harbor seals, harbor porpoise, elephant seals, sea otters) 

vulnerable to disturbance, injury or death from human activities in the sanctuary such as oil 

spills and entanglement in fishing gear.

100 Open Water
Submarine Canyon

HABITAT OVERVIEW

Submarine canyons are prominent geomorphic features within Monterey Bay National Marine 

Sanctuary (Figure 2). Submarine canyons, much like onshore river valleys, are erosional features 

that carve into the seafloor and expose older, underlying strata in canyon walls. Submarine 

canyons have sinuous channel axes, sometimes with a number of branching channels. Monterey 

Canyon, in the center of Monterey Bay, is the largest of these submarine features – both in the 

sanctuary and along the entire coast of North America. Similar in size to the Grand Canyon in 

Arizona, it is 470 km long and approximately 12 km wide at its widest point, with a maximum 

rim to floor relief of 1,700 meters. Numerous smaller canyons cut into the continental shelf and 

slope of the sanctuary. The walls and floors of submarine canyons constitute approximately 

16.3% of the area of the sanctuary (Table 2). Within the federal study area, the vast majority of 

canyon habitat in is soft-bottom (1,993 km2) and a much smaller portion is hard-bottom (126

km2

).

The heads of submarine canyons tend to be found near the continental shelf edge. In areas with a 

very narrow continental shelf, the canyon heads are located near the shoreline and appear to act 

as major conduits for the transport of sediments to the deep sea. The heads of Monterey Canyon, 

Carmel Canyon, and Partington Canyon reach very close to shore and are probably the most 

active conduits of materials to deep-water habitats in the sanctuary. Submarine landslides on 

steep canyon walls also deposit sediments on the canyon floor. Organic material associated with 

sediments, including nutrients and pollutants, are delivered to the canyon floor by sediment 

transport events. These processes may also lead to an accumulation of marine debris on the 

canyon floor, or move it out on the Monterey Fan. Sediment transport events are thought to be 

episodic. Potential triggering events include storms, earthquakes, moderate sea and surf 

conditions, and flooding rivers.

Most organisms observed in canyons are not unique to canyon systems but are also found at 

similar depths outsides canyons. Because submarine canyons extend from shallow waters to the 

deep sea, they contain an incredible diversity of organisms. Mobile fishes and invertebrates, such 

as prickly sharks and krill, have been found to aggregate in canyon heads and along canyon 

walls. Rocky outcrops along canyon walls are colonized by invertebrates - including sponges, 

feather stars, corals and tunicates - and provide shelter for a variety of fishes. Clams and worms 

burrow into canyon walls. Soft sediments on the canyon walls and floor support a diverse 

community of invertebrates (e.g., sea pens, sea cucumbers, brittle stars, sea stars) and fishes 

(e.g., flatfishes, ratfishes, whiptails, grenadiers, sablefish, hake, thornyheads).

SEARCH TOPIC TABLE

HABITAT FUNCTION

Functional Habitats:

Nursery Habitat: See page 102

101 Submarine Canyon
Feeding Ground: See page 103

Spawning Ground: See page 103

Migratory Corridor: See page 104

Biogenic Habitat: See page 104

Energy Flow:

Primary Production:

No specific information was found on this topic in this habitat 

category. See “Slope – Hard Bottom” habitat section for general 

information on this topic.

Benthic-Pelagic Coupling: See page 106

Key Trophic Interactions:

Detritivores, animals that feed on organic matter found in or on 

bottom sediments, dominate benthic communities in the deep

sea. Most of the detritus that arrives in deep-sea habitats, 

originated in coastal habitat and surface waters where sunlight 

fuels photosynthesis.

Key Trophic Cascades: No specific Information found during literature review

Productivity Hotspots: No specific Information found during literature review

HABITAT STRUCTURE

Species Composition: See page 107

Species Composition Shifts: See page 110

Species Diversity and Richness: See page 111

Biomass: See page 111

Key Species Interactions No specific information was found on this topic.

MOVEMENT AND DISPERSAL See page 112

SPECIES OF SPECIAL INTEREST See page 113

HABITAT SUMMARY

HABITAT FUNCTION

Functional Habitats

Nursery Habitat: The shallow waters of submarine canyon heads appear to be used as nursery 

habitats by some species of fish and invertebrates. Over time, individuals move down the canyon 

into deeper habitats as they grow larger and mature.

 Spot Prawn (Schlining and Spratt 2000). A comparison of the size distribution of male 

spot prawn (Pandalus platyceros) collected at multiple sites along the edge of Carmel 

Canyon (between 200-400 m) showed that the canyon head might be acting as a refuge 

for smaller males. The authors suspect that juveniles may use even shallower habitats of 

the canyon head, 100-200 m, as a nursery habitat.

102 Submarine Canyon
 Pacific Hake (Vetter and Dayton 1999). Juvenile Pacific hake (Merluccius productus)

were so abundant between 150 and 200 m in Scripps Canyon (in southern California), 

that at times their bodies obscured visibility. Large numbers of juvenile hake have been 

observed in Carlsbad and Redondo Canyons.

Feeding Ground: Consumers in canyons potentially experience enhanced food supply, 

compared to those at similar depths outside canyons, through several mechanisms: suspension 

feeders may benefit from accelerated currents; demersal planktivores may exploit dense layers of 

krill and zooplankton that become concentrated in canyons during downward vertical migrations; 

and food for detritivores may be increased by high sedimentation rates in canyons or through 

accumulation of macroalgal detritus (Vetter and Dayton 1998, 1999).

 Pacific Hake (Vetter and Dayton 1999). Juvenile Pacific hake were very abundant in 

Scripps, Carlsbad, and Redondo Canyons in southern California. High abundance in 

canyons may be due, in part, to higher food availability in the canyons.

 Macroalgal Detritus (Vetter and Dayton 1999). In the axis of La Jolla and Scripps 

Canyon, megafaunal abundance was positively associated with macroalgal detritus. This 

increased abundance appeared to be due to utilization of detritus as food by some species 

(e.g., sea cucumbers and sea urchins) and as food and shelter by other species (e.g., crabs 

and amphipods).

 Benthic Siphonophores (Vetter and Dayton 1999). The greater abundance of the benthic 

siphonophore Dromalia alexandri in La Jolla and Scripps Canyons, relative to adjacent 

shelf and slope habitats, may be due to enhanced current flows in canyon habitats that 

increase flux of food particles past this filter feeder. This species is common in submarine 

canyon habitats of MBNMS.

 Large Animals Falls (Smith and Baco 2003, Goffredi et al. 2004, Lundsten et al. 2010).

Recent time-series studies of natural and implanted deep-sea whale falls off California 

indicate that these carcasses initially attract mobile scavengers, such as sleeper sharks, 

hagfish, rattails and crabs, that can remove soft tissue at high rates (40-60 kg/day). 

Degrading carcasses also serve as a food source for numerous species of benthic 

invertebrates including polychaete worms, echinoderms (brittle stars, sea cucumbers, sea 

urchins), sipunculids, and nemerteans. Over a 10-year period of exploration of ~180 km2

of seafloor in Monterey Bay, the remains of eight marine mammals (three whales, two 

seals, one elephant seal, and two of unknown identity) have been discovered. Six of the 

eight remains were found in the axes of submarine canyons, suggesting that deposition of 

large animal remains is relatively common in submarine canyon habitats and an 

important source of organic matter to these habitats. Carcass degradation occurs subdecadally.

Spawning Ground: Fish that typically inhabit the deeper waters of the rise and slope may move 

up the axes of submarine canyons into the shallower waters of the canyon head to spawn. The 

restricted area of the canyon heads may concentrate spawning fish into dense aggregations.

 Elasmobranchs: Possible mating aggregations of filetail catsharks (Parmaturus 

xaniurus) and longnose skates (Raja rhina) were observed during ROV surveys of the 

headward part of Ascension Canyon (Bizzarro et al. 2003). Prickly sharks (Echinorhinus 

103 Submarine Canyon
cookeri) aggregate frequently over the head of the Monterey Canyon and it is possible 

that they are aggregating to mate (Starr et al. 1999).

 Pacific Hake: Spawning populations of Pacific hake (Merluccius productus) are found at 

depths of 130-500 m (Airamé et al. 2003).

Migratory Corridor: The axis of a submarine canyon may serve as a migratory corridor for 

mobile species. Some species may move up or down the canyon for seasonal migrations (e.g., 

feeding or breeding migrations). Some species may progressively move down the canyon as they 

grow older and larger (i.e., ontogenetic migration).

 Many species of flatfish have juveniles that settle in shallower habitats and slowly move 

into deeper waters as they mature. Many flatfish species may use progressively deeper 

soft-bottom habitats of submarine canyons during this process of ontogenic migration.

 Prickly sharks (Echinorhinus cookei), sevengill sharks (Notorynchus maculutus), and 

lysianassid amphipods are among several deep-water species that migrate up the 

Monterey Canyon into the shallow head (Varoujean 1972, Okey 2003).

Biogenic Habitat: Many species of structure-forming invertebrates are found along the walls of 

submarine canyons. Though structure-forming invertebrates are more common on hard 

substrates, some species (e.g., sea pens) are found in soft sediments. Some demersal fishes and 

mobile invertebrates (e.g., crabs and shrimp) are found in association with structure-forming 

invertebrates. Two other biogenic habitats common in canyons - chemosynthetic biological

communities (CBCs) and macrophyte (large plant) detritus - are important sources of both food 

and shelter for demersal fish and invertebrates. CBCs are most common along canyon walls 

whereas macrophyte detritus accumulates along the canyon floor. Detailed information about 

these two biogenic habitats can be found in the “Chemosynthetic Biological Communities” and 

“Macrophyte Detritus” habitat sections.

• Structure-forming Invertebrates are an important component of fish habitat. Most 

rockfish observed in Soquel Canyon were associated with some habitat structure, including 

crinoids, sea anemones, and sponges (Yoklavich et al. 2000). Monterey Bay Aquarium

Research Institute (MBARI) scientists have used ROVs to survey canyon habitats in the 

Monterey Bay region since 1989. Structure-forming species, including stony corals, black 

corals, hydrocorals, crinoids, sponges, and sea pens are frequently observed in submarine 

canyon habitat (Figures 8 and 13).

• Structure-forming Invertebrates in Ascension and Carmel Canyon (Bianchi 2011). 

The manned submersible Delta was used to survey megafaunal invertebrates and 

demersal fishes during 12 dives in Ascension Canyon (182-319 m) and 12 dives in 

Carmel Canyon (90-305 m). Structure-forming invertebrates were classified as 

megafaunal invertebrates with complex morphology and/or large size (>20 cm in height). 

Fish associations with structure-forming invertebrates were recorded.

 Ascension Canyon: A total of 3,155 structure-forming invertebrates were 

observed during 12 submersible dives. The following types of structure-forming 

species were observed (listed in order of decreasing abundance): mound sponge, 

foliose sponge, white-plumed anemone, swimming anemone, white deep-sea 

corals, shelf sponges, barrel sponges, upright sponges, sand anemones, 

Subselliflorae sea pens, vase sponges, basket stars, branching sponges, 

104 Submarine Canyon
gorgonians, plumed sea pens, and octocorals. Sebastes/Sebastomus fishes (e.g., 

darkblotched, splitnose, and rosethorn rockfish) were observed: inside vase 

sponges (n=66); under swimming anemones (n=321), foliose sponges (n=405), 

and upright sponges (n=100); and at rest next to Gorgonian corals (n=15), 

branching sponges (n=19) and vase sponges (9%).

 Carmel Canyon: A total of 6,369 structure-forming invertebrates were observed 

during 12 submersible dives in Carmel Canyon. The following types of structureforming species were observed (listed in order of decreasing abundance): foliose 

sponge, mound sponge, Subselliflorae sea pens, upright sponges, barrel sponges, 

white deep-sea corals, octocorals, gorgonians, swimming anemone, shelf sponges, 

vase sponges, branching sponges, white-plumed anemone, plumed sea pens, 

basket stars, and pom pom anemones. Sebastes/Sebastomus fishes (e.g., pygmy 

rockfish, half-banded rockfish, darkblotched rockfish, and greenstriped rockfish) 

were observed: under vase sponges (n=107), barrel sponges (n=507), and upright 

sponges (n=534); and at rest next to basket stars (n=16) and vase sponges (5%). 

We also observed Dover and/or English sole underneath plumed sea pens (n=23]) 

and next to Subselliflorae sea pens (n=676).

• Structure-forming Invertebrates Observed in MBNMS Shelf Characterization 

Surveys (IfAME and MBNMS 2011). Video transects using a remotely operated vehicle 

(ROV) and a towed camera sled were made to characterize the distribution of fishes, 

invertebrates, and seafloor habitats between 50 and 400 m at five locations in MBNMS: 

Ascension and Año Nuevo Canyons; North Monterey Bay; Carmel Bay and Point Lobos; 

Point Sur Shelf; and La Cruz Canyon and Point Piedras Blancas. Transects covered a 

varied of canyon habitat including canyon rim, canyon head, and canyon floor. Structureforming invertebrates were commonly observed in canyons. Specific locations where 

structure-forming invertebrates were observed along the transects are available through 

the Shelf Characterization and Image Display website (http://sep.csumb.edu/ifame/scid).

• Deep-sea Corals (Etnoyer and Morgan 2003, 2005). Records on 8 habitat forming deepsea coral families from 10 different institutions were gathered to create a dataset of range 

and distribution of corals along the west coast of North America. Monterey Canyon was

identified as an area of highest occurrence of deep-sea corals. Examples of species

associated with corals include: crabs and fishes (resting/refuge), fish egg cases 

(attachment substrate in well-aerated water column), and crinoids, basket stars, and 

anemones (suspension feeding).

• Deep-sea Coral Habitat Suitability (Guinotte and Davies 2012). The potential 

distribution of deep-sea corals was modeled for the U.S. West Coast Exclusive Economic 

Zone. Predicted habitat suitability in MBNMS is shown separately for 6 deep-sea coral 

taxa (Figure 10). Some of the highest habitat suitability probabilities for each taxa 

occurred in portions of submarine canyon habitat (such as canyon walls and canyon 

heads). However, the model will likely overpredict the amount of suitable habitat in some 

areas (e.g., indicate suitable coral habitat in areas that are known soft bottom regions) 

because fine-scale bathymetric features (10’s of meters), substrate, and current data were 

not available for the entire study area.

105 Submarine Canyon
Energy Flow

Benthic-Pelagic Coupling (reviewed by Raffaellia et al. 2003). There is a two-way exchange, or 

flux of matter, between the benthos and the overlying water body, which is important for both 

benthic and pelagic compartments. This flux occurs through the sinking of non-living organic 

matter (e.g., falling plankton, fecal pellets, animal carcasses, and drift algae) and the active 

movement of organisms. Areas of high productivity and areas where surface and mid-water 

planktonic species are concentrated tend to have higher rates of flux of organic matter to the 

seafloor. Additional background information located in Appendix III.

 Sources of Downward Flux:

 Marine Snow (review by Rex 1981). Most deep benthic communities are supplied 

with food by a "rain of detritus" including dead organisms, discarded feeding 

structures, fecal pellets, and other organic debris. Most of the particles that reach the 

deep seafloor are less than 5 mm in size, sink slowly, and have organic carbon levels 

that are reduced by microbial mineralization during their descent, which may last for 

months. Carbon flux associated with sinking particulate organic matter was estimated 

to range from 9-182 mg C/m2/day in the axis of Monterey Canyon (from subsurface 

sediment traps located at 450 m; Pilskaln et al. 1996). In general, open ocean 

locations with high primary productivity, such as upwelling plumes and retention 

zones, will be areas with high delivery of particulate organic carbon (POC) to the 

seafloor in the form of sinking organisms.

 Sinking Larvacean Houses (Robison et al. 2005). Larvaceans, a type of small midwater animal, feed by filtering seawater through a mucus net called a ‘house’. When 

the filtering apparatus in the house becomes clogged, the larvacean casts off the old 

house and forms a new one. Abandoned houses sink to the seafloor at rate of ~800 

m/day and they are observed along the floor of the Monterey Canyon at densities as 

high as 1/m2. Over 10 years, the average flux of houses to the seafloor was 

3.9/m2

/day. Per house, the average total organic carbon was 5.4 mg and the average 

C:N ratio was 6.09. The rate of nutrient flux was calculated to be 7.6 g C/m2

/year and 

this number is probably an underestimate. Sinking houses are not detected by 

conventional sampling methods (sediment traps) so they have never before been 

included in calculations of vertical nutrient flux. Recent models of carbon flux 

through the deep water column predict that only ~10% of the POC that sinks below 

100 m reaches depths beyond 1000 m. These results reveal a pathway through this 

region that carries substantially more carbon than has been measured by conventional 

methods. This study found that discarded mucus feeding structures carry a substantial 

portion of the upper ocean's productivity to the deep seafloor.

 Macrophyte Detritus (Harrold et al. 1998, Vetter and Dayton 1998, 1999, Okey 

2003). The higher biomass and density of soft bottom macrofauna in canyons 

(compared to sites at similar depth on the shelf and slope) are likely supported by 

nutrient enrichment from macrophyte detritus. Studies in Monterey Canyon and 

Carmel Canyon in central California and La Jolla and Scripps Canyon in southern 

California have found that drifting plant material (algae and surfgrass) accumulates in 

the heads of the canyons and is delivered periodically down the canyon mouth by 

sediment flows. A comparison of the daily flux of organic carbon derived from 

106 Submarine Canyon
macroalgal detritus in Carmel Canyon to estimates of carbon flux from vertically 

sinking POC in the nearby Monterey Canyon revealed that drift algae accounted for 

20-83% of the total POC reaching the seafloor in Carmel Canyon.

 Horizontal Delivery of Carbon Down the Axis of Submarine Canyons (Jim Barry, 

pers. comm.). Jim Barry and colleagues are using sediment traps to measure carbon 

flux down the Monterey Canyon and at one non-canyon site (at ~1300 m). The traps 

are collecting material that moves horizontally down the canyon, not just vertically 

from the surface and mid-water. They have found that the head of the canyon has 

frequent sediment movement events and that these events deliver carbon to the midcanyon site. The mid-canyon site has approximately 20 times more sediment flux to it 

than the outer canyon and non-canyon sites.

 Large Animal Falls (Rex 1981). Megafauna in the deep sea are often opportunists 

that scavenge animal carcasses on the seafloor. On February 6, 2002, a wellpreserved carcass of a gray whale was discovered at 2,891 m depth in the axis of 

Monterey Canyon (Goffredi et al. 2004). This carcass delivered approximately 20,000 

kg of organic material to the seafloor.

HABITAT STRUCTURE

Species Composition: Similar to patterns observed in benthic habitats on the continental shelf, 

slope and rise, demersal fish and invertebrates in submarine canyons tend to be distributed 

according to depth and bottom type. The distribution of seabirds and marine mammals tends to 

be influenced strongly by both distance from shore and water depth. The presence of submarine 

canyons, especially those with canyon heads that are close to shore, can allow deep-water species 

to be found in much closer proximity to shallow water species than is observed in areas without 

canyon habitats. The detailed information below refers only to observations made in submarine 

canyons.

 Infaunal Invertebrates Along the Monterey Canyon Ridge (Oliver and Slattery 1976). 

Sediment movement and depth were the most important environmental parameters 

affecting the distribution of macro-invertebrates in the head of the Monterey Canyon. All 

sampling stations were located in waters less than 30 m deep. Three distinct assemblages 

of invertebrates were identified based on depth and/or stability of the sediments:

 Deeper stations and areas of increasing substrate stability on the canyon ridge had an 

assemblage comprised of polychaete worms (Amaeana occidentalis, Nothria elegans, 

Lumbrineris luti) and crustaceans (Paraphoxus daboius, Euphilomedes oblonga, E. 

carcharodonta);

 Shallow stations and areas of decreasing substrate stability along the canyon ridge 

had an assemblage comprised of polychaete worms (Dispio uncinata, Scoloplos 

armiger, Onuphus erimita, Paraphyoxus lucubrans), cumaceans, and the mollusk

Olivella spp.;

 Intermediate depths and areas of intermediate substrate stability along the ridge 

gradient had an assemblage comprised of the crustacean Euphilomedes longiseta, the 

bivalve Tellina modesta, and the sand dollar Dendraster excentricus.

107 Submarine Canyon
 Megafaunal Invertebrates in Ascension and Carmel Canyon (Bianchi 2011). The 

manned submersible Delta was used to survey megafaunal invertebrates during 12 dives 

in Ascension Canyon (182-319 m) and 12 dives in Carmel Canyon (90-305 m). 

 Ascension Canyon: The brittle star (Ophiacantha) was the most abundant taxon and 

was common in substratum types containing boulders, boulder-mud, boulder-cobble, 

and mud-cobble. The second most abundant taxon, the hermit crab, was distributed 

evenly across all substratum types. The third most abundant taxon, the psolid sea 

cucumber, was distributed in mixed substratum consisting of boulders and mud. The 

fourth and fifth most abundant taxa were the fragile pink urchin (Allocentrotus 

fragile) and the crinoid (Florometra serratissima), which were common on all 

substratum types, except cobble-boulder.

 Carmel Canyon: The spot prawn (Pandalus platyceros) was the most abundant 

taxon and was observed in mud-pebble and mud substratum types. The second most 

abundant taxon, the brittle star, was distributed across mixed boulder-mud substratum 

types. The third, fourth and fifth most abundant taxa were squat lobsters

(Galatheidae), crinoids, and vermillion sea stars (Mediaster aequalis) and were 

distributed across all substratum types.

Note: See ‘Biogenic Habitat’ section above for more additional information on the rank 

abundance of structuring-forming megafaunal invertebrates.

 Invertebrates in Submarine Canyons in Central and Northern California (Airamé et

al. 2003). 

 Clams and worms burrow into the hard mud outcrops on more stable canyon walls. 

 Articulated brachiopods (Laqueus californianus var. vancouveriensis) are found on 

canyon walls at depths of 500-700 m. 

 Feather stars (Florometra serratissima) occur at depths of 30-1000 m on rocky ridges 

in the Monterey Bay and on the edges of the canyon slope. 

 Mushroom corals (Anthomastus ritteri) live in sediments and rocky walls at depths of 

360-1200 m. 

 Predatory tunicates (Megalodicopia hians) occur in dense aggregations in areas of 

mixed rock and mud. 

 Sea pens (Umbellula lindahli) are found on soft sediments at depths below 500 m 

throughout the Monterey Canyon. 

 Sea cucumbers, Echinocucumis hispida and Ypsilothuria bitentaculata, are the most 

abundant invertebrates in Pioneer Canyon. 

 One species of brittlestar (Ophiocantha pacifica) and one species of asteroid 

(Eremicaster gracilis) were found in both Monterey and Pioneer Canyons.

 CBCs in Monterey Bay: In the Monterey Bay region, CBCs were observed most 

commonly on steep slopes, such as the walls of Monterey Canyon, where recent seafloor 

erosion is likely to have occurred (Paull et al. 2005a). The biologic communities

associated with 4 CBCs in the Monterey Bay region, 2 of which were located in 

Monterey Canyon, were described by Barry et al. (1996) and is summarized in the

Chemosynthetic Biological Communities habitat section of this report.

108 Submarine Canyon
 Demersal Fish in Ascension Canyon (Bizzarro et al. 2003). Seafloor features and fish 

assemblages were surveyed using the Delta submersible along 50 meter depth contours, 

between 200 and 350 m in Ascension Canyon. The five most abundant fish species at 

each depth were (listed in order of decreasing abundance):

 200 m: stripetail rockfish, greenstriped rockfish, Sebastes spp. (rockfishes), 

Pleuronectiformes (flatfishes), Agonidae (poachers);

 250 m: stripetail rockfish, Sebastomus spp., Sebastes spp.(rockfishes), 

Pleuronectiformes (flatfishes), greenstriped rockfish;

 300 m: Pleuronectiformes (flatfishes), rex sole, blackbelly eelpout, bank rockfish, 

Dover sole;

 350 m: Dover sole, eelpouts, rex sole, shortspine thornyhead, splitnose rockfish.

 Demersal Fish in Soquel Canyon (Yoklavich et al. 2000). Using strip transects that 

covered an estimated 33,754 m2 in Soquel Canyon (depth range 80-360 m), a total of 

6,208 non-schooling fishes were observed representing at least 52 species. Rockfishes 

represented 77% of the total number of individuals, and included a minimum of 24 

species. The most abundant taxa observed during this study included: poachers, Pacific 

hagfish, Pacific hake, Dover sole, lingcod, shortspine thornyhead, and rockfishes 

(stripetail, bocaccio, rosethorn, greenspotted, greenstriped, darkblotched, halfbanded, 

cowcod, pygmy, yelloweye, canary, greenblotched, bank, widow, yellowtail). Six distinct 

habitat guilds of fishes were determined using habitat-based clustering analysis:

 Mud: stripetail rockfish, Dover sole, poachers, shortspine thornyhead;

 Cobble-Mud/Mud-Pebble: halfbanded rockfish, greenstriped rockfish, greenspotted 

rockfish, pygmy rockfish;

 Mud-Cobble/Mud-Rock: stripetail rockfish, rosethorn rockfish, poachers, 

greenspotted rockfish, greenstriped rockfish;

 Boulder-Mud: rosethorn rockfish, greenspotted rockfish, bocaccio;

 Mud-Boulder/Rock-Mud/Rock ridge: bocaccio, rosethorn rockfish, greenspotted 

rockfish;

 Rock-Boulder: pygmy rockfish, bocaccio.

 Fishes in Submarine Canyons in Central and Northern California (Airamé et al. 

2003). 

 Rattails and whiptails (Macrouridae) are common fishes at depths of 200-6000 m. 

Three species of macrourids (Coryphaenoides armatus, C. filifer, and C. leptolepis) 

are the most common fishes in Pioneer Canyon. 

 Flatfishes, including Dover sole (Microstomus pacificus), English sole (Pleuronectes 

vetulus), petrale sole (Eopsetta jordani), rex sole (Errex zachirus), and deep-sea sole 

(Embassichthys bathybius), are found on sand and mud bottoms in submarine 

canyons.

 Adult rockfishes (Sebastes spp.) are commonly associated with some structure, such 

as rocky cliffs, ledges, talus slopes, and cobble and boulder fields.

109 Submarine Canyon
 Sablefish (Anoplopoma fimbria) are concentrated from 400-600 m in submarine 

canyons.

 General Classification of California Marine Fishes (Allen and Pondella 2006). The 

authors used cluster analysis to determine which species occur together and in different 

habitats (by substrate type, depth, and latitude). Most of the species that are found in 

submarine canyons also occur in shelf, slope and rise habitats outside of canyons. One 

species group, composed of boccacio, bank, greenspotted, chilipepper, and rosethorn 

rockfish, was strongly associated with deep reef and submarine canyon habitats.

Species Composition Shifts: 

 Natural Changes: Sediment flows and food falls deliver natural supplies of food to deep 

canyon habitats, which in turn rapidly change the species compositions at these depths.

 Flushing events, landslides and other sediment flows down the canyon head or 

walls can dislodge or bury sessile and sedentary infaunal and epifaunal invertebrates 

and temporarily alter the species composition. Opportunistic species - species that 

disperse widely, colonize rapidly, and reproduce quickly - are most common after a 

disturbance event. 

 Food Falls: Mobile invertebrates and a few species of fish rapidly colonize mats of 

macrophyte detritus. Comparative studies (Vetter and Dayton 1998, 1999; Okey 

2003) have found substantial benthic community differences between algae patches 

and background sediment. Whale falls also alter the species composition of benthic 

habitats in submarine canyons (Smith and Baco 2003). Whale carcasses in the deep 

ocean off California may pass through three to four overlapping successional stages

and this successional process may occur rapidly, in less than 10 years (Lundsten et al. 

2010). The majority of species at Monterey Canyon whale fall communities are 

common deep-sea inhabitants of Monterey Canyon, nearby seamounts, and the 

continental slope. See “Slope – Soft Bottom” habitat summary for additional 

information.

 Human-Induced Changes: A variety of human activities can alter species composition 

in submarine canyons.

 Structure-forming Invertebrates: Structure-forming invertebrates are very 

susceptible to damage from physical structures dragged across the seafloor including 

anchor lines and fishing gear. Bottom trawling gear poses the biggest threat, but other 

gears with smaller footprints include bottom longline, pot/trap and hook-and-line 

gear. Two areas with relatively high coral concentrations are the shelf break and the 

Monterey Canyon (Morgan et al. 2005). These areas appear to have more corals 

because they have been lightly fished. Heavily fished areas have fewer corals.

 Rockfish (Yoklavich et al. 2000). Sites in Soquel Canyon that were less fished had 

larger fishes and significantly higher abundances of major commercial and 

recreational species compared to sites that were more fished. Less fished sites were 

dominated by less valuable, small, benthic rockfish species. Rockfishes in the study 

area are likely protected from excessive harvest because the habitat characteristics 

make it difficult for fishermen to locate and target fishes.

110 Submarine Canyon
Species Diversity and Species Richness: Species richness and diversity may be elevated in 

submarine canyons in comparison to the shelf or slope habitat adjacent to canyons. Increased 

heterogeneity of the substrate, steeper topography, and increased delivery of organic matter (e.g., 

macrophyte detritus) may be partially responsible for this pattern.

 Infaunal Invertebrates (Vetter and Dayton 1998). Species diversity of infauna was 

generally high in submarine canyons, but tended to increase with depth. However, when 

compared to sites at the same depth on the shelf or slope, species diversity was lower at 

canyon sites (especially at shallower depths). Species richness was similar between sites 

inside and outside canyons. 

 Megafaunal Invertebrates in Ascension and Carmel Canyon (Bianchi 2011). The 

species richness and species diversity of the megafaunal invertebrate assemblage was 

determined for Ascension Canyon (182-319 m) and Carmel Canyon (90-305 m). The 

species richness index (S) was 47 for Carmel Canyon and 42 for Ascension Canyon. 

Mean species diversity index (H’ calculated at patch level) was 1.7 for Carmel Canyon 

and 1.5 for Ascension Canyon.

 Megafauna (Vetter and Dayton 1999). Species richness of all megafauna was greater at 

sites inside canyons than outside canyons on the shelf and slope. Species richness of 

fishes was greater in the canyons at all depths for which comparative data were available 

(100 to 500 m). 

 Demersal Fish in Ascension Canyon (Bizzarro et al. 2003). Significantly higher species 

diversity was observed along the southern wall of the canyon in association with more 

heterogeneous habitat. Species diversity was significantly higher at 300 and 350 m.

 Whale Falls. Local species diversity (mean of 185 macrofaunal species) on large whale 

skeletons during the sulphophilic stage is higher than in any other deep-sea hard 

substratum community (Smith and Baco 2003). Global species richness on whale falls 

(407 species) is also high compared with cold seeps and rivals that of hydrothermal vents 

(469 species worldwide). The majority of species at Monterey Canyon whale fall 

communities are common deep-sea inhabitants of Monterey Canyon, nearby seamounts, 

and the continental slope (Lundsten et al. 2010). Upon initial arrival, whale carcasses 

host a relatively low-diversity community of mobile scavengers. Through time, diversity 

increases; however, most of the increases in species richness come from background taxa 

that exploit abundant nutrients provided by the carcass.

Biomass: The abundance of many groups of organisms is elevated in association with submarine 

canyons. Increased delivery of organic matter (e.g., macrophyte detritus) may be partially 

responsible for this pattern for demersal species. Some species of harvested species may be more 

abundant in submarine canyons because the steep topography and habitat heterogeneity may 

decrease the efficiency of gear or cause it to become entangled. The heads of submarine canyons 

may concentrate schooling prey species that undergo diel vertical migrations making these areas 

foraging hotspots for predators such as seabirds and mammals.

 Megafaunal Invertebrates in Ascension and Carmel Canyon (Bianchi 2011). The 

density of megafaunal invertebrates was assessed in Ascension Canyon (182-319 m) and

Carmel Canyon (90-305 m).

111 Submarine Canyon
 Ascension Canyon: The overall mean density of megafaunal invertebrates was 

56/100 m2 and 94/100 m2 at mid-shallow (148-234 m) and mid-deep (234-320 m) 

depths, respectively. The Ophiacantha brittle star was the most abundant taxon with 

an overall density of 25/100 m2

. Hermit crabs, the second most abundant taxon, was 

densest in mid-deep depths (29/100 m2). The third most abundant taxon, the psolid 

sea cucumber, was densest in mid-deep depths (14/100 m2).

 Carmel Canyon: The overall mean density of megafaunal invertebrates was 251/100 

m2

, 211/100 m2, and 254/100 m2 at shallow (<148 m), mid-shallow (148-234 m), and 

mid-deep (234-320 m) depths, respectively. The spot prawn (Pandalus platyceros) 

was the most abundant taxon and was densest in mid-shallow depths (61/100 m2). 

The second most abundant taxon, the Ophiacantha brittle star was densest in middeep depths (68/100 m2

). The third most abundant invertebrate, the squat lobster 

(Galatheidae), was densest in mid-deep depths (103/100 m2

). The fourth and fifth 

most abundant taxa were crinoids and vermillion sea stars (Mediaster aequalis) with 

densities at shallow depths of 97/100 m2 and 29/100 m2

, respectively.

 Invertebrates and Fishes in La Jolla and Scripps Canyons (Vetter and Dayton 1998, 

1999). The density and biomass of infaunal invertebrates were higher in the canyons than 

outside at all depths where comparative data were available (100-500 m). Biomass in the 

canyons was highest at 310 m and lowest at 700 and 900 m. Density in the canyons was 

highest at 100 m and generally declined with increasing depth. Canyons support large 

populations of macrofaunal crustaceans, which in turn support large numbers of fishes. 

Abundance of non-urchin megafauna was greater in the canyons than out. Abundance of 

fishes was greater in the canyons at all depths for which comparative data were available 

(100 to 500 m).

 Demersal Fish in Soquel Canyon (Yoklavich et al. 2000). Sites that were less fished had 

larger fishes and significantly higher abundances of major commercial and recreational 

species (e.g., lingcod and greenspotted, cowcod, greenblotched, yelloweye, bocaccio, 

darkblotched, and bank rockfish).

 Harvested Species: Recreational and commercial harvest removes biomass of targeted 

fish and invertebrate populations. For some targeted species, biomass is substantially 

reduced compared to unfished biomass levels (Tables 3 and 4). Though extraction is the 

primary reason for a reduction in biomass for many species, changing oceanographic and 

ecological conditions are an important contributing factor for some harvested species. For 

the majority of the 10 invertebrate and 156 fish stocks landed in MBNMS, the status of 

the stock has not been assessed (Tables 3 and 4).

MOVEMENT AND DISPERSAL

The axis of the submarine canyon may serve as a migratory corridor for mobile species. Some 

species may move up or down the canyon for seasonal migrations (e.g., feeding or breeding 

migrations). Some species may progressively move down the canyon as they grow older and 

larger (i.e., ontogenetic migration).

 Prickly Sharks (Starr et al. 1999). The movements of prickly sharks captured in 

Monterey Canyon were followed for up to 3 months. During that time, sharks moved 

112 Submarine Canyon
frequently and ranged in depth from as little as 5 m of water near the canyon head to as 

deep as 375 m at a distance of 10 km offshore. Preliminary analyses indicated four 

patterns of daily activity: (1) at the canyon head at night and in deep water during the 

day, (2) in deep water at night and at the canyon head during the day, (3) at the canyon 

head the entire day, and (4) completely absent from the canyon head. The reasons for 

these movement patterns are not known.

 Adult Bocaccio (Starr et al. 2002b). Of the 16 bocaccio tagged in 1998 in the Monterey 

Canyon, 10 spent less than 10% of the study time in the approximately 12-km2 study 

area. One fish stayed in the study area for about 50% of the study time. Signals from the 

remaining 5 fish were recorded in the study area the entire time. Bocaccio frequently 

moved vertically 10-20 m and occasionally displayed vertical movements of 100 m or 

greater.

 Adult Greenspotted Rockfish (Starr et al. 2002b). Fish tagged in 1997 in the Monterey 

Canyon exhibited almost no vertical movement and showed limited horizontal 

movement. Two individuals spent more than 90% of the time in a 0.58-km2 area. Three 

others spent more than 60% of the time in a 1.6-km2area, but displayed frequent 

horizontal movements of at least 3 km.

