Climate Impacts on U.S. Living Marine Resources: National 

Marine Fisheries Service Concerns, Activities and Needs 

K. E. Osgood (editor) 

U.S. Department of Commerce 

National Oceanic and Atmospheric Administration 

National Marine Fisheries Service 

NOAA Technical Memorandum NMFS-F/SPO-89 

August 2008
 
 

Climate Impacts on U.S. Living Marine Resources: National 

Marine Fisheries Service Concerns, Activities and Needs 

K. E. Osgood (editor)

NOAA Fisheries – Office of Science and Technology 

NOAA Technical Memorandum NMFS-F/SPO-89 

August 2008

U.S. Department of Commerce 

Carlos M. Gutiérrez, Secretary 

National Oceanic and Atmospheric Administration 

Vice Admiral Conrad C. Lautenbacher, Jr., USN (Ret.) 

Under Secretary for Oceans and Atmosphere 

National Marine Fisheries Service 

James W. Balsiger, Acting Assistant Administrator for Fisheries
 ii

Suggested citation: 

Osgood, K. E. (editor). 2008. Climate Impacts on U.S. Living Marine Resources: National Marine 

Fisheries Service Concerns, Activities and Needs. U.S. Dep. Commerce, NOAA Tech. Memo. NMFSF/SPO-89, 118 p. 

A copy of this report may be obtained from:

Office of Science & Technology 

NOAA, NMFS 

1315 East-West Highway, F/ST7 

Silver Spring, MD 20910 

Or online at: 

http://spo.nmfs.noaa.gov/tm/ 
 iii

Preface 

 The National Marine Fisheries Service (NMFS) is a subagency of the National Oceanic and 

Atmospheric Administration (NOAA) within the U.S. Department of Commerce. NMFS is 

responsible for the science-based management, conservation, and protection of living marine 

resources within the U.S. Exclusive Economic Zone and within the international arena. In 

regions where NMFS has living marine resource management responsibilities, it conducts 

assessments of living marine resources and their environment through numerous monitoring and 

research programs. Currently, most of these programs do not account for the climate impacts on 

the ecosystems. 

 This Climate Impacts on Living Marine Resources document was conceived to identify the 

regional climate related ecosystem impacts which concern NMFS. The document contains an 

introduction which presents an overview of the major categories of climate impacts on coastal 

and marine ecosystems, followed by chapters focused on the individual regional marine 

ecosystems for which NMFS has management responsibilities. The regional chapters highlight 

the major climate related ecosystem concerns of each regional ecosystem, what NMFS is 

currently doing to address these concerns, and what NMFS must do to adequately address these 

concerns. In addition, these chapters identify the climate information that will be required for 

NMFS to address these concerns. 

 This document draws upon the NOAA planning process, addressing many of the categories 

of climate impacts that have been identified within the NOAA program planning process. 

However, it is NMFS specific in that it is focused on living marine resources and the climate 

impacts that NMFS should be addressing in order to meet its mandates. NMFS scientists who 

examine environmental impacts on living marine resources at each of the regional fishery 

science centers contributed to, and set the priorities for, the regional ecosystem sections. These 

scientists frequently interact with NMFS’s partners and constituents in order to identify and 

advance our understanding of important issues. This plan augments the NMFS Strategic Plan for 

Fisheries Research (NMFS, 2007) by providing detailed information on NMFS responsibilities 

and needs with respect to climate change. 

NMFS. 2007. NMFS strategic plan for fisheries research. U.S. Dep. Commer., NOAA Tech. 

Memo. NMFS F/SPO-80, 170 p. 
 iv

Executive Summary 

 With the increasing recognition that climate change is occurring and having large impacts on 

living marine resources, a sound ecosystem approach to management of those resources requires 

both understanding how climate affects ecosystems and integration of that understanding into 

management processes. The National Marine Fisheries Service (NMFS) must identify how 

changing climatic conditions will impact its mission and must be prepared to adapt to these 

changes. This document identifies the climate related ecosystem concerns in the regional marine 

ecosystems for which NMFS has living marine resource management responsibilities, what 

NMFS is currently doing to address these concerns, what NMFS must do going forward to 

address these concerns, and what climate information is needed to integrate climate into resource 

management. The regional ecosystems included in this analysis are: the Northeast U.S. 

Continental Shelf; the Southeast U.S. Continental Shelf, Gulf of Mexico, and U.S. Caribbean; 

the California Current Ecosystem; the Alaskan Ecosystem Complex; the Pacific Island 

Ecosystem Complex; the Eastern Tropical Pacific; North Pacific Highly Migratory Species; and 

the Antarctic. 

Major Climate Induced Ecosystem Concerns 

 All regions for which NMFS has living marine resource management responsibilities 

identified some aspect of climate impacts on ecosystem productivity, phenology and species 

distributions as a major climate related ecosystem concern. Different aspects of this concern are 

deemed most critical in the separate regions, as denoted by the distinct concern names within the 

regional chapters. Decadal scale variability and long term changes (e.g. warming) were identified 

as major ecosystem concerns in all regions. Impacts identified include effects on productivity, 

species distributions, recruitment, community structure, and timing of biological events. These 

impacts indicate broad climate caused changes on marine ecosystems. For ecosystem concerns 

related to long-term changes including warming, all regions are likely to experience 

environmental conditions that have not been experienced before. In the California Current, 

Pacific Islands, Eastern Tropical Pacific, and for North Pacific Highly Migratory Species, the 

biological effects of El Niño-Southern Oscillation (ENSO) cycles were identified as an important 

factor. For ecosystem concerns related to climate variations such as ENSO, North Atlantic 

Oscillation, Pacific Decadal Oscillation, and the timing and strength of upwelling, it is important 

to determine how these climate variations affect the ecosystems and to know how long term 

climate change will impact the climate variability patterns. 

 The loss of sea ice is a major concern for regions of the Alaskan Ecosystem Complex and the 

Antarctic. The presence of sea ice is a key factor that influences the structure of these ecosystems; 

and sea ice extent and duration is diminishing in many areas. Sea ice provides habitat for ice 

dependent animals, serves as a refuge for some fish species, contains algal communities that 

provide food during the winter to juvenile krill in the Antarctic, and plays an important role in 

the timing of spring phytoplankton blooms and the balance between pelagic and benthic 

productivity in the Bering Sea. As sea ice retreats, species distributions are changing, reflecting 

the altered habitat. In addition, as ice melts, freshwater is added to marine ecosystems. Along the 

Northeast U.S., salinity variability on the shelf is linked to freshwater input from the Arctic and 

melting of sea ice. 

 Altered freshwater systems, due to increased air temperatures and changes in the timing, 

amount and type (i.e. rain vs. snow) of precipitation, are a major climate induced ecosystem 
 v

concern for the California Current Ecosystem. The focus is on anadramous fish such as salmon 

that use river systems and coastal regions for habitat. The primary concerns center on altered 

stream flows and warmer temperatures affecting survival and passage through tributaries, and 

changes in coastal ocean habitat quality and productivity due to altered freshwater input. 

Changes to freshwater input are also important in other regions where species depend upon 

coastal habitat or coastal currents which are influenced by freshwater input. 

 Ocean acidification, caused by the oceans absorbing large portions of the carbon dioxide that 

is being released into the atmosphere by human activities, is a major concern for many of the 

regional ecosystems. Regions of the northern North Pacific Ocean and the Southern Ocean 

around Antarctica are predicted to be among the first areas to have their surface waters become 

undersaturated with respect to aragonite, a form of calcium carbonate utilized by some marine 

organisms, due to ocean acidification. Likely impacts include reduced growth and survival of 

commercially important shellfish, reduced fitness and abundance of ecologically important prey 

(e.g. pteropods, euphausiids) of commercial fish species, and direct effects on commercially 

important fish species and coldwater corals. In tropical and subtropical regions, including the 

Pacific Islands and the Southeast U.S. Continental Shelf, Gulf of Mexico and U.S. Caribbean, the 

potential direct effects of ocean acidification on coral reefs is a primary concern. Coral reefs are 

susceptible to ocean acidification because reef calcification, and hence growth and survival, 

depends on the saturation state of carbonate minerals in the surface waters. 

 Bleaching of shallow water corals, caused primarily by high temperature events, is another 

major climate induced ecosystem concern for the Pacific Island and Southeast U.S. Continental 

Shelf, Gulf of Mexico and U.S. Caribbean regions and adds to the stress on these corals caused 

by ocean acidification. When the temperature tolerance of these corals is exceeded, the corals 

“bleach”, dissociating from the endosymbiotic algae which normally provide corals 

photosynthetic energy and their color. If the corals are not able to attain new symbiotic algae 

within the time that their nutritional needs require, bleaching results in death of the corals. 

Bleaching can also result in increased susceptibility of corals to diseases which may cause 

mortality. Increases in water temperature associated with global warming and regionally specific 

climate variations are leading to increased incidences of coral bleaching. 

 The rate of sea level rise is predicted to increase due to the thermal expansion of the oceans 

and loss of land ice. Sea level rise is a major climate related ecosystem concern for parts of the 

Southeastern U.S., northern Gulf of Mexico, and Pacific Islands. Low-lying coastal regions are 

susceptible to inundation and loss of wetlands, which could lead to the loss of important fishery 

habitat. Low-lying atolls and islands in the Pacific may be completely submerged by rising sea 

levels, leading to the loss of important habitat for endangered Hawaiian monk seals, green sea 

turtles and sea birds. In addition, reef-building corals may be unable to accrete at a sufficient rate 

to maintain close enough proximity to the surface to sustain their nutritional needs. 

Current Activities 

 In regions where NMFS has management responsibilities, it conducts assessments of living 

marine resources and their environment through numerous monitoring and research programs. In 

most cases this includes monitoring the basic environmental parameters that define the 

fundamental niche of species of interest and monitoring their key population parameters. The 

primary goal of the monitoring is to supply stock assessment scientists with the requisite data to 

make stock assessments and projections. Very few of these assessments and projections currently 

account for the climate impacts on the populations. 
 vi

 Data from many of the observation programs are being integrated to provide a more 

comprehensive view of the ecosystems and for distribution to constituents (e.g. reports of the 

status of the California Current, the Ecosystems Considerations chapter of the Alaskan Stock 

Assessment and Fisheries Evaluation plan, and ecosystem advisories of the northeast U.S. shelf). 

All regions also have some studies that explore specific environmental mechanisms that 

influence living marine resources, though these are generally not core programs with dedicated, 

long-term support. A couple of notable exceptions are the North Pacific Climate Regimes and 

Ecosystem Productivity (NPCREP) and the Fisheries And The Environment (FATE) programs, 

though these programs are supported significantly below their planned levels. NPCREP focuses 

on how changing climate conditions affect the growth, survival, and recruitment of Alaska’s 

fisheries species. FATE is a national program that supports regional studies to develop and 

evaluate ecological and oceanographic indices to be used to improve fishery stock assessments 

and advance understanding of marine ecosystem dynamics. 

Research Needs 

 A combination of retrospective, observation, process and modeling studies are required to 

advance the understanding of the impacts of climate on living marine resources and address the 

climate induced ecosystem concerns. Undertaking the necessary research will require additional 

staff and support for the studies. 

 Retrospective analyses of ecosystem parameters and climate conditions help determine 

ecosystem responses to past climate changes, shedding light on how ecosystems may respond to 

future changes. Retrospective analyses are often the initial climate impact research conducted in 

a region, since they are relatively low-cost, and much has already been done in most regions. 

However, there are still a lot of data to be analyzed with the development of new retrospective 

data techniques and in regions where limited resources have hindered progress. 

 Long term observations of climate influenced environmental variables and biological 

parameters must be maintained and expanded to document ecological responses to climate 

variability and change. All regions identify data gaps that must be filled to enable adequate 

documentation of climate impacts on the ecosystems. Observational needs include continuation 

of existing observation programs, spatial and/or temporal expansion of many observations to 

enable the coverage and resolution necessary to document climate impacts, and the development 

and implementation of new technologies and techniques. 

 Targeted process studies are required to understand the mechanisms controlling the responses 

of living marine resources to climate. Dependence on predictions based upon correlations 

without an understanding of the controlling mechanisms can lead to inaccurate predictions if 

climate conditions vary from those occurring when the correlations were established. Targeted 

process studies should include in situ and laboratory experimental studies, depending upon the 

question of concern, and detailed studies of biological processes and their responses to variable 

forcing. 

 A wide range of modeling studies are also necessary for NMFS to address the regional 

climate related ecosystem concerns. These should range from conceptual models to fully 

developed, coupled climate and ecosystem models and include models of shoreline evolution 

under higher sea level, habitat models, and a full suite of biological and ecosystem models 

(ranging from models of the physiological responses of individual species to particular forcing 

parameters to whole ecosystem models which include environmental forcing). Models help 

explain how species and ecosystems respond to climate forcing, generate hypotheses that can be 
 vii

tested, provide predictive capability of ecosystem responses to future climate changes, and 

ultimately provide predictions of the status of specific living marine resources for given climate 

prediction scenarios. 

Climate Information Needs 

 Climate observations and predictions are necessary for NMFS to address the identified 

climate induced ecosystem concerns and incorporate climate into its living marine resource 

management process. Both historical and current climate observations are needed to document 

how climate has and is changing in particular regions and for comparisons to the local ecosystem 

changes. The necessary climate observations include both the physical parameters generally 

associated with a region’s climate (e.g. air and ocean temperature, wind, and precipitation) and 

the ocean’s chemical parameters (e.g. salinity, oxygen, nutrients, and carbonate system 

parameters). These observations are required on scales that are pertinent to ecosystems. 

Specifically, sea surface and water column profiles of these parameters are necessary and 

measurements are needed on spatial and temporal scales that capture the variability experienced 

by organisms. Indices of climate variability and change are useful to quantify the state and 

tendency of climate forcing and environmental conditions. 

 Regional climate predictions are essential for including climate in projections of living 

marine resource status. Regional predictions of how the mean climate will change and how 

present climate variations will be affected are needed. Climate forecasts should be developed for 

different climate forcing scenarios and include a measure of uncertainty. These predictions need 

to include all the important climate observation parameters, physical and chemical. The 

development of coupled atmosphere-ocean models is necessary for predictions of climate 

impacts on ocean physical properties, such as temperature, salinity, currents, meso-scale features, 

stratification, and upwelling, which are important controlling factors on when and where living 

marine resources can successfully persist. Stream flow and sea level rise projections are 

important for anadramous fish and coastal habitat concerns. 
 viii

Acknowledgements 

 The contributions of the regional chapter authors and their efforts through multiple drafts are 

gratefully acknowledged. Thank you to Ned Cyr for his guidance and encouragement and to 

David Mountain who provided comments and suggestions that greatly improved this document. 
 ix

Table of Contents

 Page 

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii 

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv 

Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii 

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

Northeast U.S. Continental Shelf . . . . . . . . . . . . . . . . . . . . . . . . 11 

 Direct effects of changing environment on managed species . . . . . . . . . . . . 14 

 Effects of changing environment on species interactions . . . . . . . . . . . . . . 19 

 Effects of climate change on ecosystem productivity . . . . . . . . . . . . . . . 21 

Southeast U.S. Continental Shelf, Gulf of Mexico, and U.S. Caribbean . . . . . . . . . 31 

 Threats to coral reef ecosystems: coral bleaching, disease, and ocean acidification . . . 32 

Threats to habitat from sea level rise – loss of essential fish habitat . . . . . . . . 34 

 Climate induced changes to species phenology and distribution . . . . . . . . . . . 37 

California Current Ecosystem . . . . . . . . . . . . . . . . . . . . . . . . . 44 

 Increased variability in climate forcing . . . . . . . . . . . . . . . . . . . . 45 

 Changes to the magnitude and timing of freshwater input . . . . . . . . . . . . . 50 

 Changes in the timing and strength of the spring transition and their effect on marine 

populations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 

 Ocean warming and increased stratification and their impact on pelagic habitat . . . . . 55 

 Changes in ocean circulation and their impact on species distribution and community 

structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 

Alaskan Ecosystem Complex . . . . . . . . . . . . . . . . . . . . . . . . . . 64 

 Climate regimes and ecosystem productivity . . . . . . . . . . . . . . . . . . 66 

 Loss of sea ice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 

 Ocean acidification . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 

Pacific Island Ecosystem Complex . . . . . . . . . . . . . . . . . . . . . . . 76 

 Coral bleaching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 

 Sea level rise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 

 Ocean acidification . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 

 Changes in ENSO and ocean circulation patterns . . . . . . . . . . . . . . . . 82 

Eastern Tropical Pacific . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 

 The biological effects of ENSO cycles . . . . . . . . . . . . . . . . . . . . . 86 

 The biological effects of climate shifts, particularly the late 1970s climate shift . . . . 88 
 x

North Pacific Highly Migratory Species . . . . . . . . . . . . . . . . . . . . . 92 

 Effect of climate variability on recruitment . . . . . . . . . . . . . . . . . . . 93 

 Effect of climate variability on HMS habitats – changes in range and abundance . . . . 95 

 HMS responses to mobile oceanic gradients: fronts and meso-scale features . . . . . . 99 

Antarctic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 

 Ocean temperature, sea ice extent, and Weddell outflow variability . . . . . . . . . 107 

 Circumpolar Current variability and Upper Circumpolar Deep Water movement . . . . 110 

 Winter ocean environment and its climatic variability . . . . . . . . . . . . . . . 111 

 Ocean acidification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 

Appendix A – List of Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 117
 1

Introduction 

 The United States has extensive living marine resources that are important to its economy, its 

quality of life and the world’s ecosystems. These living marine resources support a $60 billion 

per year seafood industry and recreational fisheries that annually contribute $12 billion to the 

economy. These exploited resources and protected species also help attract vast numbers of 

people to coastal regions for tourism and recreation. In some parts of the country, native peoples 

are dependent on these same resources for subsistence and for preserving their traditions and 

culture. To maintain these resources, including the recovery and conservation of protected and 

endangered marine species, management plans must be implemented that account for the 

multiple factors affecting the ecosystems. 

 Climate is one of the most important factors controlling the distributions and abundances of 

marine organisms and how ecosystems are structured. The climate in a region ultimately controls 

most of the physical parameters of ecosystems which, to a great extent, determine the basic 

habitat suitability for marine species. By impacting species’ growth rates, reproductive success, 

and spatial and temporal distributions, the physical parameters have a large impact on the 

resulting ecosystem structure, function, and productivity. Therefore, if living marine resources 

are to be adequately managed, climate variations and changes must be understood and 

considered in the formulation of management strategies. If climate considerations are not 

incorporated into these plans, we risk implementing management plans that do not account for 

evolving environmental conditions and thereby risk over- or under-exploitation of harvested 

resources and similar mismanagement of non-harvested species. 

 A goal of climate and ecosystem studies is to be able to predict the probable consequences of 

global climate change on ecological systems and their living resources, and to deliver to 

managers the knowledge and tools needed to incorporate climate variability into the management 

plans. This includes recovery plans for overfished and listed (protected) species. NOAA has 

made large investments directed at understanding the physical climate system and describing the 

mechanisms that govern climate variability and climate change, especially as related to the 

ENSO. However, much more needs to be learned about the impacts of climate variability and 

change on biological components of ecosystems, or the implications of future climate change on 

coastal and marine ecosystems. We need to better understand the linkages between “physical 

forcing mechanisms” and “ecosystem response”. That understanding can be attained through 

increased observations, research and modeling of critical biological elements of the ecosystem 

(productivity, prey resources, predator impacts, trophic interactions, habitat suitability). Doing so 

will lead to a better understanding of the critical factors that link climate variability and 

ecosystem response. 

 Natural variability combines with human influences, including anthropogenic-induced 

climate change, to create temporally and spatially complex environments for marine populations. 

Successful management of these populations and their ecosystems requires an evolution from the 

traditional physics-to-fish correlations to a more mechanistic-based strategy that takes a holistic, 

integrative ecosystem approach. 

