pacificrockyintertidal.org
Overview − pages 1 & 2

Assessing and Monitoring 

Marine Disease in Black Abalone 

and Sea Stars − page 3 

Informing Impact Assessment 

in Coastal Oil Spills − page 4

Climate Change Impacts and 

Community Resilience − page 5

Establishment and Effectiveness 

of Marine Protected Areas in 

California − page 5

MARINe and Citizen Science

− page 6

MARINe’s Sustainability 

− page 6

CONTENTS:

Rocky intertidal shores, commonly called “tidepools”, occur at 

the interface between the terrestrial and marine environments. 

The unique physical complexity of this system lends itself to high 

biological diversity, including many species found only within this 

narrow band of coastal habitat. The accessibility of rocky shores provides 

people with an important connection to the marine environment, but also 

makes them vulnerable to degradation from human activities. Natural 

variation in environmental conditions and community structure in rocky 

intertidal systems can occur on the scale of months, years, and even decades. 

Therefore long-term, well-designed monitoring programs are essential for 

distinguishing between natural and human-induced changes.

At the core of the Multi-Agency Rocky Intertidal Network (MARINe) program 

is a simple and inexpensive, yet statistically sound approach to collecting 

long-term monitoring data. This approach has enabled the program to grow 

into a multi-organization consortium that monitors sites along the entire 

Pacific Coast of North America, from Alaska to Mexico (see map, opposite). 

The MARINe monitoring approach provides a wealth of information about 

the structure and dynamics of rocky intertidal communities along the 

Pacific Coast of North America. It is the largest and longest running program 

of its kind: sites in many regions have been sampled for 20-30 years. 

Here we provide an overview of the MARINe program and highlight how 

our data have been used to inform resource managers at the local, state, 

and federal levels about the impacts of both natural and human-induced 

disturbances.

Cover photo credits:

(clockwise from top left)

Dave Lohse, Dan Orr,

Dave Lohse, Melissa Douglas

Citation:

C. Melissa Miner and Alison Kendall 

Swearingen. 2020. Multi-Agency Rocky 

Intertidal Highlights. Santa Cruz (CA): 

University of California Santa Cruz report 

for the US Department of Interior, 

Bureau of Ocean Energy Management. 

OCS Study BOEM 2020-053.

Distinct vertical zones along the shoreline are formed by “foundation” species, such as 

rockweeds and mussels, which shape communities by creating habitat for many other 

species. As seen from low tide looking onshore in this panoramic photo of Coquille Point, 

Oregon where a MARINe biodiversity survey was being carried out (July 2019).

OVERVIEW

Rockweed zone

Mussel zone

pacificrockyintertidal.org

For more information 

about MARINe please visit:

MARINe’s “core” monitoring approach focuses 

on foundation and keystone species, with the 

idea that changes in these species will have 

broad-reaching community impact. This targeted 

approach allows us to detect community change 

at effort levels that can be sustained for the 

long-term. 

Layered upon this “core” approach are the 

goals of documenting species richness and 

changes in the distribution of species within 

and among sites over time. Our biodiversity 

surveys are designed to capture information 

about the rocky intertidal community as a 

whole (rather than targeted species).

Targeted species are monitored 

annually or semi-annually within 

fixed plots (above). Surveying 

equipment is used to collect 

topographic information along 

biodiversity sampling transects 

(below).

Biodiversity surveys require a high-level of expertise for species identification 

and are done on a less frequent schedule, typically every 5-7 years.

California Channel Islands

British Columbia

WA

OR

CA

Mexico

AK

0 150 300

miles

0 15

miles

30

Pacific Ocean

Species composition of rocky intertidal 

communities is influenced by many factors 

including geography (which includes physical 

features such as rock type and climate) and 

oceanographic currents (important for key 

drivers such as larval recruitment, water 

temperature and nutrient availability). 

The abundance and composition of species 

within neighboring sites tend to be more similar 

to one another than to those occurring farther 

away, largely because key drivers of community 

structure tend to be similar at a regional level. 

Patterns of community similarity at MARINe sites 

are indicated here by site marker color.

Photo credit: Dave Lohse

Photo credit: Melissa Miner

Photo credit: Dave Lohse

1 2
Figure 2: Changes in species composition at Alcatraz, a long-term monitoring site within San Francisco Bay 

that was impacted by the Cosco-Busan 

spill. Note the decline in abundance 

of the rockweed, Fucus, accompanied 

by a corresponding increase in bare 

rock and the opportunistic species 

complex, Ulva/Enteromorpha.