SPECIES OF SPECIAL INTEREST

Many species of special resource management interest are associated with submarine canyons in 

MBNMS Tables 3-7.

• Species Landed in MBNMS: Of the 10 invertebrate and 156 fish species that are 

commonly caught and sold in the commercial and/or recreational fisheries of MBNMS 

(Starr et al. 2002a), two invertebrates (box crab and red rock crab) and 41 fishes occur in 

canyons.

• Endangered and Threatened Species: There are no known endangered or threatened 

invertebrate species in the federal waters of MBNMS. No endangered or threatened fish 

species in the sanctuary are associated with submarine canyons. The leatherback turtle is 

the only endangered reptile to occur regularly in the sanctuary and it is commonly sighted 

over submarine canyons. All 3 of the listed seabirds and 7 of the 10 listed marine 

mammals are commonly sighted over submarine canyons.

• Other At-Risk Species: None of the invertebrate taxa in the federal waters of MBNMS

are considered to be at-risk. Five at-risk fishes occur in canyons. The leatherback turtle, 

along with all 11 at-risk birds and 6 of the 9 at-risk mammals appear to be associated 

with canyons.

Additional species of special resource management interest associated with submarine canyons 

include: 

• Structure-forming invertebrates, such as corals and sponges, due to their important 

ecological role in creating habitat structure and their vulnerability to disturbance from 

human activities;

113 Submarine Canyon
• Krill due to their important ecological role as a primary food source for seabirds, marine 

mammals and fishes;

• Sooty Shearwaters which reach extremely high densities during the summer, when

hundreds of thousands of adults forage for fishes and squid in sanctuary waters after 

migrating from the southern hemisphere;

• Seabirds (e.g., Rhinoceros Auklets) and marine mammals (e.g., elephant seals, California 

sea lion) vulnerable to disturbance, injury or death from human activities in the sanctuary 

such as oil spills and entanglement in fishing gear.

114 Submarine Canyon
Seamount

HABITAT OVERVIEW

Seamounts are mainly volcanic in origin, rise to considerable height from great depths along the 

continental rise, and are limited in length across the summit. Their vertical nature and rocky 

substrate create habitat complexity and support a very different biological assemblage than the 

soft bottom that typically surrounds them. Seamount rocky outcrops, particularly near peaks, are 

inhabited by a suite of deep-sea corals and sponges that are typically absent or quite rare in more 

typical ocean settings. 

Several seamounts - including Gumdrop, Pioneer, Guide, and Davidson Seamounts - occur off 

central California (Figure 3). On June 12, 2000, President Bill Clinton directed the National 

Oceanic and Atmospheric Administration (NOAA) to work in partnership with marine research 

institutions and universities to explore Davidson Seamount. 

Assemblages of large corals and sponges, along with many associated animals such as sea stars, 

anemones, crustaceans, octopus and fishes, are common on Davidson Seamount. Explorations in 

2002 and 2006 observed 18 species new to science. Ecological processes influencing the 

distribution, abundance and dynamics of seamount fauna are less well known than more 

accessible ecosystems such as kelp beds and corals reefs.

Though relatively close to shore and one of the largest seamounts on the West Coast, Davidson 

Seamount appears to be relatively pristine, based on observations of biological communities 

during submersible explorations in the past decade. By comparison, observations of various other 

seamounts worldwide indicate severe damage by trawling - a fishing practice that can decimate 

coral assemblages and may require decades or centuries to recover.

In March of 2009, NOAA expanded MBNMS to include the Davidson Seamount Management 

Zone (DMSZ), an area encompassing 775 square miles. Davidson Seamount is the first seamount 

to be protected within a United States national marine sanctuary.

Geological Structure and Origin of Seamounts in central California

Gumdrop, Pioneer, and Guide Seamounts are located about 120 kilometers off the California 

margin, north of Monterey Bay (Figure 3). They have a similar geological structure and origin to 

Davidson Seamount, which is located 120 kilometers due west of San Simeon. Davidson, Guide, 

Pioneer, and Gumdrop Seamounts have only recently been described as an atypical type of 

oceanic volcanism, having northeast-trending ridges that reflect the ridge-parallel structure of the 

underlying crust (Davis et al. 2002). Unlike most intra-plate ocean island volcanoes, the 

seamounts are built on top of spreading center segments that were abandoned at the continental 

margin when the tectonic regime changed from subduction to a transform margin (Davis et al. 

2007).

• Gumdrop Seamount (Davis et al. 2002, MBARI 2009a). The northernmost of the three 

seamounts, has a series of aligned cones separated by sediment-filled troughs, but these 

structures are poorly defined. The shallowest cone rises to 1,207 meters below sea level. 

The volume, estimated at about 100 km3

, is difficult to determine because the base of the 

115 Seamount
seamount is poorly defined. Samples have been recovered to age the seamount, but their 

age has not been determined.

• Pioneer Seamount (Davis et al. 2002, MBARI 2009a). Pioneer Seamount is nearly 

equidimensional with width and length of about 12.8 kilometers. It rises about 1,930 

meters above the surrounding seafloor to a minimum water depth of 820 meters. It has a 

volume of about 135 km3. The seamount is 11.0 ± 0.1 million years old.

• Guide Seamount (Davis et al. 2002, MBARI 2009a). Guide Seamount looks virtually 

identical to Davidson Seamount, except it is smaller (approximately 16.5 kilometers by 5 

kilometers). It rises about 1,440 meters above the surrounding seafloor and reaches a 

minimum water depth of 1,682 meters. The volume above the surrounding seafloor is 

about 130 km3

. The seamount is 16.6 ± 0.5 million years old. The seamount consists of 

four, nearly parallel volcanic ridges, separated by sediment-filled troughs, aligned 

parallel to magnetic anomalies in the underlying ocean crust and therefore parallel to the 

abandoned mid-ocean ridge that formed the crust.

• Davidson Seamount (Davis et al. 2002, MBARI 2009a). Davidson Seamount is the 

largest of the central California seamounts, 42 kilometers long and 13 km wide. It rises 

2,280 meters above the surrounding seafloor to a minimum water depth of 1,250 meters. 

It is almost as large as Guide, Pioneer, and Gumdrop Seamounts combined, with an 

estimated volume of 320 km3

. Davidson Seamount, like Guide, Pioneer, and Gumdrop 

Seamounts, is an elongated structure with a distinctive northeast-to-southwest orientation. 

The seamount consists of about six subparallel linear volcanic ridges separated by narrow 

valleys that contain sediment. These ridges are aligned parallel to magnetic anomalies in 

the underlying ocean crust. The seamount is 12.2 ± 0.4 million years old and formed 

about 8 million years after the underlying mid-ocean ridge was abandoned.

SEARCH TOPIC TABLE

HABITAT FUNCTION

Functional Habitats:

Nursery Habitat: See page 117

Feeding Ground: No specific information was found on this topic in this habitat 

category.

Spawning Ground: No specific information was found on this topic.

Migratory Corridor: No specific information was found on this topic.

Biogenic Habitat: See page 117

Energy Flow:

Primary Production:

No information specific to primary production at seamounts

was found during the literature review. General information on 

primary production on the slope can be found in the “Slope –

Hard Bottom” habitat summary.

Benthic-Pelagic Coupling: See page 118

116 Seamount
Key Trophic Interactions:

Invertebrate communities at Davidson and Pioneer Seamounts 

are dominated by passive suspension-feeding cnidarians (mostly 

corals), and appear to be tightly coupled to habitat type (rugged 

slopes and peaks) (Lundsten et al. 2009a).

Key Trophic Cascades: No specific information was found on this topic.

Productivity Hotspots: See page 118

HABITAT STRUCTURE

Species Composition: See page 118

Species Composition Shifts: See page 121

Species Diversity and Richness: See page 121

Biomass: No specific information was found on this topic.

Key Species Interactions No specific information was found on this topic.

MOVEMENT AND DISPERSAL See page 122

SPECIES OF SPECIAL INTEREST See page 122

HABITAT SUMMARY

HABITAT FUNCTION

Functional Habitats

Nursery Habitat: Very little is known about the early life histories of local seamount 

communities. On several occasions, numerous skate egg cases found at Davidson Seamount were 

nested near, or attached to, deep-sea corals in apparent nursery areas (Ebert and Davis 2007; 

Andrew DeVogelaere, pers. comm.). The skate egg cases could not be identified, but a female 

broad skate (Amblyraja badia) was observed swimming in the vicinity of the collected cases 

(Ebert and Davis 2007).

Biogenic Habitat: Most of the organisms found at seamounts, such as corals and sponges, are 

large, sessile organisms. These structure-forming invertebrates are used by other sessile 

organisms as a hard substrate for attachment (e.g., basket stars, sea stars, scale worms, other 

corals, other sponges) and by some mobile organisms as shelter or food (e.g., fishes, skate egg 

cases, crabs, shrimps). There is increasing evidence that many areas of deep coral and sponge 

habitats function as ecologically important habitats for fishes and invertebrates (Hourigan et al. 

2007).

 Deep-sea Coral Habitat Suitability (Guinotte and Davies 2012). The potential 

distribution of deep-sea corals was modeled for the U.S. West Coast Exclusive Economic 

Zone. Predicted habitat suitability in MBNMS is shown separately for 6 deep-sea coral 

taxa (Figure 10). Habitat suitability probabilities were highest at the Davidson Seamount 

for Suborders Calcaxonia, Alcyoniina, Scleraxonia, and Order Antipatharia. In contrast, 

suitability probabilities were lower at Davidson Seamount for Order Scleractinia and 

Suborder Holaxonia. However, the model will likely overpredict the amount of suitable 

habitat in some areas (e.g., indicate suitable coral habitat in areas that are known soft 

117 Seamount
bottom regions) because fine-scale bathymetric features (10’s of meters), substrate, and 

current data were not available for the entire study area.

Energy Flow

Benthic-Pelagic Coupling:

 Drift Algae and Surfgrass: Fronds shed by kelp growing on the rocky reef in nearshore 

waters <30 m may be transported by water currents to seamount habitats. Drift algae and 

surfgrass have been observed on the Davidson Seamount, including Alaria marginata, 

Macrocystis sp., Nereocystis luetkeana, and Phyllospadix sp. (Burton and Lundsten 

2008). For more information, see the “Macroalgal Detritus” habitat summary.

Productivity Hotspots: 

• Seamounts as Larval Sources (McClain et al. 2009). Seamount environments may 

represent optimal habitats for particular faunal groups resulting in thriving and dense 

populations encountered only rarely in other habitats. Based on research at Davidson 

Seamount and nearby Monterey Canyon, preliminary evidence suggests seamount 

communities may serve as a source of larvae for non-seamount habitats.

• Hydrographic Features at Davidson Seamount (Rizk 2006; Lundsten 2007). The 

topographic features of Davidson Seamount may affect circulation patterns of the 

California Current and California Undercurrent, perhaps trapping meanders over the 

seamount. In the summer of 2000, an onshore intrusion of the California Current 

remained directly over the Davidson Seamount from June through September. In 

addition, low frontal probabilities are seen upstream of Davidson, perhaps indicating a 

Taylor column or similar feature. These seamount-current interactions may enhance 

productivity at, and above, the seamount.

HABITAT STRUCTURE

“Distribution, diversity, and abundance of benthic organisms on seamounts has been attributed 

to various factors, including substrate type, local hydrographic conditions, reproductive modes, 

proximity to sources of larvae, geographic location, seamount topography, entrapment of 

migrating zooplankton, and elevated current velocities” (Lundsten et al. 2009a).

Species Composition: Demersal fishes and invertebrates on seamounts tend to be distributed 

according to depth and bottom type. Invertebrate communities at Davidson and Pioneer 

Seamounts are dominated by passive suspension-feeding cnidarians (mostly corals; Lundsten et 

al. 2009a). There is a high similarity among seamount fish fauna at similar depths of Davidson 

and Pioneer Seamounts, with a shift from provincial to abyssal/cosmopolitan species with 

increased depth (Lundsten et al. 2009b). There is no evidence of endemism among megafauna at 

Davidson or Pioneer Seamounts (Lundsten et al. 2009a,b; McClain et al 2009). 

• Davidson Seamount Taxonomic Guide (Burton and Lundsten 2008). In 2002 and 

2006, MBNMS led two multi-institutional expeditions to characterize the geology and 

natural history of Davidson Seamount. Approximately 140 hours of video and sample 

118 Seamount
collections were taken during 17 remotely operated vehicle (ROV) dives. Most were 

primarily on the seafloor, with opportunistic dives in the water column above the 

seamount. At least 237 taxa were observed, including 18 previously undescribed species 

(Erica Burton, pers. comm.; 8 sponges, 1 hydroid, 4 corals, 1 ctenophore, 1 nudibranch, 1 

polychaete, 1 sea star, 1 tunicate). See Table 17 for a list of species observed at Davidson 

Seamount.

• Benthic Invertebrates at Davidson and Pioneer Seamounts (Lundsten et al. 2009a). 

Abundance and distribution of benthic megafaunal invertebrates found on three 

seamounts, Davidson and Pioneer off central California and Rodriguez off southern 

California, are described. Video observations were taken during 27 remotely operated 

vehicle (ROV) dives and annotated. Video analysis yielded 134,477 observations of 202 

identified invertebrate taxa. Video transects were analyzed to quantify organism density. 

Thirteen new species were observed and collected. See Table 18 for observed frequencies 

of benthic invertebrates at Davidson and Pioneer Seamounts.

o Cnidaria, Porifera, and Echinodermata are the dominant phyla of megafaunal 

invertebrates at Davidson and Pioneer Seamounts.

o Cnidarians are most frequently observed phylum at each seamount; deep-sea 

corals dominate cnidarian observations.

o Sponges were observed more frequently at Davidson Seamount than at Pioneer

Seamount.

o Crinoid echinoderms dominated megafaunal echinoderm observations at both 

seamounts.

• Invertebrate Depth Zonation at Davidson Seamount (McClain et al. 2010). In 2006, 

33 quantitative video transects were collected by ROV on Davidson Seamount (1246–

3656 m). Bathymetric variation in benthic megafauna was examined.

o Invertebrate species composition and relative abundance shift significantly with 

depth. A 50% change in assemblage composition occurs approximately every 

1500 m. Species turnover is considerable across the flanks of the seamount (up to 

70%). In addition, the summit and base assemblages of Davidson Seamount share 

as little as 20-30% of their species. 

o Three distinct zones correspond to the summit, flanks, and base of the seamount; 

zonation patterns appear to be driven by changes in octocorals, hexactinellids, 

asteroids, and crinoids.

• Fishes at Davidson and Pioneer Seamounts (Lundsten et al. 2009b). Abundance and 

distribution of demersal fishes found on three seamounts, Davidson and Pioneer off 

central California and Rodriguez off southern California, are described. Video 

observations were taken during 27 remotely operated vehicle (ROV) dives and annotated. 

Video analysis yielded 2,151 observations of 36 identified taxa. Video transects were 

analyzed to quantify organism density. See Table 19 for observed frequencies of 

dominant fishes at Davidson and Pioneer Seamounts.

o Depth seems to be the most significant factor structuring fish communities at 

Davidson and Pioneer Seamounts 

119 Seamount
o Distribution, abundance, and natural history of fish assemblages inhabiting 

Davidson and Pioneer Seamounts support the notion that these communities can 

be distinct from those of non-seamount habitats, especially faunas of deeper 

seamount (i.e., Davidson), which may contain more rare abyssal and 

cosmopolitan species.

• 2000 Aerial Survey at Davidson Seamount (Forney 2002). In July 2000, an aerial 

survey was conducted to provide background information about the occurrence of marine 

mammals, seabirds, sea turtle, sharks, and ocean sunfish over Davidson Seamount.

Systematic observations were made by flying nine, 15-20 nautical mile-long transect 

lines. During the 135-180 nautical miles of aerial transect surveys over the Davidson 

Seamount, one sighting of each was observed: Risso’s dolphin (Grampus griseus), Blackfooted Albatross (Phoebastria nigripes), and ocean sunfish (Mola mola) (Table 20).

• 2009 Aerial Survey at Davidson Seamount (CINMS, unpubl. data). In April 2009, 

Channel Islands National Marine Sanctuary staff conducted an aerial survey of Davidson 

Seamount. The survey transect spanned a total of 136 linear nautical miles, covering 

approximately 264 square nautical miles. A total of 10 unidentified pinnipeds, and a 

single sperm whale were observed (Table 20).

• 2010 Aerial Surveys at Davidson Seamount (King and DeVogelaere, MBNMS, unpubl.

data). In 2010, MBNMS staff conducted two aerial surveys of the surface waters over 

Davidson Seamount. On January 14, 2010, approximately 542 kilometers of “on effort” 

transects were flown in five zig zag formations to the north, south, east, and west over 

Davidson Seamount. On April 19, 2010, five transects were flown perpendicular to the 

main axis of Davidson Seamount, totaling approximately 400 kilometers of “on effort” 

transects. (Table 20) provides a list of the species observed in the surface waters of the 

DSMZ.

o In January 2010, 139 individual animals were observed, for an individual 

encounter rate of 0.26 animals per kilometer, 0.20 seabirds per kilometer, and 

only 0.04 marine mammals per kilometer.

o In April 2010, 78 individual sightings were recorded, totaling 336 individual 

animals for an individual encounter rate of 0.84 animals per kilometer and 0.79 

marine mammals per kilometer.

• 2002 Ship-based Survey at Davidson Seamount (Benson 2002). In May 2002, visual 

ship-based surveys of the sea surface were conducted for seabirds, marine mammals, and 

surface-active fishes. Eight species of marine mammals, 15 seabird taxa, and two surfaceactive fishes were sighted during this investigation (Table 20).

o Dall’s porpoise (Phocoenoides dalli) and Black-footed Albatross (Phoebastria 

nigripes) were the most commonly sighted organisms encountered over the 

Davidson Seamount. 

o The most abundant organisms were the Black-footed Albatross, Pacific whitesided dolphin (Lagenorhynchus obliquidens), Northern right whale dolphin 

(Lissodelphis borealis), and Dall’s porpoise.

120 Seamount
• 2010 Ship-based Survey at Davidson Seamount (Newton et al. 2011). In July 2010, 

MBNMS staff conducted a ship-based survey of the waters above and around the 

Davidson Seamount. Eight transect lines were surveyed for a total of 605 km of “oneffort” observations. Seventeen species of seabirds and 6 marine mammal species were 

observed (Table 20).

o Cook’s Petrel (Pterodroma cookii) was the most abundant seabird observed (8.4 

birds/km2

), followed by Leach’s Storm-petrel (Oceanodroma leucorhoa; 5.6 

birds/km2).

o Of a total of 200 marine mammal sightings, fin whales (Balaenoptera physalus) 

were the most commonly encountered marine mammals (51% of sightings), 

comprising 94% of whales sighted.

Species Composition Shifts:

• Natural Changes: The seamounts off central California have only recently been studied, 

and there are no long-term data to determine changes in species composition over time.

o Species composition at Davidson Seamount (McClain et al. 2010). A significant 

shift in species composition and relative abundances of species occurs with depth. 

A 50% change in composition is observed for approximately every 1500 m. 

Davidson Seamount summit and base assemblages share as little as 20–30% of 

their species. A consistent bathymetric gradient in compositional change occurs 

across the flanks of the seamount. In addition, transects group into three distinct 

depth zones that correspond to the summit, flanks, and base of Davidson. Much of 

the compositional pattern appears to be driven by compositional changes in 

octocorals, hexactinellids, asteroids, and crinoids, with hexactinellids contributing 

the most to bathymetric variation in species dominance.

• Human-induced Changes: Many benthic species on seamounts are long-lived and slowgrowing, and not resilient to human impacts (Clark et al. 2010). Deep-seas coral and 

sponge communities on seamounts, like all benthic biogenic habitats, are susceptible to 

degradation from human activities that disturb benthic habitats such as fishing with 

bottom-tending gear, and laying physical structures (e.g., cables). Studies from around 

the world have reported severe disturbance to deep coral communities from trawling 

(Hourigan et al. 2007). Removal of, or damage to, biogenic habitats has the potential to 

temporarily or permanently alter species compositions at seamounts. The Davidson 

Seamount appears to be relatively pristine (DeVogelaere et al. 2005); however, it has 

only recently been studied, and there are no long-term data to determine changes in 

species composition. The use of bottom contact fishing gear has been prohibited in the 

DSMZ by an Essential Fish Habitat Conservation Area, which was implemented in 2006 

by NOAA’s National Marine Fisheries Service and the Pacific Fisheries Management 

Council. Take or disturbance (by methods other than fishing) of any resource below 3000 

feet within the DSMZ is regulated by MBNMS.

Species Diversity and Species Richness:

 Assemblage structure at Davidson Seamount (McClain et al. 2010). Species diversity 

and density at Davidson Seamount do not significantly change with depth, and can vary 

greatly on a single isobath. Authors suggest the lack of clear bathymetric signal in 

121 Seamount
diversity or density may reflect the proximity of Davidson to highly productive coastal 

waters fueled by coastal upwelling. However, results indicate that considerable species 

turnover, upwards of 70%, can occur across the flanks of an individual seamount (see 

Species Composition Shifts).

MOVEMENT AND DISPERSAL

Seamount environments may represent optimal habitats for particular faunal groups resulting in 

thriving and dense populations encountered only rarely in other habitats. Based on research at 

Davidson Seamount and nearby Monterey Canyon, preliminary evidence suggests seamount 

communities may serve as a source of larvae for non-seamount habitats (see McClain et al. 

2009).

SPECIES OF SPECIAL INTEREST

Many species of special resource management interest are found at Davidson Seamount (Tables 

17, 20).

• Species Landed in the MBNMS: Two invertebrates (market and Humboldt squids) and 

three fish taxa (Pacific grenadier, ocean sunfish, shortspine thornyhead) that are 

commonly caught and sold by commercial and/or recreational fisheries within MBNMS 

are observed at Davidson Seamount (Table 17). Although few species observed on and 

around seamounts are currently landed, some deep-water species might be targeted in the 

future (e.g., other grenadiers).

• Endangered and Threatened Species: There are no known endangered or threatened

invertebrate or fish species at Davidson Seamount. Of the 22 bird and 19 mammal taxa 

observed over Davidson Seamount (Table 20), one bird (Xantus’s Murrelet) is threatened 

and three mammals (humpback, fin, and sperm whales) are endangered.

• Other At-Risk Species: Ten “At-Risk” taxa have been observed at Davidson Seamount. 

One fish species (shortspine thornyhead) is listed as endangered by the IUCN (Table 17). 

Six birds are listed by the IUCN, of which one is endangered and five are vulnerable. 

Three mammals are listed by the IUCN, of which one is endangered and two are 

vulnerable (Table 20).

Additional species of special resource management interest at Davidson Seamount include: 

• Structure-forming invertebrates, such as the many species of corals and sponges that have 

been observed at Davidson Seamount (Table 17), due to their important ecological role in 

creating habitat structure and their vulnerability to disturbance from human activities. 

122 Seamount
Oxygen Minimum Zone

HABITAT OVERVIEW

Respiration by organisms reduces the concentration of dissolved oxygen in the water column. In 

the photic zone of the water column (<200 m), photosynthetic organisms produce oxygen, which 

generally offsets respiration. However, in deeper and darker waters, oxygen production is 

reduced and respiration is high, subsidized by the decomposition of sinking organic matter from 

the photic zone above. This combination results in an oxygen-minimum layer, where dissolved 

oxygen is below 0.5 ml per liter. This oxygen minimum zone (OMZ) typically occurs at depths 

from 600 to 1000 m deep (Figure 5). Oxygen concentration in the water column decreases 

rapidly approaching the upper boundary of the OMZ, continues to decline until a minimum is 

reached in the middle of the OMZ, and then gradually increases with depth to the lower 

boundary of the OMZ and beyond. The OMZ influences both the vertical distribution of pelagic 

fauna, and where the OMZ intersects the seafloor (Figure 4), the depth distribution of benthic

fauna.

Several studies have provided estimates of the depth of the OMZ off central California: 500-

1,000 m based on studies in the area between Pt. Lobos and Pt. Sur (Mullins et al. 1985,

Thompson et al. 1985 (based on Broenkow and Greene 1981)); 600-1,000 based on studies at 

Purisima Pt. (Hunter et al. 1990), Smooth Ridge (Vetter et al. 1994), and the area between Pt. 

Sur to Pt. Conception (Jacobson and Vetter 1996); and 500-1,130 m based on a study in 

Monterey Bay (MBARI 2009b). For the purpose of this report, we generally refer to 600 m as 

the upper bound and 1,000 m as the lower bound of the OMZ in central California.

However, it appears that the boundaries of the OMZ in the California Current System have been

expanding during the last several decades and this expansion is predicted to continue as the 

climate warms (reviewed in Gilly et al. 2013). Shoaling of the upper boundaries of the OMZs, 

which accompanies OMZ expansion, leads to decreased oxygen at shallower depths and can 

affect both pelagic and benthic organisms through direct and indirect mechanisms. Effects 

include altered microbial processes and changes in predator-prey dynamics. Although some

species will be negatively affected by these changes, others may expand their range or exploit 

new niches.

SEARCH TOPIC TABLE

TOPIC FRAMEWORK

Functional Habitats:

Nursery Habitat: No specific information was found on this topic.

Feeding Ground: See page 124

Spawning Ground: See page 125

Migratory Corridor: See “Movement and Dispersal” section on page 131

123 Oxygen Minimum Zone
Biogenic Habitat:

No information specific to biogenic habitat in the OMZ was 

found. See the “Biogenic Habitat” section in the Slope-Hard 

bottom, Slope-Soft Bottom and Chemosynthetic Biological 

Communities habitat summaries for related information.

Energy Flow:

Primary Production:

No information specific to primary production in the OMZ was 

found. See Slope – Hard Bottom and Slope – Soft Bottom 

habitat summaries for related information.

Benthic-Pelagic Coupling:

No information specific to benthic-pelagic coupling in the OMZ 

was found. See Slope – Hard Bottom and Slope – Soft Bottom 

habitat summaries for related information. See Appendix III. 

Benthic-Pelagic Coupling for general information.

Key Trophic Interactions:

No information specific to key trophic interactions in the OMZ 

was found. Related information can be found in the Slope – Soft 

Bottom and Open Water habitat summaries.

Key Trophic Cascades: No specific information was found on this topic.

Productivity Hotspots: See page 125

HABITAT STRUCTURE

Species Composition: See page 126

Species Composition Shifts: See page 128

Species Diversity and Richness: See page 129

Biomass: See page 130

Key Species Interactions

No information specific to key species interactions in the OMZ 

was found. See Slope – Hard Bottom and Slope – Soft Bottom 

habitat summaries for related information.

MOVEMENT AND DISPERSAL See page 131

SPECIES OF SPECIAL INTEREST

No information specific to species of special interest in the 

OMZ was found. See Slope – Hard Bottom and Slope – Soft 

Bottom habitat summaries for related information.

HABITAT SUMMARY

HABITAT FUNCTION

Functional Habitats

Feeding Ground:

• Deep Scattering Layer (reviewed in Gilly et al. 2013). The upper boundary region of 

the OMZs (and the overlying Oxygen Limited Zone (OLZ)) is an important feeding 

ground in the California Current system. Vast amounts of micronekton, particularly krill 

and myctophid fishes, take refuge from visually oriented predators in this hypoxic region 

during daytime. These small organisms compress into discrete layers, called deep 

scattering layers, which often lie in the OLZs or near the upper (and lower) boundary of 

an OMZ. Dense aggregations of organisms in these deep scattering layers provide a rich 

daytime foraging ground for a wide variety of deep-diving pelagic predators, including 

swordfish, tunas, sharks, squid, elephant seals, and sperm whales.

124 Oxygen Minimum Zone
• Benthic Fishes: The upper slope habitat between 600 and 1,200 m was identified by 

Wakefield (1990) as an important feeding ground for a diverse array of fishes, many of 

which utilize shallower nursery grounds on the shelf.

Spawning Ground: The OMZ appears to be an important spawning ground for a diverse array 

of fishes, many of which utilize shallower nursery grounds on the shelf and migrate down into 

the OMZ at later stages (Wakefield 1990). Dover sole, sablefish, and longspine and shortspine 

thornyhead, four of the most important species in the deepwater fishery off California, all have 

their peak spawning biomass in the depth range of the OMZ. Eliminating fishing deeper than 

600-800 m would protect the spawning biomass of thornyheads, Dover sole, and sablefish

(Jacobson and Vetter 1996).

• Thornyheads in OMZ (Jacobson and Vetter 1996). Peak spawning biomass for both 

thornyhead species off Oregon and central California (Point Sur to Point Conception) 

occurs in the OMZ depth range (600-1,000 m); longspine thornyheads are OMZ 

specialists that spend the entire benthic juvenile and adult phases in the OMZ. Small 

shortspine thornyheads are found in shallow water (200-600 m), but migrated to deeper 

water with growth.

• Dover Sole (Hunter et al. 1990). Ninety-eight percent of the spawning biomass of Dover 

sole (Microstomus pacificus) in central California (Half Moon Bay to Purisima Point)

waters live in the OMZ between 640-1,005 m. Dover sole spawn at these depths and the 

eggs rise to the surface layers.

• Giant Grenadier (Novikov 1970). Male and female giant grenadier (Albatrossia 

pectoralis) live separately (females prefer ~300-700 m; and males prefer >~700 m). This 

separation is rarely disturbed. During spawning, females migrate to deeper depths (depths 

may be specific to the North Pacific). The spawning period for giant grenadier is 

prolonged and not confined to definite dates.

Energy Flow

Productivity Hotspots: 

• Edges of the Oxygen Minimum Zone. Off central California (between Point Lobos and

Point Sur), Thompson et al. (1985) found that benthic invertebrate density is significantly 

greater at the upper and lower edges of the OMZ (~525 and 1,025 m) with the pattern 

more pronounced at the upper edge. The peaks in faunal density corresponded with peaks 

in the organic carbon content of the sediment. They proposed that the peak in faunal 

density may be a response to high bacterial production where the oxycline intersects the 

bottom sediment. Mullins et al. (1985) proposed that the increase in biogeochemical 

activity along the edges of the OMZ in central California is due a combination of 

dissolved oxygen concentration, bottom currents, a bacterially-mediated nutrient 

recycling process, and food supplies. The nutrient recycling process involves an increase

of biologically usable nitrate and nitrifying bacteria at OMZ edges and denitrifying 

bacteria at the core of the OMZ. The edges of the OMZs may be preferred sites of 

increased biological activity because of greater nutrient concentrations plus larger food

supplies in the form of bacteria.

125 Oxygen Minimum Zone
HABITAT STRUCTURE

Species Composition: Invertebrates and fishes are the numerically dominant animal groups in 

the OMZ. Species distributions appear to be influenced many factors including depth, sediment 

composition, and dissolved oxygen levels.

• Infauna near Davenport (John Oliver, MLML, unpubl. data). In northern Monterey Bay 

and off Davenport, sediment cores along transects have shown distinct infaunal species 

assemblages that vary by depth. The Oxygen Minimum Zone Group (700 m) is composed 

of Byblis barbarensis, Ampelisca unsocalae, Myriochele gracilis, Gammaropsis ocellata, 

Phyllochaetopterus limicolus, Lepidepecreum kasatka, Photis typhlops, Scoloura 

phillipsi, Nemertea, Harpiniopsis epistomata;

• Invertebrates Near Smooth Ridge (CSLC & MBNMS 2005). Soft-bottom, invertebrate 

faunal groups were studied at sites near Smooth Ridge ranging in depth from 25-885 m. 

Most of the biological resources that occur at in this area are found throughout the central 

California regions, especially at depths below 200 m where species tend to be 

cosmopolitan in distribution.

o Hard-bottom habitats: The typical species assemblage between 300-1,000 m 

had a greater diversity and size of sponges and echinoderms than at shallower 

depths.

o Soft-bottom habitats: 475 species of infaunal invertebrates were identified. 

Polychaete worms showed the highest abundance and species richness at most 

depths. Gammarid amphipods were relatively abundant at all stations, and were 

the most abundant species at 640, 770 and 795 m stations and the most species 

rich group at 640 and 770 m stations. Oligochaete worms were the most abundant 

taxa at 885 m station. Other groups relatively abundant on the slope included: 

caprellid amphipods (325 and 450 m); brittle stars (450 m); and bivalves (640 m). 

Sea pens, anemones, crabs and sea stars were the epifauna most commonly seen 

at all stations. Sea urchin, sea cucumber, and sea stars dominated between 280-

449 m; sea pens, gastropods, and anemones dominated between 450-599 m; and 

sea pens, Tanner crab, snails, anemones, and sea cucumber dominated deeper than 

600 m. Abundance of large invertebrates was highest at 325 and 885 m stations.

• Infaunal Invertebrates 300-1,400 m (Thompson et al. 1985). The infaunal community 

in central California (Point Lobos to Point Sur) as a whole is dominated by polychaete 

worms that lacked calcified tubes. Infaunal organisms with heavily calcified skeletons 

occurred throughout most of the study area, but at much lower abundance. The only 

water depth interval that lacked calcified infaunal organisms was 650 to 750 m, where 

oxygen concentrations drop below 0.3 ml/l O2.

• Megafaunal Invertebrates 300-1,400 m (Thompson et al. 1985). Off central California 

(Point Lobos to Point Sur), all major invertebrate taxonomic groups were found to 

increase in numbers along both the upper and lower edges of the OMZ, while having 

minimum numbers within the OMZ.

o Polychaetes were the most abundant individuals in all regions of the OMZ.

o Echinoderms exhibited a distinct depth zonation with asteroids (most commonly 

the sun star, Rathbunaster californicus) dominating the upper OMZ boundary 

126 Oxygen Minimum Zone
(400-500 m), echinoids (dominated by irregular urchin Brissopsis pacifica) most 

abundant near the lower OMZ boundary (900 m), and ophiuroids (brittle stars) 

density peaking below the OMZ. The core of the OMZ (600-800 m) was devoid 

of echinoderms. 

o Crustaceans were most abundant along the upper portions of the OMZ, 

disappeared at depths of 800-1,000 m, and reappearing in small numbers as 

oxygen values increase. A group of hermit crabs was the only epifaunal organism 

observed in the core of the OMZ (~700 m), where oxygen concentrations drop 

below 0.3 ml/l O2.

o Though mollusks were at relatively low density in all depth zones, they were most 

abundant along the lower edge of the OMZ, with peak densities at ~1,100 m.

• Benthic Fishes and Megafaunal Invertebrates West of Half Moon Bay (SAIC and 

MLML 1992). Results of cluster analysis based on density and histogram summaries 

based on species numbers, density, and biomass, indicated that benthic fish and 

megafaunal invertebrate communities are distributed primarily by depth, and are 

independent of study area boundaries. The mid-slope (500-1,200 m) community was 

characterized:

o Fishes were common and included thornyheads, Dover sole, rattails, and finescale 

codling;

o Megafaunal abundance was high and included Tanner crabs, sea stars, brittlestars, 

snails, and sea cucumbers.

• Flatfishes on Smooth Ridge (Vetter et al. 1994). Dover sole was the only flatfish at 600 

m. Dover sole and deep-sea sole co-occurred at 800-1,200 m with both species common 

at the 1,000 m site.

• Demersal Fishes off Point Sur (Wakefield 1990). A study of the fish fauna for seven 

200-m depth intervals from 400 to 1,600 m at Point Sur found that the upper slope habitat 

between 600 and 1,200 m contains a diverse array of fishes. Faunal break at 400-600 m, 

corresponds to a transition between shelf- and slope-dwelling species. The depth 

distribution of the adult population of a number of fishes (e.g., thornyheads, Dover sole, 

and sablefish) is centered within the OMZ. The following species were collected from at 

least one of the 3 stations in the OMZ (600, 800, 1,000 m): Pacific hagfish, sandpaper 

skate, bigfin eelpout, rex sole, filetail catshark, brown catshark, Dover sole, shortspine 

thornyhead, longspine thornyhead, sablefish, black hagfish, California slickhead, deepsea sole, Pacific flatnose codling, giant grenadier, two-line eelpout, blacktail snailfish, 

snakehead eelpout, blackmouth eelpout, Pacific grenadier.