 This document presents sections for each regional marine ecosystem for which NMFS has 

living marine resource management responsibilities. Each section identifies the major climate 

related ecosystem concerns for the region, what NMFS is currently doing in relation to these 

concerns, and what additional work NMFS must do to adequately address the concerns to 
2

support effective management. In addition, the sections identify the climate information that will 

be required for this work. The major climate related concerns identified for the different regional 

ecosystems are listed in Figure 1. While the specifics of the climate concerns differ between 

regions, there are common issues that reflect closely the climate issues identified in the NOAA 

program planning process. These include climate impacts on ecosystem productivity, phenology 

and species distributions; the impacts of the loss of sea ice on polar, sub-polar, and cold 

temperate ecosystems; altered freshwater systems; ocean acidification; coral bleaching; and 

ecological effects of sea level rise. For each of these topics climate changes have had major 

impacts on the living marine resources, as is discussed briefly below. 

Figure 1. The major climate related ecosystem concerns for the regional marine ecosystems for which NMFS has 

management responsibilities.

Climate Impacts on Ecosystem Productivity, Phenology and Species Distributions 

 Modifications to ecosystem productivity, phenology and species distributions often occur in 

response to altered physical forcing due to climate change. These changes may occur on 

timescales ranging from seasonal to multi-decadal or longer. Depending upon the duration and 

magnitude of the climate change, species may persevere through periods of adverse conditions, 

temporarily shift their distributions or behaviors, or modify their ranges, behaviors and 

movements over the long term. At the extreme, species may be extirpated from whole regions 

and potentially become extinct. 

Northeast

• Direct effects on 

managed species 

• Effects on 

species 

interactions 

• Effects on 

ecosystem 

productivity 

Southeast / Gulf of Mexico / 

Caribbean

• Threats to coral reef 

ecosystems – bleaching, 

disease, and ocean 

acidification 

• Threats to habitat from sea 

level rise 

• Climate induced changes to 

species phenology and 

distribution 

Alaska

• Effects on ecosystem 

structure and 

productivity 

• Loss of sea ice 

• Ocean acidification 

California Current

• Increased variability 

in climate forcing 

• Impact of changes to 

the magnitude and 

timing of freshwater 

input 

• Climate impacts on 

coastal upwelling 

• Impact of ocean 

warming, increased 

stratification on 

pelagic habitat 

• Changes in ocean 

circulation - impact 

on species 

distribution and 

community structure

Pacific Islands 

• Coral bleaching 

• Sea level rise 

• Ocean acidification 

• Changes in ENSO 

and ocean 

circulation patterns 

NMFS Regional Climate & Ecosystem Issues

Eastern Tropical Pacific 

• Biological effects of 

ENSO cycles 

• Biological effects of 

climate shifts, 

particularly the late 

1970s shift 

N Pacific Highly Migratory 

Species

• Recruitment responses to climate 

• Effect of climate on HMS habitats 

• HMS responses to climate 

impacts on fronts and meso-scale 

features 

Antarctic 

• Ocean temperature, sea ice extent and 

Weddell outflow variability 

• Antarctic Circumpolar Current variability 

and Upper Circumpolar Deep Water 

movement 

• Winter ocean environment 

• Ocean acidification
3

 Climate directly impacts regional temperature, wind and precipitation patterns. These 

physical changes may alter the habitat suitability for species directly or indirectly. Examples of 

direct effects on species include species responses to changes in temperature due to their 

physiological tolerances. Many marine fish species have been observed to shift their distributions 

poleward in response to warming waters (Murawski, 1993; Parker and Dixon, 1998; Perry et al., 

2005; Mueter and Litzow, 2008) and distributions of Atlantic surfclams have apparently shifted 

to deeper, cooler water in response to increased coastal temperatures (Weinberg, 2005). 

Similarly, the Alaskan snow crab distribution has receded northward with the warming of the 

eastern Bering Sea (Orensanz et al., 2005). As species’ distributions shift, the species 

composition of biological communities are altered with new predator-prey (or host-parasite) 

relationships formed and others disappearing, stabilizing or destabilizing existing food webs. 

This in turn can affect the seasonal distribution of apex predators such as whales and pinnipeds 

(Grebmeier et al., 2006). 

 Changes in temperature, wind and precipitation patterns can affect ocean circulation, thermal 

energy distribution, ecosystem productivity and structure, and subsequent habitat suitability for 

species. An example of this is the timing and strength of seasonal upwelling along the Pacific 

coast of North America. In 2005 the transition to upwelling favorable conditions in the northern 

California Current ecosystem was delayed by 2-3 months (Schwing et al., 2006). This delay had 

severe consequences for many components of the ecosystem, including changes in distributions, 

abundances and recruitment of many pelagic nekton species (Brodeur et al., 2006), shifts in 

California sea lion foraging strategies (Weise et al., 2006), and complete breeding failure of a 

dominant planktivorous marine bird (Sydeman et al., 2006). Similarly, El Niño events cause 

large ecosystem shifts on multi-year timescales, impacting ocean productivity and population 

distributions along the U.S. west coast (Pearcy and Schoener, 1987). Overall productivity is 

reduced during these events and individual species show marked responses. For example, market 

squid undergo severe population declines during El Niño events, California sea lions have 

greatly decreased pup production, rockfish show large reductions in reproductive success, and 

the abundance and distribution of Pacific hake are impacted. 

 By changing the seasonal timing of certain temperature, current, and stratification patterns in 

a region, the phenology of the populations that inhabit the region can be affected. Phenology 

refers to the timing of recurring natural phenomena, particularly ones that occur on an annual 

cycle. For marine ecosystems the timing and magnitude of primary production can be affected, 

thus impacting the productivity of the entire ecosystem. Changes in timing and magnitude of 

primary production can also affect population processes of individual stocks (Friedland et al., 

2008). In addition, the timing and location of reproduction by organisms and the migration dates 

and routes of organisms may change. These temporal changes have large impacts on living 

marine resource populations and their management. 

 On decadal time scales, changes in climate forcing have been observed to have large impacts 

on the productivity of marine ecosystems. These shifts have been referred to as regime or phase 

shifts since the dominant species and productivity levels markedly change. Large-scale variations 

in climate forcing have been observed in the Pacific and Atlantic Oceans. In the Pacific, changes 

such as the decadal shifts in the California Current and Alaska Current ecosystems between 

warm regimes and cool regimes are a reflection of changes in the ocean circulation and are 

indicated by climate patterns such as the Pacific Decadal Oscillation (Mantua et al., 1997) or the 

Arctic Oscillation (Overland and Stabeno, 2004). These oscillations are linked to large-scale 

shifts in ocean conditions of the North Pacific. Changes in species abundances, such as changes 
4

in the composition of zooplankton, survival of Pacific salmon, the dominance of sardines versus 

anchovies in the California Current ecosystem, and the dominance of groundfish (gadids) versus 

crustaceans (shrimp and crab) in the Gulf of Alaska ecosystem, are associated with decadal 

changes in ocean climate (Francis and Hare, 1994; Anderson and Piatt, 1999; Benson and Trites, 

2002; Chavez et al., 2003; Peterson and Schwing, 2003). The collapse of the California sardine 

fishery in the 1940s, which caused large economic and social impacts, was partially caused by a 

shift to cooler ocean conditions and resulting changes in the ecosystem structure. At that time, 

the fishery management community was not aware of these affects of climate change on the 

ecosystem. 

 In the Atlantic, the impact of the North Atlantic Oscillation (NAO), a measure of the 

atmospheric pressure difference between the subtropical high and the Icelandic low, on marine 

populations depends upon how the NAO affects local conditions and their relation to the 

preferences of the populations (Drinkwater et al., 2003). For example, the NAO has opposite 

effects on cod recruitment in parts of the western and the eastern Atlantic due to its opposite 

effects on temperatures in the two regions. Climate changes are believed to have contributed to 

the collapse of the northern cod stock off southern Labrador and northeastern Newfoundland in 

the 1990s (Drinkwater, 2002). While overfishing is believed to be the main cause of the cod 

decline, environmental conditions appear to have contributed to the decline of the cod stock by 

decreasing growth rates of the fish. The fisheries management did not take the variable 

environmental conditions into account, and the stocks were depleted to extremely low levels. To 

date, these stocks show little evidence of recovery. The impact of the Atlantic Multidecadal 

Oscillation (AMO), another source of climate variability in the Atlantic, are just beginning to be 

understood (Kerr 2005). The AMO is a 60-80 year cycle expressed primarily as variability in sea 

surface temperature. Variability in the AMO has been linked to precipitation patterns in Europe 

and North America and hurricane activity in the Atlantic. The broader ecosystem effects are 

largely unknown as are the interactions between the AMO and long-term trends in temperature 

resulting from climate change. 

Loss of Sea Ice 

 Warming temperatures and decreases in sea ice are impacting marine ecosystems in polar, 

sub-polar, and cold-temperate regions. Summertime Arctic sea ice coverage has been declining 

since the 1970s and declined to unprecedented low levels during the summer of 2007. The Arctic 

Ocean may become seasonally ice-free by 2030 (Stroeve et al., 2008). Concurrently, the Bering 

Sea is undergoing a loss of sea ice and northward biogeographical shift in response to changing 

climate conditions, with the northern regions shifting from arctic to subarctic conditions 

(Schumacher et al., 2003; Overland and Stabeno, 2004; Grebmeier et al., 2006; Stabeno et al., 

2006; Mueter and Litzow, 2008). The loss of sea ice in the subarctic and arctic has large impacts 

on the structure of these ecosystems and could result in the reproductive failure and ultimate 

extinction of some protected species of pinnipeds and polar bears. Not only does it reduce the 

amount of ice available to ice dependent species (e.g. ribbon, bearded, spotted and ringed seals, 

polar bear and walrus), it also changes the water column temperature and stratification, the 

timing and intensity of phytoplankton blooms, and the proportion of pelagic production that 

becomes available to the benthos. The benthic community includes commercially important 

flatfish and crab populations (Hunt et al., 2002) and food for many pelagic fish and whale 

predators. It will change the distribution of preferred habitat by species and may force fishers to 

expend more effort for the same level of catch. In some regions around Antarctica temperatures 
5

have increased, sea ice has declined and krill density has decreased substantially (Hewitt and 

Linen Lowe, 2000; Smith and Stammerjohn, 2001; Atkinson et al., 2004). While ice dependent 

species in both polar regions will be negatively impacted by reductions in sea ice, other species 

whose distributions are limited by sea ice may be able to take advantage of the changing 

conditions. 

 In cold-temperate regions, such as the Northeast shelf, freshwater input in the Arctic is 

responsible for driving salinity patterns through the entire region (Greene and Pershing, 2006). 

The less saline water enters the Labrador Coastal Current system (Loder et al., 1998 ) and flows 

around Newfoundland, down the Scotian Shelf, around the Gulf of Maine and Georges Bank and 

then through the Mid-Atlantic shelf (Mountain 2004). This large-scale forcing has been linked to 

changes in zooplankton community structure (Kane 2007) and links to higher trophic levels are 

being investigated. The effect of changes in sea ice on marine ecosystems illustrates that climate 

change will have local and remote impacts on regional ecosystems and understanding the 

linkages between ecosystems will be critical for evaluating both categories of impacts. 

Altered Freshwater Systems 

 Climate change will affect freshwater flows to coastal systems in much of the continental 

U.S. This will modify the productivity of coastal ecosystems and fish species that use these 

nearshore environments and may lead to shifts in the trophic structure of marine ecosystems and 

the abundance and productivity of marine fish species humans depend on. Freshwater systems 

are intimately linked to living marine resources through the water cycle, flows of water and 

nutrients from terrestrial to marine ecosystems, and the migrations of anadromous and 

catadromous fishes that transfer biomass and nutrients between the two environments. Climate 

change may result in changes in the timing and volume of river flows, thereby influencing the 

survival of fishes that require these habitats for spawning and rearing (Crozier and Zabel, 2006; 

Beechie et al., 2006). Increased water temperature from a warmer climate and altered stream 

flows may impact anadromous fishes and other aquatic species by reducing available habitat, 

increasing competition with other species, restricting river migration corridors, and causing 

changes in food supply. At the same time, human population growth will increase demands for 

freshwater that could exacerbate any flow reductions caused by climate change. Many coastal 

regions are structured by near-shore buoyancy driven (freshwater) currents and changes in 

freshwater flow will also affect these coastal regions. For example, some marine fish species 

may have evolved to have their larvae take advantage of currents to transport them to favorable 

nursery areas (e.g. Walleye pollock in the Gulf of Alaska). Changes in the timing and magnitude 

of freshwater delivery to the oceans will change the seasonal transport by currents in these 

regions. 

Ocean Acidification 

 Changes in the chemical composition of the ocean are occurring due to the oceans absorbing 

large portions of the carbon dioxide that is released into the atmosphere by human activities. This 

is causing ocean chemistry to change to a state that has not been present for hundreds of 

thousands of years (Feely et al., 2004; Sabine et al., 2004; Flannery, 2006). As the oceans absorb 

carbon dioxide, chemical reactions in the oceans result in increased concentrations of hydrogen 

ions (higher acidity, lower pH) and decreased availability of calcium carbonate; hence the term 

ocean acidification has been used to describe this process. This shifting of the carbonate 

equilibrium of the oceans, making carbonate and calcium ions less available, may be harmful to 
6

marine organisms that make structures out of calcium carbonate (Kleypas et al., 2006). These 

organisms include shallow and deep water corals, calcifying plankton, mollusks, echinoderms, 

crustaceans and many other organisms, including many of our nation’s most valuable fishery 

resource species. Continued increases in carbon dioxide could decrease the fitness of marine 

calcifiers, as the calcification rates of some organisms have been shown to decrease under 

increasing carbon dioxide concentrations (Langdon and Atkinson, 2005). However, the 

cacification rates of other organisms actually appear to increase as carbon dioxide levels increase 

(Iglesias-Rodriguez et al., 2008). Changing calcification rates will have impacts on marine 

calcifiers and the organisms that are dependent upon them for food or habitat. Ocean 

acidification has likely played a role in all major mass extinctions of the Scleractinia, the deepsea cold-water corals that are important as biodiversity hotspots by providing habitat for deepsea organisms (Turley et al., 2007). Increases in acidity also has the potential to affect a number 

of key biological processes in non-calcifying organisms such as reduction in photosynthesis, 

availability of nutrients to phytoplankton, the bioavailability of marine toxins to bacteria and 

phytoplankton, internal carbon dioxide concentrations of marine animals and reduced demersal 

egg adhesion or fertilization success of eggs broadcast into the ocean (UK Royal Society, 2005). 

The numerous pathways for effects (both direct and indirect) imply that ocean acidification will 

impact many marine species over wide geographic areas. 

Coral Bleaching 

 Coral bleaching is another marine ecosystem phenomenon for which climate plays an 

important role. Coral reefs support more species per unit area than any other marine environment. 

However, shallow water reefs are very sensitive to elevated sea surface temperature as reef 

building corals are thought to live near their thermal maxima. When their temperature tolerance 

is exceeded, the corals “bleach”, dissociating from the endosymbiotic algae which normally 

provide corals photosynthetic energy and their color. If the corals are not able to attain new 

symbiotic algae in the time period that their nutritional needs require, weeks to sometimes 

months, the bleaching of the reef results in the mortality of the affected coral. Widespread 

bleaching events are primarily caused by extended periods of heightened temperatures. There has 

been a considerable increase in the number of mass bleaching events in recent years, including 

the 1998 event where an estimated 16% of the world’s area of coral reefs was severely damaged 

(Wilkinson, 2004) and a major bleaching event in the Caribbean Sea in 2005. Comparisons of 

expected increases in sea surface temperatures with calculated bleaching thresholds suggest that 

mass bleaching events are likely to become more frequent and severe (Hoegh-Guldberg, 1999; 

Marshall and Schuttenberg, 2006). This will have significant, negative impacts on coral survival 

and on the multitude of species that utilize the reefs for food and shelter. It has been predicted 

that with increasing ocean temperatures, mass bleaching episodes will continue to increase in 

frequency and severity to the point of coral extinction (Hoegh-Guldberg, 1999). An alternative 

view suggests that the coral/algal symbiosis is flexible and adaptable and that corals that recover 

from bleaching are likely to be more resistant to future bleaching via association with more heattolerant strains of symbionts (Baker et al., 2004). Also, as ocean temperatures increase, areas 

formerly too cold for coral may become optimal for coral and thus provide new areas for coral 

communities to become established. 
7

Sea Level Rise 

 Climate change also affects coastal marine ecosystems through changing sea levels. Global 

sea level rose 0.1-0.2 m over the 20th century. There is a strong likelihood of continued sea level 

rise due to thermal expansion of the oceans and loss of land ice, with the projected range of 

global average sea level rise from 1980-1999 to 2090-2099 being 0.18-0.59 m (IPCC, 2007). 

Rising sea level has consequences for coastal regions due to its potential to alter habitat and 

ecosystems in these regions (Scavia et al., 2002). As a result of sea level rise, coastal wetlands 

and shallow water habitats are exposed to increases in water depth, salinity, wave action and 

storm surges. This can have severe consequences for organisms that inhabit these regions for all 

or part of their life cycles if there is insufficient new habitat created as water levels rise. Areas 

such as low-lying islands that could be submerged and areas with extensive human infrastructure 

that will prevent landward migration of coastal ecosystems are particularly at risk, as some 

coastal habitats could be totally lost in these regions. Areas that are subsiding are also especially 

at risk due to the very rapid local rises in sea level they will experience. 

Summary 

 All of these climate variations and changes will continue to have large impacts on marine 

ecosystems, as abiotic oceanic conditions transition to states that may not have existed for 

thousands of years. Developing the ability to predict and ameliorate the ecological consequences 

of these events and long term changes is imperative in order to support effective management. 

We must make substantial and immediate investments in marine climate change research to 

enable informed decisions by resource managers and society to ensure the future utility and 

enjoyment of coastal and marine ecosystems under changing climate conditions. The research 

needs identified in the following regional sections can guide the directions of that investment. 

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11

Northeast U.S. Continental Shelf 

Authors: 

Jonathan Hare and Maureen Taylor 

(Northeast Fisheries Science Center) 

Introduction 

 The northeast U.S. continental shelf ecosystem extends from Cape Hatteras, North Carolina 

to Nova Scotia and includes the Middle Atlantic Bight, the southern New England shelf, Georges 

Bank, and the Gulf of Maine (Figure 1). The ecosystem spans a large climate gradient from south 

to north, including a 10-15o

C temperature gradient in winter and a 4-5 psu salinity gradient year 

round. The ecosystem also experiences a large seasonal range of temperature from 

approximately 5-10o

C in the northern Gulf of Maine to near 20oC along the Mid-Atlantic coast 

(Mountain and Holzwarth, 1989). There are a number of large estuarine systems along the coast 

through which fresh waters flow onto the shelf, including Chesapeake Bay, the largest estuary in 

the United States. At the offshore edge of the shelf, a front separates shelf water from slope 

water. The fresher water along the inner boundary of the shelf and the more saline slope water at 

the outer boundary creates a cross-shelf salinity gradient of ~5-6 psu. 

 In addition to large environmental gradients, the northeast U.S. shelf has a variety of pelagic 

and benthic habitats (Stevenson et al., 2003). A number of pelagic habitats are defined by 

discrete water masses and water mass boundaries (Mountain, 2000; Waring et al., 2001). The 

shelf bottom has areas of sand, mud, and gravel bottom that create a mosaic of habitat types. The 

estuarine systems at the inner boundary of the shelf provide numerous habitats ranging in salinity 

from fresh to marine. A number of fish 

species use these habitats as nurseries (Able 

and Fahay, 1998). At the offshore edge of the 

shelf, there are several canyons and a variety 

of bottom types, which provide a complex set 

of habitats for fish species (Grimes et al., 

1986; Cooper et al., 1987). 