2005 (pre-spill)

2009 (post-spill)

Red algae

Fucus (rockweed)

Rock

Filamentous algae

Non-coralline crust

Mastocarpus (Turkish washcloth)

Prionitis (bleach weed)

Blue-green algae

Chthamalus (acorn barnacle)

Pyropia (laver)

Balanus (acorn barnacle)

Brown algae

Mytilus californianus (CA mussel)

Ulva/Enteromorpha (sea lettuce)

Odonthalia (sea brush)

0.0 0.1 0.2 0.3

Proportion cover

TAXA

Above, a trained team of intertidal experts carry out 

MARINe surveys to assess potential impacts from the 

Refugio Oil Spill at Tajiguas Beach (left) and El Capitan 

State Beach in California (right). Below, rocks containing 

Fucus are collected from the intertidal near Golden Gate 

Fields to be transplanted to Point Isabel.

Above, a healthy black abalone specimen 

(top) clings tightly to the rocks, while a 

sick abalone withers away inside its shell. 

Below, a vibrant population of ochre stars 

whose numbers dropped dramatically 

due to SSWS, a disease causing their 

tissues to waste away (bottom). 

Photo credit: Dave Lohse

Photo credits: Rachael Williams

Photo credit: Avrey Parsons-Field Photo credit: Christy Bell

Impacts of Oiling on the Seaweed, Fucus distichus

Oil spills within San Francisco Bay, CA resulted in a loss of the 

rockweed Fucus distichus, an important “foundation” species that 

provides food and shelter to a suite of other species (Figure 2). 

This rockweed is highly sensitive to both oiling and the processes used to clean-up oil spills. Because juvenile rockweeds do not 

disperse far from the parent plant, natural recovery is slow. To 

help mitigate Fucus loss, a restoration effort supported by postspill settlement funds was implemented at three sites within San 

Francisco Bay. Adult plants were transplanted to areas heavily 

impacted by oiling, with the hope that these adults would then 

“seed” the restoration areas. Fucus proved to be a challenging 

species to outplant, and the contribution of this mitigation effort 

to its overall recovery had mixed results. However, our findings 

underscore the sensitivity of particular species to oiling and the 

challenges associated with post-impact recovery efforts.

MARINe data were used to assess the impact of four oil spills 

that have occurred since 1997 – two on the outer coast of 

Santa Barbara County, CA (Torch-Platform Irene and Plains), 

and two in San Francisco Bay (Cosco Busan and Dubai Star). 

Consistency in protocols and personnel, and active incident 

command and response training means that MARINe mobilizes 

quickly when spills occur.

Rocky intertidal communities are dynamic systems; thus, a common challenge in impact assessment is distinguishing natural 

fluctuations in species’ abundances from changes due to human

-induced injuries. The power of the MARINe approach comes 

from the long-term collection of comparable data across sites 

spanning broad geographic scales. This allows for comparison 

of species trends between sites inside and outside of an impact 

zone, to determine whether the post-spill trajectories of trends at 

sites within the impact zone fall outside of the “normal” range.

A primary driving force behind the creation of MARINe was the desire to establish a baseline dataset that 

describes the natural condition (i.e., structure and composition) of intertidal communities. After many years 

of consistent data collected, MARINe has compiled a vast, comprehensive dataset that has enabled researchers 

to assess injuries to these ecosystems when oil spills occur. Indeed, MARINe data have been used to assess 

impact in all major oil spills that have occurred in California since 1997.

Informing Impact Assessment of Coastal Oil Spills 

Sea Stars Impacted by Coast-Wide Wasting Syndrome

In 2013-2015 sea stars along the entire North American Pacific coast experienced a massive die-off due to a mysterious disease called “sea star wasting 

syndrome” (SSWS). One heavily impacted species was the keystone intertidal 

predator, Pisaster ochraceus (ochre star). 

MARINe surveys revealed unprecedented declines of ochre stars across nearly 

the entire geographic range of the species. The severity of decline was higher in 

southern vs. northern regions, and this disproportionate impact has intensified 

since the initial decline due to substantial differences in ochre star recruitment 

in the north vs. south. Low levels of symptomatic sea stars are still present 

throughout the impacted range; thus, the outlook for population recovery is 

uncertain.