• Groundfish Assemblage off U.S. West Coast Slope (Tolimieri and Levin 2006). Data 

from trawl surveys along the U.S. west coast at 100 m intervals between 200-1,200 m 

revealed strong shift in fish assemblage structure at approximately 500-600 m and a 

second, more minor shift at 900-1,000 m. These shifts are likely due to temperature 

changes and possibly a response to the OMZ at 600-1,000 m. While temperature 

continues to decrease with depth, oxygen concentrations can increase below 1,000 m,

which may explain the more minor shift in assemblage structure at around 900-1,000 m. 

Five assemblages were identified based on depth and latitude (Figure 18), two of which 

127 Oxygen Minimum Zone
intersect the OMZ:

o Shallow to mid-depth (200-1,000 m)/mid-latitude to southern assemblage:

sablefish, brown cat shark, aurora rockfish, Dover sole, and shortspine 

thornyhead;

o Deep (600-1,200 m)/broad latitude assemblage: Pacific grenadier, giant 

grenadier, deepsea sole, longspine thornyhead, California slickhead, and roughtail 

skate.

• Demersal Fishes on the Slope in the MBNMS (Steve Ralston, pers. comm.). The depth 

distributions of 15 fish species/groups were determined using data from NWFSC slope 

trawl survey in the years 1999-2006 at sites in the MBNMS. Each species or genus 

generally fell into one of the following groups (Figure19):

o Common above OMZ (200-600 m): chilipepper, shortbelly, stripetail, splitnose 

and aurora rockfishes, spotted ratfish, rex sole, and bigfin eelpout;

o Common above and inside OMZ (200-1,000 m): cat sharks, Dover sole, 

sablefish, shortspine thornyhead

o Common inside and below OMZ (600->1,000 m): longspine thornyhead, 

California slickhead, grenadier

 Pelagic Invertebrates and Fishes (Robison 2004, Gilly 2013): Larger animals that 

permanently inhabit the California OMZ include species with extremely low metabolic 

rates, like the slow-moving vampire squid (Vampyroteuthis infernalis) and mysid shrimp 

(Gnathophausia ingens), which have enhanced oxygen extraction and transport abilities. 

Other common inhabitants include bathylagid owlfishes, the pelagic worm Poeobius 

meseres, filter-feeding tunicates, and a diverse array of abundant cnidarians and 

ctenophores.

• Epipelagic and Mesopelagic Organisms (Bruce Robison, pers. comm.). The upper 

1,000 m of the water column over the Monterey Canyon has been studied by Bruce 

Robison’s lab at MBARI since 1992. Table 14 provides a preliminary evaluation of the 

relative frequency of sightings of the most commonly observed organisms in 100 m depth 

strata based on data collected between 2000-2002. This table shows the composition of 

mesopelagic organisms in Monterey Canyon at different depth strata in the OMZ, such as 

around the upper and lower boundaries.

Species Composition Shifts: Dissolved oxygen levels influence the distribution and abundance 

of species. Global climate change is expected to result in the expansion and intensification of the 

OMZ. Shifts in the location of the OMZ along central California could lead to shifts in the 

species composition at a given location. Additional processes that could result in shifts in species 

composition include food falls and periods of high productivity in surface waters, which deliver 

natural supplies of food to the slope. Humans activities that can influence species composition on 

the slope are discussed in “Shelf I & II – Hard Bottom”, “Slope – Hard Bottom”, and “Slope –

Soft Bottom” habitat summaries.

• Natural Changes: Shifts in the location of the OMZ along central California could lead 

to shifts in species composition in the water column and the seafloor. 

128 Oxygen Minimum Zone
o Shifts in Vertical Distribution of Pelagic Fauna (reviewed in Gilly et al. 2013). 

The upper boundaries of OMZs have been shoaling (i.e., getting shallower) during 

the past 50 years. Shoaling of the OMZ upper boundary results in an expansion of 

hypoxic habitat for permanent OMZ dwellers, such as the vampire squid 

(Vampyroteuthis infernalis), the mysid shrimp (Gnathophausia ingens), and 

pelagic worm (Poeobius meseres). However, shoaling of the OMZ upper 

boundary also results in a vertical compression of the pelagic habitat above the 

OMZ which may alter predator-prey interactions. Vast amounts of micronekton, 

particularly krill and myctophid fishes, take refuge from visually oriented 

predators near the upper boundary region of OMZs during daytime. A shoaling 

OMZ concentrates prey at shallower depths and may increase exposure of 

mesopelagic organisms to ambient light potentially increasing daytime foraging 

pressure by visually oriented predators. This effect may have been important in 

the recent range expansion of Humboldt squid in the California Current system. 

The potential expansion of the lower boundary of the OMZ would lead to an 

analogous shift to greater depths for those organisms that preferentially inhabit 

the lower boundary of an OMZ.

o Benthic Macroinvertebrates: Thompson et al. (1985) proposed the following 

zones relating oxygen concentrations with dominant benthic invertebrate fauna 

and sedimentary structures: 

• anaerobic zone (<0.1 ml/l O2): devoid of macroinvertebrates and 

characterized by laminated sediments;

• dysaerobic zone (0.1-0.3 ml/l O2): dominated by small (1-2 mm), softbodied infauna that exhibits moderate disturbance of sediment due to 

bioturbation;

• aerobic zone (> 0.1 ml/l O2): inhabited by an abundant calcareous fauna 

and characterized by homogeneous, bioturbated sediments.

Species Diversity and Species Richness: A few studies in central California have examined 

species diversity or richness in the depth range of the OMZ. See “Slope – Hard Bottom” habitat 

summary for general information on this topic in the slope habitat.

• Invertebrates Near Smooth Ridge (CSLC & MBNMS 2005). 475 species of infaunal 

invertebrates were identified over the depth range 25-885 m. Polychaete worms showed 

the highest species richness at most depths. Gammarid amphipods were the most species 

rich group at 640 and 770 m stations. In addition, species richness was high for 

ophiuroids at the 450 m stations.

• Infauna Near Davenport (John Oliver, pers. comm.). In northern Monterey Bay and off 

Davenport, the mean number of species in sediment cores increased along the shelf, 

peaking at 109 and 150 m (at the shelf break), and then declined along the slope to 700 

m. The mean number of species per sample was similar from 700-2,000 m. The number 

of species of crustaceans followed a similar pattern.

• Megafaunal Invertebrates Inside and Outside Monterey Bay (Oliver et al. 2011). 

Estimates of soft-bottom species density were obtained by sampling benthic megafaunal 

invertebrate communities in four major sampling programs along the coast of Central and 

129 Oxygen Minimum Zone
Northern California. Three of these programs were focused around the Monterey Bay 

area. Samples from 30 to 2,000 m depths were analyzed. Presence of the OMZ did not 

account for the lower species density on the slope compared to the shelf. The center of 

the OMZ harbored a dense community of ampeliscid amphipods, forming a tube mat that 

was seen in ROV video footage along four of the transects. Samples from the tube mat 

from the center of the OMZ at 700 m were included in the upper slope depth category 

(250-750 m), where there was relatively high species density (335 species/m

2

). The 

lowest species densities (205 species/m2

) were found below the OMZ at 1000–2000 m.

• Demersal Fish Species Richness (Wakefield 1990). A study of the fish fauna on the 

slope at Point Sur found that the number of species identified from trawls was relatively 

constant at ~20 species for four 200-m depth intervals from 400 to 1,000 m, but 

decreased below 1,000 m.

Biomass: Detailed biomass studies have yet to be conducted for microbes, meiofauna, 

megafauna, or fishes within the OMZ in central California (Levin 2003). However, a few studies 

in central California have examined biomass in the depth range of the OMZ.

• Invertebrates in the OMZ off central California (Thompson et al. 1985). Correlation 

of biomass of major invertebrate groups from box core samples with dissolved oxygen 

content revealed a decrease in biomass below the 0.5 ml/1 O2 level. Most major 

taxonomic groups were absent or represented by only a few species below the 0.3 ml/1 

O2 level. The highest invertebrate biomass was observed in the deeper portion of the 

OMZ (~800-900 m) and high biomass also was observed at the upper boundary of the 

OMZ (~500 m). These patterns were driven by echinoderms and polychaetes: 

o Echinoderms constituted over 90% (57 g/m2) of the biomass within the OMZ, 

with highest density in the lower OMZ and moderate density near the upper and 

lower boundaries. Densities of up to 7/m2 were observed for asteroids, up to 

14/m2 for irregular echinoids, and greater than 50/m2 for ophiuroids 

o Polychaetes consistently dominate other groups in biomass due to their large 

numbers, but both the biomass and density of polychaetes decrease where 

echinoderms are abundant. 

• Groundfishes off Point Sur (Wakefield 1990). A study of the fish fauna on the slope at 

Point Sur found that total fish biomass was relatively constant between 400-1,000 m 

(average of 24 mt/km2

), then decreased below 1,000 m to a minimum at 1,600 m (4 

mt/km2). Longspine thornyhead, was the dominant species in the OMZ; it was estimated 

that 93% of the spawning biomass of this species is found between 500 and 1,100 m. 

Other important taxa, either in terms of numbers or biomass, included black hagfish, 

shortspine thornyhead, Dover sole, Pacific grenadier, giant grenadier, sablefish, and 

eelpouts.

• Thornyheads in central California (Jacobson and Vetter 1996). Biomass for both 

thornyhead species off central California (Point Sur to Point Conception) is concentrated 

in the OMZ (600-1,000 m). The biomass of shortspine thornyhead was relatively constant 

across depth strata (400-1,000 m) whereas that of longspine thornyhead peaked sharply at 

800–1000 m. Average biomass (kg/km2

) by depth stratum (m) were:

o Shortspine thornyhead: 

130 Oxygen Minimum Zone
 200–400 m = 44 kg/km2

 400–600 m = 714 kg/km2

 600–800 m = 531 kg/km2

 800–1000 m = 772 kg/km2

 1000–1200 m = 176 kg/km2

 1200–1400 m = 57 kg/km2

o Longspine thornyhead:

 200–400 m = 2 kg/km2

 400–600 m = 692 kg/km2

 600–800 m = 1,736 kg/km2

 800–1000 m = 2,775 kg/km2

 1000–1200 m = 216 kg/km2

 1200–1400 m = 81 kg/km2

MOVEMENT AND DISPERSAL

Almost all fishes exhibit some degree of ontogenetic shift in space utilization as they mature and 

the degree of movement or area used by adults may vary depending on species and location. This 

is particularly true of demersal species of fishes, such as flatfishes, some rockfishes, and wrasses 

(Lowe and Bray 2006). Most movement studies have been done on shallower water species. 

Ontogenetic migration (movement to deep water as fish grow and age) occurs in Dover sole and 

shortspine thornyhead.

• Dover sole. Both Hunter et al. (1990) and Vetter et al. (1994) found that Dover sole in 

central California showed a strong ontogenetic vertical migration through the OMZ. 

Juvenile Dover sole settle on the continental shelf and gradually move down the slope 

over their lifetime, reaching the OMZ as they become sexually mature. The average 

female Dover sole in central California reaches sexual maturity when about 7 years old 

and 31 cm long and occurs at a depth of about 329 m. At 16 years old, the average female 

lives at a depth of 640 m. At 27 years, the average female has descended to 1006 m. The 

greatest depth at which Dover sole was collected was 1269 m.

• Shortspine thornyhead (Point Sur to Point Conception; Jacobson and Vetter 1996). Size 

at depth analysis of thornyheads between 200-1,400 m indicate that shortspine 

thornyhead migrate ontogenetically by moving deeper with increasing size, although a 

few large fish were present at all depths. Small (<20 cm TL) shortspine thornyhead were 

seldom found at depths greater than 600 m. The mean size of shortspine thornyhead 

increased with depth and was greatest at 1000–1400 m.

131 Oxygen Minimum Zone
Chemosynthetic Biological Communities

HABITAT OVERVIEW

When marine scientists first started studying a type of deep-sea community characterized by 

bacterial mats and certain species of chemosynthetic deep-sea clams and tubeworms, these areas 

were termed ‘cold seeps communities’. However, after studying several hundred of these 

communities, Monterey Bay Aquarium Research Institute (MBARI) scientists found that many 

sites lacked signs of significant groundwater flow or seepage. Instead, these communities most 

often occurred in areas where previously buried sediments have been exposed by erosion. Such 

erosion may be caused by undersea landslides, or strong, persistent currents. For this reason, the 

phrase "chemosynthetic biological communities", or CBCs, is more general and encompasses all 

such communities including those at cold seeps (MBARI Press Room 2005).

CBCs have been observed primarily in slope, rise, and canyon habitats of the Monterey Bay 

(Figure 6; Charles Paull, pers. comm.). It is likely that CBCs occur in other portions of MBNMS, 

but very little exploration of deep-sea habitats has occurred outside the Monterey Bay area. 

CBCs in Monterey Bay have been found most frequently on steep slopes at depths exceeding 

550 m at sites where recent erosion has uncovered sediments rich in reduced chemical 

compounds such as hydrogen sulfide and methane (Paull et al. 2005a). Based on Carbon-14 

dating, CBCs could persist for centuries after the initial slide and some animals can live for many 

decades (Paull et al. 2005b).

SEARCH TOPIC TABLE

HABITAT FUNCTION

Functional Habitats:

Nursery Habitat:

No specific information was found on this topic. However, it is 

likely that the biogenic structure formed by chemosynthetic 

clams and tubeworms serves as nursery habitat for the juvenile 

phase of some mobile species such as crabs and fish.

Feeding Ground:

No specific information was found on this topic. However, 

mobile, demersal fish and invertebrates (e.g., crabs, octopus, 

snails) have been observed at CBCs. These species may be 

attracted to CBCs to forage on the large, sedentary clams that 

are characteristic of CBCs or on other prey species that are in 

high densities around CBCs.

Spawning Ground: No specific information was found on this topic.

Migratory Corridor: See page 133

Biogenic Habitat: See page 133

Energy Flow:

Primary Production: See page 133

132 CBCs
Benthic-Pelagic Coupling: See page 134

Key Trophic Interactions: See page 134

Key Trophic Cascades: No specific Information found on this topic

Productivity Hotspots:

Chemosynthesis supports the much higher species richness and 

biomass found at CBCs compared to surrounding soft sediment 

habitats in the deep sea

HABITAT STRUCTURE

Species Composition: See page 134

Species Composition Shifts: See page 135

Species Diversity and Richness:

Chemosynthesis supports the much higher species richness (>70 

species) of megafauna found at CBCs compared to surrounding 

soft sediment habitats in the deep sea (Barry et al. 1996)

Biomass: Chemosynthesis supports the higher biomass found at CBCs 

compared to surrounding soft sediment habitats in the deep sea.

Key Species Interactions See page 136

MOVEMENT AND DISPERSAL See page 136

SPECIES OF SPECIAL INTEREST

No landed, endangered and threatened or at-risk species have 

been observed at CBCs (Table 21). The structure-forming 

invertebrates that are common at CBCs are of special 

management interest due to their important ecological role in 

creating habitat structure and their vulnerability to disturbance 

from human activities.

HABITAT SUMMARY

HABITAT FUNCTION

Functional Habitats

Migratory Corridor: Some of the species observed at CBCs are obligate species that are found 

only at CBCs or other chemosynthetic habitats (e.g., hydrothermal vents, large animal falls). 

Obligate species probably use these spatially distinct habitats as stepping-stones for dispersal 

(Smith et al. 1989). Dispersal may occur during the larval stage (sessile and mobile species) or at 

older life stages (mobile species only).

Biogenic Habitat: Most of the chemosynthetic organisms found at CBCs, such as vesicomyid 

clams and vestimentiferan worms, are large, sedentary organisms. Sessile organisms use these 

structure-forming invertebrates as a hard substrate for attachment and by some mobile organisms 

as shelter or food.

Energy Flow

Primary Production: The only form of primary production in deep-sea habitats is 

chemosynthesis. Chemosynthetic bacteria, located in mats or living as symbionts in the tissues of 

larger organisms, use energy stored in certain chemical compounds (e.g., hydrogen sulfide and 

133 CBCs
methane) to convert water and carbon dioxide into organic carbon (food). The organic carbon 

fixed by chemosynthetic organisms forms the base of the food web in CBCs.

Benthic-Pelagic Coupling: The flux of material between the benthos and the overlying water 

column occurs through sinking of non-living organic matter and the active movement of 

organisms. Falling plankton, fecal pellets, animal carcasses, and drift algae serve as subsidies 

that may be scavenged by detritivores within the CBC. CBCs (along with hydrothermal vents) 

are some of the only habitats in the deep sea where falling organic matter is not the primary 

source of organic carbon for the food web. See Appendix III for more general information about 

benthic-pelagic coupling.

Key Trophic Interactions:

• Chemosynthesis supports either directly or indirectly a large portion of the species found 

in association with CBCs. Species can be classified into three groups depending on their 

level of dependence on chemosynthetic energy: 

o Obligate species: These species are only found at CBCs. These species are either 

chemoautotrophic bacteria or serve as hosts to chemoautotrophic bacterial 

symbionts.

o Potentially obligate species: These species are only found at CBCs and may 

harbor chemoautotrophic symbionts or feed almost exclusively on chemosynthetic 

organisms.

o Non-obligate (or regional species): These species occur at CBCs, but also occur 

at non-seep habitats in the region. These species are not chemoautotrophic and, 

though they may feed on chemosynthetic organisms, their diet is not restricted to 

such organisms. 

• Predation (summarized in Airamé et al. 2003). Lithodid and brachyuran crabs have been 

observed to prey on vesicomyid clams. Tanner crabs (Chionoecetes tanneri) prey on 

vesicomyid clams in the laboratory and are likely to consume clams in the field. Buccinid 

snails (Neptunea amianta) scavenge dead vesicomyid clams at cold seeps in Monterey 

Bay. Holes in vesicomyid shells provide further evidence of predation by snails or 

octopus. Surficial grazing of the shell by columbellid gastropods may benefit vesicomyid 

clams by removing bacterial films from the clams’ shells. 

HABITAT STRUCTURE

Species Composition:

• Cold Seeps in Monterey Bay (Barry et al. 1996). Four cold seeps in the Monterey Bay 

region (600-1000 m) were surveyed. Individual seeps were small, rare, highly localized 

communities. Table 21 provides a complete list of taxa found at these four sites. The 

species were placed into three groups based on their dependence on cold seeps: 

o Obligate species: At least 9 taxa, including vesicomyid clams, solomyid clams, 

tubeworms, and bacterial mats, are either chemoautotrophic or harbor 

chemoautotrophic symbionts. Vesicomyid clams tend to be the numerically 

dominant obligate species at cold seeps in the Monterey Bay area;

134 CBCs
o Potentially obligate species: At least 3 taxa, a columbellid gastropod, a 

pyropeltid limpet, and an unknown galatheid crab, may harbor chemoautotrophic 

symbionts or feed almost exclusively on chemosynthetic organisms;

o Non-obligate or Regional species: At least 55 taxa, including deep-sea coral, 

anemones, snails, segmented worms, crabs, brachiopods, crinoids, sea stars, brittle 

stars, sea urchins, sea cucumbers, hagfish, catsharks, thornyheads, and flatfish,

occur at seeps and at non-seep habitats in the region. 

• Relative Abundance of Clams at Cold Seeps in Monterey Bay (Barry et al. 1997). The 

distributions of vesicomyid clams species correspond closely to patterns of sulfide and 

methane concentrations in the sediments. The vesicomyid clam, Phreagena kilmeri, 

accounted for 85-99% of all vesicomyids at seeps with high sulfide concentrations. In 

contrast, C. pacifica dominated (73%) seeps with low sulfide levels. These species were 

also partially segregated along sulfide gradients from the center to the margin of seeps, 

analogous to zonation in rocky intertidal communities.

• Clams at Cold Seeps along the US West Coast (Goffredi et al. 2003). Vesicomyid 

clams are one of the dominant invertebrates at chemosynthesis-based communities (deepsea cold seeps and hydrothermal vents). Three vesicomyid clam species that co-occur in 

the Monterey Bay appear to be spatially segregated by depth:

o Vesicomya pacifica (type I clam): 500-1000 m;

o Vesicomya spp. (type II clam): depth range 1550-2200 m;

o Vesicomya spp. (type III clam): depth range 2200-2500 m.

Species Composition Shifts: 

• Natural Changes: CBCs differ substantially in species composition compared to the 

surrounding soft bottom habitat. Erosion that uncovers sediments with sufficient levels of 

reducing compounds to support a CBC is a natural cause of species compositions shifts in 

the deep sea. As the availability of reducing compounds in the sediments changes, the 

species composition at the CBC changes. Once the concentration of reducing compounds 

drops too low in a given area, obligate species can no longer produce enough food to 

support the community and the CBC will eventually disappear.

o Succession at CBCs in Monterey Bay (Paull et al. 2005b). The chemosynthetic 

organisms observed on slide scars in Monterey Canyon undergo a faunal 

succession based in part on their lifecycle and their ability to maintain access to 

hydrogen sulfide in the sediments. Various chemosynthetic taxa are capable of 

exploiting reduced chemical compounds at different depths below the seafloor. 

• Bacterial mats may form and die off on timescales of weeks. Bacterial 

mats occur where both oxygen and hydrogen sulfide are in close (~1 cm) 

proximity to the seafloor. 

• Vesicomyid clams live for years to perhaps a century. Some vesicomyid 

clam species can span distances of 20 cm or more, by the distension of 

their muscular foot into sulfidic sediments, while maintaining contact with 

oxygenated seawater through their ventilation siphons at their opposite 

end. 

135 CBCs
• Vestimentiferans may live over 250 years, and are known to survive on 

very low supplies of hydrogen sulfide. Vestimentiferan tubeworms have 

‘‘roots’’ that may extend over 2 m into the seafloor to obtain hydrogen 

sulfide, whereas their anterior end is exposed to oxygenated seawater.

The timing of community succession will depend on how quickly the chemical 

compounds retreat from near the surface. As the hydrogen sulfide-bearing 

horizons retreat into the subsurface, the exposed bacterial mats would cease to be 

viable, and the vesicomyids would be compelled to bore into the mudstone to 

follow receding hydrogen sulfide-bearing zones. Once access to hydrogen sulfide 

is terminated, vesicomyid clams would die, shifting to a later successional phase 

dominated by vestimentiferan worms.

• Human-induced Changes: CBCs, like all benthic biogenic habitats, are susceptible to 

degradation from human activities that disturb benthic habitats such as fishing with 

bottom-tending gear, laying physical structures (e.g., cables), dredging and waste 

disposal. Removal of or damage to chemosynthetic sessile invertebrates has the potential 

to temporarily or permanently alter species compositions at these sites.

Key Species Interactions: Little or no information is available concerning ecological processes 

that influence demographic rates of biological populations at CBCs. Predation, competition, and 

disturbance likely play a major role, but few hypotheses regarding these population processes 

have been addressed (Barry 1996).

• Mutualism: Vesicomyid clams, solomyid clams, and tubeworms support 

chemoautotrophic bacteria in a symbiotic relationship. The bacteria use energy from the 

inorganic chemical compounds present in the sediments to make organic compounds. The 

clams and worms use the organic compounds produced by the bacteria as food.

MOVEMENT AND DISPERSAL

Some species that occur at CBCs, such as chemosynthetic bacteria and clams, are also found at 

whale falls and hydrothermal vents (Smith et al. 1989, Smith and Baco 2003). CBC-associated 

organisms may use whale carcasses and vents as stepping-stones during dispersal between 

CBCs.

• Goffredi et al. (2003) found that three closely related species of vesicomyid clams were 

genetically differentiated by depth, but not by region or geographic proximity. The 

authors suggest that the presumed continuous free spawning and high fecundity of 

vesicomyids allow dispersal over the distances separating populations (generally <50 

km).

136 CBCs
Macrophyte Detritus

HABITAT OVERVIEW

Macrophytes, including large kelps, smaller algae, and seagrasses, are major primary producers 

in the marine environment, but only grow in relatively shallow nearshore habitats. Periodically 

large storms and other disturbances cause parts of the macrophytes to break loose. This material, 

which can be exported as floating rafts or as benthic deposits, then becomes a source of food and 

shelter in other marine habitats such as offshore surface waters and benthic habitats on the shelf, 

slope, and in submarine canyons. 

Floating mats of kelp provide rare physical structure in open water and tend to attract mobile 

fishes and invertebrates. Macrophyte drift that settles to the benthos provides physical structure 

to benthic communities and food for detritivores. Though macrophyte detritus can be found in 

any benthic habitat, studies in central and southern California have demonstrated that it is more 

abundant in submarine canyons than on the adjacent shelf and slope. Macrophyte detritus drifting 

along the coast in currents accumulates in canyon heads, especially in submarine canyons that 

extend into nearshore waters. Periodic sediment flows then move this material into deeper 

portions of the canyons. 

SEARCH TOPIC TABLE

HABITAT FUNCTION

Functional Habitats:

Nursery Habitat:

Juveniles of a number of sport and commercial fishes are found

in association with floating kelp mats, including jacks, sablefish, 

rockfishes, and yellowtail (Rigsby 1999a, Allen and Cross 

2006).

Feeding Ground: See page 138

Spawning Ground: No specific information was found on this topic.

Migratory Corridor: No specific information was found on this topic.

Biogenic Habitat: See page 139

Energy Flow:

Primary Production:

Harrold et al. (1998) estimated that the kelp forests lining the 

southern tip of Monterey Bay generate >2x105 metric tons (wet 

weight) of macrophyte drift each year.

Benthic-Pelagic Coupling: See page 139

Key Trophic Interactions: No specific information was found on this topic.

Key Trophic Cascades: No specific information was found on this topic.

137 Macrophyte Detritus
Productivity Hotspots:

Macrophyte detritus is a hotspot of productivity in many benthic 

habitats, especially in deeper water habitats where primary 

production does not occur (with the exception of chemosynthetic 

biological communities) and the supply of organic carbon is 

limited. Submarine canyons, especially those extending into 

nearshore waters, appear to be areas with unusually large 

concentrations of macrophyte detritus and, thus, hotspots of organic 

enrichment.

HABITAT STRUCTURE

Species Composition: See page 140

Species Composition Shifts: See page 141

Species Diversity and Richness: See page 141

Biomass: See page 141

Key Species Interactions No specific information was found on this topic.

MOVEMENT AND DISPERSAL No specific information was found on this topic.

SPECIES OF SPECIAL INTEREST

Some invertebrate and fish species of special interest have been 

observed to associate with macrophyte detritus. Examples include sea 

cucumbers, sea stars, octopus, hake, thornyheads, sablefish, and 

Dover sole. In addition, the juveniles of some fishes landed in 

MBNMS, such as jacks, sablefish, rockfish and yellowtail, associate 

with floating kelp mats in the open ocean.

HABITAT SUMMARY

HABITAT FUNCTION

Functional Habitats

Nursery Habitat:

Feeding Ground: Macrophyte detritus is a very concentrated source of organic matter. Exported 

macrophyte detritus may represent a significant source of nutrition for resident benthic 

organisms in habitats in close proximity to areas of high macrophyte density (e.g., kelp beds, 

seagrass beds). Macrophyte detritus is probably a particularly important food subsidy in deep-sea 

environments where food availability tends to be limited. Nearshore submarine canyon heads 

accumulate drift macrophytes and channel them to deeper waters.

• Carmel Canyon (Harrold et al. 1998). The stomachs of the sea urchin

Strongylocentrotus fragili collected from the canyon were packed with algal material, 

while the stomachs of sea urchins at Point Joe (the adjacent shelf and slope site) had 

much lower algal content and lower gut fullness. In addition, gonad indices of S. fragilis

from Point Joe were lower than those from the Carmel Canyon suggesting that Point Joe 

sea urchins were in a poorer nutritional state. Drift algae appears to provide a predictable 

source of nutrition for sea urchins in the canyon allowing for a higher reproductive 

condition compared to urchins on the adjacent shelf and slope at Point Joe.

138 Macrophyte Detritus
• Southern California (Vetter and Dayton 1998, 1999). In Scripps and La Jolla Canyons, 

macrophyte detritus is a source of food for many different species of invertebrates, such 

as amphipods, crustaceans, sea cucumbers, and sea urchins.

Biogenic Habitat: Macrophyte drift is a source of physical structure for shelter and food (or 

both) for a number of species.

• Floating Kelp Mats. Ocean-going mats of kelp provide shelter to many species that 

otherwise find little shelter in the open ocean, including juvenile sea turtles, swimming 

crabs, and the young of important sport and commercial fishes such as jacks, sablefish, 

rockfishes, and yellowtail (Rigsby 1999a, Allen and Cross 2006).

• Macrophyte Detritus in the axis of La Jolla and Scripps Canyon appeared to be utilized 

as food and shelter by some species of fish and invertebrates, including the crab 

Glyptolithodes cristatipes, the eelpout Eucryphycus californica, and, at depths between 

300-500 m, patches of drift surfgrass (Phyllospadix spp.) were frequently observed with 

large aggregations of amphipods (Vetter and Dayton 1999). Examples of associations 

with other structures in the canyon axis included: a small tree branch found at 700 m was 

inhabited by large numbers of snails and amphipods. A small log found at 500 m hosted 

large crabs (G. cristatipes). In the Monterey Canyon, the persimmon eelpout (Maynea 

californica) was commonly associated with macroalgae drifting on the bottom of the 

canyon at depths of 70-550 m (Cailliet and Lea 1977 cited in Airamé et al. 2003).

Energy Flow

Benthic-Pelagic Coupling: There is a two-way exchange, or flux of matter, between the benthos 

and the overlying water body, which is important for both benthic and pelagic compartments. 

This flux occurs through the passive movement of non-living organic matter and the active 

movement of organisms. Macrophytes exported from kelp beds and seagrass beds tend to float 

initially (upward flux of primary productivity into the pelagic compartment), but eventually 

settle to the seafloor (downward flux of organic matter to the benthic compartment). See 

“Appendix III– Benthic Pelagic Coupling” for a general overview.

• Monterey Canyon. Macrophyte detritus accumulates in the head of Monterey Canyon 

throughout the year, but the type and amount of algae varies according to season. Late 

spring and summer are times of accumulation and burial. In fall and winters, episodic 

flushing events deliver the algal detritus down the canyon axis (Okey 2003). Goffredi et 

al. (2004) observed relatively fresh surfgrass debris near a whale fall in the Monterey 

Canyon during all three observation periods. The density of marine debris near the whale 

fall site supported the idea of frequent and intense flow events, resulting in the 

accumulation of materials within the canyon axes.

• Carmel Canyon. Harrold et al. (1998) surveyed three sites [Carmel Canyon shallow 

(153-378 m); Carmel Canyon deep (288-454 m); adjacent shelf at Point Joe (87-357 m)] 

to examine the organic enrichment of submarine-canyon and continental shelf benthic 

communities by macrophyte drift. They found that macrophyte drift deposits were more 

frequently observed in submarine canyon habitats than on the adjacent shelf and slope 

habitats. At both shallow and deep canyon sites, deposits were more frequently observed 

at the base of canyon walls than in the middle of the canyon floor. The daily flux of 

organic carbon derived from the giant kelp (Macrocystis pyrifera) to the canyon study 

139 Macrophyte Detritus
sites was estimated to be 45.2 mg C/ m2

/ day (this is a rough approximation based on 

many assumptions). Compared to estimates of carbon flux from vertically sinking 

particulate organic carbon (POC) at 400-m depth in the nearby Monterey Canyon, drift 

M. pyrifera can account for 20-83% of the total POC reaching the seafloor in the Carmel 

Canyon. 

• La Jolla and Scripps Canyon (Vetter and Dayton 1998, 1999). Longshore transport 

delivers substantial quantities of macrophyte detritus from surfgrass (Phyllospadix 

torreyi), kelps (M. pyrifera and Egregia menziesii), and other macroalgae to the heads of 

Scripps and La Jolla Canyons. Strong tidal and gravity currents distribute this material 

throughout much of the canyon system.

• Davidson Seamount (Burton and Lundsten 2008). Drift algae and surfgrass have been 

observed on the Davidson Seamount, including Alaria marginata, Macrocystis sp., 

Nereocystis luetkeana, and Phyllospadix spp.

HABITAT STRUCTURE

Species Composition: A variety of plants and algae including, seagrasses, green algae, red algae, 

and brown algae, compose the macrophyte detritus observed in central and southern California. 

However, drift from large kelps (a type of brown algae) tends to be observed most often. A 

variety of fishes and invertebrates are commonly found in association with macroalgal detritus.

• Carmel Canyon (Harrold et al. 1998). The macrophyte drift commonly observed in 

Carmel Canyon over a 3-year study was composed of a diverse assemblage of algal 

species. Red and brown algae were most common, especially M. pyrifera. Surfgrass, 

Phyllospadix spp., was ubiquitous through all areas surveyed, but at low biomass (it 

occurred mostly as widely scattered single strands).

• Monterey Canyon (Okey 2003). Amphipods dominated natural patches of sunken algae 

in Monterey Canyon's shallow head during winter and spring, while polychaete worms 

dominated during late summer and fall. In addition, comparative sampling revealed 

substantial differences in the invertebrate communities associated with patches of 

macrophyte detritus and background sediment.

• The persimmon eelpout (Eucryphycus californicus) is commonly associated with 

macroalgae that drift on the bottom of Monterey Canyon to depths of 70-550 m (Cailliet 

and Lea 1977 cited in Airamé et al. 2003).

• La Jolla and Scripps Canyon (Vetter and Dayton 1998, 1999). The floor of Scripps 

Canyon from 15 m to >60 m is often covered with a persistent mat of kelp (M. pyrifera

and Egregia menziesii) and seagrass (Phyllospadix spp. and Zostera marina) detritus. The 

following species were associated with macrophyte detritus in La Jolla and Scripps 

Canyons between 100-500 m: amphipods (many species), polychaete worms (many 

species), heart urchins (Brissopsis pacifica), sea urchins (S. fragilis and Lytechinus 

pictus), sea stars, sea cucumbers (Pannychia moseleyi and Parastichopus spp.), benthic 

siphonophores (Dromalia alexandri), decapods (including the crab Glyptolithodes 

cristatipes), octopus, juvenile and adult hake, thornyheads, sablefish, witch eel, Dover 

sole, turbot (Pleuronichthys spp.), eel pouts (Lycodes pacifica and E. californica), and 

scorpionfish (Scorpaena guttata).

140 Macrophyte Detritus
Species Composition Shifts: 

• Natural Changes: Mobile invertebrates and a few species of fish rapidly colonize mats 

of macrophyte detritus. Comparative studies (Okey 2003, Vetter and Dayton 1998, 1999) 

have found substantial benthic community differences between algal patches and 

background sediment. In addition, Okey (2003) found that the invertebrate assemblage on

patches of macrophyte detritus shifted between an amphipod-dominated assemblage in 

the spring to a polychaete-dominated assemblage in the fall. This shift in species 

assemblage was related to both dissolved oxygen and level of disturbance (time since 

flushing events). Crustaceans, with their highly mobile adult phase, were able to rapidly 

colonize ephemeral patches of sunken drift algae and rapidly recover after disturbance, 

but were sensitive to hypoxia. The more sedentary polychaete worms were slower to 

colonization patches of algal detritus and were more sensitive to physical disturbance, but 

had a higher tolerance to hypoxia.

Species Diversity and Species Richness:

• Macrofauna associated with drift in Monterey Canyon (Okey 2003). Species richness 

was highest when both crustacean and polychaete groups inhabited detrital patches. The 

two species groups tended to co-occur at intermediate levels of disturbance and dissolved 

oxygen.

Biomass:

• Macrophyte Drift in Carmel Canyon (Harrold et al. 1998). The volume of deposits of 

macrophyte detritus was generally <0.5 m3

, but some massive deposits (up to 7 m3) were 

observed. The carbon biomass of drift M. pyrifera observed in this study spanned four 

orders of magnitude. The lowest biomass (~1-10 mg C/m2

) was consistently observed on 

the shelf and slope at Point Joe while much higher biomass (~100-10,000 mg C/m2) was 

observed in Carmel Canyon. Shallow canyon sites tended to have higher biomass than 

deep canyon sites. The lower biomass of drift algae at Point Joe was probably due to 

lower flux and higher consumption by resident herbivores at higher density (density of 

the sea urchin A. fragilis was always at least an order of magnitude higher at Point Joe).