 These large temporal and spatial 

environmental gradients and the diversity of 

habitats enable a wide variety of species to 

inhabit the ecosystem as year round and 

seasonal residents. Approximately 1,000 fish 

species occur in marine waters from Cape 

Hatteras, North Carolina to Greenland, 

including coastal, shelf, and deep-sea habitats 

(Fahay, 2007). In an exhaustive study of 

nearshore fishes of the northeast U.S. shelf, 

Able and Fahay (1998) found that 70% were 

transient, indicating the importance of 

seasonal and life history migrations in the 

region’s fish fauna. A number of marine 

mammal (~30) and sea turtle (~6) species 

-77 -75 -73 -71 -69 -67 -65

LONGITUDE (Degrees West)

35

36

37

38

39

40

41

42

43

44

45

LATITUDE (Degrees North)

GULF OF MAINE

Boston

New York

Boothbay

GEORGES

BANK

MIDDLE ATLANTIC BIGHT

NOVA

SCOTIA

60 m

100 m

NE CHANNEL

GS CHANNEL

200 m

SSW

SLW

Gulf Stream

Warm Core

GS Ring

Cold Core

GS Ring

Warm Slope

Subsurface flow of 

warm Slope water

Subsurface flow of 

cold Labrador Slope

water

Water

SLW

SSW

 = Slope Water

 = Scotian Shelf Water

Cape

Hatteras, NC

 SOUTHERN

NEW ENGLAND

Figure 1. Generalized circulation patterns of the 

Northeast U.S. Continental Shelf ecosystem. 
12

occur in the ecosystem; many of 

these species are migratory, but 

some are year round residents. In 

addition, there are about 130 species 

of marine decapod crustaceans 

inhabit the northeast U.S. continental 

shelf, with arctic-boreal species 

representing about 40% and 

temperate-tropical species 

representing 60% (Williams, 1984). 

More than 550 macrobenthic 

invertebrates are found on the shelf, 

and faunal composition varies both 

along-shelf (the boreal-temperate 

gradient) and across-shelf (the 

coastal-shelf-slope gradient) 

(Theroux and Wigley, 1998). 

Zooplankton communities also vary predictably both along-shelf and cross-shelf with 

contributions of arctic-boreal species, temperate-tropical species, nearshore species, shelf species, 

and deep-water species (Cox and Wiebe, 1979; Bourne and Yentsch, 1987). 

 The climate of the northeast region is influenced by at least two natural climate oscillations: 

the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO) (Figure 

2). The NAO is the dominant mode of winter climate variability in the North Atlantic region and 

is a large-scale seesaw in atmospheric mass between the subtropical high and the Icelandic low 

(Hurrell et al., 2003). The periodicity of the NAO is several years, and during positive periods of 

the NAO (stronger subtropical high and deeper Icelandic low), the eastern U.S. experiences mild 

and wet winter conditions; the opposite holds for negative periods of the NAO (weaker 

subtropical high and Icelandic low). The AMO describes variability in sea surface temperature in 

the North Atlantic Ocean with a longer periodicity (65-80 yrs) than the NAO and has an 

amplitude of about 0.5°C (Kerr, 2000). While in the positive phase (e.g., 1930-1965), rainfall 

over the eastern U.S. was lower and while in the negative phase (e.g., 1965-1995) rainfall was 

higher (Enfield et al., 

2001). The AMO seems 

to be switching into its 

positive phase with 

warmer ocean 

temperatures and 

decreased rainfall (Kerr, 

2005). Other climate 

oscillations also affect the 

northeast U.S. shelf, such 

as the El Niño-Southern 

Oscillation (ENSO) 

which can influence 

precipitation and 

freshwater input along the 

Figure 2. Winter NAO (bars) and winter AMO (line). Data 

from NAO winter index downloaded from http://www.cgd. 

ucar.edu /cas/ jhurrell/indices.html. AMO values downloaded 

from http://www.cdc.noaa.gov/Timeseries/AMO/ and 

smoothed with a 5-yr running average.

Figure 3. Time series of sea surface temperature measured at Boothbay 

Harbor Maine and archived by the Maine Department of Marine Research
13

east coast (Wu et al., 2005). While the magnitude of environmental variability related to these 

other oscillations is less than that associated with NAO and AMO, it is important to recognize 

that a complex interaction of climate-scale forcing drives environmental variability along the 

shelf. 

 The northeast region has experienced general warming since the 1970’s, about 0.5oC per 

decade (Mountain, 2004). The time series of coastal sea surface temperature measured at 

Boothbay Harbor, Maine (Figure 3) shows that nearshore temperature has generally increased 

since the 1980s. The high temperatures in the 1940’s and 50’s may be related to the positive 

phase of the AMO. If the current trend continues, water temperatures will be higher at Boothbay 

than at any other point during the 100-year record. Consistent with the coastal observations, 

Mountain (2003) documented that the shelf water of the Mid-Atlantic Bight was ~1°C warmer 

during 1990s relative to the previous decadal average. Further, Friedland and Hare (2007) found 

that not only have the sea surface temperatures of the northwest Atlantic increased, but the 

seasonal range of surface temperature also has increased, which may have equally important 

consequences for the living marine resources of the region as the general warming trend. 

Climate Induced Ecosystem Concerns 

 On the northeast U.S. continental shelf, a number of exploited species are over-fished and a 

number of protected species remain endangered. Many current management plans strive to 

rebuild fisheries to sustainable levels and to return protected species from their endangered or 

threatened status. However, these management strategies assume that the ecosystems on which 

these species depend are at equilibrium – variable but with no long-term trends. With 

documented increases in temperature and further increases forecast for the future, it is clear that 

novel environmental conditions will be experienced in the near future and will continue for 

decades to come. Thus, the northeast U.S. shelf ecosystem cannot be assumed to be at 

equilibrium. To be successful, sustainable management will need to consider the implications of 

these changes for the managed species and the ecosystem as a whole. Understanding these 

changes and their implications is the overall climate priority of the NEFSC. 

 To address this priority the capability to couple climate models with various ecological and 

fisheries models is needed to forecast the combined effect of fishing and climate on exploited 

populations. These models then could be used as the basis for scientific advice for rebuilding and 

sustaining the fisheries. Although such coupled climate-fishery forecasts are within reach 

(Lehodey et al., 2006, Fogarty et al. 2008), a large amount of research will be required to 

develop and apply these coupled models operationally. To this end, the primary climate 

concerns are: 

I. Direct Effects of Changing Environment on Managed Species 

II. Effects of Changing Environment on Species Interactions 

III. Effects of Climate Change on Ecosystem Productivity 

 These three concerns have a common goal: to forecast the effects of climate change on 

fisheries and protected species and incorporate these forecasts into the advice provided to 

managers. Such forecasts can predict chilling results, such as the dramatic decrease or extirpation 

of cod from the North Sea (Clark et al., 2003) and Georges Bank (Fromhoof et al., 2007). In a 

more detailed analysis, Fogarty et al. (2008) showed that the yield curves for cod in the Gulf of 
14

ΔT= 0oC

ΔT=+1o

C

ΔT=+2oC

ΔT= 0oC

ΔT=+1o

C

ΔT=+2oC

Figure 4. Predicted yield of Atlantic cod from the Gulf of 

Maine as a function of fishing mortality and changing 

temperature. The base condition (ΔT= 0o

C) represent mean 

temperatures during 1982-2003. The other two conditions 

(ΔT=+1o

C, ΔT=+2oC) represent temperature increases from the 

base condition (modified from Fogarty et al. 2008). 

Maine differ under different climate 

scenarios indicating that optimal 

harvest levels change with changing 

climate (Figure 4). This work 

suggests that as waters warm, the 

maximum sustainable yield of cod in 

the Gulf of Maine will decrease, as 

will the fishing mortality required to 

achieve this maximum yield. 

 The overall goal is a capability to 

forecast the effect of climate change 

on fishery and protected species in 

the northeast U.S. and to incorporate 

the resulting forecasts into the 

scientific advice provided to 

managers. To develop this capability, 

the mechanistic connections between 

climate and population biology or 

ecosystem function need to be 

established and quantitatively linked within population, ecosystem and climate models. Although 

understanding and predictive capability can come from correlative analyses alone (MacKenzie 

and Köster, 2004; Friedland et al. 2008), the emphasis on mechanistic connections comes from 

the repeated failure of a correlation-only approach (Myers, 1998); studies across the taxonomic 

spectrum have concluded that climate forecasts of populations and ecosystems need to be based 

on mechanistic connections regarding the causal links between climate and biology (e.g., Ohman 

et al., 2004; Lehoydey et al., 2006). To meet this need, the climate-related research priorities of 

the Northeast Fisheries Science Center (NEFSC) emphasize laboratory and processes-oriented 

field work, which are required to develop the mechanistic understanding of climate-ecosystempopulation links, and the various monitoring and modeling capabilities, which link these 

mechanisms with population, ecosystem, and climate models. 

I. Direct Effects of Changing Environment on Managed Species 

Description 

 All species have a range of environmental parameters in which they can live – defined as the 

fundamental niche (Hutchinson, 1965). Climate change will result in temporal and spatial shifts 

in the fundamental niche of a species. In addition, climate change will directly affect population 

dynamics in many species through direct environmental effects on population vital rates 

including reproduction, recruitment and survival.

 These somewhat abstract concepts have concrete examples from fishery species in the 

northeast U.S. shelf. Murawski (1993) demonstrated that the distributions of many species on the 

northeast shelf are affected by temperature. As temperature changes, species distributions will 

change in response to shifts in the temporal-spatial location of the fundamental niche (also see 

Mountain, 2000). Many fish species can move in response to changes in environmental 

conditions, but sessile benthic organisms cannot. Weinberg (2005) documented an offshore shift 

in the distribution of Atlantic surfclam and related this shift to thermal stress. Individuals did not 
15

move, but the population distribution changed as the fundamental niche constricted and mortality 

exceeded recruitment in the inshore portion of the range. In addition to affecting distribution, the 

environment can also directly influence population vital rates. Hare and Able (2007) found a 

close relationship between estuarine temperature and recruitment of Atlantic croaker. During 

warm winters, estuaries throughout the Middle Atlantic Bight allowed overwinter survival of 

young-of-the-year croaker, leading to high recruitment, whereas during cold winters, overwinter 

survival was limited to estuaries in the southern Middle Atlantic Bight resulting in lower 

recruitment. Similar results have been found for other species in Mid-Atlantic estuaries including 

striped bass (Hurst and Conover, 1998; Hurst, 2007). The interpretation is that temperature is a 

component of the fundamental niche and as temperature changes so does the distribution of the 

niche, as well as population vital rates in different parts of the niche. 

 Temperature is not the only environmental parameter that will change with changing climate. 

Precipitation patterns may change, influencing freshwater runoff into coastal areas. Sullivan et al. 

(2006) showed that American eel ingress into a New Jersey estuary was correlated with local 

precipitation; the implication is changes in precipitation patterns may have consequences on the 

number of eels recruiting in a given region. Similarly, changes in wind patterns may affect the 

transport of marine fish and invertebrate larvae. Friedland et al. (2007) suggested that changes in 

wind patterns over the Sargasso Sea affect larval transport of American and European eel and 

may contribute to trends of lower recruitment. As a final example, ocean acidification may affect 

the ability of organisms to produce carbonate structures (Orr et al., 2005) and calcification rates 

of many organisms decrease in response to decreased carbonate saturation state even when these 

states remain > 1 (Feely et al., 2004). The impacts of acidification also may differ among life 

history stages and initial calcification might be a particularly vulnerable stage (Cohen et al., 

2007). 

 The environment also directly affects the metabolism of marine species. The response of 

metabolism to temperature and salinity in large part defines the boundaries of the fundamental 

niche. But the environment also regulates the allocation of energy within the boundaries of the 

fundamental niche. All species have an optimum temperature, salinity, depth, etc. and at this 

optimum, a maximum amount of energy is available for growth and reproduction. Similarly, all 

species have physiological boundaries; environmental conditions where basic metabolic needs 

cannot be met and survival is not possible. Between these optimums and boundaries, the 

environment still influences the biology of individuals. For example: growth efficiency (the 

amount of growth per unit of food consumed) for early stage cod juveniles is highest at 8oC and 

near zero at 15o

C. So to have equal growth, a fish at 15oC would need to consume much more 

than a fish at 8oC (Peck et al., 2003). Faster growing, larger fish have a lower mortality rate 

(Anderson, 1988) and produce more and better quality eggs (Trippel and Niel, 2004). Thus, 

changes in temperature and other environmental parameters can affect growth, reproduction, 

recruitment, and natural mortality and eventually have an impact on the overall production of the 

population. The results presented by Fogarty et al. (2008) (Fig. 4) could apply to many, if not 

most, species in the region. 

Current Activities 

 The NEFSC is monitoring the basic environmental parameters that define the fundamental 

niche of marine fish species: temperature and salinity. The monitoring programs include 

approximately 2000 profiles of temperature and salinity per year. Satellites are used to provide 

high frequency, synoptic measures of surface temperature and chlorophyll distributions. In 
16

addition, the NEFSC is actively involved in the two Regional COOS that operate within the 

Northeast U.S. Continental Shelf: the Northeastern Regional Association of Coastal Ocean 

Observing Systems (NERACOOS; http://www.neracoos.org/) and the Mid-Atlantic Coastal 

Ocean Observing Regional Association (MACOORA; http://www.macoora.org/). 

 The NESFC is also monitoring basic population parameters of a variety of species in the 

ecosystem. Bottom trawl surveys of demersal and some pelagic species are conducted during the 

spring and fall. Samples taken during these surveys are used to determine abundance, 

distribution, growth, age, maturity, sex, and gut contents of a wide variety of fishery species. 

These surveys and vital statistics form the bases for many of the stock assessments conducted by 

the NEFSC. Surveys are also made of bivalve species (scallop, clam), apex predators (sharks), 

and marine mammals. Plankton monitoring occurs across the shelf six times annually; these 

surveys quantify the abundance and distribution of zooplankton - including the early life stages 

of fishery species. 

 Data from these monitoring programs are being integrated to provide a more cohesive view 

of the ecosystem and to distribute this information to a broader audience. Web-based Ecosystem 

Advisories are being produced (http://www.nefsc.noaa.gov/omes/OMES/) that present general 

trends in temperature, primary production and secondary production across the northeast U.S. 

shelf ecosystem. Monitoring and research information has also been used to develop a 

descriptive publication for the general public regarding the ecology of the shelf 

(http://www.nefsc.noaa.gov/ecosystems/Ecosystems.pdf). Finally, presentations are being made 

to the regional fishery management councils to better inform them about the ecosystem and to 

lay the foundation for ecosystem approaches to fishery management. The overall purpose of 

these and other efforts is to present general ecosystem trends on a regular basis to educate 

scientists, managers, and the public as to the structure and function of the northeast U.S. shelf 

ecosystem. Data from these monitoring programs also has provided the foundation for much of 

the research cited above examining links between climate and fisheries on the northeast U.S 

shelf (e.g., Murawski, 1993; Mountain, 2000; Weinberg, 2005, Fogarty et al. 2008). 

 Several projects are underway within the northeast U.S. Continental shelf region as part of 

the NMFS Fisheries and the Environment (FATE) program (http://fate.nmfs.noaa.gov/). These 

projects explore specific environmental mechanisms that influence fisheries. Environmental 

indicators are being developed to assist in the sustainable management of living marine resources 

in a changing climate. 

 NEFSC scientists have also examined the susceptibility of diadromous species to climate 

change focusing on interactions between climate and the complex migrations and specialized 

early life history stages characteristic of these species. American eel spawn in the Sargasso Sea 

in an area that overlaps the spawning area of the European eel. Both species are in decline due to 

recent recruitment failures attributed to the effect of changing sea surface temperature and wind 

conditions in the Sargasso Sea on their leptocephali larvae (Friedland et al., 2007). Atlantic 

salmon, an endangered resource in the Gulf of Maine, migrates to sea as juveniles and must 

contend with the match or mismatch between migration timing and the ocean climate conditions 

affecting their first months at sea (Friedland et al., 2003a; 2003b). In both cases, researchers 

suspect that population dynamics of these species is being affected by basin-scale climate drivers. 

 In addition to larger-scale studies examining the interaction between climate, life history 

stage, and migration, there is also field research underway using acoustic tags to study the short 

term (within season) movements of fishery species within estuaries (bluefish, weakfish and 

striped bass) and on the shelf (yellowtail flounder). This novel approach complements traditional 
17

tagging projects conducted cooperatively with the region’s fishers that include Atlantic cod, 

haddock, black sea bass and sharks (e.g., Hunt et al., 1998; Kohler et al., 1998). The information 

on movement is crucial to understanding how individuals move within their fundamental niche 

and to understanding the environmental conditions associated with and potentially triggering 

movement. This information could then be used to better quantify the spatial and temporal 

overlap of predators, prey, and competitors. 

Research Needs 

• Develop mechanistic understanding regarding the direct effect of environmental variables 

(e.g., temperature, salinity, currents, acidification) on population vital rates (e.g., 

recruitment, growth, maturity, fecundity, calcification), species distribution, individual 

movement, and population spatial structure. 

• Develop population and individual “indicator” variables to gauge the response of species 

to emerging climate patterns with an emphasis on retrospective analyses based on 

previously collected data and archives of biological samples. 

• Incorporate mechanistic understanding into population models and couple these 

population models with climate models to develop forecasts of the effects of climate 

change on population dynamics of managed species. 

 To more fully understand and to be able to forecast the effect of climate change on managed 

species, mechanistic understanding of the effect of the environment on population vital rates and 

spatial dynamics is needed. To develop this understanding, coordinated laboratory, field, and 

modeling efforts are needed. The goal is to quantitatively describe aspects of the fundamental 

niche of each managed species and then forecast how the spatial and temporal distribution of the 

niche changes or how production within the niche changes as a result of several climate change 

scenarios. The approach has been developed for cod and lobster (see Frumhoff et al., 2007; 

Fogarty et al., 2008) and by NMFS/OAR staff for Atlantic croaker. The specific balance of 

laboratory, field and modeling work would vary depending on the species of interest and the 

identified knowledge gaps. 

 An important step would be retrospective analyses of existing laboratory, monitoring and 

field studies. There is already a substantial amount of relevant data for many species and the 

ongoing monitoring programs provide a wealth of data for model development and evaluation. 

Once data gaps are identified, there will be the need for additional field and laboratory research, 

but the type and amount varies from species to species. For example, the temporal and spatial 

distribution of all life stages of Atlantic cod have already been mapped (Fahay et al., 2004) and 

complex individual based models have been developed based on a combination of field work and 

laboratory studies (Lough et al., 2005). These data and models could be combined to model the 

fundamental niche of cod. The next step is coupling these population models with climate 

models to forecast changes in distribution (see Fogarty et al. 2008). The main limitation is the 

ability of climate models to forecast environmental conditions in the ocean (see below). For 

other species, like sea scallops, there is a paucity of basic data regarding the distribution of early 

life stages relative to the environment and very little laboratory information to define the 

fundamental niche for any life stage. The limitations here include laboratory and field data in 

addition to the ability of climate models to forecast environmental conditions in the ocean. 

 The effect of climate on movement and connectivity in marine populations also needs to be 

elucidated. There is a large body of work that describes the effect of temperature and salinity on 

distribution (Murawski, 1993). As temperature changes, distributions will change and there is a 
18

need to understand the links between temperature and distribution and then convert this 

understanding into predictive models. Environment can also affect the timing and magnitude of 

movements and migrations. Our understanding of movement is much less developed than our 

understanding of distribution. Most marine species have dispersive early life history stages and 

movement during these stages is governed by a combination of biological and physical processes 

(Pineda et al., 2007). For most marine fishery species, movement also occurs during the juvenile 

and adult life stages. Traditional and acoustic tags have been used to study movement during 

these stages (see above). Movement, both active and passive over the whole life cycle needs to 

be considered together. Understanding the cues for spawning and for movement are necessary to 

evaluate potential changes in spawning distributions, planktonic transport, and juvenile and adult 

habitat usage. Again, both laboratory and field work is needed to study movement (passive and 

active) of fishery and protected species. Analyses of previously collected data and of data from 

ongoing monitoring programs would contribute to the overall effort. These efforts should be 

within the context of developing mechanistic understanding of the effect of the environment on 

distribution and movement of resource species with the goal of incorporating this understanding 

into population models. 

 Since there are more than 50 managed fishery species that use the northeast U.S. shelf, a 

productive approach would be to identify “indicator” species that represent certain characteristics 

of a group of species and then to develop the forecasting models for these select species initially. 