Figure 1: Long-term black abalone data at 3 sites that represent regional patterns.

Mainland populations south of Monterey Co. (red line) and on some Channel Islands

experienced massive declines and have not recovered. Mainland populations to the

north (blue) have been largely unaffected by WS. Recovery has been documented at

some Channel Island sites (green line), but populations are not yet approaching preWS levels. 

0

100

200

300

400

500

1992 1996 2000 2004 2008 2012 2016 2020

22 16 14

# of sites showing similar trend pattern:

Year

Total count

LONG TERM BLACK ABALONE DATA

Photo credit: Kari Eckdahl

Photo credit: Nate Fletcher

Photo credit: MARINe/UCSC

Photo credit: Ben Miner

Patterns of Decline and Recovery in Endangered Black Abalone

MARINe surveys documented the spread and impact of withering syndrome 

(WS) in black abalone populations in California as far north as the San Luis 

Obispo/Monterey County line. These long-term data (Figure 1), provided strong 

support for the placement of black abalone on the endangered species list in 

2009. Our surveys were integral to the development of a recovery plan for this 

species and will provide the data necessary for agencies to determine when 

de-listing criteria have been met.

Designing protocols that adequately capture the effects of disease on key aspects of focal species’ 

populations (i.e., long-term trends, size structure, outlook for recovery) has been integral to MARINe’s 

monitoring approach. Two important examples that illustrate the impact of our work can be found in 

the dramatic stories of population decline in the black abalone, Haliotis cracherodii, and the ochre star, 

Pisaster ochraceus.

Assessing and Monitoring Marine Disease

3 4
2007 2009 2011 2013 2015 2017

60

64

68

72

76

80

84

88

North

Central

South

Channel Islands

Year

Mean Regional Resilience

PATTERNS OF RESILIENCE

Membership requirements are simple—

partners can contribute through data collection, 

field support, and/or funding. 

Data compatibility among sites is accomplished 

through vetted core protocols. 

A centralized database assures data accessibility 

and compatibility across sites and over time.

Data are accessible from the website (see 

example of GIS mapping tool on right), enabling 

extensive use by students (grade school-grad 

school), researchers, citizen stakeholders, and 

resource managers.

Over 30 member organizations contribute to a 

geographically broad network, which allows for 

greater context when assessing local trends.

Network structure allows for rapid mobilization 

of teams to respond to oil spills and other 

disturbance events.

Long-term trends for “indicator species” 

that are sensitive to warming water 

temperatures, such as the sea palm, 

Postelsia palmeformis (above), might 

provide an early warning of changing 

conditions. Photo credits: Dave Lohse

GIS data display tool showing distribution 

and abundance of the mussel, Mytilus 

californianus (above). Larger, darker blue 

bubbles indicate more mussels. A healthy 

population of Mytilus at a site on Catalina 

island (right). Photo credit: Jay Smith

Since its inception in 1997, MARINe has grown from a partnership among a handful of federal agencies and universities 

monitoring sites in southern California to a collaboration among a diverse group of organizations monitoring over 200 

sites from Alaska to Mexico. Successful growth has been based on these key foundational components:

MARINe’s Sustainability

A group of citizen scientists (left) collecting sea star size and count data near 

Point Whitehorn, Washington. The sunflower star, Pycnopodia helianthoides

(right), once a common sight in the low intertidal, was severely impacted 

by SSWS. 

Photo credits: Melissa Miner

The heavily publicized 2014 Sea Star Wasting Syndrome (SSWS) event generated increased interest 

from the general public in the MARINe program. 

During the event, users accessed our website 

to view coast-wide trends in long-term sea star 

abundance, report incidents of disease, and find 

resources for symptom identification and categorization. We in turn, formed new partnerships 

with citizen science groups, generating new 

opportunities for long-term sea star data collection in areas previously not covered by MARINe. 

These collaborations have refined our ability to 

track the emergence (and re-emergence) and 

impact of SSWS along the entire west coast of 

North America.

Citizen science programs offer community members the opportunity to contribute to research and 

conservation efforts. MARINe has formed partnerships with many west coast programs to better document 

the extent and impact of sea star wasting.

MARINe and Citizen Science 

MPA’s are important for providing 

protection to harvested species such 

as the owl limpet, Lottia gigantea.