• Macrophyte Drift in Southern California (Vetter and Dayton 1998, 1999). Mats of 

macrophyte detritus in Scripps and La Jolla Canyons were commonly 7-15 m thick and 

ranged in size from <1 to >30 m2 in area. Macrophyte detrital cover on the canyon floor 

decreased with depth: 100% at 65 m, 11-13% at 280-300 m, and 5% at 500 m in Scripps 

Canyon; 13% at 300 m and 5% at 500 m in La Jolla Canyon.

• Macrofauna associated with drift in Monterey Canyon (Okey 2003). Up to 5.7 × 105

individual macrofauna/m2 inhabited naturally occurring patches of sunken drift algae in 

Monterey Canyon's shallow head.

• Fauna associated with drift in Southern California (Vetter and Dayton 1998, 1999). In 

the axis of La Jolla and Scripps Canyon, megafaunal abundance was higher near 

macrophyte detritus. Algal detritus can support very high densities of amphipod and 

crustacean densities (at times >3 million individuals/m2) with biomass exceeding 1 

kg/m2

. 

141 Macrophyte Detritus
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Figure 1. Benthic habitat categories in Monterey Bay National Marine Sanctuary.

Hard substrate (shown in brown) is likely to be under-represented, especially smaller patches, because highresolution substrate data are not available for the entire offshore environment. Data Credit: Moss Landing Marine 

Laboratories and TerraLogic GIS, Inc.

159
Figure 2. Submarine canyons in Monterey Bay National Marine Sanctuary.

The yellow outlines include both the central channel and sloping walls of submarine canyons. This data layer was 

developed by the National Center for Coastal Ocean Science (NCCOS) using California Department of Fish and 

Game multibeam bathymetry, depth variance and 50 m contours, an existing GIS dataset developed by Greene et al. 

(1999) and NCCOS's physiographic features layer. In cases where two or more canyon features were in close 

proximity and clearly part of the same geological feature, they were united.

160
Figure 3. Seamounts in and adjacent to Monterey Bay National Marine Sanctuary. 

The seamount data was developed by the NOAA’s National Center for Coastal Ocean Science (NCCOS) in 2007.

161
Figure 4. Oxygen Minimum Zone in Monterey Bay National Marine Sanctuary.

The oxygen minimum zone (orange hatching), a portion of the water column with reduced levels of dissolved 

oxygen, intersects the seafloor in the slope benthic habitat category. Upper (600 m) and lower (1,000 m) boundaries 

are based on estimates from studies in central California.

162
Figure 5. Three dimensional view of the Oxygen Minimum Zone in MBNMS.

This view helps illustrate that the oxygen minimum zone (gold shading) is a 400 m zone that occurs along the 

seafloor on the landward side of the zone and is a mid-water column feature in deeper portions of the sanctuary.

Upper (600 m) and lower (1,000 m) boundaries of the oxygen minimum zone are based on estimates from studies in 

central California.

163
Figure 6. Observations of Chemosynthetic Biological Communities in MBNMS.

Locations where Chemosynthetic Biological Communities (CBC) or seeps have been observed during Monterey 

Bay Aquarium Research Institute (MBARI) ROV surveys 1989-2009. Locations were obtained through a query of 

MBARI’s public Video Annotation and Reference System (VARS) for seeps and Vesicomyidae and taxonomic

descendents. This map does not indicate survey effort. It is likely that CBCs occur in other portions of the sanctuary, 

but very little exploration of deep-sea habitats has occurred outside the Monterey Bay region. Data credit: Monterey 

Bay Aquarium Research Institute

164
Figure 7. Depth distribution and relative abundance of deep-water algae along the central California coast.

Spalding et al. (2003) found that algae in waters deeper than 30 m were distributed in three broadly overlapping 

zones characterized by one or a few visually dominant taxa (reprinted with permission).

165
Figure 8. Observations of structure-forming invertebrates associated with hard substrate.

Locations where structure-forming invertebrates associated with hard substrates (soft, stony, and black corals, crinoids, hydrocorals and sponges) have been 

observed during Monterey Bay Aquarium Research Institute (MBARI) ROV surveys 1989-2009. Each data point represents a sighting regardless of the 

abundance of the organisms in the video frame. These organisms also occur in areas that have not been sampled by MBARI (survey effort not show). Data credit: 

Monterey Bay Aquarium Research Institute

166
Figure 9. Corals collected in National Marine Fisheries Service groundfish trawl surveys.

Historical observations of cold-water/deep-sea corals from groundfish bottom trawl surveys conducted from 1980 to 

2001 by the Alaska Fisheries Science Center and 2001 to 2010 by the Northwest Fisheries Science Center. These 

trawl surveys occurred primarily on soft substrates and were designed to survey groundfish. Data on corals represent 

incidental observations and do not adequately represent occurrences of coral communities (especially on 

undersampled hard bottoms). Data Credit: Northwest Fisheries Science Center

167
Figure 10. Predicted habitat suitability for six taxa of deep-sea coral.

Predictive habitat models for deep-sea corals in the U.S. West Coast Exclusive Economic Zone were developed by Guinotte and Davies (2012). The maps show 

the predicted suitability of benthic habitats in MBNMS for six taxa separately and for all taxa combined. The final number of models that predicted over 50 % 

coral presence per 500 m by 500 m grid are shown, with the maximum number of models per grid being 4 for suborders and 3 for orders. Models identified 

slope, temperature, salinity and depth as important predictors for most deep-sea coral taxa. Data credit: Guinotte and Davies 2012

168
Figure 11. Groundfish abundance and diversity at Point Pinos and Point Sur.

Starr et al. (2006) measured groundfish abundance and diversity at six locations, 70 to 130 meters deep off Point 

Pinos and Point Sur. The five most abundant species, at each location, are included and the remaining fishes are 

placed in five categories: other Sebastomus spp., other Sebastes spp., unidentified Sebastes spp., other fishes, and 

unidentified fishes. Associated with each graph are the observed numbers of fish (N), species (n), rockfish species 

(nrf); and the number of 10-minute transects (T).

169
Figure 12. Location of eight zones for pelagic species off central California.

Eight zones identified by USGS, NOAA, and MLML seabird, marine mammal, and sea turtle experts in order to 

depict the overall distribution of pelagic species off central California (Research Planning Inc. 2006). The zones 

differ in depth, distance from shore, and other habitat features. Table 12 provides the relative abundance and 

seasonality of species and species groups in the zones.

170
Figure 13. Observations of invertebrates associated with soft substrate.

Locations where sea pens (Order Pennatulacea) have been observed during Monterey Bay Aquarium Research 

Institute (MBARI) ROV surveys 1989-2009. Each data point represents a sighting regardless of the abundance of 

the organisms in the video frame. These organisms also occur in areas that have not been sampled by MBARI

(survey effort not show). Data credit: Monterey Bay Aquarium Research Institute

171
Figure 14. Number and abundance of infaunal taxa along a submarine cable in MBNMS.

The average number of infaunal taxa (A) and average abundance of infauna (B) per sample at each station in a 

survey along a submarine cable extending between Pillar Point and the Pioneer Seamount in the northern MBNMS 

(reprinted from Kogan et al. 2006). Samples consist of organisms from the upper 5 cm of sediments collected from 7 

cm diameter push cores. Samples taken near a submarine cable (bars on the right) are compared to those taken from 

control sites (bars on the left). “Other’ category includes Cnidaria, Echinodermata, Echiuran, Nematoda, Nemertea, 

Phoronida, Pycnogonida, and Sipunculid.

172
Figure 15. Species richness of demersal rockfishes.

Species richness of demersal rockfishes was calculated from NMFS shelf and slope trawls. Values were not 

influenced by latitude, but were highly influenced by depth. The highest rockfish richness values were observed 

along the edge between the shelf and slope (between 200 and 300 m depth). Data credit: NCCOS 2003

173
Figure 16. Species richness of demersal fishes.

Species richness of demersal fishes was calculated from NMFS shelf and slope trawls between 50 and 1280 m. The 

mean number of fish species recorded for trawls (± standard deviation) was 16 ± 5. Data credit: NCCOS 2003

174
Figure 17. Species diversity of demersal fishes.

Species diversity of demersal fishes was calculated for NMFS trawls on the shelf and slope at depths between 50 

and 1280 m. The mean diversity recorded for trawls (± standard deviation) was 1.5±0.5. The largest cluster of high 

species diversity trawls is found 20 km north and south of the border between Monterey Bay NMS and Gulf of the 

Farallones NMS. Data credit: NCCOS 2003

175
Figure 18. Depth range of groundfishes collected from slope trawl surveys.

Depth range (minimum, median and maximum in m) of groundfishes collected in fishery-independent slope trawl surveys conducted by the NMFS-NWFSC 

from 1977-2001 across the U.S. west coast (WA, OR, CA combined). Five species assemblages were identified based on depth and latitude (Tolimieri and Levin 

2006).
Figure 19. Depth distribution of continental slope species in MBNMS.

Depth distributions of continental slope species in the Monterey Bay National Marine Sanctuary based on NWFSC slope trawl survey data (1999-2006, N = 275 

trawls). Sampling locations shown in left panel. Proportion of the catch of each species collected per 100 m depth interval shown in right panel (red lines 

designate upper and lower bounds of the OMZ). Data analysis provided by S. Ralston, NMFS-SWFSC. Original data courtesy of B. Horness, West Coast 

Groundfish Survey Program, NMFS-NWFSC.
Figure 20. Hotspots, principal foraging area, and critical habitat for the leatherback sea turtle.

Hotspots, areas where leatherback sea turtles have been encountered most frequently, were identified in central 

California by the offshore Environmental Sensitivity Analysis in 2006 and updated based on personal 

communication with Scott Benson (March 2012). The principal foraging area - part of Area 1 identified in Title 50 

Code of Federal Regulations, Part 226.207 (77 Federal Register 4170) - includes the area between Point Sur and 

Point Arena extending offshore to the 200 m isobath. Critical habitat (77 Federal Register 4170) also includes 

offshore waters utilized by leatherbacks when prey availability in the principal foraging area is poor.

178
Figure 21. Hotspots for seabirds in MBNMS.

Locations of concentration, or ‘hotspots’, of seabirds were identified by USGS, NOAA, and MLML seabird, marine 

mammal, and sea turtle experts (Research Planning Inc. 2006). Hotspots tend to be areas with elevated abundance of 

prey or located adjacent to nesting habitats.

179
Figure 22. Hotspots for marine mammals in MBNMS.

Locations of concentration, or ‘hotspots’, of marine mammals identified by USGS, NOAA, and MLML seabird, 

marine mammal, and sea turtle experts (Research Planning Inc. 2006). Hotspots tend to be areas with elevated 

abundance of prey or located adjacent to rookeries or haul-outs.

180
Figure 23. Persistent upwelling zones in MBNMS

The Nature Conservancy (2006) identified upwelling zones (green hatching) as areas with persistently cold (~9-12 

oC) sea surface temperature (SST) during the upwelling season (March-September). Data source: NOAA 

Coastwatch AVHRR data (March-September 1999-2002).

181
Figure 24. CoastWatch Oceanic Front Probability Index by season.

The CoastWatch Oceanic Front Probability Index (FPI) measures the probability of sea surface temperature front formation based on data from NOAA's GOES 

satellites. Daily average sea surface temperature (SST) is generated from the GOES data. Fronts are identified by applying an edge detection algorithm to this 

daily averaged SST field (Breaker et al. 2005). Pixels with gradients greater than 0.375 °C are classified as a front. The frontal probability index is then 

calculated as the number of times a pixel is classified as a front divided by the number of cloud free days per month. Pixels with a monthly FPI of 20% or greater 

are selected and averaged for all months within a given season, for the entire duration of the data set (2001-2006). Nearshore areas are not surveyed by the GOES 

data. Data source: Coastwatch 2007 (unpublished data). 

182
Figure 25. Modeled multispecies seabird hotspots in MBNMS.

Predicted hotspots of multispecies seabird aggregations in MBNMS based on spatial models developed for the California Current Ecosystem (Nur et al. 2011). 

Data from at-sea surveys of seabirds over an 11-year period (1997-2008) were combined with information on habitat features (bathymetry and oceanography) to 

predict hotspots for seabirds. Single species model predictions for 16 species were combined to identify potential multispecies hotspots using three criteria: 

abundance, importance, and persistence. The abundance values represent the summed, standardized abundance for all 16 species in number of birds per square 

kilometer. The importance values are "highest predicted density" cells with higher values representing higher predicted abundance of all species. The persistence 

values represent the number of years a cell was in the 95th percentile of all prediction cells, averaged over all species and seasons. The spatial scale of the models 

was 38.5oN to 35oN from the shoreline to 600 km offshore. Seabird species: Black-footed Albatross (Phoebastria nigripes), Bonaparte's Gull (Larus 

philadelphia), Brandt's Cormorant (Phalacrocorax penicillatus), Brown Pelican (Pelecanus occidentalis), Cassin's Auklet (Ptychoramphus aleuticus), California 

Gull (Larus californicus), Common Murre (Uria aalge), Fork-tailed Storm-Petrel (Oceanodroma furcata), Glaucous-winged Gull (Larus glaucescens), 

Heermann's Gull (Larus heermanni), Herring Gull ( Larus argentines), Leach's Storm-Petrel (Oceanodroma homochro), Red-necked Phalarope (Phalaropus 

lobatus), Sabine's Gull (Xema sabini), Sooty Shearwater (Puffinus griseus), and Western Gull (Larus occidentalis). Data credit: PRBO Conservation Science.

183
Figure 26. Modeled densities of whales in the California Current Ecosystem.

Sightings of whales from shipboard surveys (1991-2008) were combined with in situ and remotely sensed data of environmental variables and other measures of 

habitat (e.g., water depth, bathymetric slope) to develop predictive models of animal density. The best models were selected based on a collection of quantitative 

and qualitative methods. Ship survey data are from summer and fall seasons, corresponding to the “warm-season” for cetaceans in the California Current 

Ecosystem (CCE). Predicted transect segment densities for each year were smoothed with geospatial methods to obtain a continuous grid of density (animals per 

km2

) estimates for the CCE. Annual grids were averaged to obtain a composite grid of animal densities shown as 25 by 25 km grids. Black lines are the 

boundaries of the five National Marine Sanctuaries in the CCE. Data Credit: Barlow et al.2009, Forney et al. 2012, Becker et al. in review.

184
Figure 26. (con’t.)

185
Figure 27. Stratified estimates of harbor porpoise density in MBNMS.

Carretta et al. (2009) compiled stratified estimates of harbor porpoise density in California waters from speciesspecific aerial surveys conducted between 2002-2007. Two sets of transects, one inshore (out to the 90 m isobath) 

and one offshore (between the 90 and 200 m isobath), were surveyed between the CA/OR border and Pt. 

Conception. The highest density category observed in this study (symbolized in red) is outside MBNMS and thus 

not shown on the map Data Credit: SWFSC 2009

186
Table 1. Search topics, definitions and search questions.

Search topics (left column) were used to find and compile information on offshore habitats in MBNMS. The right 

column provides a definition of the search topic and questions that were used to guide the literature review. Search 

topics were organized under four main themes: habitat function, habitat structure, movement and dispersal, and 

species of special interest. A literature review using these search topics was completed for each of the offshore 

habitat categories listed in Table 2.

Search Topic Definitions and Search Questions

HABITAT FUNCTION

 Functional Habitats:

Nursery Habitat: A habitat in which the juvenile phase of one or more species 

congregates. Does this habitat serve as a nursery for one or more 

species? Does a specific microhabitat provide higher quality habitat 

for juveniles? Does a specific habitat, or sites within the habitat, 

have relatively higher supply of juveniles (areas of high settlement 

and/or recruitment)?

Feeding Ground: An area used by a species for feeding. Is this habitat, or a specific 

area within the habitat, a foraging location for one or more species? 

Is the feeding ground year-round or seasonal?

Spawning/Breeding Ground: An area used by a species for reproduction. Is this habitat, or a 

specific area within the habitat, used for spawning/breeding by one 

or more species? Is the spawning/breeding ground year-round or 

seasonal?

Migratory Corridor: A path used by a species to move from one area to another (e.g., 

between spawning and feeding grounds). Does this habitat, or 

specific area within the habitat, serve as a migratory corridor for one 

or more species? When does the species use the migratory corridor?

Biogenic Habitat: A habitat created by a living organism (e.g., plants or animals). Is 

some of the physical structure of this habitat formed by living 

organisms? Is the biogenic habitat used by other organisms?

 Energy Flow:

Primary Production: The conversion of inorganic carbon (e.g., carbon dioxide, methane) 

into organic carbon (food) by photosynthesis or chemosynthesis.

Macrophytes: A plant or alga that is easily seen without aid of a microscope. Are 

macrophytes a significant source of primary productivity in this 

habitat? What amounts of primary production (grams of carbon fixed 

/ area / time) are observed in this habitat?

Phytoplankton: The photosynthetic component of the plankton consisting primarily 

of single-celled algae and bacteria. Are phytoplankton a significant 

source of primary productivity in this habitat? What amounts of 

primary production (grams of carbon fixed / area / time) are 

observed in this habitat?

Chemoautotrophs: Organisms that produce organic carbon through chemosynthesis. Are 

chemoautotrophs a significant source of primary productivity in this 

habitat? What amounts of primary production (grams of carbon fixed 

/ area / time) are observed in this habitat?

Benthic-Pelagic Coupling: The two-way exchange, or flux of matter, between the benthos and 

the overlying water body. Does benthic-pelagic coupling have a

significant role in the proper functioning of this habitat? What is the 

rate of vertical particle flux?

187 Table 1
Search Topic Definitions and Search Questions

Key Trophic Interactions: Trophic interactions that are necessary to the proper functioning of 

the ecosystem. Which trophic interactions are "key" in this habitat? 

How would the ecosystem be negatively impacted if the key 

interactions were lost or modified?. 

Key Trophic Cascades: Trophic cascades that are necessary to the proper functioning of the 

ecosystem. Are there any "key" trophic cascades in this habitat? 

Which species or species assemblages are at each tropic level in the 

cascade. How would changes in the trophic cascade impact the 

function of the focal ecosystem?

Productivity Hotspots: A place of higher than usual productivity. Have any productivity 

hotspots been identified in the focal habitat? If so, where are they 

located? Are they always present or only present at certain times of 

year?

HABITAT STRUCTURE

 Species Composition: The assemblage of species that are characteristic of an area. What

species assemblages are characteristic of the habitat? Do different 

sites or microhabitats differ in their species assemblages?

 Species Composition Shifts: Have shifts in species composition been observed in this habitat?

What are the possible causes, either natural or human-induced, of the 

shift?

 Species Diversity and Species 

Richness:

An index of the number species in a system (i.e., species richness) 

and their relative abundance. What is the typical species diversity 

and species richness in this habitat? Are there certain microhabitats 

or sites with higher or lower than average species diversity or 

richness?

 Biomass: The total quantity or weight of organisms in an area. What is the 

typical biomass in this habitat? Are there certain microhabitats or 

sites with higher or lower than average biomass?

 Key Species Interactions Species interactions (e.g., predation, competition, mutualism, 

facilitation) that are characteristic of this habitat or important to 

maintaining the structure or function of the habitat. Which species 

interactions are characteristic of the habitat? Are certain species 

interactions key to maintaining habitat structure and function?

MOVEMENT AND DISPERSAL The ontogenetic, seasonal, and daily movement patterns exhibited 

by juvenile and adults stages of mobile species. What types of 

movement patterns are exhibited by the mobile species in this 

habitat? Do some species use this habitat during ontogenetic 

movement? Describe the scale of these movements. Do some 

species have home ranges or exhibit territorial behavior? If so, what 

is the average size of a territory or home range?

SPECIES OF SPECIAL 

INTEREST 

Species in MBNMS that receive relatively greater interest and 

attention from resource managers. This interest is due to a variety 

of factors, including ecological role, sensitivity to disturbance, low 

population size, or economic value. What species in the focal 

habitat are of special interest to resource managers?

 Species landed in MBNMS Species commonly caught and/or sold in the commercial fishery and 

recreational fishery in MBNMS. Which species that occur in the 

focal habitat are landed by fisheries?

188 Table 1
Search Topic Definitions and Search Questions

 Endangered and Threatened 

Species

Species or populations that have been listed under the federal 

Endangered Species Act (ESA) or California Endangered Species 

Act (CESA). Which ESA and CESA listed species occur in the focal 

habitat?

 Other "At Risk" Species Species that have been listed as "Critically Endangered", 

"Endangered" or "Threatened" on the International Union for 

Conservation of Nature Red List, species listed as “Candidate 

Species” or "Species of Special Concern” under the ESA or CESA, 

and fish stocks listed as "Overfished" by the National Marine 

Fisheries Service. Which other “at risk” species occur in the focal 

habitat?

189 Table 1
Table 2. Area of benthic habitats in Monterey Bay National Marine Sanctuary.

The area of each primary benthic habitat (as defined by depth zone and substrate type) and the percent area of the 

habitat in the entire MBNMS and in the federal study area are provided. Submarine canyon, oxygen minimum zone,

and seamount are secondary habitat types (i.e., they overlap the primary benthic habitat categories). The areas of 

secondary habitats were calculated independently. The nearshore habitat is shaded grey because it does not occur in 

the federal study area.

Habitat Name Depth Range 

(m)

Substrate 

Type

Area in 

entire 

MBNMS 

(km2

)

% of entire 

MBNMS

Area in 

Federal 

Study Area 

(km2

)

% of 

Federal 

Study Area

Nearshore 0-30 Hard 140 0.89 0 0.00

Nearshore 0-30 Soft 574 3.64 0 0.00

Shelf I 30-100 Hard 196 1.24 42 0.38

Shelf I 30-100 Soft 2546 16.13 338 3.08

Shelf II 100-200 Hard 69 0.44 33 0.30

Shelf II 100-200 Soft 1115 7.06 619 5.63

Slope 200-3,000 Hard 507 3.21 466 4.24

Slope 200-3,000 Soft 8740 55.37 7598 69.11

Rise >3,000 Hard 176 1.12 176 1.60

Rise >3,000 Soft 1720 10.90 1720 15.65

Submarine 

Canyon various Hard 189 1.20 126 1.15

Submarine 

Canyon various Soft 2380 15.08 1993 18.13

Oxygen 

Minimum Zone 600-1,000 Hard 58 0.37 48 0.44

Oxygen 

Minimum Zone 600-1,000 Soft 2283 14.47 1896 17.25

Seamount 1,250-3,530 Hard 373 2.37 373 3.40

Seamount 1,250-3,530 Soft 27 0.17 27 0.25

190 Table 2
Table 3. Invertebrate species of special interest in MBNMS.

Invertebrate species in MBNMS that receive relatively greater interest and attention from resource managers, including species that are landed by fisheries in 

MBNMS. Only species that occur in offshore habitats of MBNMS during one or more life stage were included. Habitat categories are defined in Table 2. When 

available, the current population size/biomass relative to the historically high population size/biomass and the recent trend in population size are provided; 

increasing trend (↑), decreasing trend (↓), trend not significant (NS), unknown (unk). Population status information in red ink denotes information that is more 

than 5 years old (pre-2007). No invertebrate species in the study area qualified for the categories ‘Endangered and Threatened species’ or ‘other at-risk species” 

so these categories were not included in the table. J = juvenile life stage; A = adult life stage. * = several species

Scientific Name/ 

Taxonomic Group Common Name

Landed

in 

MBNMS

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

CanyonRise 

- soft

Slope 

- Hard

Slope 

- Soft

Shelf II 

- Hard

Shelf II 

- Soft

Shelf I 

- Hard

Shelf I 

- Soft

Nearshore

Phylum Porifera Sponges* J, A J, A J, A J, A J, A

Order Antipatharia Coral, black* J, A J, A J, A J, A

Order Scleractinia Coral, stony* J, A J, A J, A J, A J, A

Order Alcyonacea 

(including 

Gorgonacea)

Coral, soft* 

(including sea 

fans and sea 

whips)

J, A J, A J, A J, A

Order Pennatulacea Sea pens* J, A J, A J, A J, A J, A

Family Stylasteridae Hydrocorals* J, A J, A J, A J, A J, A

Metridium spp.

Plumose 

anemones J, A J, A J, A J, A J, A

Phylum Brachiopoda Brachiopods* J, A J, A J, A J, A J, A

Haliotis rufescens Abalone, red < 40%1,2 ↓ or 

NS 1,2 J, A J, A

Kelletia kelletii Whelk, Kellet’s unk8 unk8 J, A J, A J, A J, A J, A

Tresus spp. Clam, gaper* X unk3 NS3 J, A J, A

Octopus spp. Octopus* X NS4,5 J, A J, A J, A J, A J, A

Doryteuthis (=Loligo) 

opalescens Squid, market X unk6 unk6 J, A J, A J, A

Euphausia pacifica Krill J, A J, A

Thysanoessa spinifera Krill J, A J, A

Pandalus platyceros Prawn, spot X unk6 unk6 J, A J, A J

Cancer magister Crab, Dungeness X unk7 NS7 A A J, A J, A

Lopholithodes 

foraminatus Crab, box X J, A J, A J, A J, A J, A

191 Table 3
Scientific Name/ 

Taxonomic Group Common Name

Landed

in 

MBNMS

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

CanyonRise 

- soft

Slope 

- Hard

Slope 

- Soft

Shelf II 

- Hard

Shelf II 

- Soft

Shelf I 

- Hard

Shelf I 

- Soft

Nearshore

Cancer antennarius Crab, brown rock X unk7 ↓ or 

NS4,5 J, A J, A J, A

Cancer productus Crab, red rock X unk7 ↓ or 

NS4,5 J, A J, A J, A J, A J, A

Parastichopus spp. Cucumber, sea* X unk6 unk6 J, A J, A J, A

Class Crinoidea Crinoids* J, A J, A J, A J, A

Mesocentrotus 

(=Strongylocentrotus ) 

franciscanus

Urchin, red X unk7 NS 

or↓7 J, A J, A

1 CDFG 2010a, 2

CDFG 2008a, 3 Leet et al. 2001; 4 Starr et al. 2002a; 5 based on CPUE data, 6 CDFG 2008b, 7 CDFG 2004, 8 CDFG 2010b

192 Table 3
Table 4. Fish species of special interest in MBNMS.

Fish species in MBNMS that receive relatively greater interest and attention from resource managers, including species landed in MBNMS, Endangered and 

Threatened species (E/T) , and other ‘at risk’ species (defined in Table 1). Only species that occur in offshore habitats of MBNMS during one or more life stage 

were included. Habitat categories are defined in Table 2. When available, the current population size/biomass relative to the historically high population 

size/biomass and the recent trend in population size are included; increasing (↑), decreasing (↓), trend not significant (NS), or unknown (unk). Population status 

information in red ink denotes information that is more than 5 years old (pre-2007). SSC = Species of Concern; VU = Vulnerable; EN = Endangered; OF = 

Overfished. J = juvenile life stage; A = adult life stage.

Taxonomic 

Group Scientific Name Common Name Landed E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

CanyonRise -

Soft

Slope 

- Hard

Slope 

- Soft

Shelf II 

- Hard

Shelf II 

- Soft

Shelf I 

- Hard

Shelf I 

- Soft

Nearshore 

Hagfishes Eptatretus deani Hagfish, black X J, A

Eptatretus stoutii Hagfish, Pacific X unk1 unk1 J, A J, A J, A J, A J, A

Sharks, cow Hexanchus 

griseus

Shark, bluntnose 

six gill X unk2 unk2 J, A A

Notorynchus 

cepedianus

Shark, broadnose 

seven gill X unk2 unk2 J, A A J, A J, A

Sharks, dogfish Squalus suckleyi Shark, spiny 

dogfish X 63%3 ↓3 J, A

Sharks, thresher Alopias vulpinus Shark, thresher X unk4 ↑4 J, A

Sharks, basking Cetorhinus 

maximus Shark, basking SSC, EN 10%28 ↓ or 

NS28 J, A

Sharks, mackerel Carcharodon 

carcharias Shark, white VU unk2 J, A

Isurus oxyrinchus Shark, shortfin 

mako X unk4 unk4 J, A

Sharks, cat Galeorhinus 

galeus

Shark, soupfin 

(tope) X unk2 ↓6 J, A

Houndsharks Mustelus 

californicus

Shark, gray 

smoothhound X J, A J, A

Mustelus henlei Shark, brown 

smoothhound X A A J, A

Triakis 

semifasciata Shark, leopard X unk5 unk5 J, A J, A J, A

Sharks, requiem Prionace glauca Shark, blue X unk2 unk2 J, A

Sharks, angel Squatina 

californica

Shark, Pacific 

angel X unk6 ↓6 J, A A J, A A J, A J, A

Rays, torpedo 

electric

Torpedo 

californica

Ray, Pacific 

electric X J, A J, A J, A J, A J, A J, A J, A J, A

Skates Raja binoculata Skate, big X J, A J, A J, A J, A

Raja inornata Skate, California X J, A J, A J, A J, A

Raja rhina Skate, longnose X 66%7 NS J, A J, A J, A J, A J, A J, A J, A J, A

193 Table 4
Taxonomic 

Group Scientific Name Common Name Landed E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

CanyonRise -

Soft

Slope 

- Hard

Slope 

- Soft

Shelf II 

- Hard

Shelf II 

- Soft

Shelf I 

- Hard

Shelf I 

- Soft

Nearshore 

Rays, eagle Myliobatis 

californica Ray, bat X unk2 A J, A J, A

Chimaeras, 

shortnose

Hydrolagus 

colliei Ratfish, spotted X J, A J, A J, A J, A J, A J, A J, A J, A

Sturgeons Acipenser 

medirostris Sturgeon, greena T SSC unk8 unk8 J, A J, A

Herrings Alosa sapidissima Shad, American X J, A

Clupea pallasii Herring, Pacific X ~28%2,10 ↓6 J, A J, A

Sardinops sagax Sardine, Pacific X ~33%9,10 ↑9 J, A

Anchovies Engraulis mordax Anchovy, 

Northern X ~25%9,10 NS9 J, A J

Trouts and 

Salmons

Oncorhynchus 

kisutch Salmon, cohoe E ~11%12 J, A J, A

Oncorhynchus 

mykiss irideus Trout, steelheade X T ~15%12 J, A

Oncorhynchus 

mykiss irideus Trout, steelheadf X T ~5-15%12 NS or 

↑12 J, A

Oncorhynchus 

tshawytscha Salmon, chinookb X SSC, OF

NS or 

↑11 J, A J, A

Oncorhynchus 

tshawytscha Salmon, chinookc X T ~20-30%12 NS or 

↑12 J, A J, A

Oncorhynchus 

tshawytscha Salmon, chinookd X E ~10-14%12 NS or 

↑12 J, A J, A

Smelts Allosmerus 

elongatus Smelt, whitebait X unk2 unk2 J, A J, A J, A

Hypomesus 

pretiosus Smelt, surf X unk2 ↓6 J, A J, A

Spirinchus starksi Smelt, night X unk2 ↓6 J, A J, A

Lizardfishes Synodus lucioceps Lizardfish, 

California X J, A J, A J, A J, A J, A

Lancetfishes Alepisaurus ferox Lancetfish, 

longnose X J, A

Cods Microgadus 

proximus Tomcod, Pacific X J, A J, A J, A J, A

Grenadiers Coryphaenoides 

acrolepis Grenadier, Pacific X unk6 ↓6 J, A J, A

Hakes, merlucciid Merluccius 

productus

Hake, Pacific 

(whiting) X 31-38%7 ↑7 J, A J, A J, A J, A J, A J, A J, A J, A

Toadfishes Porichthys 

notatus

Midshipman, 

plainfin X J, A A A A A J, A J, A

Sauries Cololabis saira Saury, Pacific X J, A

194 Table 4
Taxonomic 

Group Scientific Name Common Name Landed E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

CanyonRise -

Soft

Slope 

- Hard

Slope 

- Soft

Shelf II 

- Hard

Shelf II 

- Soft

Shelf I 

- Hard

Shelf I 

- Soft

Nearshore 

Silversides, New 

World Atherinops affinis Topsmelt X unk2 J, A J, A

Atherinopsis 

californiensis Jacksmelt X unk2 J, A J, A

Opahs Lampris guttatus Opah X unk2,13 J, A

Rockfishes Sebastes 

atrovirens Rockfish, kelp X unk2 ↓6 J, A J, A

Sebastes 

auriculatus Rockfish, brown X unk2 ↓6 J J, A J, A J, A J, A J, A

Sebastes aurora Rockfish, aurora X ↓6 J, A J, A

Sebastes babcocki Rockfish, 

redbanded X NS6 J, A J, A J, A J, A J, A J, A

Sebastes carnatus Rockfish, gopher X 97%7 ↓7 J, A J, A

Sebastes caurinus Rockfish, copper X unk2 ↓6 J, A J J, A J J, A

Sebastes 

chlorostictus

Rockfish, 

greenspotted X 31%27 ↑27 J, A A A A A J, A J, A

Sebastes 

chrysomelas

Rockfish, blackand-yellow X unk2 ↓6 J, A J, A

Sebastes 

constellatus Rockfish, starry X ↓6 J, A J, A J, A J, A

Sebastes crameri Rockfish, 

darkblotched X 30%17 ↑17 J J, A A A J, A J, A J, A J, A

Sebastes dallii Rockfish, calico X unk2 unk2 J, A J J, A J J, A J J, A

Sebastes 

diploproa

Rockfish, 

splitnose X 66%7 ↑7 J, A A J, A A J, A

Sebastes 

elongatus

Rockfish, 

greenstriped X 81%7 ↑7 J, A J, A J, A J, A J, A J, A J, A J, A

Sebastes ensifer Rockfish, 

swordspine X J, A A J A J A J

Sebastes 

entomelas Rockfish, widow X 51%19 ↑19 J, A A J, A J, A J

Sebastes eos Rockfish, pink X NS6 A A J A J A J

Sebastes flavidus Rockfish, 

yellowtail X 55%7,13 NS 7,13 J, A A A A A J, A

Sebastes goodei Rockfish, 

chilipepper X 70%7 ↑7 J, A J, A A A A J J, A

Sebastes 

helvomaculatus

Rockfish, 

rosethorn X NS6 J, A J, A J J, A J

Sebastes hopkinsi Rockfish, 

squarespot X NS6 J, A J, A J, A J, A J, A

195 Table 4
Taxonomic 

Group Scientific Name Common Name Landed E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

CanyonRise -

Soft

Slope 

- Hard

Slope 

- Soft

Shelf II 

- Hard

Shelf II 

- Soft

Shelf I 

- Hard

Shelf I 

- Soft

Nearshore 

Sebastes jordani Rockfish, 

shortbelly X 73%7 NS or ↑7 J, A J, A J, A J, A J, A J

Sebastes levis Rockfish, cowcod X SSC, 

OF 5%7,16 ↑7,16 J, A A J, A J J, A J

Sebastes maliger Rockfish, 

quillback X unk2 ↓6 A A J, A J, A

Sebastes 

melanops Rockfish, black X 71%7 ↑7 J, A J, A J, A J, A J, A

Sebastes 

melanostomus

Rockfish, 

blackgill X 30%15 ↑15 J A A A J J

Sebastes miniatus Rockfish, 

vermilion X 41-89%18 ↑18 J, A J, A J J, A J J, A J J, A

Sebastes mystinus Rockfish, blue X 30%7 ↑7 J A A J, A J J, A

Sebastes 

nebulosus Rockfish, China X unk2 ↓6 J, A J, A J, A

Sebastes 

nigrocinctus Rockfish, tiger X NS6 J, A J, A J, A

Sebastes ovalis Rockfish, 

speckled X ↓6 J, A J, A J, A J, A J, A

Sebastes 

paucispinis

Rockfish, 

bocaccio X SSC 28%7 ↑7 J, A J, A A A A J, A

Sebastes pinniger Rockfish, canary X OF 23%25 ↑25 J, A J, A A J, A J J, A J J, A

Sebastes proriger Rockfish, 

redstripe X J, A J, A J, A

Sebastes 

rastrelliger Rockfish, grass X unk2 ↓6 J, A J, A

Sebastes rosaceus Rockfish, rosy X ↓6 J, A J J, A J J, A J J, A

Sebastes 

rosenblatti

Rockfish, 

greenblotched X ↓6 J, A A J, A A J, A A J, A

Sebastes 

ruberrimus

Rockfish, 

yelloweye X OF 21%26 ↑26 J, A J, A J, A J, A

Sebastes 

rubrivinctus Rockfish, flag X ↓6 J, A J, A J, A J, A

Sebastes rufus Rockfish, bank X 25-31%14 ↓14 J, A J, A J J, A J J, A J

Sebastes saxicola Rockfish, 

stripetail X NS6 J, A A A A J, A A J, A J

Sebastes 

semicinctus

Rockfish, 

halfbanded X J, A A J, A A J, A A J, A

Sebastes 

serranoides Rockfish, olive X unk2 ↓6 J, A J, A J J, A J J, A

196 Table 4
Taxonomic 

Group Scientific Name Common Name Landed E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