Such groups could include southern migrants (e.g., Atlantic croaker), cold-water residents (e.g., 

cod or haddock), nearshore species (e.g., winter flounder), benthic invertebrates (e.g. sea scallop 

or surfclam). The focus on “indicator species” would provide a range of anticipated responses for 

the suite of managed species. Once models and forecasts are developed for the “indicator 

species”, work could begin on the other managed species in the system. Further, a process for 

reviewing and revising forecasts could be established so at some interval (5-10 years) managers 

could expect an update on the best scientific information available. 

Resource Needs 

• Increased support for current monitoring programs to collect additional data (e.g., in situ 

primary production, components of the carbonate cycle) to contribute to the development 

of mechanistic understanding and the operational implementation of coupled 

environment-population models. 

• Staff support for retrospective data-mining activities to analyze all relevant laboratory 

and field data regarding environment-population links for managed species in the region. 

• Targeted lab and field studies aimed at developing and testing mechanistic understanding 

of the links between environment and populations and for parameterizing linked 

environment-population models. To conduct the necessary laboratory work, an 

investment would need to be made in the NEFSC seawater laboratory facilities. 

Additionally, ship time and equipment would be required for process-oriented field work. 

Finally, staff would be needed to operate laboratories and conduct field work. 

• Synthesis and modeling activities require staff. Activities would need to be coordinated 

with ongoing monitoring and research activities and with ongoing assessment activities. 

Interactions with climate models would also need to be developed. 
19

Climate Information Needs 

• Standardized hindcasts (past 100 years) of important environmental variables (priority 

should be given to temperature, salinity, and currents) on standard 3D grid of northeast 

U.S. shelf ecosystem. 

• Standardized forecasts (forward 100 years) of important environmental variables (priority 

should be given to temperature, salinity, and currents) on standard 3D grid of northeast 

U.S. shelf ecosystem. Forecasts should be developed for different climate forcing 

scenarios and should include a measure of uncertainty. 

• Ongoing measurement of environmental variables used in a data assimilative approach to 

update climate forecasts on a regular basis. Measurements would need to include more 

emphasis on the ocean interior. 

• Tools to extract pertinent environmental data from climate model outputs for linking to 

environment-population models. 

II. Effects of Changing Environment on Species Interactions 

Description 

The fundamental niche describes the environmental boundaries in space and time within 

which a population can potentially live. As a result of interactions with other species (e.g., 

predators, competitors, prey), the realized niche is narrower and represents a set of 

environmental and biological conditions within which a population can sustain itself. 

 A number of different approaches have been used to examine the effect of environmental 

change on species interactions, but relatively little work has been done in the northeast U.S. shelf 

ecosystem. In one of the few ecosystem-specific examples, Manderson et al. (2007) found that 

predation risk of winter flounder juveniles in estuaries was higher at higher temperatures and 

higher salinities because of the greater spatial and temporal overlap with predators. Thus, climate 

related environmental change could increase or decrease predatory interactions and ultimately 

affect production of winter flounder. Working in the North Sea, another ecosystem at the 

temperate-boreal boundary, Lynam et al. (2005) proposed that climate variability, specifically 

the North Atlantic Oscillation, may mediate the competitive interactions between herring larvae 

and jellyfish, resulting in a cyclic impact on herring recruitment. In another, more distant 

example, Petersen and Kitchell (2001) used a bioenergetic model to estimate that consumption of 

predators on juvenile Chinook salmon was higher during warm decades than cold decades and 

this environment-predation interaction potentially contributed to population variability. In yet 

another example, Ciannelli et al. (2007) inferred that age-0 cod survival in the Barents Sea was 

related to the distribution of older cod; as climate affects the distribution of older cod, the pattern 

of survival of age-0 cod will change resulting in changes in recruitment. These studies indicate 

that climate can affect the dynamics of species interactions, thereby influencing the temporal and 

spatial distribution of the realized niche and population production within the niche space. 

 Since so many of the northeast U.S. shelf fishery species migrate at some portion of the year 

or during some portion of their life cycle, the changes in the phenology or timing of prey, 

predators, or competitors could also greatly influence population productivity. A paradigm in 

recruitment research is the importance of the match of prey production to the spawning time of 

marine fishes (Cushing, 1990). Platt et al. (2003) found that haddock recruitment on the Scotian 

Shelf was correlated to the timing of the spring bloom, with high recruitment in years with an 

earlier bloom. The inference is that earlier blooms provide a better match of prey production for 
20

larval haddock, which results in higher recruitment. Recent work on the northeast US shelf 

(Friedland et al., 2008) has found that timing of the spring bloom is not related to recruitment, 

but the magnitude of the fall bloom is. This dichotomy indicates that the interplay of climate and 

species interactions is likely system and species specific, making the work of forecasting species 

response to climate change a challenging task. 

Current Activities 

 The NEFSC Food Web Dynamics program samples gut contents of fishes collected in the 

Bottom Trawl Survey. This program has been in operation since 1963 and has undergone several 

major changes in sampling protocols. The food habits database contains diet information from 

more than 500,000 stomach samples from over 100 species. These data allow predatory and 

potential competitive interactions to be identified. The other monitoring data described above 

also allows for spatial overlaps among species to be documented and related to environmental 

conditions. 

 In addition, NEFSC scientists have been involved in the U.S. GLOBEC Georges Bank 

Program, a multi-disciplinary, multi-year oceanographic effort. The proximate goal is to 

understand the population dynamics of key species on the Bank: two important fishery species 

(cod and haddock) and several zooplankton species (Calanus finmarchicus and Pseudocalanus 

spp.). The program emphasizes the coupling of these species to the physical environment and the 

links between these species as predator and prey (see Buckley and Durbin, 2006). The ultimate 

goal is to be able to predict changes in the distribution and abundance of these species as a result 

of changes in their physical and biotic environment, as well as to anticipate how their 

populations will respond to climate change. The Georges Bank program is in its final stage of 

synthesis and the U.S. GLOBEC Program is preparing for Pan-regional synthesis, with the goal 

of comparing among marine ecosystems. 

Research Needs 

• Develop mechanistic understanding of the effect of environmental variables (e.g., 

temperature, salinity, currents) on species interactions (e.g., predation, competition, 

phenology). 

• Develop multi-species environmentally explicit population models 

• Couple environment-multispecies models with climate models to develop forecasts of the 

effects of climate change on population dynamics of managed species 

 Quantifying species interactions is a difficult task. Predatory relationships are relatively 

straightforward to document, but the ability of predators to select and switch among prey makes 

modeling the effect of predation on population dynamics more difficult. Identifying competitive 

interactions is even more challenging: species must vie for the same resource and this resource 

must be limiting to one or both species. A combination of laboratory and field studies is 

necessary to understand and develop models of predatory and competitive interactions. Such 

studies must be carefully designed, because the results from short-term experiments do not 

necessarily match those of longer-term experiments and field observations (e.g., Buckel et al., 

1995). 

 In addition to understanding and quantifying species interactions, there is a need to examine 

the role of the environment in mediating these interactions. Quantifying environmental effects on 

predatory and competitive processes is important – for example the effect of temperature on 

consumption, assimilation, and activity (Claireaux et al., 1995). Understanding the effect of the 
21

environment on the distribution and production of species in time and space is also important. 

For example, changing temperature and salinity may change the spatial overlap of predators and 

prey (Manderson, 2007) or may change the temporal overlap of predators and prey (Juanes and 

Conover, 1995), thereby influencing the predatory and competitive interactions. The goal is to 

develop mechanistic understanding, and both laboratory and field research are needed to achieve 

this goal. Again, the specific needs will depend on the species. 

 Of equal importance is developing the population models that include mechanistic 

understanding of the effect of the environment on species interactions. One approach is to use 

discrete-time predator prey models (e.g. Collie and Spencer, 1994) but to include the climate 

effects through individual species models that include direct effects (described in Section I). 

Alternatively, individual-based models can be used to examine the effect of different 

environmental conditions on predator-prey interactions – such an effort could build upon the 

work of Lough et al (2005) on Atlantic cod. A third approach is incorporating environmental 

effects into multi-species Virtual Population Analysis. This approach was used by Jurado-Molina 

and Livingston (2002). They examined the influence of climate on trophicly linked groundfish 

species in the Bering Sea and found that the effects of climate change on recruitment had a 

comparable effect on population dynamics as fishing and predatory interactions (see also 

Livingston, 2000). The important need is the coupling of ecological models with ocean-climate 

models with the specified goal of providing scientific advice and forecasts to managers. 

Resource Needs 

• Investment is needed to redevelop the seawater laboratory facilities necessary to conduct 

the required laboratory research identified above. Additionally, ship time and equipment 

will be required for process-oriented field work. Finally, staff will be needed to operate 

laboratories and conduct field work. 

• Resources and staff are required for synthesis and modeling activities. Activities will 

need to be coordinated with ongoing monitoring and research activities and with ongoing 

assessment activities. Interactions with climate models also will need to be developed. 

Climate Information Needs 

 The climate information needs are the same as described in Section I. 

III. Effects of Climate Change on Ecosystem Productivity 

Description 

 Changes in ecosystem function or structure can impact fisheries separately from direct 

environmental effects and changes in species interactions. Large-scale regime shifts are well 

documented on the west coast (Hare and Mantua, 2000; Hollowed et al., 2001) and their 

influence on fisheries is being considered in the scientific advice process (Livingston, 2000; 

Jurado-Molina and Livingston, 2002). Such large-scale ecosystem changes have only recently 

been recognized on the east coast of North America. Frank et al. (2005) proposed that 

overfishing of benthic groundfish on the Scotian Shelf caused a re-organization of the ecosystem, 

whereby the abundance of small pelagic fishes and benthic macroinvertebrates increased 

markedly. The stability of the new ecosystem state is unknown, as is the potential composition of 

other stable states.
22

 Changes similar to those noted on the Scotian Shelf have been documented in Narragansett 

Bay (an estuary bordering the northeast U.S. shelf), but these changes were linked to warming 

not fishing (Oviatt, 2004). A decrease in benthic groundfish was accompanied by an increase in 

pelagic fish and benthic invertebrates. Large-scale changes have also been noted in the Gulf of 

Maine and Georges Bank, but have yet to be linked to changes in fisheries. Mountain (2004) 

documented multi-year fluctuations in salinity and Greene et al. (2003) and Kane (2007) linked 

these salinity fluctuations to broad changes in zooplankton community structure in the Gulf of 

Maine and on Georges Bank. Work is underway now to understand the effects of these lower 

trophic level changes on fishery species. These studies indicate that the flow of energy in a 

system can change in response to fishing and climate change. A major challenge is 

understanding the system dynamics well enough to establish the cause of such changes and 

anticipate the timing and composition of new system states. 

 There are basic gaps in our knowledge of the northeast U.S. shelf ecosystem that limit our 

ability to describe and understand the response of the system to climate change. For example, in 

a recent review, Purcell (2005) concluded that gelatinous zooplankton will likely increase in 

temperate boreal systems as a result of ocean warming. Attrill et al. (2006) documented an 

increase in the abundance of jellyfish in the North Sea, which was correlated to positive phases 

of the NAO and lowering of pH. They coupled these statistical correlations to a climate model 

and forecasted that jellyfish abundance in the North Sea would increase. Such an increase would 

dramatically change the flow of energy through the system, as well as impact the recruitment of 

some fish species (see Lynam et al., 2005). In the northeast U.S. shelf ecosystem, gelatinous 

zooplankton may be a major component in the movement of energy through the system (Link et 

al., 2006), but our knowledge is incomplete at best and the effect of increases in abundance 

cannot be adequately assessed. Gelatinous zooplankton are but one example of a basic lack of 

knowledge of ecosystem structure that limits predictive capabilities of the effect of climate 

change on fisheries through ecosystem dynamics. 

 Ocean acidification also could have dramatic effects on northeast U.S. resources, but the 

issue is under-studied. Decreases in ocean pH are forecast to occur in the coming decades (Orr et 

al., 2005). These decreases will be caused by the ocean’s uptake of anthropogenic carbon dioxide 

from the atmosphere. Increased ocean CO2 could have severe consequences for calcifying 

organisms (Caldeira, 2007), particularly those that produce aragonite (Orr et al., 2005). Changes 

in ocean CO2 can also affect the physiological functions of fishes, and changes in these functions 

may reduce growth rate and population size (Ishimatsu et al., 2005). These are emerging issues 

that may result in ecosystem-scale changes similar to the effects of changing temperature. 

However, our ability to anticipate, let alone forecast, the effects of ocean acidification are limited 

by a basic lack of research. 

 In addition to changes in structure, at some large-scale, the amount of fisheries production in 

a system is linked to the amount of primary production (Nixon, 1988; Iverson, 1990). Changes in 

the magnitude of primary production could result in changes in the amount of fisheries 

production. Richardson and Schoeman (2004) found that sea surface warming in the Northeast 

Atlantic is accompanied by increasing phytoplankton abundance in cooler regions and decreased 

abundance in warmer regions. In Chesapeake Bay, climatic forcing appears to be a major factor 

in the timing and magnitude of primary productivity (Miller and Harding, 2007). Decreases in 

chlorophyll on the northeast U.S. shelf have been noted 

(http://www.nefsc.noaa.gov/omes/OMES/spring2007/advisory.html), but the causes and 

consequences of these changes on energy entering or moving through the system have not been 
23

investigated. However, there is an interesting correlation; haddock recruitment is highly 

correlated to the magnitude of the fall bloom (Friedland et al., 2008). The mechanisms behind 

the correlation have yet to be investigated but there is some evidence to suggest that climatedriven changes in primary production could impact the region’s fisheries. The challenge is not 

only understanding the relationship between environment and individual species and the 

interactions among several species, but understanding the function of the system as a whole and 

building the tools that can convert this scientific understanding to management advice. 

Current Activities 

 The Energy Modeling and Analysis eXercise (EMAX, Link et al., 2006) was undertaken by 

the NEFSC to evaluate the response of the northeast U.S. shelf ecosystem to a number of human 

perturbations, including climate change. The primary goal of EMAX was to establish an 

ecological network model of the entire food web. The model was parameterized based on the 

extensive datasets collected by the NEFSC over the past four decades. The emphasis is to 

explore the particular role of small pelagic fishes in the ecosystem and preliminary results show 

that these species are clearly keystone species in the ecosystem. The model is now being used for 

comparing the response of sub-artic ecosystems to climate change. In the future, EMAX will 

contribute to the development of Ecosystem-Based Approaches to Fisheries by serving as a 

coherent catalog of information and data, identifying major trophic fluxes in the ecosystem, 

serving as a basis for further analytical models, and acting as a tool for evaluating ecosystem 

responses to various system perturbations. 

 The NEFSC is also reviewing its Ecosystem Monitoring programs with the goal of collecting 

data to support single-species fishery management while also monitoring the biomass and 

production of the different components of the ecosystem. Future programs would build on 

current efforts, but take advantage of new technologies (e.g., video-plankton recorders, wet 

chemistry nutrient sensors) and new platforms (e.g., the NOAA Ship Henry Bigelow, 

autonomous underwater vehicles) to more thoroughly describe the ecosystem and monitor its 

components over time. The information gathered by future programs would support EcosystemBased Approaches to Management and would contribute to developing a quantitative 

understanding of the effect of climate change on fishery resources. The data could also be used 

to develop and evaluate the coupled ocean-climate models that will be used in forecasting the 

effects of climate change. 

Research Needs 

• Development of a suite of ecosystem models including network models, NutrientPhytoplankton-Zooplankon models (NPZ) models, habitat models, size-spectrum models, 

aggregated models that include the effect of the environment. 

• Directed research to understand the effect of ocean acidification on resource species, their 

prey and predators, and overall ecosystem structure and function. 

• Testing and evaluation of model assumptions and development of mechanistic 

understanding linking the environment to ecosystem dynamics 

• Additional data collection to better understand ecosystem structure and function 

including environmental (e.g., pH, dissolved oxygen, nutrients), biomass, and production 

data for understudied species and functional groups (e.g., gelatinous zooplankton, benthic 

epifauna and infauna) and ecosystem-level data (e.g., biodiversity, size-spectra) 
24

 Modeling, monitoring, and research efforts are needed to develop the capacity for assessing 

the impact of climate on ecosystem structure and function to support the development of 

assessments. The EMAX project has developed a network, biomass-based, ecosystem model. 

This model needs to be linked with other regional ecosystem models to begin to understand the 

large-scale functioning of the ecosystem. For example, the northeast U.S. shelf model could be 

linked with estuarine specific models to better understand the importance of connections between 

the shelf and estuarine dynamics (Monaco and Ulanowicz, 1997). Similarly, the shelf model 

could be linked with models both upstream and downstream on the shelf (Bundy, 2005) to 

address the linkages across ecosystem boundaries and the effect that climate may have on these 

linkages. 

 Another approach that could contribute to understanding ecosystem effects on fisheries is 

Nutrient-Phytoplankton-Zooplankton (NPZ) modeling. These models provide a tool to examine 

the movement of energy and nutrients through the lower trophic levels. These NPZ models can 

be linked to individual species models to understand and forecast the effect of changes in the 

ecosystem on specific fishery species (Aydin et al., 2005; Werner et al., 2007). 

 Other modeling approaches need to be investigated including size-spectrum approaches, 

aggregated functional group approaches, and larger-scale ecosystem approaches. The overall 

goal of this work would be developing and evaluating models for their use in forecasting the 

effect of climate change of ecosystem productivity and in this regard the models need to include 

the mechanistic description of the effect of environmental change. These mechanisms can then 

be directly linked to climate forecasts. These models and mechanisms can also be evaluated 

through direct process-oriented research or comparative studies that utilize previously collected 

data. 

 In addition to modeling needs, ecosystem research and monitoring activities need to be 

augmented. There are components of the ecosystem that are not currently monitored, which may 

be very important to the flow of energy through the system (e.g., gelatinous zooplankton). Also, 

our measurement of surface properties is frequent and at fine resolution – satellites sample at 

spatial resolutions of kilometers and temporal resolutions of hours-days – but our measurements 

of subsurface properties is at the scale of 10 km’s and months. New technologies and 

collaborations will be needed to provide data for the ocean’s interior where much of the 

production and flow of energy occurs. Also, as mentioned above the effects of ocean 

acidification on resource species is an emerging issue. There is evidence of dramatic effects on 

resource species, but published studies are scarce. A large-scale effort is needed to determine the 

effects of ocean acidification on marine systems. 

 Finally, the role of Marine Protected Areas (MPAs) in protecting ecosystem structure and 

function in the face of climate change needs to be evaluated. Several studies have pointed out 

that the objectives of spatially fixed management approaches may be eroded by climate change 

(e.g., Burns et al. 2003). An MPA may protect spawning individuals today, but as spawning 

activities shift in response to changing climate, they may move outside of the protected area. 

This recognition requires an assessment of the vulnerability of MPAs to climate change. The 

goals and objectives of the protected area need to be quantified and then evaluated in terms of 

the effect of climate change on these goals and objectives. The individual, multi-species and 

ecosystem understanding described above will be critical to the ability to make these assessments. 
25

Resource Needs 

• Dedicated staff and resource to integrate satellite data and more comprehensive vertically 

discrete data into ecosystem models and fisheries assessments 

• Dedicated staff and resources to develop and apply new technologies to the monitoring of 

marine ecosystems with an emphasis on those components of the ecosystem that are 

linked to environmental and climate change. 

• Dedicated staff and resources to examine the direct and indirect effects of ocean 

acidification on resource species. 

• Dedicated staff and resources to develop, test, and apply ecosystem models that include 

the effect of the environment on ecosystem structure and function 

Climate Information Needs 

• Regional coupled ocean-climate models that include ecosystem dynamics and are linked 

to basin-scale forcing 

• Increased spatial and temporal measurements of the vertical structure of ocean properties 

(e.g., temperature, salinity, nutrients, plankton, components of the carbon cycle) 

• Increased integration of ocean-climate data both from historical and ongoing data 

collection platforms 

 Regional coupled ocean-climate models need to be linked to the models of ecosystem 

structure and function. There are several ways to link ecosystem models (e.g., EcoPath and 

EcoSim) to climate models, but these methods have not been thoroughly evaluated. NPZ models 

have been linked to climate models (e.g., Pierce, 2004) and to the dynamics of higher trophic 

levels (Megrey et al., 2007; Rose et al., 2007). Size-spectrum and aggregate models could also be 

linked, but these modeling approaches and techniques need dedicated investigation. Such efforts 

need to be undertaken on the northeast U.S. shelf and need to occur in collaboration with the 

development of coupled ocean-climate models. One approach is to simply use outputs of climate 

models to force ecosystem models. However, a more productive approach would be the 

development of truly coupled ocean-climate-ecosystem models. The effect of climate on 

ecosystem would be included, but the effects of ecosystem on climate would also be included; 

such feedbacks may be an important component to forecasting climate change. 