MARINe Biodiversity Surveys were a primary data source used in the Marine 

Protected Area (MPA) Network design and planning process in California to 

estimate the area required to include 90% of the available biodiversity for intertidal habitats. These methods estimated that approximately 0.5 linear miles 

of rocky intertidal habitat must be encompassed by an MPA to ensure ecological 

representation. 

MARINe monitors 161 sites, both inside and outside MPAs across the entire 

MPA network in California. Many were established long before MPA protections 

were put in place, resulting in a crucial data set for: 1) assessing the effectiveness of MPAs, 2) prioritizing strategies for adaptive management of the MPA 

Network, and 3) informing California 

Department of Fish and Wildlife’s 

long-term monitoring plan.

Establishment and Effectiveness of 

Marine Protected Areas in California

A preliminary analysis based on our biodiversity surveys suggests that intertidal 

community composition has shifted poleward —the direction expected due to 

impacts of climate change—over the past 15 years. 

There are substantial regional differences in the ability of rocky intertidal 

communities to resist or recover from change. Change in response to warm 

water disturbance events tended to be less extreme at sites in northern 

(central California to Washington) vs. southern regions (southern California 

and Channel Islands) as seen in Figure 3. 

Resilience was linked to presence of the mussel, Mytilus californianus, an 

important foundation species in this system. Mussel beds in southern regions 

experienced greater decline than those in northern regions during the period 

examined. 

Long-term data were used to explore how rocky intertidal communities responded to perturbation in the form of periodic warm water events. The ability 

to distinguish resilient from non-resilient sites and the factors likely responsible 

for such patterns have significant implications for resource management and 

conservation. Our findings suggest that:

Resilience, as defined by scientists, is a system’s ability to resist change or recover quickly following 

a disturbance. MARINe data are well-designed for detecting shifts in species distributions that might 

result from impacts due to a changing climate, such as sea level rise or elevated water temperatures. 

Our data have also been used to assess community-level resilience to climate change impacts.

Climate Change Impacts and Community Resilience 

Figure 3. Patterns of resilience over time, 

as represented by annual mean similarity (annual regional resilience) values 

across sites within each region. Sites were 

grouped into regions based on previously 

described biogeographic provinces as 

follows: “North” (Washington, Oregon, 

northern California: 19 sites), “Central” 

(San Francisco to Point Conception, CA: 

20 sites), “South” (Point Conception to 

San Diego, CA: 16 sites), and the northern 

“Channel Islands” off the coast of Santa 

Barbara, CA (19 sites).

5 6
Many other regional groups partner with MARINe to collect 

compatible data at a coast-wide scale. 

Please see pacificrockyintertidal.org for a complete list.

The Ocean Protection Council (OPC) has funded 

sampling and data management support for numerous 

sites in CA to help inform CDFW’s management of the 

state’s 124 MPA’s and support policy decisions.

The Partnership for Interdisciplinary Studies 

of Coastal Oceans (PISCO) funded in large part by 

the David and Lucile Packard Foundation, has been a 

long-time MARINe partner, supporting numerous sites 

in CA and providing database funding.

The Bureau of Ocean Energy Management (BOEM) 

assists with data collection and provides funding to 4 

universities to monitor 24 sites in California and 8 in 

Oregon. BOEM also contributes roughly one third of 

the database development and maintenance costs. 

Survey methods from the National Park Service 

(NPS), one of the original MARINe partners, provided 

the foundation for the development of MARINe core 

protocols. NPS supports monitoring efforts at 6 

sites in WA, 1 in OR, and 39 in CA. 

US Navy (Navy Marine Ecology Consortium) has 

funded sampling and data management support for 

8 sites on San Clemente and San Nicholas Islands and 

2 mainland sites in San Diego. 

MARINe is a true collaborative effort, with funding and other support coming from over 30 

different federal, state, university and private organizations, including these primary funders: 

Acknowledgements

A MARINe field crew headed for breakfast after an early morning of sampling Photo credit: Christy Bell

at Ecola State Park on the Oregon coast.

Study collaboration and funding were provided by the US Department 

of the Interior, Bureau of Ocean Energy Management (BOEM), Environmental Studies Program, Washington, DC, under Agreement Number 

M15AC00007. This report has been technically reviewed by BOEM, and it 

has been approved for publication. The views and conclusions contained 

in this document are those of the authors and should not be interpreted 

as representing the opinions or policies of the US Government, nor does 

mention of trade names or commercial products constitute endorsement 

or recommendation for use.