CanyonRise -

Soft

Slope 

- Hard

Slope 

- Soft

Shelf II 

- Hard

Shelf II 

- Soft

Shelf I 

- Hard

Shelf I 

- Soft

Nearshore 

Sebastes serriceps Rockfish, treefish X unk2 ↑6 J, A J, A

Sebastes 

zacentrus

Rockfish, 

sharpchin X NS6 J, A J, A J, A

Thornyheads Sebastolobus 

alascanus

Thornyhead, 

shortspine X EN 63%7 NS7 J, A J, A J, A J, A J, A J, A J, A J, A

Sebastolobus 

altivelis

Thornyhead, 

longspine X 71%7 ↓7 J, A J, A

Sablefishes Anoplopoma 

fimbria Sablefish X 33%20 ↓20 J, A A J, A J J

Greenlings Hexagrammos 

decagrammus Greenling, kelp X 49%7 J, A J, A J, A

Ophiodon 

elongatus Lingcod X 74%7 ↑7 J, A J, A J, A J, A J, A J, A J, A J, A

Oxylebius pictus Greenling, 

painted X J, A J, A

Sculpins Hemilepidotus 

hemilepidotus Irish lord, red X J, A J, A J, A J, A

Hemilepidotus 

spinosus Irish lord, brown X J, A J, A

Leptocottus 

armatus

Sculpin, Pacific 

staghorn X J, A J, A

Scorpaenichthys 

marmoratus Cabezon X 45%21 ↑21 A J, A

Basses, striped Morone saxatilis Bass, striped X ~33%2 J, A J, A

Basses, sea and 

groupers

Paralabrax 

clathratus Bass, kelp X J, A J, A

Tilefishes Caulolatilus 

princeps Whitefish, ocean X J, A J, A

Jacks Seriola lalandi Jack, yellowtail X unk2,13 J, A

Trachurus 

symmetricus Mackerel, jack X unk6,13 NS6 J, A J J

Croakers and 

Drums

Atractoscion 

nobilis Seabass, white X unk5 unk5 A J, A J J, A J J, A

Genyonemus 

lineatus Croaker, white X unk2 J, A J, A J, A J, A

Surfperches Amphistichus 

argenteus Surfperch, barred X unk2 ↓6 J, A J, A J, A

Brachyistius 

frenatus Perch, kelp X J, A J, A

Cymatogaster 

aggregata Perch, shiner X J, A J, A J, A J, A J, A

197 Table 4
Taxonomic 

Group Scientific Name Common Name Landed E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

CanyonRise -

Soft

Slope 

- Hard

Slope 

- Soft

Shelf II 

- Hard

Shelf II 

- Soft

Shelf I 

- Hard

Shelf I 

- Soft

Nearshore 

Embiotoca 

jacksoni Perch, black X J, A J, A

Embiotoca 

lateralis Seaperch, striped X unk2 NS or ↓6 J, A J, A

Hyperprosopon 

argenteum

Surfperch, 

walleye X unk2 ↓6 J, A J, A J, A J, A J, A

Hyperprosopon 

anale Surfperch, spotfin X J, A J, A

Hyperprosopon 

ellipticum Surfperch, silver X J, A J, A J, A

Hypsurus caryi Seaperch, 

rainbow X J, A J, A

Phanerodon 

atripes

Seaperch, 

sharpnose X J, A J, A J, A J, A

Phanerodon 

furcatus Seaperch, white X J, A J, A J, A

Rhacochilus 

toxotes

Seaperch, 

rubberlip X unk2 ↓6 J, A J, A J, A

Rhacochilus 

vacca Perch, pile X J, A J, A J, A

Damselfishes Chromis 

punctipinnis Blacksmith X J, A J, A

Wrasses Oxyjulis 

californica Senorita X A J, A J, A

Semicossyphus 

pulcher

Sheephead, 

California X unk2 ↑6 J, A J, A

Clinids Heterostichus 

rostratus Kelpfish, giant X J, A J, A

Gibbonsia metzi Kelpfish, striped X J, A

Neoclinus 

blanchardi

Fringehead, 

sarcastic X J, A J, A

Sandfishes Trichodon 

trichodon Sandfish, Pacific X J, A J, A J, A J, A

Wolffishes Anarrhichthys 

ocellatus Wolf-eel X NS6 J A A A A

Sand Lances Ammodytes 

hexapterus

Sand lance, 

Pacific X J, A J, A

Gobies Lepidogobius 

lepidus Goby, bay X J, A J, A

Lythrypnus zebra Goby, zebra X J, A J, A

Barracudas Sphyraena 

argentea

Barracuda, 

Pacific X unk6,13 NS6 J, A

198 Table 4
Taxonomic 

Group Scientific Name Common Name Landed E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

CanyonRise -

Soft

Slope 

- Hard

Slope 

- Soft

Shelf II 

- Hard

Shelf II 

- Soft

Shelf I 

- Hard

Shelf I 

- Soft

Nearshore 

Mackerels Katsuwonus 

pelamis Tuna, skipjack X unk4 unk4 J, A

Sarda chiliensis Bonito, Pacific X unk1 unk1 J, A

Scomber 

japonicus

Mackerel, Pacific 

chub X ~21%9 ↑9 J, A

Thunnus alalunga Tuna, albacore X 47%4 NS4 J, A

Thunnus 

albacares Tuna, yellowfin X ~284 NS4 J, A

Thunnus obesus Tuna, bigeye X VU 24%4 ↑4 J, A

Thunnus thynnus Tuna, bluefin X 40-60%4 ↓4 J, A

Louvars Luvarus 

imperialis Louvar X unk2,13 unk2 J, A

Butterfishes Peprilus 

simillimus Pompano, Pacific X J, A J, A J, A

Flounders, sand Citharichthys 

sordidus Sanddab, Pacific X unk6 NS6 J, A J, A J, A J, A

Citharichthys 

stigmaeus

Sanddab, 

speckled X unk6 NS6 J, A J, A

Citharichthys 

xanthostigma Sanddab, longfin X unk6 NS6 J, A J, A J, A

Hippoglossina 

stomata Sole, bigmouth X J, A J, A J, A J, A

Paralichthys 

californicus

Halibut, 

California X unk22 unk22 J, A J, A J, A

Xystreurys 

liolepis Sole, fantail X J, A J, A

Flounders, 

righteye

Atheresthes 

stomias

Flounder, 

arrowtooth X 79%7 A J, A J J

Eopsetta jordani Sole, petrale X 18%24 NS24 J, A A J, A J, A J, A

Glyptocephalus 

zachirus Sole, rex X unk6 ↓6 J, A J, A J, A J, A J, A

Hippoglossus 

stenolepis Halibut, Pacific X A A J, A J, A J, A

Isopsetta isolepis Sole, butter X A A J, A J, A

Lepidopsetta 

bilineata Sole, rock X unk6 NS6 J, A J, A J, A J, A J, A J, A J, A

Lyopsetta exilis Sole, slender J, A J, A J, A J, A

Microstomus 

pacificus Sole, Dover X 84%23 ↓23 J, A A J J J

Parophrys vetulus Sole, English X 116%7 ↑7 A A A J, A J, A

199 Table 4
Taxonomic 

Group Scientific Name Common Name Landed E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

CanyonRise -

Soft

Slope 

- Hard

Slope 

- Soft

Shelf II 

- Hard

Shelf II 

- Soft

Shelf I 

- Hard

Shelf I 

- Soft

Nearshore 

Platichthys 

stellatus Flounder, starry X 62%7 ↓7 A J, A J, A

Pleuronichthys 

coenosus Sole, C-O X J, A J, A J, A J, A J, A J, A J, A

Pleuronichthys 

decurrens Sole, curlfin X J, A J, A J, A J, A

Pleuronichthys 

guttulatus Turbot, diamond X J, A J, A

Psettichthys 

melanostictus Sole, sand X unk2 ↓6 J, A J, A J, A J, A

Molas Mola mola Sunfish, ocean X J, A

a Southern DPS; b Sacramento River Fall/Late Fall ESU; c Central Valley Spring ESU; d Sacramento River Winter ESU; e Central California Coast ESU; f

South/Central California 

Coast ESU.

1 CDFG 2010b; 2 Leet et al. 2001; 3 Gertseva and Taylor 2011; 4 PFMC 2011; 5 CDFG 2008b; 6 Starr et al. 2002a; 7 PFMC & NMFS 2011; 8 NOAA Fisheries Office of Protected 

Resources 2012; 9 PFMC 2005; 10 population size strongly influenced by environmental conditions; 11 PFMC 2006;12 PCSRF 2005; 13 abundance off central California increases 

during warm water events; 14 Piner et al. 2000; 15 Field and Pearson 2011 (draft); 16 assessed stock occurs outside the MBNMS; 17 Stephens et al. 2011; 18 MacCall 2005; 19 He et al. 

2011; 20 Stewart et al. 2011; 21 Cope and Key 2009; 22 CDFG 2004; 23 Hicks and Wetzel 2011 (draft); 24 Haltuch et al. 2011; 25 Wallace and Cope 2011; 26 Taylor and Wetzel 2011 

(draft); 27 Dick et al. 2011; 28 http://www.nmfs.noaa.gov/pr/species/fish/baskingshark.htm

200 Table 4
Table 5. Reptile species of special interest in MBNMS.

Reptile species in MBNMS that receive relatively greater interest and attention from resource managers, including Endangered and Threatened species (E/T), and 

other ‘at risk’ species (defined in Table 1). Habitat distribution is provided based on habitat categories as defined in Table 2. The current population size/biomass 

relative to the historically high population size/biomass and the recent trend in population size are included; decreasing (↓). Population status information in red 

ink denotes information that is more than 5 years old (pre-2007). CR = Critically Endangered. 

Taxonomic Group Scientific Name Common Name E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

Canyons

Rise Slope Shelf 

II

Shelf 

I

Nearshore

Sea Turtle Dermochelys coriacea Turtle, Leatherback E CR <30% 1 ↓1 X X

1

Reviewed in CEC 2005

201 Table 5
Table 6. Seabird species of special interest in MBNMS.

Searbid species in MBNMS that receive relatively greater interest and attention from resource managers, including Endangered and Threatened species (E/T),

and other ‘at risk’ species (defined in Table 1). Only species that occur in offshore habitats in MBNMS were included. Habitat distribution is provided based on 

habitat categories as defined in Table 2. When available, the current population size/biomass relative to the historically high population size/biomass and the 

recent trend in population size are included; increasing (↑), decreasing (↓), trend not significant (NS), or unknown (unk). Population status information in red ink 

denotes information that is more than 5 years old (pre-2007). SSC = Species of Concern; VU = Vulnerable; EN = Endangered.

Taxonomic 

Group Scientific Name Common 

Name E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

Canyon

Rise Slope Shelf II Shelf I Nearshore

Loons Gavia spp

Loons 

(Pacific, 

Red-necked)

>40% 2 unk1 X X

Grebes Aechmophorus

spp

Grebes 

(Clark’s, 

Western)

>40% 2 unk1 X X

Albatrosses Phoebastria 

albatrus

Albatross, 

Short-tailed E SSC, VU low 3 ↑3 X X

Phoebastria 

immutabilis

Albatross, 

Laysan reduced 3 NS or ↓3 X X

Phoebastria 

nigripes

Albatross, 

Black-footed VU reduced 3 ↓3 X X

Shearwaters, 

Petrels

Fulmarus 

glacialis

Fulmar, 

Northern >40% 2 ↑1 X X

Puffinus bulleri Shearwater, 

Buller's VU unk1 X X

Puffinus 

creatopus

Shearwater, 

Pink-footed VU NS 1 X X X

Puffinus griseus Shearwater, 

Sooty >40% 2 ↓1 X X X X

Puffinus 

opisthomelas

Shearwater, 

Black-vented >40% 2 NS 1 X X X X

StormPetrelsOceanodroma 

furcata

Storm-Petrel, 

Fork-tailed SSC unk 3 ↓3 X X

Oceanodroma 

homochroa

Storm-Petrel, 

Ashy

SSC, 

EN unk 3 NS or ↓3 X X

Oceanodroma 

melania

Storm-Petrel, 

Black SSC unk 3 maybe ↓3 X X

202 Table 6
Taxonomic 

Group Scientific Name Common 

Name E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass

Recent 

Trend

Open 

Water

Canyon

Rise Slope Shelf II Shelf I Nearshore

Pelicans

Pelecanus 

occidentalis 

californicus

Pelican, 

California 

Brown

high 3 NS or ↑3 X X

Cormorants Phalacrocorax 

pelagicus

Cormorant, 

Pelagic high 3 NS 3 X X

Phalacrocorax 

penicillatus

Cormorant, 

Brandt's <75% 3 NS or ↓3 X X X

Phalaropes Phalaropus 

lobatus

Phalarope, 

Red-necked >40% 2 NS 1 X X

Auks

Brachyramphus 

marmoratus 

marmoratus

Murrelet, 

Marbled E EN <8% 4 NS 4 X X X

Cepphus 

columba

Guillemot, 

Pigeon high 3 NS or ↑3 X X X

Cerorhinca 

monocerata 

Auklet, 

Rhinoceros reduced 3 ↑ 3,5 X X X

Fratercula 

cirrhata

Puffin, 

Tufted SSC reduced 3 ↓3 X X

Ptychoramphus 

aleuticus

Auklet, 

Cassin's SSC reduced 3 ↓3 X X

Synthliboramphu

s hypoleucus

Murrelet, 

Xantus's T VU <50-70% 3 ↓3 X X

Uria aalge Murre, 

Common <50% 3,5 ↑ 3,5 X X X X

1 Recent population trend based on analysis of shipboard survey data sets from 1985-2001 as published in NCCOS 2003; 2 Appendix G in CDFG 2008a; 3

USFWS 2005; 4 central California population, McShane et al. 2004; 5 central California breeding population

203 Table 6
Table 7. Marine mammal species of special interest in MBNMS.

Marine mammal species in MBNMS that receive relatively greater interest and attention from resource managers, including Endangered and Threatened species 

(E/T), and other ‘at risk’ species (defined in Table 1). Only species that occur in offshore habitats in MBNMS were included. Habitat distribution is provided 

based on habitat categories as defined in Table 2. When available, the current population size/biomass relative to the historically high population size/biomass 

and the recent trend in population size are included; increasing (↑), decreasing (↓), trend not significant (NS), or unknown (unk). Population status information in 

red ink denotes information that is more than 5 years old (pre-2007). SSC = Species of Concern; VU = Vulnerable; EN = Endangered.

Taxonomic 

Group Scientific Name Common 

Name E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass Recent Trend Open Water

Canyons

Rise Slope Shelf 

II

Shelf 

I

Nearshore

Baleen 

Whales

Eschrichtius 

robustus Whale, Gray high 1,3 NS or ↑1 X X X X

Megaptera 

novaeangliae 

Whale, 

Humpback E unk 1,4 ↑1,2 X X

Balaenoptera 

musculus Whale, Blue E EN unk 1,4 NS 1,2 X X

Balaenoptera 

physalus Whale, Fin E EN unk 1,4 ↑10 X X

Balaenoptera 

borealis Whale, Sei E EN unk 1 unk 1,2 X X

Eubalaena 

japonica

Whale, North 

Pacific Right E EN <1% 1 unk 1 X

Toothed 

Whales

Physeter 

macrocephalus Whale, Sperm E VU unk 1,4 unk 1,2 X X X

Dolphins Orcinus orca Whale, Killer c E ~ 43% 1 NS1 X X

Porpoises Phocoena 

phocoena

Porpoise, 

Harbor d unk 1,4 NS1 X X X X

Phocoena 

phocoena

Porpoise, 

Harbor e unk 1,4 NS1 X X X X

Phocoena 

phocoena

Porpoise, 

Harbor f unk 1,4 ↑1 X X X X

Seals Phoca vitulina Seal, Harbor a high 1,3 NS 1 X X X X

Mirounga 

angustirostris

Seal, Northern 

Elephant high 1,3 ↑1 X X X X X

204 Table 7
Taxonomic 

Group Scientific Name Common 

Name E/T AtRisk

Population Status Habitat Categories

Relative 

Biomass Recent Trend Open Water

Canyons

Rise Slope Shelf 

II

Shelf 

I

Nearshore

Sea Lions, 

Fur Seals

Callorhinus 

ursinus 

Fur Seal, 

Northern VU N/A7 ↑1 X X

Eumetopias 

jubatus 

Sea Lion, 

Steller b T EN <50% 1,6 NS 1,6 X X X X

Arctocephalus 

townsendi 

Fur Seal, 

Guadalupe T VU unk 1 ↑1 X X

Zalophus 

californicus

Sea Lion, 

California high 1,3 ↑1 X X X X X

Sea Otters Enhydra lutris 

nereis

Sea Otter, 

Southern T EN ~17% 8,9 NS or ↓ 8 X X X

a California Stock; b Eastern Stock; c Eastern North Pacific Southern Resident Stock; d San Francisco-Russian River stock; e Monterey Bay stock; f

Morro Bay 

stock;

1 NOAA Fisheries OPR Marine Mammals Stock Assessment Reports by Species/Stock website http://www.nmfs.noaa.gov/pr/sars/species.htm accessed in June 

2012; 2 based on estimates for the stock off the U.S. west coast; 3 population may be approaching carrying capacity; 4 historic population size unknown; 5

Appendix G in CDFG 2008a; 6 for the population in central California only; 7 colony on San Miguel Island established in late 1960s; 8 Tinker et al. 2006; 9USGS 

Western Ecological Research Center California Sea Otter Survey Results website 

http://www.werc.usgs.gov/ProjectSubWebPage.aspx?SubWebPageID=16&ProjectID=91 accessed in June 2012; 10 Moore and Barlow 2011

205 Table 7
Table 8. The relative abundance of megafaunal invertebrates at three sites on the shelf.

Relative abundance of megafaunal invertebrates at Portuguese Ledge, Point Sur, and Big Creek was calculated

based on surveys from a manned submersible (Graiff 2008). A mix of benthic habitats, ranging from high-relief rock 

to soft sediment, were surveyed at each site.

Phylum Taxa Common Name

% Observations

Portuguese 

Ledge Point Sur Big Creek

Annelida Serpula spp. tubeworm <0.01 0.11

Arthropoda Lopholithodes foraminatus crab, brown box <0.01

Cancer spp. crab, Cancer <0.01

Loxorhynchus crispatus crab, decorator <0.01 0.05 <0.01

hermit crab crab, hermit 0.07

unknown crab spp. crab, unknown 0.02

Munida quadrispina lobster, squat 9.75

Pandalus platyceros prawn, California spot 0.04 11.43

Brachiopoda Laqueus californicus brachiopod 41.76 22.35

Bryozoa Heteropora pacifica bryozoan, northern staghorn 2.11

Chordata Urochordata spp. tunicates 0.03

Cnidaria Anthopleura spp. anemone, Anthopleura spp. <0.01

Urticina piscivora anemone, fish eating 1.84

Metridium farcimen anemone, giant white-plumed 1.29 0.02 4.69

Stomphia coccinea anemone, swimming 0.34 <0.01 0.4

unknown anemone anemone, unknown 0.04 <0.01

unknown sand anemone anemone, unknown sand 0.83

Urticina spp. anemone, Urticina spp. <0.01 0.8

unknown coral coral, unknown 0.02

Gorgonacea sea fan/sea whip 1.5 0.23 0.43

sea fan sea fan 0.04 0.02

Ptilosarcus gurneyi sea pen, fleshy 0.1 0.17

Subselliflorae sea pen sea pen, Subselliflorae spp. 5.13 0.5 10.91

Echinodermata Gorgonocephalus 

eucnemis basket star 0.24 0.07

Ophiuridae brittle stars 14.86 <0.01 4.94

Florometra serratissima feather star 18.87 65.1 8.6

Parastichopus spp. sea cucumber, Parastichopus

spp.

0.45

Parastichopus californicus sea cucumber, California 0.88 0.06

Patiria miniata sea star, bat 0.03 21.69

Patiria miniata/Mediaster 

aequalis sea star, bat/vermillion 2.54

Mediaster aequalis sea star, vermillion 12.95 2.6 7.18

Ceramaster patagonicus sea star, cookie 0.02 0.86 0.3

Pteraster tesselatus sea star, cushion <0.01 0.01

Stylasterias forreri sea star, fish eating 0.22 0.37

Stylasterias 

forreri/Orthasterias 

koehleri

sea star <0.01

Linckia columbiae? sea star, fragile <0.01

Henricia spp. sea star, Henricia spp. 0.06 0.04 0.76

Dermasterias imbricata sea star, leather <0.01

206 Table 8
Phylum Taxa Common Name

% Observations

Portuguese 

Ledge Point Sur Big Creek

Leptasterias spp. sea star, Leptasterias spp. 0.08

Pisaster spp. sea star, Pisaster spp. 0.17

Pycnopodia/Rathbunaster sea star, 

Pycnopodia/Rathbunaster 0.85 <0.01 0.85

Orthasterias koehleri sea star, redbanded 0.25

Luidia foliolata sea star, sand/mud 0.33 0.09 0.38

Pisaster brevispinus sea star, short-spinned 0.38

unknown sea star sea star, unknown 0.05 0.03 0.1

Pteraster militaris sea star, wrinkled <0.01 0.03 0.1

Lytechinus pictus urchin, white sea 2.65

Mollusca Dorididae spp. dorids <0.01

Octopus spp. octopus 0.08

Pleurobranchea 

californica sea slug, California <0.01

Porifera barrel sponge sponge, barrel 0.14 0.76 0.57

branching sponge sponge, branching 0.07

flat sponge sponge, flat 0.05 3.5 2.76

foliose sponge sponge, foliose 0.12 0.96 3.25

mound sponge sponge, mound <0.01 <0.01 0.26

vase sponge sponge, vase 0.03 0.09 0.09

207 Table 8
Table 9. Summary of baseline characterization data for eight marine protected areas.

Summary of data collected by Starr and Yoklavich (2008) in the deep portions of eight Marine Life Protection Act marine protected areas (no shading) and 

associated reference sites (grey shading) that are located inside MBNMS. A manned submersible was used to survey benthic habitat, megafaunal invertebrates, 

and fishes from 24–365 m deep in Monterey Bay and along the Big Sur coast. Ranks of relative abundance of fish groups based on pie chart diagrams in Starr 

and Yoklavich (2008). SMCA = State Marine Conservation Area; SMR = State Marine Reserve; RF = rockfish; YOY = Young-of-the-Year; U = Unknown

Habitat Category/

 Site Name

Benthic Habitat 

Surveyed

Dominant 

Megafaunal 

Invertebrates

Mean 

Density Relative Abundance of Fishes by Groups

(% of total area) (% total counted) (fishes/ 

100 m2) rank 1 rank 2 rank 3 rank 4 rank 5 rank 6 rank 7 rank 8 rank 9

Shelf I (<100 m)

Soquel Canyon 

SMCA (inside)

55% = high-relief rock, 

mud, cobble mixtures; 

45% = low-relief mud, 

mud-rock, mud-cobble

79% = feather stars, 

brittlestars, sea stars, 

nipple sponges

45.6 Fished 

RF > Other RF > Dwarf RF > Flatfish ≈ Other > Sea Perches > U

Portuguese 

Ledge SMCA 

(inside)

51% = mud habitats; 

38% rock ridges, rockmud, rock-boulder, 

rock-cobble

83% = sea stars, 

feather stars, corals, 

brittlestars

50.3 Dwarf 

RF > Fished RF > Other > Other RF ≈ YOY RF > Rays ≈ Sea Perches > Flatfish ≈ U

Portuguese 

Ledge SMCA 

(reference)

47% = rock-ridge, 

rock-cobble, rockboulder, rock-mud; 

37% = mud

50% = brachiopods, 

feather stars; sea stars, 

brittlestars, sea whip 

corals also common

66.1 Dwarf 

RF > YOY RF > Fished RF > Other > Other RF > Rays ≈ Sea Perches ≈ Flatfish ≈ U

Point Lobos 

SMR (inside)

96% = rock, boulder, 

cobble

94% = sea stars, corals, 

brittlestars, sponges 56 Dwarf 

RF > Other ≈ Fished RF > YOY RF ≈ Other RF > Rays ≈ Sea Perches ≈ Flatfish ≈ U

Point Lobos 

SMR (reference)

92% = rock, cobble, 

boulder

62% = sea stars; sea 

whip corals, 

hydrocorals also 

abundant

48 YOY 

RF ≈ Other ≈ Dwarf RF ≈ Fished RF > Other RF > U > Sea Perches

Point Lobos 

SMCA (inside)

37% = cobble; 33% = 

rock; 21% = mud, mudpebble, mud-rock

93% = brachiopods, 

feather stars, 

brittlestars

69.3 Dwarf 

RF > Fished RF > Flatfish ≈ Other RF > Other ≈ YOY RF ≈ Rays ≈ Sea Perches ≈ U

Point Lobos 

SMCA 

(reference)

70% = rock, cobble, 

boulders; 27% = mud, 

mud-cobble, mud-rock

Brittlestars, feather 

stars, sea stars 48 YOY RF ≈ Other ≈ Dwarf RF ≈ Fished RF > Other RF > U > Sea Perches

Point Sur SMR 

(inside)

91% = rock-ridge, 

rock-sand, rock-cobble

97% = bat sea stars, 

red gorgonian corals, 

hydrocorals, nipple 

sponges

12.5 Other > Fished 

RF > Other RF > YOY RF > Flatfish ≈ Sea Perches ≈ U ≈ Dwarf RF

Point Sur SMR 

(reference) 95% = rock

Sea stars, sponges, sea 

whip corals, 

hydrocorals

20.5 Fished 

RF > Other > YOY RF > Other RF ≈ Sea Perches > U

Point Sur SMCA 

(inside)

80% = rock, boulder, 

cobble; 16% = mud, 

mud-boulder, mudcobble, mud-rock

83% = brachiopods; 

sea stars, sea whip 

corals, feather stars 

also common

64.7 YOY 

RF > Other ≈ Dwarf RF ≈ Fished RF > Other RF > Rays ≈ Sea Perches ≈ Flatfish ≈ U

208 Table 9
Habitat Category/

 Site Name

Benthic Habitat 

Surveyed

Dominant 

Megafaunal 

Invertebrates

Mean 

Density Relative Abundance of Fishes by Groups

(% of total area) (% total counted) (fishes/ 

100 m2) rank 1 rank 2 rank 3 rank 4 rank 5 rank 6 rank 7 rank 8 rank 9

Point Sur SMCA 

(reference)

90% = mixtures of rock 

and boulder habitats

~97% = sea stars, red 

gorgonian corals, 

feather stars, barrel 

sponges, brachiopods 

91.9 YOY 

RF > Fished RF ≈ Dwarf RF > Other > Other RF > Sea Perches ≈ Flatfish ≈ U

Big Creek SMR 

(inside)

50% = complex rock 

habitats; 50% lowrelief sand and mud

73% = sea stars, 

sponges, brittlestars 32.5 Fished RF > Other > YOY RF > Flatfish > Dwarf RF > Sea Perches ≈ Other RF ≈ U

Big Creek SMR 

(reference)

39% = rock; 30% = 

mud; 28% = sand

66% = brachiopods, 

sea stars, sponges

17 Fished 

RF > Other > YOY RF > Flatfish > Other RF ≈ Sea Perches ≈ U

Shelf II (100-200 m)

Soquel Canyon 

SMCA (inside)

55% = high-relief rock, 

mud, cobble mixtures; 

45% = low-relief mud, 

mud-rock, mud-cobble

Feather stars, 

brittlestars, sea stars, 

nipple sponges

22 Fished 

RF > Dwarf RF ≈ Flatfish ≈ Other ≈ Other RF > U > Rays > Sea Perch

Soquel Canyon 

SMCA 

(reference)

58% = high-relief rock 

ridges, rock-mud 

slopes; 42%= mud, 

mud-cobble, mud-rock

81% = brachiopods, 

brittlestars, red sea 

stars

17 Fished 

RF > Other > Other RF ≈ Dwarf RF ≈ Flatfish > U > Rays > Sea Perch

Portuguese 

Ledge SMCA 

(inside)

51% = mud habitats; 

38% rock ridges, rockmud, rock-boulder, 

rock-cobble

83% = sea stars, 

feather stars, corals, 

brittlestars

14.9 Dwarf 

RF > Flatfish ≈ Other > Other RF > Fished RF > U

Portuguese 

Ledge SMCA 

(reference)

47% = rock-ridge, 

rock-cobble, rockboulder, rock-mud; 

37% = mud

50% = brachiopods, 

feather stars; red sea 

stars, brittlestars, sea 

whip corals also 

common

25.2 Dwarf 

RF > Fished RF > Other > Other RF ≈ Flatfish > YOY RF ≈ U ≈ Rays ≈ Sea Perch

Point Lobos 

SMCA (inside)

37% = cobble; 33% = 

rock; 21% = mud, mudpebble, mud-rock

93% = brachiopods, 

feather stars, 

brittlestars

28.2 Dwarf 

RF > Fished RF > Other RF > Other > Flatfish > U

Point Lobos 

SMCA 

(reference)

70% = rock, cobble, 

boulders; 27% = mud, 

mud-cobble, mud-rock

Brittlestars, feather 

stars, sea stars

(especially batstars)

12.8 Fished 

RF > Dwarf RF ≈ Other RF > Other ≈ Flatfish > U

Point Sur SMCA 

(inside)

80% = rock, boulder, 

cobble; 16% = mud, 

mud-boulder, mudcobble, mud-rock

83% = brachiopods; 

sea stars, sea whip 

corals, feather stars 

also common

22.4 Fished 

RF > Dwarf RF > Other > Other RF > Flatfish

Point Sur SMCA 

(reference)

90% = mixtures of rock 

and boulder habitats

Sea stars, red 

gorgonian corals, 

feather stars, 

brachiopods, barrel 

sponges

150.7 Dwarf 

RF > Fished RF > Other RF > YOY RF ≈ Other > U

Big Creek SMR 

(inside)

50% = complex rock 

habitats; 50% lowrelief sand and mud

73% = sea stars, 

sponges, brittlestars 47 Dwarf RF > Fished RF > Other RF > Other > Flatfish > U ≈ Sea Perch

209 Table 9
Habitat Category/

 Site Name

Benthic Habitat 

Surveyed

Dominant 

Megafaunal 

Invertebrates

Mean 

Density Relative Abundance of Fishes by Groups

(% of total area) (% total counted) (fishes/ 

100 m2) rank 1 rank 2 rank 3 rank 4 rank 5 rank 6 rank 7 rank 8 rank 9

Big Creek SMR 

(reference)

39% = rock; 30% = 

mud; 28% = sand

66% = brachiopods, 

sea stars, sponges

35.4 Dwarf 

RF > Fished RF ≈ Other RF > Other ≈ Flatfish > Sea Perch ≈ YOY RF ≈ U ≈ Rays

Big Creek 

SMCA (inside)

58% = rock, boulder, 

cobble; 42% = mud, 

mud-rock, mud-cobble

81% = brittlestars, sea 

stars, shelf sponges 28.3 Fished RF > Other RF > Dwarf RF > Other > Flatfish > U

Big Creek 

SMCA 

(reference)

55% = rock; 45% = 

mud 70% = brachiopods 25.3 Dwarf RF > Fished RF > Other RF > Flatfish > Other > YOY RF ≈ Rays

Slope (>200 m)

Soquel Canyon 

SMCA (inside)

55% = high-relief rock, 

mud, cobble mixtures; 

45% = low-relief mud, 

mud-rock, mud-cobble

Feather stars, 

brittlestars, sea stars, 

nipple sponges

17.6 Other > Fished 

RF > Flatfish > Other RF ≈ Dwarf RF > U ≈ Rays

Soquel Canyon 

SMCA 

(reference)

58% = high-relief rock 

ridges, rock-mud 

slopes; 42%= mud, 

mud-cobble, mud-rock

81% = brachiopods, 

brittlestars, red sea 

stars

14.6 Fished 

RF > Flatfish ≈ Other > Other RF ≈ Dwarf RF > U ≈ Rays

Portuguese 

Ledge SMCA 

(inside)

51% = mud habitats; 

38% rock ridges, rockmud, rock-boulder, 

rock-cobble

83% = sea stars, 

feather stars, corals, 

brittlestars

27.2 Fished 

RF > Other ≈ Other RF > Flatfish > Dwarf RF > Rays > U

Portuguese 

Ledge SMCA 

(reference)

47% = rock-ridge, 

rock-cobble, rockboulder, rock-mud; 

37% = mud

50% = brachiopods, 

feather stars; red sea 

stars, brittlestars, sea 

whip corals also 

common

15.3 Fished 

RF > Other ≈ Flatfish > Other RF > Dwarf RF > U ≈ Rays

Point Lobos 

SMCA (inside)

37% = cobble; 33% =

rock; 21% = mud, mudpebble, mud-rock

93% = brachiopods, 

feather stars, 

brittlestars

16.2 Fished 

RF > Other > Flatfish > Dwarf RF ≈ Other RF > U

Point Lobos 

SMCA 

(reference)

70% = rock, cobble, 

boulders; 27% = mud, 

mud-cobble, mud-rock

Brittlestars, feather 

stars, sea stars

(especially batstars)

13.4 Fished 

RF > Other > Flatfish > Other RF > Dwarf RF > U ≈ Rays

Big Creek SMR 

(inside)

50% = complex rock 

habitats; 50% lowrelief sand and mud

73% = sea stars

sponges, brittlestars 12.6 Fished RF > Other ≈ Other RF > Flatfish ≈ Dwarf RF Rays ≈ U

Big Creek SMR 

(reference)

39% = rock; 30% = 

mud; 28% = sand

66% = brachiopods, 

sea stars, sponges

11.7 Other > Fished 

RF ≈ Other RF ≈ Flatfish > Dwarf RF > U

210 Table 9
Table 10. Typical rockfish assemblage in each of five habitat categories.

The typical rockfish assemblage in each of five habitat categories off central and northern California (modified from Love et al. 2002). Habitat categories 

determined by water depth. X = multiple life stages present; YOY = young-of-the-year is the most common life stage present; J = juvenile (sometimes including 

YOY) is the most common life stage present.