 There is also need to include more information about the ocean interior in coupled oceanclimate models. The timing and magnitude of both the spring and fall bloom has been variable 

(see http://www.nefsc.noaa.gov/omes/OMES/spring2006/advisory.html), and there is evidence 

that the change in regional hydrographic properties and water column stratification plays a role. 

Stratification, which is common throughout the northeast U.S. shelf, is important to ecosystem 

dynamics and needs to be represented in coupled ocean-climate models. These processes can 

only be examined with observations made through the water column and with fully 3-D models 

that include the local, regional-scale and basin scales. 

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31

Southeast U.S. Continental Shelf, Gulf of Mexico, and U.S. Caribbean 

Author: 

Michael Burton 

(Southeast Fisheries Science Center) 

Introduction 

 The southeastern United States region includes the continental shelf ecosystem extending 

from Cape Hatteras, North Carolina through to the Texas-Mexico border, as well as the insular 

areas of Puerto Rico and the U. S. Virgin Islands. There are substantial biological, climatic, and 

geological differences between the temperate and tropical areas of the overall managed region. 

These areas are influenced by the warm waters of the Florida Current and its northward 

extension, the Gulf Stream (Fig 1.). The temperate area, represented by wide-shelf systems, 

includes the area from Cape Hatteras to Cape Canaveral, Florida and the Gulf of Mexico. This 

area supports important commercial and recreational fisheries, as well as valuable recreational 

tourist industries such as charter fishing, SCUBA diving, and recreational boating. The tropical 

component of the region is represented by the narrow shelf systems of the area from Jupiter, FL 

to the Dry Tortugas, FL, as well as Puerto Rico and the U. S. Virgin Islands. These areas are best 

known for the presence of coral reefs and the diverse tropical fish communities that accompany 

them. The island regions support important subsistence fisheries as well as tourist industries, 

both dependent on healthy coral reef ecosystems. 

Fig.1. Southeast U.S., Gulf of Mexico and U.S. Caribbean. 

Puerto 

Rico 

U.S. Virgin Islands

Dry Tortugas

Gulf 

Stream 

Gulf of Mexico Jupiter 

Cape Canaveral 

Cape Hatteras
32

Climate Induced Ecosystem Concerns 

 The major climate induced ecosystem concerns for the southeast U.S. continental shelf, Gulf 

of Mexico and U.S. Caribbean in order of importance are: 

I. Threats to coral reef ecosystems: coral bleaching, disease, and ocean acidification 

II. Threats to habitat from sea level rise – loss of essential fish habitat 

III. Climate induced changes to species phenology and distribution 

I. Threats to coral reef ecosystems: coral bleaching, disease, and ocean acidification 

Description 

 Coral reef ecosystems are increasingly recognized in the scientific and management 

communities as among the most threatened ecosystems on Earth. Tropical hard corals are the 

foundation of these ecosystems, building the physical structure which provides fisheries habitat, 

coastal protection, and recreational value. Mass coral bleaching episodes in the Southeast 

(Florida and Caribbean) have been increasing in frequency over the past decades, thought to be 

primarily in response to an increase in high temperature events (Marshall and Schuttenberg, 

2006). 

 Another mechanism of climate impact on corals is disease virulence and the potential for 

coincidence with temperature induced bleaching events (Jones et al., 2004). Recent laboratory 

experiments show that corals affected by yellow band disease suffer significantly greater rates of 

mortality at increased temperature (i.e., 32o

C) than either unaffected corals at 32oC or affected 

corals at moderate temperature (Cervino et al., 2004). Warm temperatures correlate with 

increased incidence of White Pox disease on A. palmata (Patterson et al., 2002). 

Fig. 2. Diseased Elkhorn coral, Acropora palmata. Photo courtesy of Margaret Miller, NMFS, SEFSC, Miami, FL. 

 Thus, coral colonies subject to heat stress may additionally be more susceptible to disease. 

Recent observations following the massive 2005 Caribbean bleaching event support this 
33

possibility. Many bleached colonies in the U.S. Virgin Islands were observed to recover from 

bleaching, but subsequently succumb to disease mortality (Muller et al.,2008; Miller et al., 2006).

 Both shallow and deep water corals are also susceptible to ocean acidification as declining 

pH/carbonate saturation state of seawater reduces the calcification rate of reef-building corals. 

That is, building of coral skeleton and hence, reef habitat for fisheries, becomes more 

energetically expensive and occurs at a reduced rate. This phenomenon, along with bleaching 

and disease, increases the risk to already fragile coral ecosystems. 

 

Fig. 3 Mountainous star coral, Montastrea faveola, showing bleaching and disease. Photo courtesy of Margaret 

Miller, NMFS, SEFSC, Miami, FL. 

 

Current Activities 

 Currently monitoring of coral bleaching events and water quality is being conducted 

throughout the southeastern U.S. and Caribbean in areas where coral bleaching is an issue. The 

NOAA Coral Reef Conservation Program is working to raise awareness of coral bleaching 

events and to identify outbreaks of coral disease. Satellites are used to derive an index of 

cumulative high ocean temperatures, called Degree-Heating Weeks, in order to predict where 

severe bleaching events may occur. There is a cooperative bleaching assessment effort in Florida 

conducted under the auspices of the Florida Reef Resilience Program. 

 Some laboratory experiments are ongoing in various academic laboratories to determine the 

causes and mechanisms of coral bleaching and disease, as well as the impacts of ocean 

acidification on hard corals. Some current research activities are seeking predictive patterns 

between broad scale temperature patterns (e.g. satellite sea surface temperature) and observed 

disease outbreaks. 

Research Needs

 1. Targeted and rapid effort to elucidate the mechanisms and develop strategies to ameliorate 

the synergies of warming, coral bleaching, and coral health/disease. 
34

 There are currently no effective management or mitigation actions to curtail coral mortality 

from bleaching and disease, which will continue to get worse in the near and medium-term future. 

This represents a huge obstacle in effective recovery planning for Endangered Species Act listed 

corals, Acropora palmata and A. cervicornis. Accelerated research activities to determine the 

causes of coral diseases, the ecology of coral microbial pathogens, and the effects of increased 

temperature or acidity on mechanisms of coral resistance/immunity to disease are crucial for 

identifying possible mitigating actions to curtail the accelerating pace of coral loss in Florida and 

the Caribbean. 

 2. Understand the likely effects of increased acidification on larval recruitment of corals. 

 Larval corals of broadcast spawning species lack symbiotic algae and so spend one to several 

weeks swimming in the plankton without the benefit of feeding or photosynthetic subsidy. Hence 

energy may become a limiting factor for these larvae in completing settlement and 

metamorphosis (onset of calcification) when in a more acidic environment. 

 3. Continue documenting species composition, diversity, and abundance of reef fish 

communities under regimes of declining coral habitat and conduct studies to understand fish 

species’ dependence on coral habitat to anticipate changes in species composition. 

 As corals die from bleaching or disease, architectural habitat complexity may be maintained 

by standing dead coral skeletons in the short term. However, increasing erosive processes under 

altered climate regimes (e.g., acidification and/or increased hurricane intensity/frequency) may 

accelerate degradation of reef fish habitat.

Resource Needs

 The resource needs to address coral mortality from bleaching and diseases are acute. A wide 

range of resources (e.g., funding for external grants, laboratory infrastructure for microbial 

challenge experiments, live coral material for laboratory experiments) are needed to accelerate 

research in this area to develop mitigation strategies to abate currently observed rates of coral 

mortality. Such activities could be coordinated via the Coral Disease and Health Consortium. 

Climate Information Needs 

 Predictive capacity for coral bleaching events is fairly well-developed. Climate information 

needs are much greater with regards to acidification/alkalinity. These needs include: 

 1. Seawater pH in reef waters. 

 2. Temporal (e.g., seasonal, decadal) and spatial (e.g., geographic, with depth) variation in 

reef pH. 

 3. Determining predictive relationships or proxies among other environmental factors which 

are easier to measure (e.g. remotely sensed). 

II. Threats to habitat from sea level rise – loss of essential fish habitat 

Description 

 Coastal wetlands in the northern Gulf of Mexico provide critically important fishery habitat, 

supporting large fisheries on shrimp, blue crabs, red drum, southern flounder, spotted sea trout, 

and menhaden. These wetlands are threatened by rising sea level because their existence depends 

upon a balanced tolerance to tidal inundation that will be exceeded under most sea level rise 

scenarios. Increased inundation from sea level rise causes loss of wetlands. Salt water intrusion 
35

kills salt-intolerant vegetation, making barrier islands and wetlands more vulnerable to increased 

wave action and erosion from coastal storms and hurricanes, leading to loss of land. 

 The different bay systems in the Gulf of Mexico vary in their fishery production potential. 

The link between habitat and associated fishery production in these systems, however, is not 

understood well enough to explain this variation, either under current conditions or in the face 

sea level rise under different climate change scenarios. Investment in this area of ecosystem 

science is needed to support future management of the Gulf of Mexico fisheries. 

 Sea level rise could also lead to loss/changes in estuarine habitat and coastal habitat used by 

bottlenose dolphins and their prey. This habitat loss might adversely affect the dolphin 

populations in some or all of the following ways: 

 - Change in prey abundance and/or availability 

 - Change in "nursery" areas for mothers with calves 

 - Disruption of social structure, breeding structure 

 - Disruption of migratory patterns 

Current Activities

 A multi-agency effort is underway to measure sea level rise and assess the rate of land 

(marsh) subsidence in impacted areas such as Louisiana. Since most of the geodetic and water 

level data needed to do this accurately are more than two decades old, NOAA is cooperating 

with local and state agencies in a two-stage approach to acquire the necessary information to 

effectively monitor threats from sea level rise. 

 NOAA Fisheries is conducting inundation analyses to assess the effects of frequency and 

duration of inundation on marsh vegetation by high waters at water level stations. NOAA 

Fisheries Restoration Center is also actively engaged in on-the-ground restoration projects in 

Louisiana. 

 The abundance and distribution of resident estuarine, coastal migratory, and pelagic stocks of 

bottlenose dolphins are monitored along the southeastern U.S. coast using a combination of 

small-boat based and aerial visual surveys. The surveys range in frequency from 

monthly/seasonal to irregular. While none of the abundance estimates are precise enough to 

detect small changes in population trends, they are capable of detecting large changes in 

population size. The detection of fine scale changes in population size will require a more 

detailed monitoring program. The current sampling regime is designed to collect baseline 

population estimates of bottlenose dolphin stocks that can be compared to future estimates in 

order to assess the health of marine mammal stocks. These population assessments will provide 

valuable information to scientists studying the effects of climate variability on living marine 

resources of the southeastern United States. 

Research Needs 

 1. Model effects of changing sea level regimes on fishery production and yields. This 

research would characterize wetland support systems in different estuaries of the northern Gulf 

of Mexico in relation to their potential for fishery production. Specific objectives should include: 

 a. Sample habitat specific densities and measure growth rates of juvenile fishery species 

in a range of estuarine systems of the Gulf using comparable quantitative methods. 

 b. Characterize and predict changes in wetlands by combining analyses of land-water 

patterns derived from remote imagery with field measurements of marsh slope and elevation. 
36

This part of the study will rely heavily on the extensive series of tide gauges already 

established by the National Ocean Service to define current inundation regimes. 

 c. Complete development of production models for key fishery species (shrimp, blue crab, 

red drum, southern flounder and others) and parameterize the models for different estuarine 

systems in the Gulf. 

 2. Select marine mammal stocks with sufficiently large populations and relatively limited 

distribution patterns in areas predicted to experience impacts from climate change and establish 

fine scale monitoring programs aimed at understanding marine mammal ecology, reproduction 

and feeding behavior. Understanding the food habits of most marine mammals is difficult as 

most stomach samples come from sick or stranded animals. More in-depth studies on feeding 

ecology are needed and once major prey sources are identified these trophic interactions, 

including changes in prey distribution and abundance in response to climate change, need to be 

monitored. 

 3. Generate digital elevation models that can be used to assist with the design, construction 

and engineering of new marsh surfaces by linking tidal databases to geodetic databases using 

GPS and leveling techniques. 

Resource Needs 

 We don't have a good handle on what the effect on fisheries production would be for different 

rates of sea level rise. Simulation models should be developed or improved that could predict 

how changes in sea level would affect coastal habitats and the fisheries that depend on them. 

Scale is an important consideration in these models (i.e., models that are relevant at the scale of 

an estuary would be more useful to the fisheries management community than those at the scale 

of the northern Gulf coast). NOAA should dedicate resources to understand the relationships 

among climate change, accelerated sea level rise, wetlands, and coastal fishery production. The 

goal should be to develop simulation models that could predict the change in coastal fisheries 

production from climatic conditions. 

 Monitoring of marine mammal stocks at the intensity necessary to detect small changes in 

population parameters is not possible given current funding and staffing levels. Currently, no site 

is monitored at the level required and monitoring that does occur is conducted irregularly. The 

monitoring would need to be increased by at least an order of magnitude to provide the data 

required to evaluate population parameters. Several estuarine and nearshore sites along the 

Atlantic coast and in the Gulf of Mexico would need to be selected and monitored. Monitoring 

would include satellite-linked telemetry studies to describe habitat usage, sampling to estimate 

abundance, and sampling to monitor changes in other population parameters (e.g., survival, 

disease processes). This would require significant expansion of the marine mammal staff as well 

as significant increases in travel and field operations budgets. Some of the necessary studies 

could be conducted in cooperation with academic programs, but this would not negate the need 

for more FTEs and increased operating budgets. 

Climate Information Needs 

 1. Sea surface temperature over a broad spatial area – necessary to study linkages between 

climate change and distribution of living marine resources, especially pelagic species. 

 2. Bottom temperature data – an important factor for many fisheries species, limiting their 

distribution. 

 3. Long term monitoring of sea level rise at fixed stations located in important wetland areas. 
37

III. Climate induced changes to species phenology and distribution 

Description

 Ocean warming caused by climate change, while not directly causative of marine species 

invasions, could allow establishment of non-indigenous species through changing thermal 

regimes more tolerable to the invasive species. Marine species invasions have the potential to 

lead to fundamental shifts in the ecology of a region by modifying ecosystem processes, 

community composition and food-web dynamics (Verlaque and Fritayre, 1994; Shiganova, 1998; 

Grosholz et al., 2000). Semmens et al. (2004) document 16 non-native species that have been 

seen in biological surveys in the southeastern United States since 1999. The suspected 

mechanism for release in U.S. waters is either ballast water or aquarium release. Lionfish 

(Pterois volitans) is the most recent species to gain notoriety as an invasive species, being found 

in the warm-temperate waters from northern Florida to North Carolina in water depths from 35 

to 90 meters. While lionfish are currently limited to these thermally stable depths by minimum 

winter water temperatures, a warming climate has the potential to increase lionfish growth rates, 

increase the length of the reproductive season, shift the range of lionfish northward, and release 

them from the current depth limits by increased inshore winter bottom temperatures. This would 

allow them to settle in shallower habitats, increase the ecological impact on native community 

species, and would likely result in increased numbers of negative human interactions as more 

divers and fisherman encountered their venomous spines. 

 Two climate change impacts on fisheries are: a) shifts in spawning seasons (observable 

through either gonadosomatic indices of adult fish from fishery-dependent samples or spawning 

date back-calculations from juvenile fish in a fishery-independent survey); and b) changing 

migration dates / routes in coastal pelagics such as cobia and mackerel. These could be related to 

climate change either directly (i.e., increasing seawater temperatures result in longer spawning 

seasons) or indirectly (changing temperatures influence prey availability, disrupting migration 

patterns). In the case of expanded spawning seasons, those stocks of fish could be subjected to 

extra fishing pressure due to the targeting of spawning aggregations. The disruption and altering 

of migration routes, evolved over generations, could lead to reproduction failures and stock 

collapse. These changes are difficult to discern given the extent of annual variation and require 

long-term (20 years +) monitoring. A third possible impact is the effect of changing climate on 

basic life history parameters such as growth rates. Environmental variability can strongly affect 

fish growth, though the degree of this influence is still poorly quantified for many species. Such 

studies would require high quality, long-term time series of growth data. 

 Climate change also has the potential to affect sea turtles. All sea turtle species studied to 

date exhibit temperature-dependent sex determination, with higher incubation temperatures 

producing a greater number of female hatchlings (Mrosovsky, 1994). As a result, if sea turtles 

continue to only use existing nesting sites, increases in global temperatures will increase the 

proportion of females in sea turtle populations and an insufficient number of males in breeding 

populations may limit reproductive success. Within the aquatic environment, as sea turtles are 

predominantly poikilothermic organisms, their northern range is limited by water temperature, 

with individuals most often preferring temperatures of 14oC or greater (Witzell and Azarovitz, 

1996). Increases in overall water temperature may result in extended foraging seasons in 

northern areas, or an overall shift in foraging habitat, if tropical areas become unsuitable due to 

extremely high temperatures. This expansion or shift of sea turtle habitat northward along the 
38

coast has the potential to increase interactions with fishing gears that might account for a rise in 

anthropogenic mortality. Increased contact between animals originating from diverse areas in 

newly-available foraging habitats has the potential to facilitate transmission of diseases into 

previously unaffected areas. Although fibropapilloma (FP), a potentially lethal, tumor-causing 

disease, has typically only been found in turtle populations inhabiting tropical areas such as 

Florida and Hawaii, recently FP has been detected in two turtles from North Carolina waters, a 

previously unaffected area (Harms et al., 2004). Additionally, increased water temperatures can 

exacerbate the severity of symptoms in diseased turtles (George, 1997). On a broader scale, 

warming water temperatures and increased sea levels have the potential to appreciably modify 

extant oceanic current regimes, which would affect migratory pathways, foraging habitat 

availability, and feeding strategies for all sea turtle life stages, oceanic and neritic. The El Niño 

Southern Oscillation in the Pacific has been linked to the availability of prey and the frequency 

of leatherback (Saba et al., 2006) and green turtle (Limpus and Nicholls, 1988) nesting, 

suggesting that altered current regimes could significantly influence the reproductive success of 

sea turtles. 

 Climate change will inevitably affect ocean processes and hence marine life on all space and 

time scales. For example, global scale changes in ocean circulation will eventually affect 

regional and local marine populations due to the connectivity of the ocean current systems. A 

slowing down or speeding up of the Atlantic Subtropical Gyre will cause changes in the Loop 

Current and Gulf Stream that may dramatically affect larval distribution patterns in the 

Caribbean and Gulf of Mexico. Feedback mechanisms between large-scale meteorological 

phenomena, such as the North Atlantic Oscillation, and the inter-tropical convergence zone, sea 

surface temperatures and wind-driven currents may have important implications for the regional 

ecosystems and will need to be taken into account for successful, sustainable fishery 

management.

Fig. 4. Lionfish, Pterois volitans, feeding on purple reef fish on hardbottom habitat off North Carolina. Photo 

courtesy of Doug Kesling, NOAA, NURC, UNC-Wilmington. 
39

Current Activities

 NMFS and NOS research at the NOAA Beaufort Laboratory is assessing the ecological 

impacts of lionfish on marine ecosystems of the western Atlantic; developing a quantitative 

model of dispersal aimed at understanding the mechanisms influencing the spread of lionfish, 

assessing human interactions and impacts, and evaluating factors facilitating the introduction in 

the hopes of using this information to prevent, mitigate, and manage future introductions. 

Researchers have initiated the long term monitoring of bottom seawater temperatures and fish 

community composition at several offshore sites in order to better understand the link between 

climate change and changing biodiversity. 

 Currently the SEFSC conducts fishery dependent sampling programs in recreational and 

commercial fisheries from North Carolina throughout the entire Gulf of Mexico. Samplers 

collect hard parts for ageing and gonads for reproductive studies as requested. Most of this work 

concentrates on data needs of stock assessment scientists for updated age-growth studies. 

MARMAP conducts fishery independent sampling in the Atlantic Ocean from North Carolina 

waters to Florida, collecting mostly adult fishes using trap and hook and line gear. Otoliths and 

gonads are collected on all fishes. The archived otolith databases from these surveys could yield 

valuable information about the effect of climate change on growth rates of reef fishes as well as 

to changes in timing of annuli deposition that might occur due to changing water temperatures. 

Additionally, there is one long-term fishery independent survey collecting larval and juvenile 

fishes systematically at one location, the Beaufort Bridge-net Survey. Specimens collected from 

this survey could be processed for back-calculation of spawning dates to determine if climate 

change is affecting timing of reproduction in fishes. 

 SEFSC researchers have recently initiated a study examining the usefulness of 

dendrochronology (tree ring techniques) to better understand these interrelationships between 

recruitment, growth, and the effects of climate variability. Using archived red snapper (Lutjanus 

campechanus) otoliths, scientists are developing a high-resolution chronology using ring widths 

of otolith growth increments. Red snapper is sufficiently long-lived to construct a chronology 

several decades in length. As indicated by periods of episodic recruitment, including several 

years since 1989, red snapper may be sensitive to environmental variability. If climate is an 

important driver of the ecology and reproduction of this species, awareness of climate-growth 

relationships may help improve management of this valuable species. 

 In 1980 NMFS formally established the Sea Turtle Stranding and Salvage Network (STSSN) 

with the intent of documenting sea turtle strandings along the Atlantic and Gulf coasts of the U.S. 

The network mainly encompasses the coastal areas of eighteen states from Maine to Texas, and 

is carried out through cooperation with the U. S. Fish and Wildlife Service and the wildlife and 

fisheries agencies specific to each participatory state. Network participants collect detailed 

information regarding all reported strandings, including date, location, species, condition, 

whether any tags are present on the turtle, size, weight, and any distinguishing marks. When 

possible, necropsies are conducted to attempt to determine cause of death and the sex of the 

stranded animal. Stranding information is compiled within a centralized STSSN data base that is 

made available to the public (http://www.sefsc.noaa.gov/seaturtleSTSSN.jsp). 

 Beginning in 1988, NMFS established a long-term sea turtle research program to assess sea 

turtle populations in the inshore waters of North Carolina. NMFS biologists accompany pound 

net fishermen to their nets and any captured turtles are measured, tagged, and sampled. This 

study has made it possible to collect information regarding growth rates, sex ratios, genetic 

structure, and seasonal distributions. In addition, the project provides estimates of abundance and 
40

demographic parameters (such as survival, recruitment, emigration, and immigration) needed to 

construct accurate population assessments. Since 2004, an additional component of this project 

has involved outside collaborations to measure physiological variables in wild juvenile 

loggerhead sea turtles to develop baseline health indices and examine seasonal and multiple year 

trends. In-water sea turtle monitoring is also being conducted by a university led effort in the 

Mosquito and Indian River Lagoon system on the east coast of Florida. In addition, a number of 

nesting beach surveys are in place that provide important information regarding survival and 

trends in nesting populations. All data currently being collected by these studies are valuable 

baseline information against which to assess the health of future populations in the face of 

changing climate regimes. 

 The data yielded by the various aspects of both of these long-term programs assist with 

determining the current status of sea turtle populations, which in turn provides a benchmark 

against which to detect future changes that may occur in response to environmental pressures, 

including climate change. 

Research Needs 

1. In situ ecological community studies of the warm-temperate waters off the SE coast are 

needed. As invasive species (e.g., lionfish) successfully establish populations, the potential for 

them to alter the native community assemblage increases, especially as climate change leads to 

more favorable environmental conditions. There is a need to collect baseline data for fishes, 

corals, algae, and other invertebrates to quantify changes attributed to these invasions. Repeated 

sampling of the warm-temperate community, at a variety of inshore and offshore locations, will 

establish a baseline of community assemblage structure and will allow any community shifts to 

be detected in the face of natural background inter-annual variability. By monitoring cryptic and 

small taxa in addition to more conspicuous ecosystem inhabitants, researchers may be able to 

elucidate phase shifts and ecosystem flips that are difficult to quantify. This would improve our 

understanding of ecosystem structure, help identify essential fish habitat (with regards to food, 

cover, spawning, nursery, etc.) and assist in the conservation and management of fishery 

resources throughout the region. 

 2. Studies on biology, reproduction and ecology of all invasive species, including lionfish, 

are needed to better understand the role of climate change in the success or failure of attempts to 

establish invasive populations. 

 3. New observational oceanographic process studies are needed to better understand how 

future climate change will affect fisheries issues. For example, the linkage between larval 

distributions and ocean currents could be examined by interdisciplinary field operations in 

critical areas. 

 4. Numerical models will be critical to providing an understanding of the interconnection 

between meteorological forcing, ocean conditions and currents, and fisheries issues as the 

climate changes. Observations will also be needed for calibration and validation of these 

numerical models before they can be used in a predictive mode. 

 5. Additional in-water sea turtle research programs located in inshore, nearshore, and 

offshore areas along the Atlantic and Gulf coasts are needed. Only through increased effort will 

it be possible to establish a solid baseline of knowledge regarding sea turtle population 

characteristics and distribution against which potential changes, including those brought about by 

climate change, can be detected. 
41

Resource Needs 

 Scientists at the Beaufort Laboratory are currently monitoring invasive lionfish occurrence 

and abundance at 12 hardbottom stations off North Carolina. This number of stations should be 

increased and funds provided to ensure regular long-term monitoring at these sites. Sampling 

should be initiated at inshore sites, where reduced temperature variability resulting from climate 

change is most likely to lead to increased establishment of lionfish and increased chances of 

human encounter. Collection of bottom seawater temperature data at a larger number of offshore 

and inshore stations is necessary to predict the potential range expansion of invasive species in 

light of climate change. Additionally, monitoring of south Florida reefs for potential 

establishment of other invasive species documented there by Semmens et al. (2004) should be 

initiated, along with increased collection of seawater temperatures. This effort would leverage 

ongoing efforts that document instances of coral bleaching and disease throughout the Florida 

reef tract. 

 Additional resources (personnel and research dollars) are needed to continue and expand the 

type of extended larval/juvenile fish sampling (e.g., Beaufort Bridge net survey) necessary to 

document changes in life history parameters (growth rates, reproductive timing) that may be 

affected by changing climate. 

 Existing in-water sea turtle surveys in North Carolina provide essential demographic 

information, but due to lack of full time personnel and funding, it has not yet been possible to 

determine specific habitat requirements and usage patterns for the sea turtle species inhabiting 

this area. Such information is vital for providing a baseline against which future impacts due to 

climate change can be compared. Expanding the geographic scope of in-water surveys is equally 

critical if we are to obtain data that can provide a true picture of sea turtle population status and 

trends. Success of current and future in-water projects is contingent upon commitment of 

additional funds, particularly to support permanent employees that can provide program 

continuity and can also address additional research questions that existing staff have not yet been 

able to investigate. 

 Additional funding to cover costs of telemetry (satellite, radio, and sonic) and habitat 

sampling equipment, as well as research vessel use, is also needed. Of particular interest in North 

Carolina is the establishment of an acoustic detection array of wireless radio-linked hydrophones 

whose components could detect turtles outfitted with sonic tags operating within a certain range 

of frequencies (e.g. Grothues et al., 2005). Given that access to North Carolina’s extensive 

inshore sound system is limited to a small number of inlets, positioning detection buoys at key 

locations within the sounds, as well as the inlets, would yield invaluable information regarding 

residency and habitat use. At least one other such acoustic array is already operational along the 

east coast of the U.S. (Grothues et al., 2005) and therefore if turtles tagged in North Carolina 

migrate to locations in the vicinity of other arrays, they would also be detected there. 

Climate Information Needs

 1. Bottom temperature data is the limiting factor in the expansion of invasive species such as 

lionfish to inshore areas (Kimball et al., 2004). Enhancement of our capability to predict lionfish 

range expansion into inshore areas requires the increased collection of bottom temperature data 

into more inshore stations. Bottom temperature data is also needed to understand the ecosystem 

dynamics of important fishery species (e. g., shrimp, flounder) in the northern Gulf of Mexico 

under climate change scenarios. 
42

2. Analyses of the effects of climatic conditions on sea turtle distribution require continuing 

access to environmental data such as sea surface temperature, tidal patterns, and the presence, 

absence, and nature of major current systems and eddies. 

References 

Cervino J. M., R. L. Hayes, S. W. Polson, S. C. Polson, T. J. Goreau, R. J. Martinez and G. W. 

Smith. 2004. Relationship of Vibrio species infection and elevated temperatures to yellow 

blotch/band disease in Caribbean corals. Applied and Environmental Microbiology 70: 

6855–6864. 

George, R. H. 1997. Health problems and diseases of sea turtles. In: Biology of Sea Turtles, vol. 

I (eds. P. Lutz and J. Musick,). CRC Press, Boca Raton, p. 363. 

Grosholz, E. D., G. M. Ruiz, C. A. Dean, K. A. Shirley, J. L. Maron and P. G. Connors. 2000. 

The impacts of a nonindigenous marine predator in a California bay. Ecology 81: 1206-1224. 

Harms, C. A., G. A. Lewbart, J. Beasley, A. M. Mexas, T. L. Reynolds, D. E. Malarkey, and L. 

H. Herbst. 2004. Fibropapillomas in loggerhead sea turtles in North Carolina, USA. 24th 

Annual Symposium on Sea Turtle Conservation and Biology, San Jose, Costa Rica, 22-29 

February. 

Jones R. J., J. Bowyer, O. Hoegh-Guldberg and L. L. Blackall. 2004. Dynamics of a 

temperature-related coral disease outbreak. Mar. Ecol. Prog. Ser. 281: 63-77. 

Kimball, M. E., J. M. Miller, P. E. Whitfield and J. A. Hare. 2004. Thermal tolerance and 

potential distribution of invasive lionfish (Pterois volitans/miles complex) on the east coast of 

the United States. Mar. Ecol. Prog. Ser. 283: 269-278. 

Limpus, C. J. and N. Nicholls. 1988. The Southern Oscillation regulates the annual numbers of 

green turtle, Chelonia mydas, breeding around northern Australia. Australian Wildlife 

Research 15(2): 157-161. 

Marshall, P. A., and H. Z. Schuttenberg. 2006. A Reef Manager’s Guide to Coral Bleaching. 

Great Barrier Reef Marine Park Authority, Australia (ISBN 1-876945-40-0). 

Miller, J., R. Waara, E. Muller, and C. Rogers. 2006. Coral bleaching and disease combine to 

cause extensive mortality on reefs of the US Virgin Islands. Coral Reefs 25:418. 

Muller, E. M., C. S. Rogers, A. S. Spitzack, and R. S. van Woesik. 2008. Bleaching increases 

likelihood of disease on Acropora palmata. Coral Reefs 27:191-195. 

Patterson K. L., J. W. Porter, K. B. Ritchie, S. W. Polson, E. Mueller, E. C. Peters, D. L. Santavy, 

and G. W. Smith 2002. The etiology of white pox, a lethal disease of the Caribbean elkhorn 

coral, Acropora palmata. Proceedings of the National Academy of Sciences, USA 99: 8725-

8730. 

Saba, V. S., P. Santidrian-Tomillo, R. D. Reina, J. R. Spotila, F. V. Paladino, J. A. Musick, and 

D. A. Evans. 2006. ENSO determines the reproductive frequency of eastern Pacific 

leatherbacks. In: Book of Abstracts. Twenty Sixth Annual Symposium on Sea Turtle 

Biology and Conservation (compilers M. Frick, A. Panagopoulou, A. F. Rees, and K. 

Williams). International Sea Turtle Society, Athens, Greece, p. 355. 

Semmens, B. X., E. R. Buhle, A. K. Salomon, and C. V. Pattengill-Semmens. 2004. A hotspot of 

non-native marine fishes: evidence for the aquarium trade as an invasion pathway. Mar. Ecol. 

Prog. Ser. 266: 239-244. 

Shiganova, T. A. 1998. Invasion of the Black Sea by the ctenophonre Mnemiopsis leidyi and 

recent changes in pelagic community structure. Fish Ocean. 7: 305-310. 

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Witzell, W. N., and T. Azarovitz. 1996. Relative abundance and thermal and geographic 

distribution of sea turtles off the U.S. Atlantic Coast based on aerial surveys (1963-1969). 

NOAA Tech. Memo. NMFS-SEFSC-381. National Marine Fisheries Service, Miami, Florida. 
44

California Current Ecosystem 

Authors: 

William Peterson 

(Northwest Fisheries Science Center) 

Franklin Schwing 

(Southwest Fisheries Science Center) 

Introduction 

 The California Current Ecosystem (CCE) is designated by NOAA as one of eight large marine 

ecosystems (LMEs) within the U.S. exclusive economic zone. However, the CCE is typified by 

latitudinal gradients in both physical forcing and biological response. The northern end of the 

current is dominated by strong seasonal variability in winds, temperature, upwelling, plankton 

production and the spawning times of many fishes, whereas the southern end of the current has 

much less seasonal variability in these parameters. For some groups of organisms, the northern end 

of the CCE is dominated by sub-arctic boreal fauna whereas the southern end is dominated by 

tropical and sub-tropical species. Faunal boundaries, i.e., regions where rapid changes in species 

composition are observed, are known for the waters between Cape Blanco Oregon and Cape 

Mendocino California, and in the vicinity of Point Conception California. Higher trophic level 

organisms often take advantage of the strong seasonal cycles of production in the north by 

migrating to the region during the summer to feed. Animals exhibiting this behavior include 

pelagic seabirds such as black-footed albatross and sooty shearwaters, fishes such as Pacific 

whiting and sardines, and humpback whales. 

 Climate and ecosystem studies in the North Pacific have been assigned a high priority by 

NOAA because climate signals in this region are quite strong. During the past 10 years, the North 

Pacific has seen two El Niño events (1997/98, 2002/03), one La Niña event (1999), a four-year 

climate regime shift to a cold phase from 1999 until late 2002, followed by a four-year shift to 

warm phase from 2002 until 2006. The response of ocean conditions, plankton and fish to these 

events is well documented in the scientific literature. The biological responses are often so strong 

that the animals themselves give an early warning before such shifts are noticed in the physical 

oceanographic records. 

Climate Induced Ecosystem Concerns 

 In the CCE, numerous climate stressors (e.g., warming, sea level rise, freshwater flow) 

impact productivity and structure throughout the ecosystem. It is difficult to isolate the effect of 

individual stressors on most individual species, and most of these stressors impact many species 

at multiple trophic levels. Overall, the climate-species linkages in the CCE are extremely 

complex. With this caution, we highlight the most important climate-induced concerns below, 

and identify species or species groups that reflect the response of the system to those concerns. 

The five issues of greatest concern in the CCE are: 

I. Increased variability in climate forcing 

II. Changes to the magnitude and timing of freshwater input 
45

III. Changes in the timing and strength of the spring transition and their effect on marine 

populations 

IV. Ocean warming and increased stratification and their impact on pelagic habitat 

V. Changes in ocean circulation and their impact on species distribution and community 

structure 

I. Increased variability in climate forcing 

Description 

 One of the likely consequences of global climate change will be a more volatile climate with 

greater extreme events on the intraseasonal to interannual scales. For the CCE this will mean 

more frequent and severe winter storms, with greater wind mixing, higher waves and coastal 

erosion, and more extreme precipitation events and years, which would impact coastal 

circulation and stratification. Increased variability in physical forcing could translate into 

problems for living marine resources of the CCE. For example, in the Pacific Northwest the 

summer of 2005 was characterized by a three-month delay to the start of the upwelling season 

resulting in a lack of significant plankton production until August (rather than the usual AprilMay time period). Thus fish, birds and mammals that relied upon plankton production occurring 

at the normal time experienced massive recruitment failure. In contrast, the summer of 2006 had 

some of the strongest upwelling winds on record yet many species again experienced recruitment 

failure, in part because there was a one-month period of no winds (mid-May to mid-June) that 

occurred at the time when many bird and fish species are recruiting. The northern California 

Current appears to have recovered from the two summers of poor productivity -- the ocean was 

cold during the winter of 2006-07, the spring transition to upwelling conditions was very early 

(February), and zooplankton biomass returned to levels not seen since summer of 2004. 

 Some global climate models predict a higher frequency of El Niño events, while others 

predict the intensity of these events will be stronger. If true, primary and secondary production 

will be greatly reduced in the CCE, with negative effects transmitted up the food chain. 

 Most models project roughly the same timing and frequency of decadal variability in the 

North Pacific under the impacts of global warming. However, combined with the global 

warming trend, the CCE is likely to experience a greater frequency of years consistent with 

historical periods of lower productivity, e.g., positive Pacific Decadal Oscillation (PDO) values. 

We know from ongoing observations that a positive PDO (corresponding to warmer ocean 

conditions in the California Current) results in dominance of small warm-water zooplankton 

(which are lipid-depleted) which may result in food chains with lower bioenergetic content. By 

about 2030, it is expected that the minima ocean temperatures due to decadal variability will be 

above the historical mean of the 20th Century (i.e., the greenhouse gas warming trend will be as 

large as natural variability). 

Current Activities 

 Studies by NMFS scientists at NWFSC and SWFSC encompass ecosystem-scale data 

collection, assessments and forecasts. Research includes assessing, understanding and predicting 

the effects of climate and environmental variability on the production of living marine resources, 

ecosystem structure and ecosystem function. 

 Numerous sea-going observation programs contribute to our understanding of living marine 

resources, their environment, and relationships to climate variability. There are a number of 
46

surveys focused on particular fisheries, including surveys for pelagic fish (Northern Anchovy 

and Pacific Sardine), juvenile salmon, Pacific whiting, pre-recruit rockfish and other groundfish, 

and adult groundfish. There are also surveys of protected marine species, including surveys for 

west coast cetaceans, coastal pinnipeds, coastal cetaceans, gray whales, and coastal leatherback 

turtles and their jellyfish prey. In addition, some surveys document ocean conditions through 

hydrographic measurements and sampling of plankton, euphausiids, and larval fish (Figures 1 

and 2). The CalCOFI surveys of the southern California Current pelagic ecosystem conducted in 

cooperation with Scripps Institution of Oceanography and California Department of Fish and 

Game have been conducted continuously since 1949, making this an invaluable record of climate 

variability in the CCE, particularly for temperature and salinity changes (DiLorenzo et al., 2005) 

and euphausiids (Brinton and Townsend, 2003). Data from many of these observation programs 

are being integrated to provide a comprehensive view of the CCE and for distribution to 

constituents through publications and web pages (e.g. Peterson et al., 2006b; 

http://www.nwfsc.noaa.gov/research/divisions/fed/oeip/a-ecinhome.cfm). 

 Research being conducted at the Northwest Fisheries Science Center that relates to climate 

and ecosystems includes studies of the oceanographic factors that lead to harmful algal blooms in 

coastal waters off Washington (in particular in waters within and adjacent to the Olympic 

National Marine Sanctuary) with an eye towards determining if a warmer and more stratified 

ocean will lead to increased incidence of HABs. Research has begun on causes of hypoxia in the 

central Oregon “dead zone” to determine its potential impact on zooplankton – does low oxygen 

kill eggs of krill and copepods? If so, the dead zone could have a large impact on zooplankton 

production. Related to this, research continues on the dependence of copepod and euphausiid 

production rates on phytoplankton blooms. Finally, research is focused on determining the 

potential impacts of climate change on juvenile salmonids both in their natal freshwater streams 

as well as in the ocean – top-down and bottom-up effects on salmon growth and survival are 

emphasized both in freshwater as well as in the ocean. The need for freshwater studies is 

outlined in the next section of this report. 