Common Name of 

Rockfish Species Scientific Name Intertidal Nearshore (to 

30 m)

Shelf I 

(30-100 m)

Shelf II (100-

200 m)

Slope (> 

200 m)

Aurora Sebastes aurora X

Bank S. rufus X X

Black S. melanops YOY X X

Blackgill S. melanostomus X

Black-and-yellow S. chrysomelas X

Blue S. mystinus YOY X X

Bocaccio S. paucispinis J X X X

Brown S. auriculatus X X

Canary S. pinniger YOY J X X

Chilipepper S. goodei J X X X

China S. nebulosus X X

Copper S. caurinus X X

Cowcod S. levis J X X

Darkblotched S. crameri X

Flag S. rubrivinctus X

Gopher S. carnatus X

Grass S. rastrelliger X X

Greenblotched S. rosenblatti X X

Greenspotted S. chlorostictus J X

Greenstriped S. elongatus J X X

211 Table 10
Common Name of 

Rockfish Species Scientific Name Intertidal Nearshore (to 

30 m)

Shelf I 

(30-100 m)

Shelf II (100-

200 m)

Slope (> 

200 m)

Halfbanded S. semicinctus X X

Kelp S. atrovirens X

Olive S. serranoides X

Pygmy S. wilsoni X X

Quillback S. maliger X

Redbanded S. babcocki X

Rosethorn S. helvomaculatus X X

Rosy S. rosaceus X

Sharpchin S. zacentrus X X

Shortbelly S. jordani J X X

Speckled S. ovalis J X X

Splitnose S. diploproa J X

Squarespot S. hopkinsi X

Starry S. constellatus X

Stripetail S. saxicola J X

Vermilion S. miniatus X X X

Widow S. entomelas J J X

Yelloweye S. ruberrimus X X

Yellowtail S. flavidus YOY J X

Longspine thornyhead Sebastolobus altivelis X

Shortspine thornyhead Sebastolobus alascanus X

212 Table 10
Table 11. Fish species assemblages from "A Biogeographic Assessment of North/Central California"

Assemblages (species that tend to be caught together) were determined from data collected using four different 

methods: CDFG fishery dependent recreational fishing trips targeting rockfish (hook and line), NMFS fishery 

independent benthic trawls on the shelf and slope, and NMFS fisheries independent trawls in midwater (NCCOS 

2003). Assemblages were named according to the most influential species in each group (from the clustering 

analysis). Non-italicized species were consistently placed into the same species assemblage >80% of the time; 

italicized species occurred in other assemblages with random sampling. Assemblages differed by depth and to some 

extent by sampling method. Bottom type was not provided as a descriptor of the different assemblages. Rocky 

bottom on the shelf was probably the habitat most frequently sampled in the CDFG recreational data set. Gently 

sloping soft bottom on the shelf and slope was probably most frequently sampled in NMFS trawl surveys (highly 

sloped rocky bottom was not sampled).

Assemblage 

Name

Sampling 

Method

Approximate 

Depth Range 

(m)

Common Names of Species in Assemblage

Gopher rockfish CDF&G 

recreational 13-39 black rockfish, brown rockfish, china rockfish, gopher 

rockfish, cabezon, kelp greenling

Blue rockfish CDF&G 

recreational 13-82 blue rockfish, olive rockfish

Yellowtail 

rockfish

CDF&G 

recreational 24-119

canary rockfish, rosy rockfish, starry rockfish, yellowtail 

rockfish, copper rockfish, vermillion rockfish, lingcod, 

Pacific sanddab

Bocaccio CDF&G 

recreational 55-119 bocaccio, flag rockfish, speckled rockfish, widow 

rockfish, yelloweye rockfish

Greenspotted 

rockfish

CDF&G 

recreational 77-157 chilipepper rockfish, greenstriped rockfish, greenspotted 

rockfish

Pacific herring NMFS shelf 

trawl 62-121

California market squid, American shad, Chinook

salmon, curlfin sole, Dungeness crab, longspine 

combfish, northern anchovy, Pacific herring, Pacific 

pompano, white croaker, Pacific electric ray

Halfbanded 

rockfish

NMFS shelf 

trawl 74-112 halfbanded rockfish, Pacific mackerel, jack mackerel, 

Pacific argentine

Pacific sanddab NMFS shelf 

trawl 62-194 Pacific sanddab, English sole, petrale sole, pink 

seaperch, plainfin midshipman, lingcod

Big skate NMFS shelf 

trawl 62-194 spiny dogfish, big skate, California skate

Chilipepper 

rockfish

NMFS shelf 

trawl 82-320

bocaccio, chilipepper rockfish, greenstriped rockfish, 

greenspotted rockfish, shortbelly rockfish, cowcod, 

stripetail rockfish

Darkblotched 

rockfish

NMFS shelf 

trawl 216-379 bank rockfish, darkblotched rockfish, redbanded 

rockfish, splitnose rockfish

Blackgill 

rockfish

NMFS shelf 

trawl 277-463

lingcod, aurora rockfish, black eelpout, blackgill 

rockfish, blacktail snailfish, brown cat shark, filetail cat 

shark, lanternfish

213 Table 11
Assemblage 

Name

Sampling 

Method

Approximate 

Depth Range 

(m)

Common Names of Species in Assemblage

Rex sole NMFS shelf 

trawl

All depths (62-

463) rex sole, slender sole, spotted cusk-eel

Pacific hake NMFS shelf 

trawl

All depths (62-

463) Pacific hake, longnose skate, spotted ratfish

Shortspine 

thornyhead

NMFS shelf 

trawl

All depths (71-

463)

shortspine thornyhead, Bering skate, bigfin eelpout, 

Dover sole, sablefish

Stripetail 

rockfish

NMFS slope 

trawl 214-312

bocaccio, chilipepper rockfish, greenstriped rockfish, 

lingcod, darkblotched rockfish, English sole, petrale 

sole, sharpchin rockfish, shortbelly rockfish, spot prawn, 

stripetail rockfish, rosethorn rockfish, slender sole, 

redbanded rockfish, Pacific electric ray

Splitnose 

rockfish

NMFS slope 

trawl 214-649 Bering skate, bigfin eelpout, longnose skate, Pacific 

hake, rex sole, splitnose rockfish, spotted ratfish

Filetail catshark NMFS slope 

trawl 364-649 black eelpout, filetail cat shark, California grenadier, 

flapjack devilfish, Pacific glass shrimp

Longspine 

thornyhead

NMFS slope 

trawl 662-1207

black skate, California slickhead, crimson pasiphaeid, 

deepsea sole, giant grenadier, grooved tanner crab, 

longspine thornyhead, Pacific flatnose, Pacific grenadier, 

snakehead eelpout, twoline eelpout

Pacific 

viperfish

NMFS slope 

trawl 1017-1207

black hagfish, deepsea skate, fangtooth, longfin 

dragonfish, Pacific blackdragon, Pacific viperfish, 

rhomboid squid, sawtooth eel, smooth grenadier, 

threadfin slickhead, vampire squid, magistrate armhook 

squid

Aurora rockfish NMFS slope 

trawl

All depths (214-

1063 m)

aurora rockfish, blackgill rockfish, Dover sole, spiny 

dogfish, bank rockfish

Sablefish NMFS slope 

trawl

All depths (214-

1207 m)

blacktail snailfish, brown catshark, sablefish, shortspine 

thornyhead

Pacific hake 

(juvenile)

NMFS 

midwater 

trawl

Shallowest depth California smoothtongue, Deep-sea smelt, euphausiid, 

Myctophid, Pacific hake (juv), slender barracudina

Canary rockfish 

(juvenile)

NMFS 

midwater 

trawl

Intermediate 

depth

black rockfish (juv), blue rockfish (juv), bocaccio (juv), 

canary rockfish (juv), chilipepper rockfish (juv), pygmy 

rockfish (juv), shortbelly rockfish (juv), squarespot 

rockfish (juv), stripetail rockfish (juv), widow rockfish 

(juv), yellowtail rockfish (juv)

Medusafish

NMFS 

midwater 

trawl

Intermediate 

depth King-of-the-salmon, medusafish, rex sole (juv)

Slender sole 

(juvenile)

NMFS 

midwater 

trawl

Intermediate 

depth

Pacific tomcod (juv), slender sole (juv), sand sole (juv), 

slender sole (adult)

214 Table 11
Assemblage 

Name

Sampling 

Method

Approximate 

Depth Range 

(m)

Common Names of Species in Assemblage

Spiny dogfish

NMFS 

midwater 

trawl

Intermediate 

depth Pacific hake (adult), spiny dogfish

Pacific sanddab 

(juvenile)

NMFS 

midwater 

trawl

Intermediate 

depth

brown rockfish (juv), copper rockfish complex, dover 

sole (juv), Northern anchovy (larval), Pacific argentine 

(juv), Pacific sanddab (juv), speckled sanddab (juv)

Market squid

NMFS 

midwater 

trawl

Deepest depth

Lingcod (juv), market squid, Northern anchovy, Pacific 

butterfish, Pacific electric ray, Pacific sanddab, Pacific 

sardine, plainfin midshipman

215 Table 11
Table 12. Relative abundance and seasonal occurrence of sea turtles, seabirds, and marine mammals off central California.

The relative abundance and seasonal occurrence of sea turtles, seabirds, and marine mammals in eight pelagic zones off central California (Research Planning 

Inc. 2006). Figure 12 shows the location of each zone. - = rare or absent; x = secondary area of occurrence / present irregularly; xx = primary area of occurrence; 

xxx = primary area of occurrence and high densities (compared to other areas).

Common Name Scientific Name Zone 1

(0-100m)

Zone 2

(0-200m)

Zone 3

(0-200m)

Zone 4

(0-200m)

Zone 5

(0-200m)

Zone 6

(200-

3000m)

Zone 7

(100-

200m)

Zone 8

(>3000m)

Seasonal 

presence

Sea Turtles

Leatherback Turtle Dermochelys 

coriacea xxx xx xx x x x x x May-Nov

Seabirds

Pacific Loons Gavia pacifica xx xx xx x xx - x - Oct-May

other Loons Gavia spp. xx xx xx x x - x - Oct-May

Clark's and Western 

Grebes Aechmophorus spp. xx xx xx x xx - - - Sept-May

Horned and Eared 

Grebes Podiceps spp. x x x x x - - - Sept-May

Black-Footed Albatross Phoebastria nigripes - - - x - xx xx x Dec-Aug

Sooty Shearwater Puffinus griseus xx xxx xxx x xx x xx - MarchNov

Other Shearwaters Puffinus spp. x x x x xx x xx - Year-round

Ashy Storm-Petrel Oceanodroma 

homochroa - - - - - xx x - Year-round

other Storm Petrel Oceanodroma spp. - - - - - xx x x March–

Nov

Brown Pelican Pelecanus 

occidentalis xx xx xx x xx - x - March-Dec

Cormorants Phalacrocorax spp. xx xx xx xx xx - xx - Year-round

Surf Scoter Melanitta 

perspicillata xx xx xx x xx - - - Sept–April

White-Winged Scoter Melanitta fusca xx x xx x xx - - - Oct–April

Phalaropes Phalaropus spp. x x x - x xx xx x Year-round

216 Table 12
Common Name Scientific Name Zone 1

(0-100m)

Zone 2

(0-200m)

Zone 3

(0-200m)

Zone 4

(0-200m)

Zone 5

(0-200m)

Zone 6

(200-

3000m)

Zone 7

(100-

200m)

Zone 8

(>3000m)

Seasonal 

presence

Gulls (multiple species) Larus spp. xx xx xx x xx x xx - Year-round

Common Murre Uria aalge xx xxx xx x xx x-xx xxx - Year-round

Pigeon Guillemot Cepphus columba x xx xx x xx - xx - Feb–Sept

Marbled Murrelet Brachyramphus 

marmoratus xx xx x x x - - - Year-round

Xantus's Murrelet Synthliboramphus 

hypoleucus - - - - - xx x - July–Oct

Cassin's Auklet Ptychoramphus 

aleuticus x xx xx - xx xx xx - Year-round

Rhinoceros Auklet Cerorhinca 

monocerata xx xx xx x xx x xx - Year-round

other seabirds x x x x x x x x Year-round

Marine Mammals

Northern Right Whale Eubalaena japonica x x x x x x x x Mar-May

Humpback Whale Megaptera 

novaeangliae xx xx xx xx xx xx xx x Mar–Nov

Minke Whale Balaenoptera 

acutorostrata xx x xx xx x x xx x Year-round

Sei Whale Balaenoptera 

borealis - - - - - x - x Year-round

Fin Whale Balaenoptera 

physalus x x x x x xx x xx Year-round

Blue Whale Balaenoptera 

musculus x x xx x xx xx xx x June–Nov

Gray Whale Eschrichtius robustus xx xx xx xx xx - x - Nov-May

Sperm Whale Physeter 

macrocephalus - - - - - x - x Year-round

Pygmy and Dwarf 

Sperm Whale Kogia spp. - - - - - x - x Year-round

Cuvier's Beaked Whale Ziphius cavirostris - - - - - x - x Year-round

217 Table 12
Common Name Scientific Name Zone 1

(0-100m)

Zone 2

(0-200m)

Zone 3

(0-200m)

Zone 4

(0-200m)

Zone 5

(0-200m)

Zone 6

(200-

3000m)

Zone 7

(100-

200m)

Zone 8

(>3000m)

Seasonal 

presence

Baird's Beaked Whale Berardius bairdii - - - - - x - - May-Oct

Mesoplodon Beaked 

Whale Mesoplodon spp. - - - - - x - x Year-round

Bottlenose Dolphin Tursiops truncatus x xx xx x xx - - - Year-round

Short-beaked Common 

Dolphin Delphinus delphis x x x x xx xx x xx Year-round

Long-beaked Common 

Dolphin Delphinus capensis x x x x xx x x x Year-round

Pacific White-sided 

Dolphin

Lagenorhynchus 

obliquidens x x x xx x xx xx x Year-round

Northern Right Whale 

Dolphin Lissodelphis borealis - - x x x xx xx x Year-round

Risso's Dolphin Grampus griseus x x xx xx xx xx xx x Year-round

Killer Whale Orcinus orca x x x x x x x x Year-round

Short-finned Pilot 

Whale

Globicephala 

macrorhynchus x x x x x x x x Year-round

Harbor Porpoise Phocoena phocoena xx xx xx x xx - x - Year-round

Dall's Porpoise Phocoenoides dalli x xx xx xx xx x xx x Year-round

Guadalupe Fur Seal Arctocephalus 

townsendi - - - - - x - x Year-round

Northern Fur Seal Callorhinus ursinus x x x x x xx x xx Year-round

California Sea Lion Zalophus 

californianus xx xx xx xx xx x xx x Year-round

Steller Sea Lion Eumetopias jubatus x xx x x - x xx - Year-round

Harbor Seal Phoca vitulina xx xx xx x x x xx - Year-round

Northern Elephant Seal Mirounga 

angustirostris xx xx x xx x xx xx x Year-round

Southern Sea Otter Enhydra lutris nereis x xx xx xx xx - - - Year-round

218 Table 12
Table 13. Fish species associated with soft-bottom habitats in central California.

(A) Ecologically important species in middle shelf (31-100 m) and outer shelf (100-200 m) habitats off North-Central California (Cape Mendocino to San 

Simeon) as determined by Allen (2006). 'Ecologically important' species were defined as frequently occurring within a depth zone and likely to play important 

ecological roles (generally with regard to feeding) in the soft-bottom community. (B) Common benthic and benthopelagic fishes on the upper slope (200-500 m), 

middle slope (500-2,000 m), lower slope (2,000-3,000 m) and rise (>3,000 m) off California, as identified by Allen (2006) and Neighbors and Wilson (2006).

Common Name Scientific Name

A B

Middle 

Shelf

(31-100 m)

Outer Shelf 

(101-200 m)

Upper 

Slope (201-

500 m)

Middle Slope 

(501-2000 m)

Lower Slope 

(2001-3000 m)

Rise 

(>3000 m)

Hagfish, Black Eptatretus deani X X X

Ratfish, Spotted Hydrolagus colliei X X

Catshark, Brown Apriturus brunneus X

Catshark, Longnose Apriturus kampae X X

Catshark, Filetail Parmaturus xaniurus X X

Dogfish, Combtooth Centroscyllium nigrum X X

Dogfish, Spiny Squalus suckleyi X X

Shark, Pacific sleeper Somniosus pacificus X

Ray, Pacific electric Torpedo californica X

Skate, Big Raja binoculata X X

Skate, Longnose Raja rhina X

Skate, Deep-sea Bathyraja abyssicola X X

Skate, Black Bathyraja trachura X

Slickhead, California Alepocephalus tenebrosus X X

Slickhead, Threadfin Talismania birfurcata X

Lizardfish, Highfin Bathysaurus mollis X X X

Cuskeel Barathronus pacificus X

Cuskeel, Paperbone Lamprogrammus niger X

Cuskeel, Pudgy Spectrunculus grandis X X X

Cuskeel, Spotted Chilara taylori X X X

Codling, Pacific Flatnose Antimora microlepis X X X X

219 Table 13
Common Name Scientific Name

A B

Middle 

Shelf

(31-100 m)

Outer Shelf 

(101-200 m)

Upper 

Slope (201-

500 m)

Middle Slope 

(501-2000 m)

Lower Slope 

(2001-3000 m)

Rise 

(>3000 m)

Grenadier, Pacific Coryphaenoides acrolepis X X

Grenadier, Abyssal Coryphaenoides armatus X X

Grenadier, Threadfin Coryphaenoides filifer X

Grenadier, Ghostly Coryphaenoides leptolepis X X

Grenadier, Giant Coryphaenoides pectoralis X X

Grenadier, Rough abyssal Coryphaenoides yaquinae X

Grenadier Echinomacrurus occidentalis ?? X

Grenadier, Bluntnose Nezumia kensmithi X ??

Grenadier, Smooth Nezumia liolepis X X

Grenadier, California Nezumia stelgidolepis X X

Whiting, Pacific (Hake) Merluccius productus X X X X

Midshipman, Plainfin Porichthys notatus X X

Rockfish, Copper Sebastes caurinus X

Rockfish, Greenspotted Sebastes chlorostictus X

Rockfish, Splitnose Sebastes diploproa X

Rockfish, Stripetail Sebastes saxicola X X

Thornyhead, Shortspine Sebastolobus alascanus X X

Thornyhead, Longspine Sebastolobus altivelis X X

Sablefish Anoplopoma fimbria X X X

Lingcod Ophiodon elongatus X X

Combfish, Longspine Zaniolepis latipinnis X

Sculpin, Blob Psychrolutes phrictus X X

Sculpin, Roughback Chitonotus pugetensis X

Sculpin, Slim Radulinus asprellus X

Sculpin, Threadfin Icelinus filamentosus X

220 Table 13
Common Name Scientific Name

A B

Middle 

Shelf

(31-100 m)

Outer Shelf 

(101-200 m)

Upper 

Slope (201-

500 m)

Middle Slope 

(501-2000 m)

Lower Slope 

(2001-3000 m)

Rise 

(>3000 m)

Poacher, Blacktip Xeneretmus latifrons X

Snailfish, Blackfinned Careproctus cypselurus X X

Snailfish, Smalldisk Careproctus gilberti X X

Snailfish, Blacktail Careproctus melanurus X X X

Snailfish, Swellhead Paraliparis cephalus X

Snailfish, Longnose Rhinoliparis barbulifer X

Croaker, White Genyonemus lineatus X

Seaperch, Pink Zalembius rosaceus X X

Eelpout, Two-line Bothrocara brunneum X X

Eelpout, Bigfin Lycodes cortezianus X

Eelpout, Snakehead Lycodes crotalinus X X

Eelpout, Black Lycodes diapterus X X

Eelpout, Deepwater Lycodes endemoscotus X X

Eelpout, Blackbelly Lycodes pacificus X

Eelpout, Black mouth Lycodapus fierasfer X X

Sanddab, Pacific Citharichthys sordidus X

Sole, Deep-sea Embassichthys bathybius X X

Sole, Dover Microstomus pacificus X X X X

Sole, English Pleuronectes vetulus X

Sole, Petrale Eopsetta jordani X X X

Sole, Rex Glyptocephalus zachirus X X X

Sole, Slender Lyopsetta exilis X X

221 Table 13
Table 14. Epipelagic and mesopelagic organisms observed by MBARI in MBNMS.

The relative frequency of sightings of midwater organisms by MBARI scientists during ROV research dives in Monterey Canyon (data provided by the Robison 

Lab). An annotation was made each time an organism (or group of organisms of the same type) was observed during a dive. For each depth category (in meters), 

the percentage of the total number of annotations (averaged over the years 2000, 2001, 2002) was calculated for each type of organism. XXX = over 10% of the 

total annotations at a given depth; XX = between 5-10% of the total annotations; X = between 1-5% of the total annotations; - = less than 1% of the total 

annotations; o = none observed.

Scientific Name or 

Taxonomic Group Group Name 0-99 100-

199

200-

299

300-

399

400-

499

500-

599

600-

699

700-

799

800-

899

900-

1000

Foraminiferida Forams x - x x - - - - o o

Mitrocoma cellularia Hydromedusae xxx xx xx x xx xx xx xx x x

Aegina citrea Narcomedusae x x x x xx xxx xxx xxx xxx xxx

Solmissus spp. Narcomedusae x x xx xx x x x - - -

Siphonophorae Siphonophores xx x x x x x x x x x

Apolemia uvaria Siphonophore - - - - x x x xx x x

Nanomia bijuga Siphonophore xxx xxx xxx xxx xxx xx x - - o

Calycophorae Siphonophores x xx xx xx xx xx xx xx xx xx

Cydippida Comb Jellies xx x x x x x x x x x

Lobata Comb Jellies xx x x x x x x x x x

Bolinopsis spp. Comb Jellies xx x x - - x x x x xx

Beroe spp. Comb Jellies x x x - x x x x - -

Poeobius meseres Polychaete Worm x - - x xx x x x x xx

Euphausiidae Krill x xx xx x - - - - - o

222 Table 14
Scientific Name or 

Taxonomic Group Group Name 0-99 100-

199

200-

299

300-

399

400-

499

500-

599

600-

699

700-

799

800-

899

900-

1000

Sergestes similis Shrimp x x x xxx xx xx x - - -

Mysidae Mysid Shrimp - - - - - x xx xx xxx xxx

Acanthamunnopsis spp. Isopod x xx xxx - - - - - - -

Rathbunaster californicus Sun Star (larvae) o xx x x - o - - o o

Salpida Salp xx x x xx xxx xx x x - -

Doliolida Tunicate - - - - x xx xx xxx xxx xxx

Appendicularia Larvaceans xx x xx xx xxx xxx xx xx xx xx

Bathochordaeus spp. Larvaceans x xx x - - - - o o o

Mesochordaeus 

erythrocephalus Larvacean - - - x x - - - o -

Sinker Larvacean House x x x x xx xx xx xx xx xx

Chaetognatha Arrow Worm x xx xx xx xx x x x x xxx

Osteichthyes Fish - Bony Fish x - - - x x x x x x

Myctophidae Fish - Lanternfish x x x x x x - - - -

Merluccius productus Fish - Pacific Hake - x x x x x x - - o

Leuroglossus stilbius Fish - Smooth Tongue - - - - x xx x x - -

223 Table 14
Table 15. Ichthyoplankton assemblage along the U.S. West Coast.

The prevailing ichthyoplankton assemblages along the U.S. West Coast during spring include a Coastal/Shelf 

assemblage, a Slope assemblage, and an Oceanic assemblage (Doyle et al. 2002). Taxa selected for the assemblage 

analysis were those that were commonly collected during the study (occurred in 5% or more of samples from one or 

more cruises). The Slope assemblage represents a transition between the Coastal/Shelf and Oceanic assemblages, 

containing some species from both.

Common Name Scientific Name Coastal/ 

Shelf Slope Oceanic

Smelts Osmeridae X

Blacksmelt, Pacific Bathylagus pacificus X X

Blacksmelt, Popeye Bathylagus ochotensis X X

Argentine, Bluethroat Nansenia candid X X

Viperfish, Pacific Chauliodus macouni X X

Headlightfish, California Diaphus theta X X

Flashlightfish, California Protomyctophum crockeri X X

Flashlightfish, Northern Protomyctophum thompsoni X X

Lampfish, Pinpoint Lampanyctus regalis X

Lampfish, Broadfin Lampanyctus ritteri X

Lampfish, Northern Stenobrachius leucopsarus X X X

Lanternfish, Blue Tarletonbeania crenularis X X

Lanternfishes Lampanyctus spp X X

Lanternfishes Myctophidae X X

Tomcod, Pacific Microgadus proximus X

Bigscales Melamphaidae X

Thornyheads Sebastolobus spp X X

Rockfishes Sebastes spp X X

Snailfishes Liparis spp. X X

Flounder, Starry Platichthys stellatus X

Sanddab, Pacific Citharichthys sordidus X X

Sole, Butter Isopsetta isolepis X

Sole, Dover Microstomus pacificus X

Sole, English Pleuronectes vetulus X

Sole, Rex Glyptocephalus zachirus X X

Sole, Sand Psettichthys melanostictus X

Sole, Slender Lyopsetta exilis X X

224 Table 15
Table 16. Epipelagic, mesopelagic and bathypelagic fish assemblages in MBNMS.

General depth of occurrence of fish species found in the open water habitats of central California. Epipelagic species 

tend to be found within 200 m of the surface, mesopelagic species are associated with the middle layer of the open 

ocean (generally 200-1000 m) and bathypelagic species are associated with the deepest portion of the open ocean 

(usually deeper than >1000 m). Many mesopelagic species undergo diurnal vertical migration and, thus may also 

spend time in the epipelagic habitat. This list includes many of the fish species inhabiting the open water habitats of 

the MBNMS, but is not comprehensive (sources include Silver et al. 1996 and Allen and Cross 2006). Depth 

information from Love (1996), Miller and Lea (1972), Fishbase, and Allen and Cross (2006).

Common Name Scientific Name

Epipelagic 

(<200 m)

Mesopelagic 

(200-1000 m)

Bathypelagic 

(>1000 m)

Shark, Basking Cetorhinus maximus x

Shark, Bigeye Thresher Alopias superciliosus x

Shark, Common Thresher Alopias vulpinus x

Shark, Blue Prionace glauca x

Shark, Megamouth Megachasma pelagios x x

Shark, Salmon Lamna ditropis x

Shark, Shortfin Mako Isurus oxyrinchus x

Shark, Soupfin Galeorhinus galeus x

Shark, White Carcharodon carcharias x x

Dogfish, Spiny Squalus suckleyi x

Ray, Bay Myliobatis californica x

Ray, Pacific Electric Torpedo californica x x

Stingray, Pelagic Dasyatis violacea x

Ratfish, Spotted Hydrolagus colliei x

Herring, Pacific Clupea pallasi x

Sardine, Pacific Sardinops sagax x

Anchovy, Northern Engraulis mordax x

Salmon, Chinook Oncorhynchus tshawytscha x

Salmon, Coho Oncorhynchus kisutch x

Lancetfish, Longnose Alepisaurus ferox x x

Blacksmelt, Snubnose Bathylagus wesethi x

Blacksmelt, Pacific Bathylagus pacificus x x

Smoothtongue, California Leuroglossus stilbius x x

Blacksmelt, Popeye Lipolagus ochotensis x x

Blacksmelt, Robust Pseudobathylagus milleri x x

Spookfish, Javelin Bathylychnops exilis x

Mentodus facilis x x

Tubeshoulder, Shining Sagamichthys abei x

Bristlemouth, Benttooth Cyclothone acclinidens x x

Bristlemouth, Tan Cyclothone pallida x x

Bristlemouth, Showy Cyclothone signata x x

225 Table 16
Common Name Scientific Name

Epipelagic 

(<200 m)

Mesopelagic 

(200-1000 m)

Bathypelagic 

(>1000 m)

Argentine, Pacific Argentina sialis x x

Hatchetfish, Slender Argyropelecus affinis x

Hatchetfish, Silver Argyropelecus lychnus x

Hatchetfish, Silvery Argyropelecus sladeni x x

Bottlelights Danaphos oculatus x

Hatchetfish, Diaphanous Sternoptyx diaphana x

Blackchin, Pacific Scopelengys tristis x x

Lightfish, Panama Vinciguerria lucetia x x

Barreleye, Pacific Macropinna microstoma x x

Spookfish, Brownsnout Dolichopteryx longipes x

Dragonfish, Highfin Bathophilus flemingi x

Dragonfish, Longfin Tactostoma macropus x

Viperfish, Pacific Chauliodus macouni x x

Blackdragon, Pacific Idiacanthus antrostomus x

Loosejaw, Shining Aristostomias scintillans x

Barracudina, Slender Lestidiops ringens x x x

Blackchin, Pacific Scopelengys tristis x

Daggertooth, North Pacific Anotopterus nikparini x x x

Headlightfish, California Diaphus theta x x

Lanternfish, Longfin Diogenichthys atlanticus x x

Lampfish, Pinpoint Nannobrachium regale x x

Lampfish, Broadfin Nannobrachium ritteri x x

Flashlightfish, California Protomyctophum crockeri x x

Lampfish, Northern Stenobrachius leucopsarus x x x

Lanternfish, California Symbolophorus californiensis x x

Lanternfish, Blue Tarletonbeania crenularis x x

Flying Fish, California Cypselurus californicus x

Whiting, Pacific (Hake) Merluccius productus x x

Saury, Pacific Cololabis saira x

Oreo, Oxeye Allocyttus folletti x x

Opah Lampris guttatus x x

Dreamer, Spiny Oneirodes acanthias x x

Bigscale, Crested Poromitra crassiceps x x

Bigscale, Twospine Scopelogadus mizolepis bispinosus x x

Fangtooth Anoplogaster cornuta x x

Eelpout, Pallid Lycodapus mandibularis x x

Eelpout, Midwater Melanostigma pammelas x x

Oarfish, Crested Lophotus lacepede x

226 Table 16
Common Name Scientific Name

Epipelagic 

(<200 m)

Mesopelagic 

(200-1000 m)

Bathypelagic 

(>1000 m)

Oarfish Regalecus glesne x x

King-of-the-salmon Trachipterus altivelis x x

Snailfish, Tadpole Nectoliparis pelagicus x x

Snailfish, Pygmy Lipariscus nanus x

Remora Remora remora x

Yellowtail Seriola lalandi x

Mackerel, Jack Trachurus summetricus x

Pomfret, Sickle Taractichthys steindachneri x

Pomfret, Pacific Brama japonica x

Dolphinfish Coryphaena hippurus x

Seabass, White Atractoscion nobilis x

Barracuda, California Sphyraena argentea x

Prowfish (juveniles) Zaprora silenus x

Ragfish (juveniles) Icosteus aenigmaticus x

Frostfish, North Pacific Benthodesmus pacificus x x

Oilfish Ruvettus pretiosus x x

Escolar Lepidocybium flavobrunneum x x

Mackerel, Pacific (Chub) Scomber japonicus x

Mackerel, Bullet Auxis rochei x

Tuna, Skipjack Katsuwonus pelamis x

Bonito, Pacific Sarda chiliensis x

Tuna, Albacore Thunnus alalunga x

Tuna, Bigeye Thunnus obesus x

Tuna, Bluefin Thunnus thynnus x

Tuna, Yellowfin Thunnus albacares x

Swordfish Xiphias gladius x

Marlin, Striped Tetrapturus audax x

Louvar Luvarus imperialis x

Medusafish Icichthys lockingtoni x

Driftfish, Bluefin Psenes pellucidus x x

Squaretail, Smalleye Tetragonurus cuvieri x

Butterfish, Pacific Peprilus simillimus x

Sunfish, Ocean Mola mola x

227 Table 16
Table 17. Taxa observed at Davidson Seamount and their listing categories.

Biological observations are from 17 ROV Tiburon dives (~140 hours of video and sample collections) completed 

during 2002 and 2006; primarily on the seafloor, with opportunistic dives in the water column above the seamount 

(Burton and Lundsten 2008). Taxa are listed in phylogenetic order. Listing categories for species of special interest 

are defined in Table 1.

Phylum Taxa Common Name

Listing Category

Landed E/T AtRisk

Foraminifera XENOPHYOPHOREA sp. 1 xenophyophore, unidentified

XENOPHYOPHOREA sp. 2 xenophyophore, unidentified

Radiozoa RADIOLARIA spp. radiolarian, unidentified

Phaeophyta Alaria marginata kelp, ribbon (drift)

Alaria sp. kelp, ribbon (drift)

Macrocystis sp. kelp, giant (drift)

Nereocystis luetkeana kelp, bull (drift)

Anthophyta Phyllospadix sp. surfgrass (drift)

Porifera PORIFERA sp. 1 sponge

PORIFERA sp. 2 sponge

PORIFERA sp. 3 sponge

PORIFERA sp. 4 sponge, striated

PORIFERA sp. 5 sponge, stalked (white)

PORIFERA sp. 6 sponge

PORIFERA sp. 7 sponge, stalked ruffled (white)

PORIFERA sp. 8 sponge, ruffled (yellow)

PORIFERA sp. 9 sponge, encrusting gray

Thenea muricata sponge

POECILOSCLERIDA sp. sponge, stalked flute

Asbestopluma sp. nov. sponge, branched (white)

Asbestopluma sp. 1 sponge, single (white)

Heterochone calyx sponge, goiter (yellow/orange) 

Chonelasma sp. nov. sponge, trumpet (white)

Farrea occa sponge, ruffle (white)

Sclerothamnopsis compressa sponge

Saccocalyx pedunculata sponge, stalked goiter (white)

Atlantisella sp. nov. sponge, creeping (white)

Regadrella sp. nov. sponge, vase (white)

Caulophacus sp. nov. sponge, mushroom (white)

Crateromorpha sp. nov. sponge

Hyalascus sp. nov. sponge

Staurocalyptus sp. nov. sponge, yellow

Cnidaria Atolla sp. jelly, crown

Periphylla periphylla jelly, crown

Poralia rufescens jelly

228 Table 17
Phylum Taxa Common Name

Listing Category

Landed E/T AtRisk

Tiburonia granrojo jelly, big red

HYDROZOA sp. 1 hydroid

HYDROZOA sp. 2 hydroid

HYDROZOA sp. 3 hydroid

HYDRACTINIIDAE sp. nov. hydroid

Chiarella sp. hydroid

MYRIOTHELIDAE sp. hydroid

Aegina citrea narcomedusa, golf tee

Aegina sp. narcomedusa

Aeginura sp. narcomedusa

Cunina sp. narcomedusa, mesopelagic

Solmissus sp. narcomedusa

Halicreas minimum jelly

Benthocodon sp. jelly

Colobonema sericeum medusa, silky 

Crossota millsae jelly

Nanomia bijuga siphonophore

Stephanomia amphytridis siphonophore

Apolemia sp. siphonophore

Physophora hydrostatica siphonophore

Stephalia dilata siphonophore, benthic

Thermopalia taraxaca siphonophore

Gymnopraia lapislazula siphonophore

Trissopathes pseudotristicha black coral

Trissopathes sp. (cf. T. 

tetracrada) black coral

Bathypathes sp. black coral

Lillipathes sp. black coral

Umbellapathes sp. black coral

CERIANTHIDAE sp. 1 tube-dwelling anemone

CERIANTHIDAE sp. 2 tube-dwelling anemone

CERIANTHIDAE sp. 3 tube-dwelling anemone

ACTINIARIA sp. 1 (poss. 