 Scientists in the Southwest Fisheries Science Center are involved in a variety of areas of 

research concerned with how climate influences on the ocean environment affect the dynamics 

of marine resources. Beginning in 1986, standardized annual midwater trawl surveys provided 

information on the abundance and distribution patterns of pelagic juvenile rockfish off central 

California in relation to their habitat. Research on the ocean ecology of juvenile salmon off 

California determines interannual variability of juvenile salmon physiology and the influences of 

biotic and abiotic environmental factors. Advanced survey technologies, including acoustics and 

submersibles, employ non-intrusive in situ survey techniques to perform stock assessments and 

abundance estimates of several stocks, including endangered populations. Telemetered tagging 

of highly migratory and anadramous species allow tracking of these animals and mapping their 

environment. Ship surveys assess the abundance and distribution of marine mammals and to 

characterize the pelagic ecosystem off the U.S. West Coast. Aerial censuses of pinnipeds monitor 

trends and abundance of CCE populations. 

 The Pacific Coastal Ocean Observing System (PaCOOS, http://www.pacoos.org/) has been 

established to integrate and provide the ecosystem observations and information needed for 

management of fishery resources, protected marine mammals, marine birds, and turtles, and to 

forecast the ecosystem consequences of fisheries removals, environmental variability and climate 

change in the CCE. 
47

Figure 1. Location of regular CalCOFI survey grid. 

This grid has been sampled since 1984 on a quarterly 

basis. 

Figure 2. Location of Newport Line (at 44°40’N) 

that has been sampled for hydrography and 

zooplankton biweekly since 1996; location of broadscale survey transects sampled by the Bonneville 

Power Administration supported program in May, 

June and September for hydrography, zooplankton 

and salmon since 1998; location of transects south of 

Newport sampled for hydrography and zooplankton 

(1998-2003) and salmon (2000, 2002), and by 

PaCOOS when NOAA ships become available.

 NMFS efforts in the CCE include a wide variety of modeling activities. Stock assessments 

are conducted for those fishery populations managed by the Pacific Fisheries Management 

Council, and for a number of marine mammals and sea turtles. Diagnostic studies use individualbased models, lower trophic level and statistical models, and more complete coupled physicalbiological and ecosystem models to understand trophic relationships and to develop indicators of 

environmental variation. Ecosystem models, such as Atlantis, are now being applied to simulate 

the California Current fishery ecosystem, examine fisheries management options, and project the 

ecological impacts of climate change. With genetic models, researchers are looking at population 

structure and dispersal. In general, however, these models are only beginning to consider the 

influences of climate variability in their assessments and forecasts. 

 In addition to traditional stock assessments, NMFS scientists are developing and distributing 

a variety of data products and assessments. The long tradition of developing data bases and 

conducting research on west coast fishery-related effects of natural environmental variability is 

being refocused to incorporate aspects of anthropogenic climate change. A number of projects, 

supported by the NMFS Fisheries and the Environment (FATE) program, are developing and 
48

evaluating leading ecological indicators for west coast populations, including salmon, hake, 

rockfish, and small pelagics, and the lower trophic levels that are the forage base for these 

populations. These products are being developed in the context of an ecosystem approach to 

fisheries management, and specifically as indicators for the CCE Integrated Ecosystem 

Assessment (IEA) process. 

Research Needs 

A workshop was convened November 2006 in La Jolla, CA focused on climate impacts on 

the California Current ecosystems. 45 academics and 15 state and federal employees from 

various west coast institutions attended the workshop. A science plan was developed based upon 

the workshop discussions. The plan emphasized the development of the ability to forecast the 

response of lower trophic level organisms and living marine resources to climate variability and 

change through increased frequency of physical and biological observations in the California 

Current, and through development of better coupled physical-biological models of the Current. 

The elements and products of that plan are as follows: 

• Develop wind-driven coupled physical-biological models. 

• Coordinate coast-wide observations and data sets that improve model validation. 

• Forecast recruitment of zooplankton and pelagic fish species 6-12 months in advance, 

based on data from long-term observing systems and atmospherically forced coupled 

physical-biological oceanographic models. 

• Develop and evaluate ecological indicators and integrated ecosystem assessments that 

describe the state of the California Current, in collaboration with the NOAA FATE 

program. 

• Increase simulation modeling efforts to address climate change impacts to the CCE. 

Moreover, efforts need to be initiated that seek to downscale global climate models to 

regional and local conditions. Specific classes of regional models that are needed include 

coupled physical-biological models, individual based models of zooplankton and 

euphausiids, and ecosystem modeling. 

• Develop regional scenarios of ecosystem response to climate change based on climatedriven ecosystem models that are run in an “if-then” mode. 

• Provide data and information for the pilot Integrated Ecosystem Assessment (IEA) of the 

California Current, one of the NOAA Regional Priority Areas. 

• Provide web-based access to data, model output, and reports which assess the status of 

the California Current for selected regions. Examples include reports prepared in British 

Columbia and Newport and that are available at http://www.pac.dfompo.gc.ca/sci/psarc/OSRs/Ocean_SSr_e.htm and 

http://www.nwfsc.noaa.gov/research/divisions/fed/oeip/a-ecinhome.cfm

• Conduct annual “State of the California Current” stakeholders meetings. 

 Resource Needs 

 The greatest needs are for funds to maintain on-going long-term observation programs (e.g., 

ship-based surveys conducted in the Southern California Bight, Monterey Bay, Arcata, and 

Newport), glider surveys off S. California, Oregon and Washington, and CODAR stations 

(which measure surface currents off Oregon and California). The latter two efforts (gliders and 
49

CODAR) have begun to be funded through the Regional Associations (discussed below), 

however ship-based surveys continue to struggle. 

 The CCE is covered by three of the eleven geographically distinct members of the National 

Federation of Regional Associations that comprise the coastal ocean component of IOOS. These 

are the Northwest Association of Networked Ocean Observing Systems (NANOOS, 

http://www.nanoos.org/), the Central and Northern California Ocean Observing System 

(CeNCOOS, http://www.cencoos.org/), and the Southern California Ocean Observing System 

(SCOOS, http://www.sccoos.org/). These Regional Associations (RAs) are comprised of NOAA 

and other federal, state and local agencies, academic institutions, non-government organizations, 

resource managers, and industry, and coordinate ocean observing activities and apply regional 

solutions to societal problems. They are key in integrating and leveraging ongoing work. The 

three west coast RAs have received multi-million dollar awards from NOAA to support 

modeling, moorings, CODAR and modeling of the coastal part of the California Current. 

Missing are funds to support biological observations programs. 

Climate Information Needs 

 Climate information needed for the California Current ecosystem concerns will come from 

four categories of NOAA climate data: i) climate data archived at NODC and NCDC, ii) global 

and regional monitoring, iii) coupled biophysical models, and iv) climate products and forecasts. 

Climate data 

• Climate data and products from NOAA data centers are needed to provide the climate 

forcing and environmental context for characterizing and understanding climate impacts 

on the CCE. These data allow critical retrospective analyses to study past climate 

variability and forcing for coupled models. 

• Climate data and information is needed as the basis for developing science-based 

operational indicators for resource managers to implement climate variability to decision 

and policy making. Particular to this concern is the need to adequately describe 

conditions during interannual (e.g., ENSO) and decadal extremes. 

• Continuity of satellite data and products is vital to provide full, high-resolution spatial 

coverage of important forcings and indicators of state – winds, SST, altimetry, currents, 

and ocean color. 

Monitoring 

• Large-scale monitoring (e.g., ARGO) will provide gyre-scale circulation that drives 

regional circulation, material transport, and the distribution of source waters. Variability 

in basin circulation and in source waters which feed the California Current related to 

climate change is responsible for much of the forcing of the CCE. 

• Because ecological interactions occur near the coast and on small spatial scales, better 

monitoring in the coastal region is needed.

• Maintaining NDBC monitoring and data archives will ensure information about regional 

climate forcing.

Models 

• Modeling of climate and atmospheric and oceanic physics needs to be linked with similar 

work being carried out by NOAA and its partners. NOAA GFDL is working to build 

coupled physical-biological models as part of an Earth System Model, so there is 

potential for collaboration. The GFDL global climate model is particularly attractive 
50

because it is able to simulate the PDO and other key climate variability signals. Another 

strong area of collaboration will be with NOAA NCEP’s environment modeling activities. 

Climate products and forecasts 

• Indicators and indices of climate variability (e.g., SOI, PDO) are needed as proxies for 

quantifying the state and tendency of climate forcing and environmental conditions. 

• Seasonal and longer-term forecasts and projections are necessary for forcing coupled 

physical-biological models and implement into management strategies and stock 

recovery plans. Seasonal climate forecasts (NOAA OAR ESRL) and models will be 

needed to couple to ecological models for seasonal population forecasts. They will be 

critical components of Integrated Ecosystem Assessments, and may ultimately be useful 

in adjusting fishing quotas. 

• ENSO forecasts (NOAA NWS CPC) are useful for projecting future conditions in the 

CCE, but additional research is needed to understand the mechanisms linking equatorial 

ENSO processes and teleconnections with California Current conditions and their 

populations. Not all past El Niño events have had the same impact on the CCE. 

II. Changes to the magnitude and timing of freshwater input 

Description 

 The focus is anadramous fish such as salmon that use the Columbia, Klamath and 

Sacramento River systems. While variability in ocean conditions has substantial impacts on 

salmon survival and growth, future changes in freshwater and river conditions will likely have a 

great effect on salmon production. 

 Warmer air temperatures will result in more precipitation and less snowpack per unit of 

precipitation. Changes in the seasonal and interannual timing and intensity of rainfall and 

snowpack, for example, are likely to increase winter and spring runoff but decrease summer 

runoff. This may change the way the water of the Columbia and Sacramento Rivers is managed 

for hydropower generation and water storage, which in turn may affect the way salmon and 

estuarine-dependent species would need to be managed. 

 Climate models project the 21st Century will feature greater annual precipitation in the 

Pacific Northwest, extreme winter precipitation events in California, and a more rapid spring 

melt leading to a shorter, more intense spring period of river flow and freshwater discharge 

(Figure 3). This will greatly alter coastal stratification and mixing, riverine plume formation and 

evolution, and the timing of transport of anadramous populations to and from the ocean. Current 

allocation of western U.S. water resources between salmon and human requirements has been a 

critical factor in the success of many salmon populations, and will be more so if future water 

availability is altered. 

 Likely impacts of climate change on Pacific salmon include the following: 

• Altered stream flow and warmer temperatures will reduce the available habitat, life 

history diversity and freshwater survival rates for juvenile salmon. 

• Altered air temperatures will increase heating of mainstem reservoirs and affect juvenile 

and adult salmon survival and passage timing through sections of regulated rivers such as 

the Columbia, Klamath, and Sacramento. 

• Changes in coastal ocean habitat quality due to changes in productivity and seasonal 

cycles of production, and food chain bioenergetics. 
51

Figure 3. Annual April-July unimpaired runoff in the Central Valley (CA) compared to total annual runoff. Blue 

curve is nine-year moving average. Dashed line is linear trend prior to 1945; solid line is linear trend after 1945. The 

reduced April-July runoff is due to a reduced seasonal Sierra snowpack and more rapid melting. (Courtesy of 

Michael Dettinger, USGS). 

Current Activities 

 1. Since 1998 the Northwest Fisheries Science Center has conducted hydrographic, plankton 

and pelagic fish surveys in May, June and September. This research program focuses on climaterelated interannual variations in abundance of juvenile coho and Chinook salmon, and the 

variability of their pelagic ocean habitat. One goal is to forecast coho and Chinook returns at 

least one year in advance, and to determine the influence of climate change on these rates. 

 2. The Southwest Fisheries Science Center conducts hydrographic and plankton surveys off 

northern and central California, with a focus on fall Chinook salmon populations that originate 

from the Sacramento system and coastal rivers. These surveys, in combination with the 

Northwest Fisheries Science Center studies, will allow study of differences in the response of 

regional salmon populations to climate change. Of particular interest is the potential for 

alongshore gradients in temperature and transport in the California Current and the differential 

response of California stocks as compared to Oregon or Washington stocks. 

 3. Puget Sound monitoring and modeling studies include juvenile outmigrant sampling along 

the eastern side of Puget Sound to characterize the seasonal and annual variation in juvenile 

salmon abundance and size distributions in different riverine, estuarine and nearshore habitats. 

Information on seasonal habitat use is used to model priority-rearing habitats for protection and 

restoration under alternative future conditions. Modeling and statistical analyses related to 

climate impacts on salmon include those highlighting the primary freshwater, estuarine and 

ocean drivers of salmon population dynamics and diversity and explorations of the effectiveness 

of protection and restoration strategies on salmon populations in the face of alternative climate 

futures. 

 4. Freshwater studies within the Columbia River and its tributaries include prediction of 

stream flow and temperature changes in Columbia River mainstem and tributaries, evaluation of 

changes in survival of all Chinook salmon life history types in relation to changes in stream flow 

and temperature (using rivers with flow diversions as an analogue to rivers affected by climate 

change), long-term monitoring of juvenile salmon migration and survival in selected tributaries, 
52

through the main stem, and estuary, and development of salmon habitat restoration strategies that 

are robust to climate change. 

 5. The Klamath River Chinook salmon assessment is being conducted to improve forecasts of 

Chinook salmon returns to the Klamath River system. Incorporating climate change via 

environmental variables into estimates of return abundance of California Chinook salmon may 

increase the accuracy and precision of these estimates (Wells et al., 2007). Spring ocean 

conditions have a direct effect on Chinook salmon maturation, and are used to estimate return 

numbers a year in advance. Freshwater resources in the Klamath basin are critical to Chinook 

survival (cit.), so variability in stream flow can help forecast adult returns. 

Research Needs 

 A holistic approach to salmon management and salmon recovery efforts, which is focused on 

the combined effects of climate change on the oceanic and freshwater habitats of Pacific salmon, 

is needed because (a) global warming will likely have dramatic and predictable impacts on both 

marine and freshwater ecosystems, and (b) changes in oceanic and freshwater productivity each 

account for a significant share of the interannual variability in the population dynamics of Pacific 

salmonids. These stocks have never been studied in such a holistic manner. Success will depend 

on collaborations between freshwater, ocean and atmospheric scientists. Specifically, we need to: 

• Develop a research program to determine how interannual and decadal variations in 

climate affect simultaneously the coastal ocean ecosystems (where most salmon growth 

occurs) and the freshwater ecosystems (upon which Pacific salmon rely for spawning and 

rearing habitats). 

• Develop improved understanding of potential responses of Pacific salmon in freshwater 

and coastal ecosystems to climate-related habitat changes including sea level rise, 

changes in stream flow and temperature regimes, and shifts in the ENSO cycle and 

climate indices such as the PDO. 

• Identify salmon populations that are most sensitive to climate change, and develop longterm strategies for salmon recovery that are robust to climate change, compatible with 

societal goals, and meet NOAA’s regulatory mandates for commercial fish and 

endangered species. 

Resource Needs 

 What is most needed is funding that would bring together a team of NOAA and academic 

atmospheric, freshwater and marine scientists with expertise in climate modeling, weather 

prediction and freshwater and marine habitat studies. 

Climate Information Needs 

• In addition to the information needs described in Concern I, data and models specific to 

quantifying and forecasting regional precipitation and stream flow patterns is critical. 

• Climate information and predictions for watershed and ocean habitats are needed, 

including observations and predictions of weather patterns, stream flows, snowpack, and 

ocean properties. 
53

III. Changes in the timing and strength of the spring transition and their effect on marine 

populations

Description 

 The focus is on primary and secondary production and the timing of the spring bloom, 

upwelling, and length of the upwelling season. Sentinel species of concern include zooplankton, 

krill, sablefish, some rockfish, and sea birds. This is a research focus for the northern and central 

California Current, where upwelling is strongest. 

 Phenology is the study of the timing of recurring natural phenomena, and has been 

principally concerned with the dates of first occurrence of natural events in their annual cycle. In 

the ecological literature, the term is used more generally to indicate the time frame for any 

seasonal phenomena, including the dates of first and last appearance of a migratory species. 

Because many such phenomena are very sensitive to small variations in climate, especially to 

temperature, phenological records can be a useful proxy for temperature in the study of climate 

change. 

 The chief phenological issues for the CCE relate to the onset and length of the upwelling 

season. The interest is when the upwelling season begins and ends, both physically and 

biologically (i.e., the spring and fall transitions). These are the onset and end of physical 

upwelling and when the shelf-slope zooplankton community transitions between a winter-time 

Davidson current (warm water) community and a spring-summer upwelling (cold water) 

community. The biological transition times provide an estimate of when seasonal cycles of 

significant plankton and euphausiid production are initiated. 

 Coastal upwelling has become stronger over the past several decades due to greater contrasts 

between warming of the land (resulting in lower atmospheric pressure over the continent) 

relative to ocean warming. The greater cross-shelf pressure gradient will result in higher 

alongshore wind speeds and the potential for more upwelling (Bakun, 1990). Regional climate 

models project that not only will upwelling-favorable winds will be stronger in summer, but that 

the peak in seasonal upwelling will occur later in the summer (Snyder et al., 2003). 

Future climate scenarios indicate greater variability in seasonal climate forcing, which could 

lead to stronger interannual variability in the timing of the upwelling season. It has also been 

projected that the onset of seasonal upwelling in spring will be delayed, with a later peak in 

summer upwelling. Animals (such as whiting, sardines, shearwaters, leatherback turtles, and blue 

whales) that migrate both to and within the CCE to take advantage of feeding opportunities 

associated with the seasonal cycle of production, and time their spawning, breeding or nesting with 

peaks in the seasonal cycles of production, may have to make adjustments in the timing of such 

activities.

 Even though southward winds that cause coastal upwelling are likely to increase in 

magnitude, these winds may be less effective in driving vertical transport of nutrient-rich water. 

Given that the future climate will be warmer, the upper ocean at the basin scale will almost 

certainly be, on average, more stratified. This will make it more difficult for winds and upwelling 

to mix the upper layers of the coastal ocean, and will make offshore Ekman pumping less 

effective at bringing nutrients into the photic zone. The result will be lower primary productivity 

everywhere (with the possible exception of the nearshore coastal upwelling zones). 

 Finally, should global warming result in shorter winters in the north Pacific, areas where 

production is light limited, e.g. the northern California Current, may see higher productivity. 

Phytoplankton blooms are initiated as early as February off northern California in years when 
54

storm intensity is low, as has been the case in most years since 2002. These early blooms result 

in bursts in egg production by both copepods and euphausiids, initiating a cohort of animals that 

reach adulthood one-two months earlier than a cohort that is initiated with the onset of upwelling 

in March or April. The result would be a longer plankton production season. Alternatively, 

regional climate projections are for a later shift in the start time, peak times and end of the 

upwelling season, which could counter the idea of a longer upwelling season. 

 Interest in, and awareness of, phenology of organisms in the CCE is very high among 

fisheries oceanographers because of events observed during the summer of 2005. During that 

summer, the onset of upwelling was delayed by several months leading to a delay in plankton 

production. Delayed lower trophic level production was accompanied by (a) a failure of many 

rockfish species to recruit, (b) low survival of coho and Chinook salmon, (c) complete nesting 

failure by the sea bird, Cassin’s Auklet, and (d) widespread deaths of other seabirds such as 

common murres and sooty shearwaters. Organisms such as whiting, sardines, shearwaters, and 

blue and humpback whales that migrate within the CC to take advantage of feeding opportunities 

associated with the seasonal cycle of production, encountered poor feeding conditions upon their 

arrival in spring 2005 (Sydeman et al., 2006; Mackas et al., 2006; Schwing et al., 2006; Kosro et 

al., 2006). 

 Similar mismatches have occurred in recent years in which upwelling began early (as in 2006 

and 2007) but was interrupted at a critical time (May-June). Marine organisms that had come to 

exploit expected production peaks, found little food. The organisms which seem to be the most 

affected by delayed upwelling include juvenile salmon that were just entering the coastal ocean 

in April/May, whiting that were migrating northward, seabirds which are nesting at that time and 

all other animals that migrate to the northern California Current in summer to feed. Both salmon 

and seabirds experienced increased mortality in 2006 and 2007, attributed to poor ocean 

conditions over a relatively short period in late spring. 

Current Activities 

 Ongoing ocean sampling programs that aid in the study of questions related to changes in 

upwelling and phenology were listed under Concern I, above. 