Bathyphellia sp.) anemone

ACTINIARIA sp. 2 anemone

ACTINIARIA sp. 3 anemone

ACTINOSTOLIDAE spp. anemone

Stomphia sp. (prob. S. 

didemon) anemone

HORMATHIIDAE sp. anemone

Liponema brevicornis anemone, pom-pom

229 Table 17
Phylum Taxa Common Name

Listing Category

Landed E/T AtRisk

ZOANTHIDEA sp. 1 zoanthid

ZOANTHIDEA sp. 2 zoanthid

CORALLIMORPHARIA spp. anemone

Corallimorphus sp. anemone

CARYOPHYLLIINA sp. coral, stony

Javania cailleti coral, stony

Anthomastus ritteri coral, mushroom soft 

Anthomastus robustus coral, soft

Anthomastus sp. 1 coral, soft

Paragorgia arborea coral, bubble gum

Paragorgia sp. 1 coral, bubble gum

Sibogagorgia cauliflora coral, bubble gum (white 

morph)

Corallium sp. coral, precious

Acanthogorgia sp. coral

Swiftia kofoidi coral, red sea fan

Chrysogorgia monticola coral, golden gorgonian

Chrysogorgia pinnata coral, golden gorgonian

Calyptrophora bayeri coral

Calyptrophora sp. (cf. C. 

antilla) coral

Calyptrophora sp. coral

Narella sp. coral

Parastenella ramosa coral

Parastenella sp. coral

Acanella sp. coral, bamboo 

Keratoisis sp. coral, bamboo 

Lepidisis sp. coral, bamboo 

Ctenophora Aulacoctena sp. ctenophore

Hormiphora sp. ctenophore

Tjalfiella tristoma ctenophore

LOBATA sp. nov. ctenophore, lobate

Bathocyroe spp. ctenophore, lobate

Lampocteis cruentiventer ctenophore, lobate

Lampocteis sp. ctenophore, lobate

Mollusca PATELLOIDEA sp. limpet

TURRIDAE sp. turrid

NUDIBRANCHIA sp. nov. nudibranch, mystery mollusk

Tritonia sp. (cf. T. diomedea or

sp. nov.) nudibranch

BATHYDORIDIDAE sp. nudibranch

230 Table 17
Phylum Taxa Common Name

Listing Category

Landed E/T AtRisk

NEOLORICATA sp. chiton

Acesta mori clam

?PECTINIDAE sp. scallop

Doryteuthis (=Loligo)

opalescens squid, California market X

Galiteuthis sp. squid, glass

Gonatus onyx squid, clawed armhook 

Dosidicus gigas squid, Humboldt X

Opisthoteuthis sp. devilfish, flapjack

Japetella sp. octopus, pelagic

Benthoctopus sp. octopus, benthic 

Graneledone boreopacifica 

(pacifica) octopus

Annelida Tomopteris sp. polychaete, tomopterid

Laetmonice sp. polychaete, sea mouse

POLYNOIDAE sp. scale worm, blue

Euchone sp. nov. polychaete, sabellid

SERPULIDAE spp. polychaete, serpulid

Poeobius meseres polychaete, holopelagic

Flota sp. polychaete

Arthropoda PYCNOGONIDA sp. sea spider

SCALPELLOMORPHA sp. barnacle, stalked

VERRUCOMORPHA sp. barnacle

Sergestes similis shrimp, midwater 

CARIDEA spp. shrimp

Pandalopsis ampla shrimp, deepwater bigeye

LITHODIDAE sp. (probably 

juvenile) crab, (probably juvenile)

Neolithodes diomedeae crab

Neolithodes sp. crab, spiny 

Paralomis multispina crab

Paralomis verrilli crab, vermillion

Munida sp. lobster, squat 

Munidopsis spp. lobster, squat 

BRACHYURA sp. crab

Chorilia longipes crab, longhorn decorator

MYSIDA spp. shrimp, opossum

AMPHIPODA spp. amphipod

CAPRELLIDAE spp. caprellid

ISOPODA spp. isopod

MUNNOPSIDAE spp. isopod

231 Table 17
Phylum Taxa Common Name

Listing Category

Landed E/T AtRisk

Ectoprocta ECTOPROCTA sp. 1 bryozoan

ECTOPROCTA sp. 2 bryozoan

Echinodermata Hyocrinus sp. crinoid, 5-arm

BATHYCRINIDAE sp. crinoid, 10-arm

Florometra serratissima crinoid, (feather star) 

Benthopecten sp. (possibly B. 

claviger) sea star, prickly

Ceramaster patagonicus sea star

Ceramaster sp. sea star

Evoplosoma voratus sea star

Hippasteria californica sea star

Hippasteria spinosa sea star

Mediaster spp. sea star

Hymenaster koehleri sea star

?Pteraster sp. 1 sea star

Pteraster sp. 2 (possibly

Hymenaster sp.) sea star

Pteraster sp. 3 (possibly

Hymenaster sp.) sea star

Pteraster sp. 4 sea star

Pteraster sp. 5 sea star

Lophaster furcilliger sea star

Solaster spp. sun star

Henricia sp. sea star

?Anteliaster sp. sea star

Myxoderma sacculatum sea star

ZOROASTERIDAE sp. sea star, pink

BRISINGIDA spp. sea star, brisingid

OPHIUROIDEA spp. brittle star

Gorgonocephalus sp. basket star

OPHIACANTHIDAE sp. brittle star

ECHINOIDEA sp. urchin

Aporocidaris milleri urchin, pencil

Tromikosoma panamense urchin

Tromikosoma sp. urchin

Cystocrepis setigera urchin

HOLOTHUROIDEA sp. 1 sea cucumber

HOLOTHUROIDEA sp. 2 sea cucumber

Abyssocucumis abyssorum sea cucumber

Psolus squamatus sea cucumber

Paelopatides confundus sea cucumber

232 Table 17
Phylum Taxa Common Name

Listing Category

Landed E/T AtRisk

SYNALLACTIDAE sp. sea cucumber

Oneirophanta mutabilis sea cucumber

Peniagone sp. sea cucumber

Scotoplanes globosa sea cucumber

Pannychia moseleyi sea cucumber

Benthodytes sp. 1 sea cucumber

Benthodytes sp. 2 sea cucumber

Chaetognatha CHAETOGNATHA spp. chaetognath

Hemichordata ENTEROPNEUSTA sp. acorn worm

Chordata Culeolus sp. tunicate, stalked

SALPIDA spp. salp

Doliolenetta sp. nov. salp

DOLIOLIDA spp. salp

Bathochordaeus sp. larvacean, Giant

APPENDICULARIA spp. larvacean

RAJOIDEI spp. skate, egg cases, unidentified

Bathyraja abyssicola skate, deepsea

Amblyraja badia skate, broad

Aldrovandia sp. lizardfish, salty (or halosaur)

SYNAPHOBRANCHIDAE 

sp. eel, cutthroat

Venefica tentaculata eel, witch 

Serrivomer sp. (possibly S. 

sector) eel, sawtooth

Cyema atrum eel, bobtail 

BATHYLAGIDAE spp. smelt, deep-sea

ALEPOCEPHALIDAE sp. 

(poss. Conocara 

salmoneum)

slickhead

Cyclothone sp. bristlemouth

Bathysaurus mollis lizardfish, highfin 

MYCTOPHIDAE spp. lanternfish

Luciobrotula sp. brotulid

Spectrunculus grandis cusk-eel, giant 

Albatrossia pectoralis grenadier, giant

Coryphaenoides acrolepis grenadier, Pacific X

Coryphaenoides 

armatus/yaquinae

grenadier, abyssal/rough 

abyssal 

Coryphaenoides filifer grenadier, filamented

Coryphaenoides leptolepis grenadier, ghostly 

Antimora microlepis codling, finescale (or Pacific 

flatnose)

MORIDAE sp. (Lepidion sp. codling

233 Table 17
Phylum Taxa Common Name

Listing Category

Landed E/T AtRisk

or possibly Laemonema 

sp.)

Chaunocops coloratus sea toad, deep 

Sebastolobus alascanus thornyhead, shortspine X EN

Psychrolutes phrictus sculpin, blob (or no-name)

Careproctus ovigerus

(juvenile) snailfish, abyssal (juvenile)

LIPARIDAE sp. snailfish, unidentified 

(blackhead)

Bothrocara brunneum eelpout, twoline 

Lycenchelys spp. eelpout

Lycodapus fierasfer eelpout, blackmouth

Lycodapus mandibularis eelpout, pallid

Pachycara bulbiceps eelpout, snubnose

ZOARCIDAE spp. eelpout

234 Table 17
Table 18. Dominant invertebrate phyla observed at Davidson and Pioneer Seamounts.

Percent observation of three dominant invertebrate phyla, and for taxa within each of the three dominant phyla, are 

listed (from Lundsten et al. 2009a). Mean organism density (all taxa observed within transects) was calculated from 

quantitative video transects at Davidson (n=33; between 1298 and 3276 m depth) and Pioneer (n=7; between 844 

and 1240 m depth), and was significantly different between the two seamounts (2-tailed t-test, t(38)=-5.13, 

p<0.001).

Phylum Taxa Common Name

% Observation

Davidson Seamount Pioneer Seamount

Porifera 29.5 20.2

Chonelasma sp. sponge, trumpet 6.4 9.7

Farrea sp. sponge, ruffle 22.5 11.4

Heterochone sp. sponge, goiter 5.9 17.7

Schlerothamnopsis sp. sponge 14.8 1.7

Staurocalyptus sp. sponge 13.2 13.1

Thena muricata sponge rare 16.1

unidentified sponge, unidentified 31.9 25.4

Cnidaria 34.2 39.8

Alcyonacea coral, soft 4.7 38.6

Anthipatharia coral, black 21.8 0.2

Gorgonians sea fan/sea whip 73.0 61.0

Pennatulacea sea pens rare rare

Scleractinia coral, stony 0.4 0.15

Zoanthidea anemone, zoanthid 0.09 0.0

Echinodermata 32.4 34.4

Asteroidea sea stars 10.3 9.0

Crinoidea feather stars 44.6 61.7

Echinoidea urchins 0.4 0.02

Holothuroidea sea cucumbers 16.1 23.4

Ophiuroidea brittle stars 28.7 5.9

Mean organism 

density 0.87 ± 0.10 ind./m2 2.19 ± 0.27 ind./m2

235 Table 18
Table 19. Dominant fish families observed at Davidson and Pioneer Seamounts.

Percent observation of eight dominant fish families at Davidson and Pioneer Seamounts (from Lundsten et al. 

2009b). Mean fish density (all taxa observed within transects) was calculated from quantitative video transects at 

Davidson (n=33; between 1298 and 3276 m depth) and Pioneer (n=7; between 844 and 1240 m depth), and differed 

between the two seamounts.

Family Common Name

% Observation

Davidson Seamount Pioneer Seamount

Bythitidae brotulas 3.8 1.3

Liparidae snailfishes 11.5 4.6

Macrouridae grenadiers 53.1 37.8

Moridae codlings 10.2 8.8

Ophidiidae cusk-eels 14.7 0.3

Pleuronectidae righteye flounders 0.3 1.6

Scorpaenidae scorpionfishes 0.3 42.1

Zoarcidae eelpouts 5.2 3.0

Mean fish density 0.0028±0.0006 ind/m2 0.025 ± 0.0024 ind/m2

(n = 22 taxa) (n = 18 taxa)

236 Table 19
Table 20. Sea-surface species observed within Davidson Seamount Management Zone.

Sea-surface species were recorded during four aerial surveys and two ship-based surveys within the Davidson Seamount Management Zone (DSMZ). Species are 

listed in phylogenetic order. Listing categories for species of special interest are defined in Table 1. E/T = Endangered/Threatened; SSC = Species of Concern; 

VU = Vulnerable; EN = Endangered

Common Name Scientific Name

Survey Listing Category Aerial Shipboard

2000 

Jul 1

2009 

Apr 2

2010 

Jan 3

2010 

Apr 3

2002 

May 4

2010 

Jul 5 Landed E/T AtRisk

Fishes

shark, unidentified shark, unidentified X X

sunfish, ocean Mola mola X X X X X

Seabirds and Shorebirds

Albatross, Laysan Phoebastria immutabilis X X VU

Albatross, Black-footed Phoebastria nigripes X X EN

Fulmar, Northern Fulmarus glacialis X X

Petrel, Stejneger's Pterodroma longirostris X VU

Petrel, Cook's Pterodroma cookii X VU

Shearwater, Pink-footed Puffinus creatopus X X VU

Shearwater, Sooty Puffinus griseus X

Shearwater, unidentified Puffinus sp. X

Storm-petrel, Leach's Oceanodroma leucorhoa X X

Storm-petrel, unidentified Oceanodroma sp. X X

Plover, Black-bellied Pluvialis squatarola X

Sandpiper, Least Calidris fuscicollis X

Phalarope, Red Phalaropus fulicaria X

Phalarope, Red-necked Phalaropus lobatus X

Jaeger, Parasitic Stercorarius parasiticus X

Jaeger, Pomarine Stercorarius pomarinus X

Jaeger, unidentified Stercorarius sp. X

Gull, Western Larus occidentalis X

gull, unidentified gull, unidentified X

237 Table 20
Common Name Scientific Name

Survey Listing Category Aerial Shipboard

2000 

Jul 1

2009 

Apr 2

2010 

Jan 3

2010 

Apr 3

2002 

May 4

2010 

Jul 5 Landed E/T AtRisk

Tern, Arctic Sterna paradisaea X

Murrelet, Xantus's Synthliboramphus hypoleucus X T VU

alcid, unidentified alcid, unidentified X

Marine Mammals

fur seal, Northern Callorhinus ursinus X VU

fur seal, unidentified fur seal, unidentified X X

sea lion, California Zalophus californianus X X X X

otariid, unidentified otariid, unidentified X

elephant seal, Northern Mirounga angustirostris X

pinniped, unidentified pinniped, unidentified X

whale, gray Eschrichtius robustus X

whale, humpback Megaptera novaeangliae X X E

whale, fin Balaenoptera physalus X E EN

rorqual, unidentified rorqual, unidentified X

whale, sperm Physeter macrocephalus X X X X E VU

beaked whale, Cuvier's Ziphius cavirostris X

whale, unidentified whale, unidentified X X

dolphin, Pacific white-sided Lagenorhynchus obliquidens X X

dolphin, Northern right whale Lissodelphis borealis X X

dolphin, Risso's Grampus griseus X

whale, killer Orcinus orca X X *

porpoise, Dall's Phocoenoides dalli X X

dolphin, unidentified dolphin, unidentified X X

1 Forney 2002; 2 CINMS, unpublished data; 3 King and DeVogelaere, MBNMS, unpublished data; 4 Benson 2002, 5 Newton et al. 2011

* It could not be determined if the individuals sighted were members of the “Endangered” southern resident killer whale population or other non-listed populations of killer whales. 

238 Table 20
Table 21. Species observed at four CBCs in Monterey Bay.

Organisms are listed by scientific name and the higher taxonomic groups to which the organisms belong are 

provided (from Barry et al. 1996). Obligate species are species that are only found at CBCs or other areas where 

chemosynthesis is possible (e.g. whale falls, hydrothermal vents). Y = yes, N = no, U = unknown, ? = information is 

uncertain.

Taxonomic Group Scientific Name Obligate

Species?

Bacteria Beggiatoa sp. Y

Cnidaria

Anthozoa Anthomastus ritteri N

Umbellula lindahli N

Stomphia sp. N

Paractinostola sp. N

Unknown sp. N

Mollusca

Polyplacophora Leptochiton sp. U

Gastropoda Unknown sp. U

Pyropelta sp. U

Neptunea amianta N

Amphissa bicolor N

Mitrella permodesta Y

Bivalvia Solemya sp. Y

Nuculana sp. N

Yoldia sp. N

Vesicomyidae Phreagena kilmeri Y

Calyptogena pacifica Y

Calyptogena packardana sp. nov. Y

Calyptogena c.f. phaseoliformis Y

Vesicomya gigas Y

Vesicomya stearnsii Y

Unknown sp. Y

Annelida

Polychaeta Eclysippe sp. N

Ampharetidae genus 1 N

Chloeia sp. N

Capitella capitata N

Brada sp. N

Pherusa sp. N

Nereis sp. 1 N

Nereis sp. 2 N

Lepidonotus sp. N

Amphitritnae sp. N

Terebellides sp. N

Pogonophora Polybrachia sp. Y

Vestimentifera Lamellibrachia barhami? Y

Arthropoda

Decapoda Paguridae-unknown sp. N

Lithodes aequispina? N

Lithodes couesi? N

Chorilia longipes N

Chionoecetes tanneri N

Munidopsis sp. Y?

Munida quadrispina N

239 Table 21
Taxonomic Group Scientific Name Obligate

Species?

Brachiopoda Terebratulina sp. N

Laqueus californianus californica N

L.c. vancouveriensis N

Glottidia albida? N

Echinodermata

Crinoidea Florometra serratissima. N

Asteroidea Thrissacanthias penicillatus N

Hippasteria californica N

Solaster borealis N

Pteraster jordani? N

Zoraster sp. N

Rathbunaster californicus N

Brisingella? sp. N

Unknown sp. N

Ophiuroidea Unknown sp. N

Asteronyx loveni N

Echinoidea Strongylocentrotus fragilus N

Brisaster latifrons N

Holothuroidea Psolus sp. N

Pannychia moseleyi N

Chordata

Agnatha Eptatretus sp. N

Chondrichthyes Apristurus brunneus N

Osteichthyes Coryphaenoides acrolepis N

Nezumia stegidolepis? N

Aprodon cortezianus N

Sebastolobus alascanus N

Sebastolobus altivelis N

Embassichthys bathybius N

Microstomus pacificus N

240 Table 21
Appendix I. Catalogue of Research Studies

Listed alphabetically by author.

Study Timing of Study Location of Study Habitat (depth; 

substrate)

Sampling Method

Anderson and 

Yoklavich 2007

October 1993 Pt. Pinos, Monterey Bay, 

California

60-260 m, hard and 

soft bottom

Manned submersible, 

video

Anderson et al. 

2009

September 2002 Cordell Bank, central 

California

Shelf, slope; hard and 

soft bottom

Manned submersible, 

video

Barry et al. 1996, 

1997

1992-1994 Monterey Bay, California 600-1000 m; soft 

bottom

ROV, sediment cores

Barry et al. 2004 June-July 2001 85 nm west of Moss 

Landing, California

3600 m ROV, PVC corrals

Becker and 

Beissinger 2006

1895-1911, 1998-

2002

Central California Open water Stable isotope chemistry

Benson 2002 May 2002 Davidson Seamount Open water Shipboard surveys

Benson et al. 2002 Summer 1996-1999 Monterey Bay, California Open water Line-transect shipboard 

surveys

Benson et al. 2007 Late summer & fall, 

1990-2003

Oregon-California border 

to Pt. Conception, 

California

Coast to 92 m 

isobath; open water

Aerial line-transect 

surveys

Benson et al. 2011 2000-2007 Pacific Ocean Open water Satellite telemetry

Bianchi 2011 September 1994 Ascension and Carmel 

Canyons, California

90-319 m, canyon; 

soft and hard bottom

Manned submersible

Bizzarro et al. 

2003

October 2001 Ascension and Año Nuevo 

Canyons, California

200-350 m, canyon; 

soft and hard bottom

Manned submersible

Bjorkstedt et al. 

1997, 2002

Upwelling seasons, 

1993 & 1994

Central California Open water Tucker trawl with 200 

μm mesh

Brown 2006 1998-2000 Monterey Bay, California 0-200 m; soft bottom Otter trawl

Burton and 

Lundsten 2006

September 2006 Pt. Sur, central California 430 m; soft bottom ROV, video

Burton and 

Lundsten 2008

May 2002, Jan/Feb 

2006

Davidson Seamount 1246-3289 m; soft 

and hard bottom; 

seamounts

ROV video and 

collection

Butler et al. 1989 

(and Wakefield 

unpubl. data)

Jan/Feb 1987, 

Mar/Apr 1988

Half Moon Bay to Purisima 

Pt., central California

100-1500 m; soft 

bottom

Bottom trawls

Cailliet et al. 1992, 

1999

1988, 1991, 1992 West of Farallon Islands, 

near Pioneer Canyon, near 

Monterey Canyon

2300-3300 m; soft 

bottom

Otter trawl, beam trawl, 

traps, camera sled, 

submersible

Carr et al. 2008 N/A Monterey Bay, California Open water ROMS model

241 Appendix I
Study Timing of Study Location of Study Habitat (depth; 

substrate)

Sampling Method

Carretta et al. 2009 2002-2007 OR/CA border to Pt. 

Conception, California

Open water Aerial surveys

Chavez 1996 1992 Monterey Bay, California Open water Temperature, salinity, 

wind, nutrients, 

chlorophyll, 

phytoplankton

Chavez et al. 2002 1989-1999 Central California Open water CTD casts, bottle 

samples, moorings, 

SeaWiFS satellite

Chavez et al. 2003 1910-2000 Eastern North Pacific Open water CO2, air and sea surface 

temperature; seabird, 

anchovy, sardine 

abundance

Croll et al. 2005 1992-1996 Monterey Bay, California Open water, canyon Shipboard surveys

CSLC & MBNMS 

2005

Aug – Oct 2003 Monterey Bay, California 25-885 m; mostly 

soft bottom

ROV, video, SmithMcIntyre grabs, push 

cores

Davis et al. 2002 1978, 1979, 1998, 

2000

Davidson, Guide, Pioneer, 

Gumdrop, Rodriquez 

Seamounts

1119-2860 m; hard 

bottom; seamounts

Multibeam and sidescan mapping; dredge 

and ROV rock 

collection

Davis et al. 2007 1976, 1978, 1979, 

2000, 2002

Pioneer and Davidson 

Seamounts

1000-3500 m; hard 

bottom, seamounts

Dredge and ROV 

collections

de Marignac and 

Burton 2003

September 2003 Cambria, central California 275 m; soft bottom Manned submersible, 

video

deMarignac et al. 

2009

June 2006 CBNMS and GFNMS 113-152 m; soft 

bottom

ROV surveys, sediment 

grab samples

Doyle et al. 2002 1980-1994 (seven 

cruises in spring)

Washington to California Open water Ichthyoplankton tows

Drazen et al. 2001 1997-1998 US/Canada border to Pt. 

Conception, California

188-1260 m; 

substrate not 

specified

Bottom trawl and tube 

traps

Drazen et al. 2003 Summer, 2000-2002 Gorda Escarpment, 

northern California

1300-3000 m; soft 

and hard bottom

ROV video

Ebert and Davis 

2007

May 2002, January 

2006

Davidson Seamount 1310-1319 m; hard 

bottom; seamounts

ROV collection

Engel and Kvitek 

1998

1994-1996 Pt. Lobos to Pt. Sur, central 

California

180 m; soft bottom Photos, videos, bottom 

grab samples, bottom 

trawling

Firme et al. 2003 Summer 1999 Pt. Arena to Pt. 

Conception, California

Open water (over 

shelf and slope)

Surface water sampling

Foote et al. 2006 May 2003, May 

2004

Southern Monterey Bay, 

California

25-40 m; soft bottom Video camera, ROV, 

sidescan sonar

242 Appendix I
Study Timing of Study Location of Study Habitat (depth; 

substrate)

Sampling Method

Forney et al. 2001 1990-1998 Monterey Bay, California Open water Bycatch observations, 

fishing effort, beach 

deposition rates

Forney 2002 July 2000 Davidson Seamount and 

MBNMS

Open water Aerial line-transect 

surveys

Forney et al. 2012 1986-2006 California Current 

Ecosystem

Open water Shipboard surveys, 

oceanographic data 

(various sources)

Forsythe et al. 

2004

Spring & fall 2000, 

summer 2001

Southern Monterey Bay, 

California

20-60 m; soft bottom ROV, video

Glover and Smith 

2003

1989-1996; literature 

review

Station M (west of Pt. Sal, 

California)

4100 m; soft bottom N/A

Goffredi et al. 

2003

1991-2001 Eastern Pacific Ocean, 

including Monterey Bay, 

California

650-2200 m; 

chemosynthesisbased communities

Manned submersible, 

ROV

Gofffredi et al. 

2004

February-October 

2002

Monterey Canyon, 

California

2891 m; soft bottom ROV, photos, sediment 

cores

Graham 1994; 

Graham and 

Largier 1997

1988-1993 Monterey Bay area, 

California

Open water Salinity, temperature, 

nutrients, currents, 

productivity 

Graham et al. 2010 March-November 

2003-2007

Bodega Bay to Monterey 

Bay, California

Open water Tucker trawl, midwater 

trawl, ecosounders

Graiff 2008 1993, 1994, 1997, 

1998 

Portuguese Ledge, Pt. Sur, 

Big Creek, central 

California

19-252 m; hard and 

soft bottom

Manned submersible, 

video

Greene et al. 2002 May-June 1998 Central California 30-3700 m; hard and 

soft bottom

Multibeam sonar

Harrold et al. 1998 1989-1991 Pt. Joe and Carmel 

Canyon, central California

Shelf/slope: 87-357 

m, canyon: 153-454 

m; soft bottom

ROV surveys

Hixon and Tissot 

2007

September 1990 Coquille Bank, Oregon 183-361 m; soft 

bottom

Visual surveys from 

manned submersible

Hunter et al. 1990 1985-1988 Half Moon Bay to Pt. 

Conception, California

69-1394 m; soft 

bottom

Bottom trawls, Nansen 

bottles 

Hutchins et al. 

1998

June 1996, June 

1997

Mendocino and Big Sur 

coasts, California

Open water, over 

shelf

Surface water sampling

Hyland 1991 1986-1989 Purisima Pt. to Pt. San 

Luis, Santa Maria Basin, 

California

90-565 m; soft 

bottom

Box cores, near-bottom 

hydrocasts

IfAME and 

MBNMS 2011

2007-2010 Pt. Ano Nuevo to Pt. 

Piedras Blancas, California

50-400 m; hard and 

soft bottom, canyon

ROV, towed camera 

sled, video transects

Jacobson and 

Vetter 1996

March-April 1988 Pt. Sur to Pt. Conception, 

central California, and 

200-1400 m; 

primarily soft bottom

Bottom trawls

243 Appendix I
Study Timing of Study Location of Study Habitat (depth; 

substrate)

Sampling Method

Oregon

Jacobson et al. 

2001a

1988-1997 Washington to Lopez Pt., 

central California

183-1280 m; 

primarily soft bottom

Commercial bottom 

trawl surveys

Johnson et al. 2001 March 1995 –

February 1996

Monterey Bay, California 40-100 m; primarily 

soft bottom

Otter trawl

Jorgensen et al. 

2009

2000-2008 Eastern North Pacific Open water; over 

nearshore and shelf

Satellite PAT tags

Keiper et al. 2005 1986-1994 and 1997-

1999

Bodega Bay to Cypress Pt., 

California

Open water, coast to 

250 km offshore

Ship transects

Kelly and Klimley 

2003

October 2000 –

February 2001

Pt. Reyes Headlands, 

California

Open water; over 

nearshore and shelf

Shipboard observations

Klimley et al. 2001 October 1997 Año Nuevo Island, 

California

Open water; over 

nearshore and shelf

Tracking with ultrasonic 

tags

Kogan et al. 2006 October 2002, 

February and July 

2003

Pillar Pt. to Pioneer 

Seamount, California

14-2000 m; primarily 

soft bottom

Side-scan sonar, ROV, 

video, sediment cores

Kuhnz et al. 2011 November 2007-

April 2008; JanuaryApril 2010

Northern Monterey Bay to 

Smooth Ridge

19-1007 m; primarily 

soft bottom

ROV video, sediment 

cores

Laidig et al. 2009 August-September 

2004

Davenport, California 65-110 m; primarily 

hard bottom

Manned submersible, 

video

Larson et al. 1994 April & May/June, 

1987 & 1988

Pt. Reyes to Monterey, 

California

Open water Midwater trawls

Lea et al. 1999 July 1978-December 

1985

Monterey Bay to Morro 

Bay, central California

10-110 m; primarily 

hard bottom

Hook-and-line, 

spearfishing

Lenarz et al. 1991 mid-May- June & 

late March - midApril, 

1983 -1990

Pt. Reyes to Monterey, 

California

Open water Modified Cobb 

midwater trawl

Levin et al. 2006 June-August 1980-

2001

U.S. west coast (WA, OR 

CA)

55-366 m; soft 

bottom

Fishery-independent 

bottom trawls

Little 2003 January 1998-

December 2001

Monterey Bay, California Open water CTD, temperature array, 

ACDP, fluorometer, net 

tows

Lundsten 2007 2006, 2007 Davidson, Pioneer and 

Rodriguez Seamounts

619-3289 m; soft and 

hard bottom; 

seamounts

ROV video

Lundsten et al. 

2009a

2006, 2007 Davidson, Pioneer and 

Rodriguez Seamounts

619-3289 m; soft and 

hard bottom; 

seamounts

ROV video

Lundsten et al. 

2009b

2006, 2007 Davidson, Pioneer and 

Rodriguez Seamounts

619-3289 m; soft and 

hard bottom; 

ROV video

244 Appendix I
Study Timing of Study Location of Study Habitat (depth; 

substrate)

Sampling Method

seamounts

Lundsten et al. 

2010

2002-2009 Monterey Canyon 382-2893 m; soft 

bottom; canyon

ROV video

Marinovic et al. 

2002

May to November in 

1997–1999

Monterey Bay, California Open water CTD casts, hydroacoustic zooplankton 

sampling, Bongo nets

MBARI 2009a 1998 Davidson, Pioneer, Guide, 

Gumdrop Seamounts

800-4000 m; hard and 

soft bottom; 

seamounts

Multibeam mapping

McClain et al. 

2009

2000, 2002, 2006, 

2007

Davidson Seamount 1246-3656 m; soft 

and hard bottom; 

seamounts

ROV video and 

collection

McClain et al. 

2010

2006 Davidson Seamount 1246-3656 m; soft 

and hard bottom; 

seamounts

ROV video and 

collection

Mullins et al. 1985 1981 Pt. Lobos to Pt. Sur, 

California

300-1400 m; soft 

bottom

Box cores, gravity cores, 

bottom photographs

Nelson et al. 2008 June 2003 West coast of Washington, 

Oregon and California

40-112 m; soft 

bottom

Sediment grabs

Newton et al. 2011 July 2010 Davidson Seamount Open water Seabird and marine 

mammal shipboard 

surveys

NMFS-NWFSC 

unpubli. data

1999-2006 MBNMS 200-1200 m Bottom trawl

Novikov 1970 1962-1965 North Pacific (Bering Sea, 

Sea of Okhotsk, Aleutian 

Islands)

200-1200 m; softbottomBottom trawl

Nur et al. 2011 1997-2008 West coast of Washington, 

Oregon and California

Open water Seabird shipboard 

surveys, oceanographic 

data (various sources)

Nybakken et al. 

1998 

1988, 1991, 1992 West of Farallon Islands, 

Pioneer Canyon, Monterey 

Canyon, California 

1085-3300 m; soft 

bottom

Camera sled, beam 

trawl, otter trawl

Okey 2003 1988-1991 Monterey Canyon head, 

California

30-500 m; soft 

bottom

Experimental 

manipulation of 

macrophyte patches, 

ROV, sediment cores

Oliver and Slattery 

1976

June 1971-April 

1973

Monterey Canyon head, 

California

<30m; soft bottom Sediment cores

Oliver et al. 2011 1999-2006 OR/CA border to Pt. 

Conception, California

30-2000 m, soft 

bottom

Sediment grabs

Paull et al. 2005a 1989-2002 Monterey Bay, California Slope, canyon; soft 

and hard bottom

ROV, video database

245 Appendix I
Study Timing of Study Location of Study Habitat (depth; 

substrate)

Sampling Method

Paull et al. 2005b 2000-2002 Monterey Bay, California Canyon; soft bottom ROV, video, sediment 

cores

Pearcy et al. 1977 1971-1975 Oregon Shelf and slope; soft 

bottom

Bongo tows, midwater 

trawls, beam trawl

Pearcy et al. 1982 1963-1976 Oregon, Washington, 

central North Pacific

400-5180 m; soft 

bottom

Beam trawl, otter trawl

Pilskaln et al. 1996 August 1989 –

December 1992

Station S1 and Station H3, 

Monterey Bay, California

Open water Subsurface sediment 

traps (450 m at S1) and 

water samples (at H3)

Pirtle 2005 September 2002 Cordell Bank, California 55-250m; hard and 

soft bottom

ROV; 27 video transects

Pyle et al. 1996 1968-1992 South Farallon Islands, 

California

Open water; over 

nearshore and shelf

Shorebased observations

Rizk 2006 2000-2006 Davidson and San Juan 

Seamounts, California 

Current, California 

Undercurrent

Open water, 

seamounts

Analysis of 

oceanographic data from 

CalCOFI, SeaWiFS, 

MBARI AUV, National 

Data Buoy Center, 

MBARI M2 buoy

Robison et al. 

2005

1994-2003 Axis of Monterey Canyon, 

California

Midwater abundance: 

100-1000 m; seafloor 

sinkers: 200-2979 m; 

soft bottom

Quantitative video 

transects; ROV 

collections

Ruhl and Smith 

2004

1989-2002 Station M (west of Pt. Sal, 

California)

4100 m; soft bottom Photo line transects; 

otter trawl; sediment 

trap

Ryan et al. 2005 August 2000 Monterey Bay, California Open water AUV surveys, ADCP, 

SST remote sensing

SAIC and MLML 

1992

September-October 

1991

Gulf of the Farallones, 

Pioneer Canyon, west of 

Half Moon Bay, California

72-1800 m; soft 

bottom

Bottom trawls, ROV 

video and photo 

quadrats

Schlining and 

Spratt 2000

July 1996-June 1997 Carmel Canyon, California 200-400 m; primarily 

soft bottom

Commercial spot prawn 

traps

Scholin et al. 2000 May-June 1998 Central California Open water Remote sensing, 

phytoplankton samples, 

nutrients, histology, 

toxicology

Schroeder and 

Love 2002

1995-2000 Southern California Bight, 

California

100-300 m; primarily 

hard bottom

Manned submersible

Sekula-Wood et al. 

2009

Nov 2004-June 2006, 

April 2006-Dec 2007

Southern California Bight, 

California

550-800m; soft 

bottom

Sediment traps

Silver et al. 1998 October 1989-

January 1993

Monterey Bay, California Open water ROV, sediment traps

246 Appendix I
Study Timing of Study Location of Study Habitat (depth; 

substrate)

Sampling Method

Sloan 1987 August 1986 Howe Sound, British

Columbia, Canada

Shelf; soft bottom Traps

Smith et al. 1989 November 1987, 

1988

Santa Catalina Basin, 

California

1,240 m; soft bottom ROV, sediment and 

bone samples

Smith et al. 2001 8 years Station M (west of Pt. Sal, 

California)

Open water, 600 and 

50 m above seafloor 

(4100 m)

Sediment traps

Spalding et al. 

2003

1999-2000 Cypress Pt. to Pt. Sur, 

central California

30-77 m; hard bottom SCUBA quadrats, ROV 

video transects

Starr et al. 1999 1999 Monterey Bay, California 5-375 m, canyon; 

primarily soft bottom

Acoustic tags, 

directional hydrophone, 

subsurface listening 

station

Starr et al. 2002b 1997-1998 Soquel Canyon, Monterey 

Bay, California

100-250 m (canyon 

flank); soft and hard 

bottom

Acoustic tags, longline 

gear, modified trolling 

gear

Starr et al. 2006 August 2004 Pt. Pinos and Pt. Sur, 

central California

70-130 m; hard 

bottom

Video strip transects 

from a manned 

submersible

Starr and 

Yoklavich 2008

2007 Soquel Canyon to Big 

Creek, central California

24-365 m; hard and 

soft bottom

Visual strip transects 

from a submersible, 

video

Sullivan 1995 May 1987-December 

1992

Pescadero Pt. to Pt. Sur, 

central California

9-274 m; hard shelf 

(bottom habitat not 

assumed, not 

specified)

Hook and line fishing 

gear

Summers and 

Nybakken 2000

1990, 1991, 1992 West of Farallones, Pioneer 

Canyon, Monterey Canyon, 

California

550-3085 m; soft 

bottom

Box cores, bottom 

trawls 

Tamburri et al. 

2000

NA (≤1999) Monterey Canyon, 

California

625 m ROV, CO2 release rig

Thistle et al. 2005 N/A Monterey Bay, California 3,250 m; soft-bottom ROV, CO2 injection, 

sediment cores, pH

Thompson et al. 

1985

1981 NW of Pt. Sur, central 

California

300-1400 m; soft 

bottom

Box cores, gravity cores, 

photo quadrats

Tissot et al. 2006 2002 Southern California 32-320 m; hard and 

soft bottom

Video transects from a 

submersible

Tolimieri 2007 1999-2002 Northern Washington to 

southern California (47°N 

to 33°N)

200-1200 m; soft 

bottom

Bottom trawls

Tolimieri and 

Levin 2006

1999-2002 Northern Washington to 

southern California (48°N 

to 32°N)

200-1200 m; soft 

bottom

Bottom trawls

247 Appendix I
Study Timing of Study Location of Study Habitat (depth; 

substrate)

Sampling Method

Toole et al. 1997 1989-1994 Oregon 50-400 m; soft 

bottom

Commercial shrimp 

trawl

Vetter and Dayton 

1998, 1999

July and August 

1995

Scripps and La Jolla 

Canyon, southern 

California

100-900 m 

(shelf/slope, 

canyons); soft bottom

Sediment cores and 

ROV

Vetter et al. 1994 1991-1992 Smooth Ridge, Monterey 

Bay, California

100-1400 m; soft 

bottom

Bottom trawls, CTDs, 

Niskin bottles

Voight and Grehan 

2000

Aug 1995, Oct 1997, 

July 1998

Cascadia Basin, Oregon 2600 m; hard bottom Manned submersible, 

ROV, video

Wakefield 1990 May 1984-May 1985 Pt. Sur, California 200-1600 m; 

primarily soft bottom

Bottom trawl

Wakefield and 

Smith 1990

May 1984-May 1985 Monterey to Pt. Sur, central 

California

400-1600 m; 

primarily soft bottom

Bottom trawl

Watters et al. 2010 1993-94, 1997-98, 

2007

Ascension Canyon to Big 

Creek Ecological Reserve, 

central California

20-365 m; primarily 

hard bottom

Delta submersible, video

Weng et al. 2007 1999-2005 Eastern North Pacific Open water; over 

nearshore and shelf

Satellite telemetry

Williams and 

Ralston 2002

1977-1998 Southern Oregon to 

southern California (43°N 

to 34°N)

50-500 m; soft 

bottom

Bottom trawl

Wing et al. 1998, 

2003

1992-1997 Gulf of the Farallones, 

California

Open water Plankton tows, 

hydrography, settlement 

surveys

Yoklavich et al. 

2000

August 1992, 

October 1993

Soquel Canyon, Monterey 

Bay, California

80-360 m; hard and 

soft bottom 

Side-scan sonar, manned 

submersible, video/laser 

transects

Yoklavich et al. 

2002

Fall 1997, Fall 1998 In and adjacent to Big 

Creek Ecological Reserve, 

central California

20-250 m; hard and 

soft bottom

Side-scan sonar, manned 

submersible, video 

transects

Zeidberg and 

Robison 2007

1989-2004 Monterey Bay, California 0-1000 m; open water ROV, video

Zimmerman 2006 June – September; 

1995, 1998, 2001

Vancouver Island, Canada 

to southern California

55-500 m; soft 

bottom

Bottom trawl

248 Appendix I
Appendix II. Catalogue of GIS Data

Figure 

#

Data Type Developer 

(Date)

Description Data Download

1 Hard substrate TerraLogic 

GIS, Inc.

(2004) 

High-resolution substrate data are not available for the entire offshore environment so 

only low-resolution substrate data are shown. Hard substrate (especially smaller patches) 

is likely to be under-represented. The hard substrate data was developed by the Center 

for Habitat Studies, Moss Landing Marine Laboratories by synthesizing geological 

seafloor characteristics for the California coast, including substrate type and areas 

defined as submarine canyons, from various sources such as side-scan sonar and 

multibeam bathymetry. TerraLogic GIS, Inc then compiled this data with seafloor data 

from Oregon and Washington to delineate the geological seafloor characteristics of the 

continental margin of the West coast. These data were developed for Pacific States 

Marine Fisheries Commission in cooperation with the National Marine Fisheries Service 

Northwest Region and the Pacific Fishery Management Council in support of an 

Environmental Impact Statement (EIS) to consider the designation and conservation of 

Essential Fish Habitat (EFH) for Pacific Coast Groundfish. These data were consolidated 

and integrated in a GIS format to support spatially explicit groundfish habitat modeling 

and impacts assessment on a coastwide scale. This is a summarized data set, it has been 

dissolved on the Induration attribute to produce a simpler file for GIS analysis.

http://marinehabitat.psmfc

.org/physical-habitat.html

1 National 

Marine 

Sanctuary 

boundaries

ONMS (2008) The National Marine Sanctuary Program manages a system of sanctuaries and other 

managed areas around the country. These GIS compatible digital files are based on the 

legal definition of each sanctuary as defined in Title 15 Code of Federal Regulations, 

Part 922 and the subparts for each national marine sanctuary. These digital files are 

provided to promote an understanding of the boundaries of each national marine 

sanctuary; they are not intended and should not be relied upon for use in navigation or 

legal purposes. 

http://sanctuaries.noaa.go

v/library/imast_gis.html

1 Depth zones TerraLogic 

GIS, Inc.

(2004)

MBNMS staff developed the depth zones using the 10-meter depth zone polygons in the 

marine areas off California. These 10 m contour data were created by TerraLogic GIS 

Inc. for Pacific States Marine Fisheries Commission in cooperation with the National 

Marine Fisheries Service Northwest Region and the Pacific Fishery Management 

Council in support of an Environmental Impact Statement (EIS) to consider the 

designation and conservation of Essential Fish Habitat (EFH) for Pacific Coast 

Groundfish. These data were consolidated and integrated in a GIS format to support 

spatially explicit groundfish habitat modeling and impacts assessment on a coastwide 

scale. NOTE: The link indicates where to download the 10-m contours but a user will 

have to select the depth zone contour themselves to create the GIS file.

http://marinehabitat.psmfc

.org/physical-habitat.html

249 Appendix II
Figure 

#

Data Type Developer 

(Date)

Description Data Download

1 Statewaters NOAA (2012) The “Statewaters” polygon represents the State Tidelands and Submerged Lands, which 

are defined as shoreline to 3 nautical miles offshore and includes Monterey Bay. Coastal 

states, such as California, were granted ownership of these lands and resources by the 

federal Submerged Lands Act of 1953. 

http://www.marinecadastr

e.gov/data/default.aspx

(under "Submerged Lands 

Act Boundary") 

1

Hillshade and 

bathymetry of 

ocean

CDFG (2001)

California Department of Fish and Game staff created this grid file from 75 original tiled

Digital Elevation Models (DEMs) that were mosaicked into one grid and resampled to 

200 meters. The DEMs were produced by Teale Data Center. Land values are coded as 

zero.

http://ccma.nos.noaa.gov/

ecosystems/sanctuaries/ca

lifornia/html/data/

2 Canyons NCCOS

(2007)

The Canyons (channels) polygon shapefile shows the location of submarine canyons and 

channels off the coast of California. Features were delineated using bathymetry, depth 

variance and 50 m contours and an existing GIS dataset developed by Greene et al. 

(1999). The base bathymetry layer is a mosaic of multibeam datasets collected for the 

California Department of Fish and Game bathymetry development project and 

resampled to 200 m. This bathymetry layer was chosen for its fine-scale spatial 

resolution and accuracy in shallow to moderate depth waters. Features greater than 5 km 

long and having a central channel more than 100 m below the surrounding seascape were 

digitized at 1:200000. Additional features were located and digitized with the help of 

existing GIS datasets developed by Greene et al. (1999) and NOAA NCCOS (2007). 

Features include both the central channel and sloping walls. In cases where two or more 

features where in close proximity and clearly part of the same benthic feature, they were 

united. Major named submarine canyons such as Monterey, Pioneer, Lucia and Sur 

canyons are included as well as 62 additional canyons and channels.

Not available

3 Seamounts NCCOS 

(2007)

Polygons outlining physiographic areas such as canyons, seamounts and banks were 

developed by NOAA National Centers for Coastal Ocean Science in 2007 using 

bathymetric products from NOAA and MBARI. Only the polygons outlining seamounts 

are shown in Figure 3.

Not available

4 & 5 Oxygen 

minimum 

zone

MBNMS 

(2007)

The Oxygen Minimum Zone boundaries were developed using the 10-meter depth zone 

polygons in the marine areas off California. These 10 m contour data were developed by 

TerraLogic GIS, Inc. for Pacific States Marine Fisheries Commission in cooperation 

with the National Marine Fisheries Service Northwest Region and the Pacific Fishery 

Management Council in support of an Environmental Impact Statement (EIS) to 

consider the designation and conservation of Essential Fish Habitat (EFH) for Pacific 

Coast Groundfish. These data were consolidated and integrated in a GIS format to 

support spatially explicit groundfish habitat modeling and impacts assessment on a 

coastwide scale. NOTE: The link indicates where to download the 10-m contours but a 

user will have to select the 600 and 1000 m contour themselves.

http://marinehabitat.psmfc

.org/physical-habitat.html

250 Appendix II
Figure 

#

Data Type Developer 

(Date)

Description Data Download

6 Chemosynthetic 

Biological 

Communities

MBNMS/

MBARI 

(2012)

Locations where Chemosynthetic Biological Communities (CBC) have been observed 

during Monterey Bay Aquarium Research Institute (MBARI) remotely operated vehicle

(ROV) surveys. Locations were obtained through a query of MBARI’s public Video 

Annotation and Reference System (VARS) for seeps and Vesicomyidae and 

descendents. It is likely that CBCs occur in other portions of MBNMS, but very little 

exploration of deep-sea habitats has occurred outside the Monterey Bay area. In 21 years 

of ROV diving (1989-2010), over 16,000 hours of high-resolution video have been 

archived, annotated, and maintained as a centralized institutional resource. This video 

library contains detailed footage of the biological, chemical, geological, and physical 

aspects of the Monterey Canyon and other areas. MBARI developed VARS to facilitate 

the creation, storage, and retrieval of video annotation records from the ROV dive tapes.

http://www.mbari.org/var

s/

8 Structureforming 

invertebrates

on hard 

substrate

MBNMS/

MBARI 

(2012)

The data layer shows the result of a MBARI VARS query in August 2012 using the 

following search terms: Hexactinellida and descendants (sponges), Cladorhizidae and 

descendants (sponges), Crinoidea, Alcyonacea, Stylasteridae, Antipatharia, and 

Scleractinia, all with descendants. See Figure 6 (above) for more information on VARS.

http://www.mbari.org/var

s/

9 NMFS trawl 

corals (1980-

2010)

Northwest 

Fisheries 

Science 

Center (2011)

Records of cold-water/deep-sea corals caught incidentally in bottom trawl surveys of 

groundfish conducted from 1980 to 2001 by the Alaska Fisheries Science Center 

(AFSC) and 2001 to 2010 by the Northwest Fisheries Science Center (NWFSC). Both 

science centers recorded some invertebrate catch as part of regular surveys of groundfish 

off the coasts of Washington, Oregon and California; however, the level of attention 

given to some invertebrate taxa (e.g., crabs, corals) has increased in recent years. Only 

records where corals were identified in the total catch are included. Each coral specimen 

was identified to the family level (when possible) by the biologists onboard; therefore 

identification was dependent on their expertise. Each tow "event" is represented by a 

point geo-referenced to either the vessel track midpoint position for AFSC surveys or 

"best position" (i.e., priority order: 1) gear track midpoint 2) vessel track midpoint, 3) 

vessel start point, 4) vessel end point, 5) station coordinates) for NWFSC surveys. Data 

were compiled by the NWFSC Fishery Resource Analysis and Monitoring Division and 

AFSC Resource Assessment and Conservation Engineering Division. Average lengths of 

tows along the seafloor for NWFSC and AFSC surveys were 1.4 and 2.6 km, 

respectively. It is important to note that these records represent only presence of corals in 

the area swept by the trawl gear. Since bottom trawl gears used during these surveys 

were not designed to sample emergent epifauna, absence of corals in the catch does not 

necessarily mean they do not occupy the area swept by the trawl gear. Trawl gear is not 

designed to sample the habitats in which many coral taxa reside, particularly those 

habitats characterized by rocky substrate and high relief. That means that the surveys 

http://pacoos.coas.oregon

state.edu/

251 Appendix II
Figure 

#

Data Type Developer 

(Date)

Description Data Download

tend to actively avoid untrawlable habitat. Also, until late 1990’s the bottom trawl 

surveys extended only to approximately 550 m and the combined shelf/slope surveys

since 2003 have surveyed habitat from approximately 55 m to approximately 1300 

meters.

10 Predicted 

habitat 

suitability for 

deep-sea 

corals

Guinotte and 

Davies (2012)

Predictive habitat models for deep-sea corals in the U.S. West Coast Exclusive 

Economic Zone were developed for NOAA-NMFS’ Office of Habitat Conservation. 

Models are intended to aid in future research/mapping efforts, assess potential coral 

habitat suitability both within and outside existing bottom trawl closures (i.e., Essential 

Fish Habitat), and identify suitable habitat in National Marine Sanctuaries (NMS). Deepsea coral habitat suitability was modeled at 500 x 500 m spatial resolution using a 

variety of physical, chemical and environmental variables known or thought to influence 

the distribution of deep-sea corals. Maxent models identified slope (1 km), temperature, 

salinity and depth as important predictors for most deep-sea coral taxa. Predicted habitat 

suitability results are not meant to identify coral areas with pin point accuracy and 

probably over-predict actual coral distribution due to model limitations and 

unincorporated variables (e.g., substrate) that are known to limit their distribution. 

Predicted habitat results should be used in conjunction with multibeam bathymetry, 

geologic maps, and other tools to guide future research efforts to areas with the highest 

probability of harboring deep-sea corals. Field validation of predicted habitat is needed 

to quantify model accuracy, particularly in areas that have not been sampled.

Not Available

12 Zones RPI (2006) The Environmental Sensitivity Index (ESI) data for central California were collected, 

mapped, and digitized to provide environmental data for oil spill planning and response. 

The zones differ in depth, distance from shore, and other habitat features. See the central 

California offshore sensitivity map for details of species present in each zone. 

http://response.restoration

.noaa.gov/esi

13 Pennatulacea 

(sea pens)

MBARI/

MBNMS 

(2012)

Data layer shows the result of a MBARI VARS query using the search term 

Pennatulacea with descendants (August 2012). See above for more information on 

VARS.

http://www.mbari.org/var

s/

15 Demersal 

rockfish 

richness

NCCOS 

(2003)

This is a point file of NMFS demersal fish trawls on the continental shelf and slope that 

took place during the summer and fall between 1977 and 2001. Species richness values 

were derived from 1336 trawls conducted between 50 and 1280 meters. Species 

richness is defined as the number of fish species present at a given location. To calculate 

rockfish richness, data were tabulated to determine the number of rockfish species

Sebastes or Sebastolobus present in each trawl. Trawls are only possible along relatively 

flat bottom areas with a minor incline and no data were available for rocky, highly 

sloped areas so rockfish might be under-represented in the trawl catch.

http://ccma.nos.noaa.gov/

ecosystems/sanctuaries/ca

lifornia/html/data/

252 Appendix II
Figure 

#

Data Type Developer 

(Date)

Description Data Download

16 Demersal fish 

richness

NCCOS 

(2003)

This is a point file of NMFS demersal fish trawls on the continental shelf and slope that 

took place during the summer and fall between 1977 and 2001. Species richness values 

were derived from 1336 trawls conducted between 50 and 1280 meters. To calculate 

demersal fish richness, data were tabulated to determine the number of species present in 

each trawl. Trawls are only possible along relatively flat bottom areas with a minor 

incline and no data were available for rocky, highly sloped areas.

http://ccma.nos.noaa.gov/

ecosystems/sanctuaries/ca

lifornia/html/data/

17 Demersal fish 

diversity

NCCOS 

(2003)

This is a point file of NMFS demersal fish trawls on the continental shelf and slope that 

took place during the summer and fall between 1977 and 2001. Diversity estimates were 

derived from 1336 trawls conducted between 50 and 1280 meters. Diversity reflects the 

distribution of species abundance within a trawl and was calculated using the Shannon 

index (H'). Trawls are only possible along relatively flat bottom areas with a minor 

incline and no data were available for rocky, highly sloped areas.

http://ccma.nos.noaa.gov/

ecosystems/sanctuaries/ca

lifornia/html/data/

20 Leatherback 

sea turtle 

critical habitat

NMFS (2012) This data layer is intended to represent the areas designated as critical habitat for the 

endangered leatherback sea turtle. This data set is meant as a general locational reference 

for these designated areas. Please refer to the Federal Register Notice titled " 

Endangered and Threatened Species: Final Rule to Revise the Critical Habitat 

Designation for the Endangered Leatherback Sea Turtle " (77 Federal Register 4170, 

January 26, 2012) for details and the legal definition. 

http://www.nmfs.noaa.go

v/gis/data/critical.htm#nw

20 Leatherback 

sea turtle 

hotspots and 

principal 

foraging area

MBNMS 

(2012)

These GIS data layers were developed by the Monterey Bay National Marine Sanctuary 

staff under the direction of Scott Benson (NMFS Southwest Fisheries Science Center) to 

portray hotspots and principal foraging area of the leatherback sea turtles. Hotspots are 

areas within the principal foraging area where leatherback sea turtles have been 

encountered most frequently. The principal foraging area extends offshore to the 200 m 

isobaths and is part of Area 1 identified in 77 Federal Register 4170, January 26, 2012. 

The preferred prey of leatherback sea turtles, brown sea nettles (Chrysaora. fuscescens), 

are found in abundance and high densities in this area particularly within upwelling 

shadows and retention areas. 

Not Available

21 Offshore 

hotspots for 

seabirds

RPI (2006) Eight zones were created by the USGS, NOAA and MLML seabird experts in order to 

depict the overall distribution of pelagic species on the Central California Offshore 

Sensitivity Map. These polygons were developed to provide a regional overview of the 

environmentally sensitive offshore resources of the Central CA coast and the MBNMS 

as part of the Environmental Sensitivity Index (ESI) which characterizes marine and 

coastal environments and wildlife by their sensitivity to spilled oil.

http://response.restoration

.noaa.gov/esi

253 Appendix II
Figure 

#

Data Type Developer 

(Date)

Description Data Download

22 Offshore 

hotspots for 

marine 

mammals

RPI (2006) Eight zones were created by the USGS, NOAA and MLML marine mammal experts in 

order to depict the overall distribution of pelagic species on the Central California 

Offshore Sensitivity Map. These polygons were developed to provide a regional 

overview of the environmentally sensitive offshore resources of the Central CA coast 

and the MBNMS as part of the Environmental Sensitivity Index (ESI) which 

characterizes marine and coastal environments and wildlife by their sensitivity to spilled 

oil.

http://response.restoration

.noaa.gov/esi

23 Upwelling 

zones

TNC (2006) To identify recurring patterns of cold water as indicators of upwelling zones, The Nature 

Conservancy (TNC) utilized 1999-2002 AVHRR (Advanced Very High Resolution 

Radiometer, 1.1 km resolution) data compiled by NOAA Coast Watch (west coast node) 

to derive average sea surface temperatures during the upwelling season (March -

September). For this analysis TNC used the High Resolution Monthly Composites 

product from NOAA which compiles AVHRR data by month for scene footprints that 

are approximately 300,000 km2

. The composites were created using night time images 

only, computing median values. A monthly composite for each month (March -

September) and each year 99-02 was downloaded making for a total of 96 files (6mo * 

4years * 4 scenes).

Not Available

24 Frontal 

probability 

index > 20% 

per quarter

Coastwatch 

(2007)

The CoastWatch Oceanic Front Probability Index measures the probability of sea surface 

temperature (SST) front formation based on data from NOAA's GOES satellites. Daily 

average SST is generated from the GOES data. Fronts are identified by applying an edge 

detection algorithm to this daily averaged SST field (Breaker et al. 2005). Pixels with 

gradients greater than 0.375 °C are classified as a front. The frontal probability index

(FPI) is then calculated as the number of times a pixel is classified as a front divided by 

the number of cloud free days per month. Pixels with a monthly FPI of 20% or greater 

are selected and averaged for all months within a given season (Jan-March, April-June, 

July-Sept., Oct-Dec.) for the entire duration of the data set (2001-2006). Nearshore areas 

are not surveyed by the GOES data.

Not Available

254 Appendix II
Figure 

#

Data Type Developer 

(Date)

Description Data Download

25 Predicted 

hotspots of 

multispecies 

seabird 

aggregations

PRBO (2012) Data from at-sea surveys of seabirds over an 11-year period (1997-2008) were combined 

with information on habitat features (bathymetry and oceanography) to predict hotspots 

for seabirds (Nur et al. 2011). Single species model predictions for 16 species were 

combined to identify potential multispecies hotspots using three criteria: abundance, 

importance, and persistence. The spatial scale of the models was 38.5oN to 35oN from 

the shoreline to 600 km offshore. Seabird species: Black-footed Albatross (Phoebastria 

nigripes), Bonaparte's Gull (Larus philadelphia), Brandt's Cormorant (Phalacrocorax 

penicillatus), Brown Pelican (Pelecanus occidentalis), Cassin's Auklet (Ptychoramphus

aleuticus), California Gull (Larus californicus), Common Murre (Uria aalge), Forktailed Storm-Petrel (Oceanodroma furcata), Glaucous-winged Gull (Larus glaucescens), 

Heermann's Gull (Larus heermanni), Herring Gull ( Larus argentines), Leach's StormPetrel (Oceanodroma homochro), Red-necked Phalarope (Phalaropus lobatus), Sabine's 

Gull (Xema sabini), Sooty Shearwater (Puffinus griseus), and Western Gull (Larus 

occidentalis).

The “Abundance” values represent the summed, standardized abundance for all 16 

seabird species as number of birds per square kilometer.

To calculate ‘importance’ for each of the 16 species, PRBO staff ranked all prediction 

cells according to the predicted abundance of that species by month and year. Then they 

identified the smallest set of cells that together constituted 25% of the species’ total 

predicted abundance within the study region. These "highest predicted density" cells 

were considered to indicate a species’ "core area" and were assigned a score of 2. The 

set of cells that together made up the next quartile of the species’ total abundance based 

on predicted density, were considered important "shoulder" areas and were assigned a 

score of 1 The remaining 50% of cells received a score of 0. Importance was calculated 

for each species and a weighted average was then calculated over all species. The 

weighting function was scaled to have mean = 1. The product of the weighting factor 

and the number of core cells for each species was the same across all species. 

Importance was calculated separately by month and year, and then results were averaged 

over all years and months.

‘Persistence’ was first calculated for individual species for each month separately 

(February, May, July, October). The number of years (out of 11) that a cell was in the 

top 5 percent of predicted abundance for that species was scored (i.e., in the 95th 

percentile of all prediction cells for that month). The persistence score for a cell was then 

averaged over species and months.

Not Available

255 Appendix II
Figure 

#

Data Type Developer 

(Date)

Description Data Download

26 Cetacean 

modeled 

species 

densities

Barlow et al.

(2009), 

Forney et al. 

(2012,)

Becker et al. 

(in review).

NMFS staff used data from 16 shipboard cetacean and ecosystem assessment surveys to 

develop habitat models to predict density for 12 cetacean species in the California 

Current Ecosystem (CCE). The CCE study area included the offshore area South of 48oN 

(Puget Sound in WA) and North of 30oN (US-Mexico border) and out to 131͝oW (about 

300 nautical miles offshore) (Hamilton et al. 2009). All data were collected by NOAA’s 

Southwest Fisheries Science Center (SWFSC) from 1986-2008 using accepted, peerreviewed survey methods. The expected number of groups seen per transect segment and 

the expected size of groups were modeled separately as functions of habitat variables. To 

evaluate predictive power, Generalized Additive Models (GAMs) with nonparametric 

smoothing functions were used to build the best-and-final models using 5 km transect 

segments. Oceanographic habitat data from in situ measurements and remotely sensed 

measurements from satellites were integrated in the final models. Only sea surface 

temperature (SST) and measures of its variance were available from remotely sensed 

sources, whereas the in situ measurements also included sea surface salinity, surface 

chlorophyll and vertical properties of the water-column. In some years, in situ data also 

included net tows and acoustic backscatter. Model predictions were then used in 

standard line-transect formulae to estimate density for each transect segment for each 

survey year. Predicted densities for each year were smoothed with geospatial methods to 

obtain a continuous grid (25 by 25 km grids) of density estimates for the CCE. These 

annual grids were then averaged to obtain a composite grid that represents the best 

estimates of cetacean density (animals per km2) over the years in the CCE. 

http://cetsound.noaa.gov/c

da.html

27 Stratified 

estimated 

harbor 

porpoise 

density

SWFSC 

(2009)

Stratified estimates of harbor porpoise density were compiled from species-specific 

aerial surveys from 2002-2007. Two sets of transects, one inshore (out to the 90 m 

isobath) and another offshore (out to roughly the 200 m isobath) were surveyed to ensure 

that all harbor porpoise habitat was included in the surveys.

http://cetsound.noaa.gov/c

da.html

256 Appendix II
Appendix III. Benthic-Pelagic Coupling

Benthic-pelagic coupling - the two-way exchange, or flux, of matter between the benthos and the 

overlying water column - is important for both benthic and pelagic compartments. This flux 

occurs through the sinking of non-living organic matter and the active movement of organisms 

both upward into the water column and downward to the seafloor. Sinking, non-living organic 

matter comes in numerous forms (reviewed by Smith and Demopoulos 2003) including: 1) very 

small organic particles (e.g., particulate organic carbon and particulate total nitrogen); 2) small 

aggregates of detritus that consist of dead plankton, discarded feeding structures, fecal pellets, 

and other organic debris – also called marine snow; 3) detritus from marine plants and algae –

also called macrophyte detritus); and 4) carcasses of large animals (e.g., fishes, seabirds, marine 

mammals). 

Most of the small particles and aggregates of marine snow that reach the deep seafloor are less 

than 5 mm in size and sink slowly - their descent may last for months (Robison et al. 2005). The 

quality and quantity of sinking food material varies both temporally and spatially. Pulses of 

small particle flux are coupled to periods of high surface productivity (Pilskaln et al. 1996, Smith 

and Demopoulos 2003). Areas of high surface productivity (e.g., upwelling zones) and areas 

where surface and mid-water planktonic species are concentrated (e.g., retention zones, frontal 

zones) tend to have higher rates of flux of organic matter to the seafloor. Shelf and slope 

sediments beneath upwelling zones typically are more enriched with organic matter and the 

availability of organic matter appears to play a dominant role in controlling regional variations in 

biotic structure of benthic faunal communities (Smith and Demopoulos 2003).

In addition to small sinking particles, organic matter is delivered passively to the benthos in 

larger parcels ranging in size from drifting algal mats to fish carcasses to whale carcasses. These 

depositional events deliver large quantities of organic matter to the seafloor and support 

associated benthic communities for a few weeks, in the case of macroalgal detritus, up to many 

years, in the case of a whale fall (Smith and Demopoulos 2003). In general, deposition of large 

particles is not predictable over space or time. However, macroalgal detritus tends to accumulate 

in certain areas, such as the heads of submarine canyons down current from kelp beds.

Flux of organic matter between benthic and pelagic compartments also occurs through the active 

movement of organisms. The deep scattering layer is composed of a loose assemblage of pelagic 

species that moves up to surface waters at night and down to the mesopelagic layer during the 

day in a process called diel vertical migration. Animals that undertake diel vertical migration 

(e.g., krill, jellyfish, sergestid shrimp, and lanternfishes) feed at the surface and carry the food in 

their guts down to midwater depths. This process greatly increases the export of carbon from the 

surface to the meso- and bathypelagic waters (reviewed in Raeffiella et al. 2003). In addition, 

fecal pellets that are voided at depth during the day greatly increase the flux of carbon from the 

surface to the seafloor. It has been estimated that, in the Pacific, some 43% of the individuals and 

47% of the biomass migrate from below 400 m by day to above this depth at night (Maynard et 

al. 1975, cited in Raeffiella et al. 2003). 

Upward flux occurs when pelagic organisms feed on demersal organisms. For example, northern 

elephant seals and sperm whales dive hundreds of meters to feed on demersal fishes. Jellyfish 

have been observed "feeding" on the bottom and then re-entering the water column and a large 

257 Appendix III
isopod was observed grabbing a larvacean house off the bottom and taking it up into the water 

column presumably to feed on it (Bruce Robison, pers. comm.). In addition, many benthic 

organisms, such as infaunal and epifaunal invertebrates and demersal fishes, release buoyant 

eggs or larvae into the water column (see Wakefield and Smith 1990 for an example). Pelagic 

larval fishes and invertebrates spend weeks to months (depending on the species) in the water 

column, often consuming small phytoplankton and zooplankton and being consumed by larger 

pelagic organisms. The settlement of the surviving larvae as benthic juveniles is another 

significant source of downward flux of organic matter.

258 Appendix III
Appendix IV. Definition of Terms

Assemblage: a general term for species that co-occur in a particular area without regard to their 

ecological interactions or their relative abundance.

Bathypelagic Zone: aphotic layer of the open sea, from 1,000 meters to at least 4,000 meters 

deep.

Benthic: relating to the seafloor

Benthic-Pelagic Coupling: the two-way exchange, or flux of matter, between the benthos and 

the overlying water body. This flux occurs through sinking of non-living organic matter (e.g. 

plankton tests, fecal pellets, animal carcasses, drift algae) and the active movement of organisms.

Benthopelagic: organisms swimming or drifting in the waters immediately over the seafloor

Biogenic Habitat: the physical structure of the habitat is created by living organisms.

Biological diversity (biodiversity): a measure of the variability among living organisms from all 

sources including diversity within species, between species and of ecosystems. 

Biomass: The total quantity or weight of organisms in an area.

Chemosynthesis: the process by which organisms use energy from chemicals, such as hydrogen 

sulfide, to convert water and carbon dioxide into organic carbon (carbohydrates). 

Chemosynthetic organisms found in the ocean are bacteria, but many of these bacteria live inside 

larger organisms (such as clams or tube worms).

Consumers: an organism that feeds on other living organisms.

Demersal: close to or lying on the bottom, but not attached or buried.

Deposit feeder: animal that feeds on organic matter that settles on the bottom.

Detritivores: animals that feed primarily on detritus.

Detritus: decaying organic matter found in bottom sediments. 

Epifauna: animals that live on the surface of the seafloor.

Epipelagic Zone: photic layer of the open ocean usually from the surface to about 200 meters 

deep.

Facilitation: a type of species interaction that benefits at least one of the participants and causes 

harm to neither. Mutualism and commensalism are types of facilitation.

Federal Waters: ocean waters between 3 and 200 nautical miles offshore, which comprises the 

Exclusive Economic Zone (EEZ).

Fauna: the animals of particular habitat or area.

Feeding Ground: An area used by a species for feeding.

Filter feeder: animals that feed by straining suspended matter and food particles from water, 

typically by passing the water over a specialized filtering structure (a sub-group of suspension 

feeders).

259 Appendix IV
Ichthyoplankton: includes fish eggs, newly hatched eggs, young fish, and adults of small fish 

that are not strong swimmers.

Infauna: animals that live burrowed in the sediments.

Macrofauna and meiofauna: animals that live on or in the sediments and are not readily visible 

to the naked eye. Meiofauna are smaller than macrofauna, but the size limit that distinguishes the 

groups is not agreed upon universally.

Macrophyte: plant or alga that is easily seen without aid of a microscope.

Marine Snow: aggregations of detritus, visible to the naked eye, that consist of dead organisms, 

discarded feeding structures, fecal pellets, and other organic debris. In the deep ocean, marine 

snow is a continuous shower of mostly organic detritus that originates in the productive photic 

zone. 

Megafauna: animals readily visible to the naked eye. This group is comprised mainly of the 

echinoderms (e.g. sea stars, sea cucumbers), arthropods (e.g. crabs, shrimp), bottom fishes, 

cnidarians (e.g. anemones, sea pens) and larger polychaetes (segmented worms).

Mesopelagic Zone: disphotic zone from 200 to 1,000 meters deep, where little light penetrates 

and the temperature gradient is even and gradual with little seasonal variation. This zone 

contains an oxygen minimum layer and usually has the maximum concentrations of the nutrients 

nitrate and phosphate. It overlies the bathypelagic zone and is overlain by the epipelagic zone.

Migratory Corridor: a path used by a species to move from one area to another (e.g., between 

spawning or breeding grounds and feeding grounds).

Nekton: ocean organisms that are active swimmers, such as fishes, squid, and marine mammals.

Nursery Habitat: a habitat in which the juvenile phase of one or more species congregates. 

Habitats used as nurseries may provide advantages to juveniles, such as increased growth rates or 

lower predation rates, compared to non-nursery habitats.

Overfished: stock size below 25% of unfished biomass.

Oxygen Limited Zone (OLZ): the region immediately above or below an OMZ with an oxygen 

concentration of <60 μmol/kg

Oxygen Minimum Zone (OMZ): zone in which oxygen saturation in seawater is at its lowest

(<0.5 ml/L or <20 μmol/kg). This zone occurs at depths of about 600 to 1,000 meters, depending 

on local circumstances.

Pelagic: inhabiting the open ocean, especially near the surface.

Photosynthesis: process of using the energy in sunlight to convert water and carbon dioxide into 

organic carbon (carbohydrates). Photosynthetic organisms found in the ocean are phytoplankton, 

algae, and marine plants. 

Phytoplankton: the photosynthetic component of the plankton consisting primarily of singlecelled algae and bacteria. 

Planktivores: animals that feed primarily on plankton.

Plankton: plants and animals that float or drift in the water. 

260 Appendix IV
Primary Production: conversion of inorganic carbon (e.g, carbon dioxide, methane) into 

organic carbon (food). Photosynthesis and chemosynthesis are two processes used by organisms 

to complete this conversion.

Productivity Hotspot: A place of higher than usual productivity.

Sebastomus Group: natural assemblage of rockfishes (and valid subgenus of the genus 

Sebastes) sharing various morphometric characteristics, most notably 4-5 white dorsal blotches. 

Species in this group include, greenblotched, greenspotted, pink, pinkrose, rosethorn, rosy, 

starry, and swordspine rockfishes.

Spawning/Breeding Ground: An area used by a species for reproduction.

Species Composition: The assemblage of species that are characteristic of an area.

Species Diversity: there are several measure of diversity, the simplest index is species richness

(the number of species in a system); other indices include a measure of abundance, such as

evenness (the relative abundance of each species in a system). These measures do not detect 

species substitutions or replacements and, thus may not capture substantial changes in biological 

systems.

State Waters: ocean waters between the coastline and 3 nautical miles offshore. There are, 

however, exceptions to the distance offshore, as in Monterey Bay.

Suspension Feeder: an animals that feeds by straining suspended matter and food particles from 

water.

Topography: the surface features of an area

Trophic: the feeding habits or food relationship of different organisms in a food chain

Upwelling: process by which water rises from a deeper to a shallower depth, usually as a result 

of offshore surface water flow. It is most prominent where persistent wind blows parallel to a 

coastline so that the resultant Ekman transport moves surface water away from the coast.

Zooplankton: animal component of the plankton consisting of both microscopic and much 

larger organisms. 

261 Appendix IV
Appendix V. List of Acronyms

AFSC: Alaskan Fisheries Science Center

ASFA: Aquatic Sciences and Fisheries Abstracts

CBCs: Chemosynthetic Biological Communities

CDFG: California Department of Fish and Game

CESA: California Endangered Species Act 

DA: Domoic Acid

DSMZ: Davidson Seamount Management Zone

EFH: Essential Fish Habitat

EIS: Environmental Impact Statement

ESA: federal Endangered Species Act

GIS: Geographical Information Systems

HAB: Harmful Algal Bloom

IfAME: Institute for Applied Marine Ecology

IUCN: World Conservation Union

MARS: Monterey Accelerated Research System

MBARI: Monterey Bay Aquarium Research Institute

MBNMS: Monterey Bay National Marine Sanctuary

MLML: Moss Landing Marine Laboratories

MLPA: Marine Life Protection Act (in the state of California)

MPA: Marine Protected Area

NCCOS: National Centers for Coastal Ocean Science

NMFS: National Marine Fisheries Service

NOAA: National Oceanic and Atmospheric Administration

NWFSC: Northwest Fisheries Science Center (part of NMFS)

OLZ: Oxygen Limited Zone

OMZ: Oxygen Minimum Zone

PDO: Pacific Decadal Oscillation

PFMC: Pacific Fisheries Management Council

POC: Particulate Organic Carbon

POM: Particulate Organic Matter

262 Appendix V
PTN: Particulate Total Nitrogen

ROV: Remotely Operated Vehicle

SWFSC: Southwest Fisheries Science Center (part of NMFS)

UCSC: University of California, Santa Cruz

USGS: United States Geological Survey

VARS: Video Annotation and Reference System

VOM: Vertical Ontogenetic Migration

YOY: Young-of-the-Year

263 Appendix V
Appendix VI. List of Persons Providing Personal Communication

James Barry, Monterey Bay Aquarium Research Institute

Scott Benson, National Marine Fisheries Service, Southwest Fisheries Science Center

Andrew DeVogelaere, Monterey Bay National Marine Sanctuary

Karin Forney, National Marine Fisheries Service, Southwest Fisheries Science Center

Charles Paull, Monterey Bay Aquarium Research Institute

John Oliver, Moss Landing Marine Laboratories

Steve Ralston, National Marine Fisheries Service, Southwest Fisheries Science Center

Bruce Robison, Monterey Bay Aquarium Research Institute

Mary Silver, University of California Santa Cruz

Curt Storlazzi, United States Geological Survey, Pacific Coastal and Marine Science Center

Robert Vrijenhoek, Monterey Bay Aquarium Research Institute

Curt Whitmire, National Marine Fisheries Service, Northwest Fisheries Science Center

264 Appendix VI