Research Needs 

 Study of phenology requires precise knowledge of when the upwelling season begins and 

ends, when marine organisms reproduce, and when migrants arrive at/depart from their feeding 

grounds. A number of data sets exist (see current activities under Concern 1) which should be 

analyzed by various techniques to provide insight into these issues. However, to attain high 

precision, phenological studies will require new observational efforts to collect data routinely at 

high frequency (preferably daily, although weekly could be acceptable). 

In addition, coastal ocean models are needed to provide analysis of upper ocean conditions, 

including transport of nutrients into the photic zone, and future (synoptic to seasonal) forecasts 

of coastal upwelling. In combination with the data sets mentioned above, new and improved 

indices of upwelling should be developed, tested, and made operational. Variations in coastal 

upwelling can have significant impacts on fish populations and other biological components in 

coastal ocean ecosystems. Therefore, it is critical to accurately estimate and forecast upwelling 

and its ecological impacts for the benefit of fisheries and ecosystem management. While existing 

upwelling indices have been reliable in scores of oceanographic and biological studies, there are 

limits to their use due to their coarse spatial resolution and the simple application of Ekman 
55

theory. Improvements to this index to explain the biological impacts of upwelling can be made in 

several areas, including: a more realistic and higher-resolved wind product, the inclusion of 

ocean structure, and short-term predictions based on forecast winds. 

Resource Needs 

 Support for more high frequency field observations of organisms in their environment and 

data analysis is needed. The most efficient use of resources would be to add more frequent 

measurements at selected stations which are part of existing observation programs and are 

convenient to marine laboratories such as off Newport. 

Climate Information Needs 

 Since climate change is likely to affect upwelling in various (poorly understood) ways, we 

have the following information needs relative to climate change and upwelling response. 

• Dates of spring and fall transition, length of upwelling season, overall average magnitude 

of upwelling, and some measure of the frequency of upwelling events in relation to 

meanders in the jet stream (sensu Bane et al., 2007). A forecast of the approximate date 

of spring transition would be useful in forecasting migration and recruitment for many 

species. 

• An index of when the upwelling system has truly transformed from a winter unproductive 

state to a summer productive state. This will require an index of biological variables. 

• Actual measures of the effectiveness of upwelling in terms of the depths from which 

water upwells, and the nutrient content of that water. A connection between upwelling 

and stratification will allow study of the biological effectiveness of upwelling. 

• Better spatially-resolved coastal wind fields, from satellites or blended measuredmodeled products. 

• Improved atmospheric models with high-resolution winds, ocean models with upper 

ocean and coastal circulation and density and nutrients 

• Improved regional climate models with projections of the timing, intensity and location 

of coastal upwelling. 

• Ocean models with reliable coastal physics and high resolution to capture Ekman 

transport and ocean stratification, and can be coupled to biological models to determine 

phytoplankton production, biomass, subduction, and grazing. 

• Forecast models to give short-term and seasonal predictions of wind forcing and 

upwelling in coastal areas. 

• An El Niño/La Niña forecast to assist in determining the timing and strength of upwelling, 

as well as the quality of source water. 

IV. Ocean warming and increased stratification and their impact on pelagic habitat

Description 

 This concern is focused on the central and southern California Current, and on the organisms 

that utilize the upper ocean habitat in this region. 

 Generally warmer ocean conditions will cause a northward shift in the distribution of most 

species, and possibly the creation of reproductive populations in new regions. Existing faunal 

boundaries are likely to remain as strong boundaries, but their resiliency to shifts in ocean 

conditions due to global climate change is not known. 
56

 Warmer air temperatures will increase the heat flux into the ocean. Mixing and diffusion are 

not likely to redistribute this heat rapidly enough to prevent an increase in thermal stability and 

stratification of the coastal CCE. The vertical gradient in ocean temperature off California has 

intensified over the past several decades (Palacios et al., 2004) (Figure 4). Roemmich and 

McGowan (1995) credited this change in temperature structure for the observed long-term decline 

in zooplankton biomass. Areas with enhanced riverine input into the coastal ocean will also see 

greater vertical stratification. Moreover, increased melting of glaciers in the Gulf of Alaska 

coupled with warmer sea surface temperatures will result in increased stratification of the Gulf. 

Since some of the source waters that supply the northern CC originate in the Gulf of Alaska, more 

stratified source waters will contribute to increased stratification of coastal waters of the northern 

CC. 

Figure 4. Time series of variables defining stratification in a 1° coastal box off central California (36°N 127°W 

southwest corner of box), 1950-93. Top panel is maximum vertical gradient in ocean temperature (°C/m), middle 

panel is depth of maximum gradient (m), bottom panel is temperature at that depth (°C). Light grey curves are 

monthly series, colored curves are 37-point moving averages. Black lines are linear trend for series. Adapted from 

Palacios et al. (2004). 

The long-term observations program in Monterey Bay is suggesting that as a result of 

increased stratification, the phytoplankton community is changing from one dominated by 

diatoms to one dominated by dinoflagellates (Francisco Chavez, MBARI, pers. comm.). 

Although we do not know what impact this might have on zooplankton grazers, it is clear that 

diatoms are the primary source of lipids that contribute to lipid- and energy-rich food chains. 

Dinoflagellates on the other hand are more protein-rich. 

Current Activities 

Field observations programs were listed under Concern I. Each of those activities has the 

capacity to investigate how changes in ocean temperatures, water column stratification, and the 

Max 

Zmax

Tmax
57

potential for changes in phytoplankton species will affect sentinel species and other living 

marine resources through changes in species composition at the base of the food chain. 

In addition, recent developments in telemetry and biologging technology have greatly 

enhanced our ability to enlist apex marine predators to sample their environment. Biologging is a 

particularly effective observing strategy, as it enables large-scale monitoring of species’ ranges 

and distributions while collecting large quantities of oceanographic data at the scale of the 

animals’ behavior. These animals can be instrumented with electronic tags to identify their 

critical foraging habitats, migration corridors, and regions of high occupancy, i.e. biological hot 

spots, and how climate variability affects the distribution, size, and character of these hot spots. 

The Tagging of Pacific Pelagics (TOPP) program, a Census of Marine Life pilot project, has 

tagged 23 species in the eastern Pacific and acquired over 200,000 days of data between 2002-06 

on species movements and behaviors. From this data set, various regions of the California 

Current System have emerged as important hot spots for a number of apex predators. How robust 

these locations are to future climate change is not known. 

Research Needs 

• Long term surveys must be maintained of coastal pelagic species (e.g. anchovy, sardine, 

jack mackerel, Pacific mackerel, market squid). The surveys need to cover the geographic 

spawning range of these species, as well as the geographic dispersion of their juvenile 

stages, and measure critical environmental variables sensitive to climate variability 

(temperature, salinity, nutrients, currents, chlorophyll, zooplankton size and species 

composition). 

• Surveys are needed to provide information on the survival of eggs and larvae into the 

juvenile stages and contribute to estimates of climate influences on recruitment. These 

surveys also would provide the data necessary to resolve current uncertainties regarding 

impacts of climate variability on stock structure, migration patterns, geographic variation 

in vital rates and trophic interactions. 

• Because coastal pelagic species respond to climatic forcing, detailed information on their 

life histories is required to accurately forecast population trajectories. 

• Because coastal pelagic species are the forage base for many of the piscivorous fish, 

marine mammal and seabird populations in the CCE, knowledge of trophic interactions is 

required to understand their roles in the functioning of the system. Such information is 

necessary if we are going to be able to predict the likely consequences of depletion of a 

given forage fish species in the context of climate change. 

• Similarly the CalCOFI program, through the PaCOOS program, needs to be expanded to 

include the surveys off Eureka (CA), Oregon and Washington such that climate-related 

changes in stratification and lower trophic level organisms can be evaluated within the 

entire CCE. 

• Continued deployments of electronic tags on targeted marine predators are needed to 

expand our monitoring of temporal variability in species ranges and distributions. These 

data also provide significant information on the physical structure of the ocean. 

Resource Needs 

New surveys could be conducted as an extension of the spring and summer (or fall) CalCOFI 

surveys. The CalCOFI surveys are currently limited to the Southern California Bight (San Diego 

to Point Conception) with limited coverage further north to San Francisco. Thirty sea days on a 
58

second research vessel will be required to provide near-synoptic coast-wide coverage (Baja 

California to British Columbia). In addition, support for additional sample processing and 

enhanced data management will be required. Also, funding for increased use of electronic tags 

on marine predators will be needed. 

Climate Information Needs 

• In addition to the climate information described in Concern I, this concern requires data 

on the factors that contribute to upper ocean stratification. These include coastal wind 

(for estimating wind stress, mixing, and latent heat exchange), air-sea heat fluxes, and 

streamflow and freshwater discharge throughout the CCE region. 

• High-resolution synoptic mapping of ocean variables that define biological “hot spots” 

must be maintained to monitor changes in the pelagic habitat and relations to climate 

variability. 

• Regional models with reliable precipitation and stream flow projections are necessary to 

model future coastal pelagic ocean conditions. 

• IPCC projections of future temperature and stratification are needed to allow long-term 

estimates of changes in upper ocean structure and productivity, which will determine the 

pelagic habitat for many coastal species. 

V. Changes to ocean circulation and their impact on species distribution and community 

structure 

Description 

 This is a climate-induced ecosystem concern primarily for the northern California Current, 

although changes in transport are known to have subtle effects on the entire Current. A particular 

biological concern here is variability in the transport of organisms, which impacts zooplankton 

species composition and regional recruitment patterns for demersal fish stocks. 

 Decadal variations in regional water mass characteristics such as salinity, nutrients, and 

chlorophyll are linked to shifts in regional and large-scale circulation (Parrish et al., 2000; 

DiLorenzo et al., 2008). The circulation of the North Pacific subtropical gyre combines with 

regional and local upwelling and advection, creating a complex coastal circulation. Basin-scale 

adjustments in the subtropical gyre due to changing global wind stress curl are thought to be a 

principal factor in these decadal fluctuations within the CCE, and can explain variations in 

regional water mass characteristics and related biological variables that are not correlated with 

surface indicators such as the PDO. 

 The California Current extends from the northern tip of Vancouver Island, Canada to 

southern Baja California, Mexico. As the current flows from north to south, the waters warm 

and mix with offshore waters such that both temperature and salinity increase gradually in a 

southward direction. Not surprisingly, observations of the biota of the California Current show 

pronounced latitudinal differences in the species composition of plankton, fish, and benthic 

communities, ranging from cold-water sub-arctic species in the north to warm-water subtropical 

species in the south. Changes in abundance and species composition can be gradual in some 

cases, but it is widely accepted that ocean faunal boundaries (zones of rapid change in species 

composition) are present in the vicinity of Capes Blanco and Mendocino, and at Point 

Conception. Strongest contrasts are seen during summer. 
59

Figure 5. Schematic of the flow of the North Pacific Current 

south into the California Current and north into the Gulf of 

Alaska. Cool years (such as La Niña and negative PDO years) are 

associated with greater flow into the California Current, which 

favors a southward displacement of cold-water and warm-water 

species. 

 A strong contrast in species composition is also seen between the continental shelf and 

offshore waters during summer, due to the upwelling process. A combination of upwelling and 

sub-arctic water that feeds the 

inshore arm of the northern end of 

the CCE creates conditions 

favorable for development of a 

huge biomass of sub-arctic 

zooplankton. During the cool phase 

of the PDO, all of the northern 

CCE becomes more sub-Arctic in 

character (both shelf-slope-oceanic 

regions); during the warm phase, 

the water masses and associated 

copepod community become more 

similar to a sub-tropical 

community. During the warm 

phase copepod biodiversity 

increases in coastal waters, due to 

shoreward movement of offshore 

waters onto the continental shelf, 

caused by either weakening of 

southward wind stress in summer 

or strengthening of northward wind 

stress in winter. Thus, when the 

PDO is in the warm phase, a 

greater proportion of the water 

entering the northern end of the 

Current is sub-tropical in character 

rather than sub-Arctic. 

 Regardless of the season, the 

source waters that feed into the 

California Current from the north 

and offshore can exert some 

control the over the phytoplankton 

and zooplankton species that 

dominate the current (Figure 5). 

Hooff and Peterson (2006) suggest 

that knowledge of source waters is 

critical to understanding ecosystem 

dynamics in the shelf waters of the Northern CCE because waters from the Gulf of Alaska carry 

large, lipid-rich copepods to the shelf waters, whereas waters coming from an offshore source 

carry small, oceanic lipid-poor copepods to the shelf waters. Thus changes reflected by PDO 

shifts may result in local food chains that have vastly different bio-energetic content. Given, for 

example, that (a) salmon returns are low when the PDO is in a positive, warm-water phase, but 

high when the PDO is negative, and (b) salmon returns to Pacific Northwest rivers are highly 

correlated with copepod community structure (Peterson and Schwing, 2003, Peterson et al., 
60

2006b) variations in the bio-energetic content of the food web may represent a mechanistic link 

between PDO sign change and salmon survival. 

 Northward shifts in distribution of zooplankton and fish species are also possible. Generally 

warmer conditions could result in a northward shift in the distribution of some species, and 

possibly the creation of reproductive populations in new regions. Examples include Pacific 

whiting, which migrate farther north during warm summers. A long-term shift toward greater 

(lesser) abundance of southern (northern) fish (W. Watson, NOAA/SWFSC, personal 

communication; Peterson et al., 2006a) and intertidal (Barry et al., 1995) species is thought to be 

due to warmer (cooler) conditions, which in part is the result of reduced (increased) southward 

transport. Moreover, there is evidence that both whiting and sardines are now spawning in waters 

off Oregon and Washington (R. Emmett, NOAA/NWFSC, personal communication). 

 Alternatively, if upwelling strengthens due to global climate change, regardless of the sign of 

the PDO, cold-water species should still be favored in the coastal upwelling zones. However, the 

onshore-offshore gradients in temperature and species abundance should strengthen if offshore 

waters become warmer and upwelling becomes stronger, creating stronger upwelling fronts, and 

perhaps a greater level of mesoscale activity. It is unclear how faunal boundaries might be 

affected. 

 West coast groundfish stocks are characterized by highly variable recruitment, with 

interannual variation in cohort strength often ranging over two orders of magnitude. This 

variation in reproductive success is the predominant source of variation in stock productivity, 

such that knowledge of impending recruitment has the potential to significantly increase the 

accuracy of stock assessment forecasts and annual catch limits. However, we now know that the 

coastwide distribution of age-0 pre-recruit rockfish is strongly affected by ocean climate 

conditions, requiring a large-scale survey to adequately characterize interannual variation in 

year-class strength. Since 2001, efforts by the SWFSC and the NWFSC have resulted in a 

coordinated coastwide survey of pre-recruit groundfish (i.e., rockfish and Pacific whiting) that is 

capable of providing informative indices of impending recruitment. However, this broader scale 

survey has revealed significant changes in the distribution of young of year (YOY) groundfish, 

apparently in response to changing ocean conditions. Notably, beginning in 2004 certain stocks 

of rockfish have developed a more southerly YOY distribution, while others have become 

increasingly distributed to the north (Steve Ralston, NOAA/SWFSC). These findings provide 

clear evidence of latitudinal shifts in distribution and ecosystem restructuring and point toward 

the kinds of biological changes we can expect from climate change. 

 Another aspect of the local circulation that is thought to be related to zooplankton population 

abundance and fish habitat size is the level of mesoscale structuring of continental shelf waters, 

e.g., the level of eddy kinetic energy (EKE) caused by the development of fronts and eddies in 

the alongshore flow. Initial studies provide some evidence that local levels of EKE in the 

California Current is related to the PDO (J. Keister and T. Strub, Oregon State University, 

personal communication), and it has been suggested that the complexity of coastal circulation is 

related to the speed of the subtropical gyre (U.S. GLOBEC Reports 11 and 17). 

Current Activities 

 See list of monitoring efforts identified in Concern I. 
61

Research Needs 

To better understand linkages between climate forcing, transport of the California Current, 

and changes in food web structure, we need new research that will achieve the following goals: 

• Understand the degree to which climate variability leads to variations in the large-scale 

circulation and source of water transported into the California Current and how these 

variations may be related to food chain structure (size and bioenergetic content of 

phytoplankton and zooplankton) and recruitment success of planktivorous fishes in the 

California Current; 

• Use remote sensing data to identify physical oceanographic features (fronts, eddies) that 

appear to be linked with spatial variation in biological features such as chl-a, zooplankton 

and fish distributions, and determine how climate variability may affect such features. 

• Characterize the interannual variations in size of suitable habitat for juvenile rockfish and 

adult small pelagic fishes, using time series of satellite data and in situ observations. 

• Develop regional coupled bio-physical models capable of accurately resolving seasonal 

and longer variability in the large-scale and mesoscale circulation of the California 

Current and transport of key physical, chemical, and biological components. 

To accomplish these four goals, we need to focus on how sub-basin scale winds affect the 

transport of different water types that enter the northern California Current, using both the 

altimeter (sea surface height) and QuikSCAT (winds). SST and ocean color data could be 

applied to identify large scale and mesoscale physical and biological oceanographic features such 

as fronts and eddies, and when linked to meteorological forcing, should provide a better 

understanding of the coupling between meteorological events and physical oceanographic 

features in continental shelf and slope waters off Washington, Oregon and California. 

Resource Needs 

• Existing long-term surveys must be maintained, especially the central California 

midwater trawl (juvenile rockfish) surveys, Newport time series and the newlyinaugurated time series at Eureka. 

• Expand sardine, anchovy, rockfish and whiting surveys coast-wide where possible. 

• Make greater use of data streams from satellites (sea surface height, winds, SST, color). 

• Improve models relating transport and water mass type to biology. 

 Additional staffing will be required as this would allow a more comprehensive evaluation of 

potential applications of the coast-wide midwater trawl (juvenile rockfish) survey, including 

characterizing interannual variation in community composition of rockfish as well as 

micronekton in relation to the ocean environment. Currently, observations aboard the chartered 

F/V Excalibur, a 65’ trawler, are limited to biological sampling of the catch. Enhanced 

hydrographic capability aboard that vessel (e.g., CTD casts) would significantly increase our 

understanding of epipelagic habitat variability over the entire west coast continental shelf and 

slope during the peak of the upwelling season. 

Climate Information Needs 

• Water mass climatology and anomaly fields (using water mass characteristics to 

distinguish water type and sources in near real-time), and satellite and blended satellitemodel reanalysis products to provide the details of water sources and transport patterns in 

near real-time. 
62

• Basin-scale ocean circulation observations and models to determine changes in gyre 

circulation and source and advection of water mass types. 

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247: 198-201. 

Bane, J. M., Y. H. Spitz, R. M. Letelier and W. T. Peterson. 2007. Jet stream intraseasonal 

oscillations drive dominant ecosystem variations in Oregon’s summertime coastal upwelling 

system. Proc. Natl. Acad. Sci. 104(33): 13262-13267. 

Barry, J. P., C. H.Baxter, R. D. Sagarin and S. E. Gilman. 1995. Climate-related, long-term 

faunal changes in a California rocky intertidal community. Science 267: 672-675. 

Brinton, E. and A. W. Townsend. 2003. Decadal variability in abundance of the dominant 

euphausiid species in the southern sectors of the California Current. Deep-Sea Res. II-Topical 

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DiLorenzo, E., A. J. Miller, N. Schneider and J. C. McWilliams. 2005. The warming of the 

California Current: dynamics and ecosystem implications. J. Phys. Oceanogr. 35: 336-362. 

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North Pacific Gyre Oscillation links ocean climate and ecosystem change. Geophys. Res. 

Lett., 35, L08607, doi:10.1029/2007GL032838. 

Hooff, R. C. and W. T. Peterson. 2006. Recent increases in copepod biodiversity as an indicator 

of changes in ocean and climate conditions in the northern California current ecosystem. 

Limnol. Oceanogr. 51: 2042-2051. 

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versus biological spring transition: 2005, Geophys. Res. Lett., 33, L22S03, 

doi:10.1029/2006GL027072. 

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anomalies in the California Current system before and during the warm ocean conditions of 

2005, Geophys. Res. Lett., 33, L22S07, doi:10.1029/2006GL027930. 

Palacios, D. M, S. J. Bograd, R. Mendelssohn, and F. B. Schwing. 2004. Long-term and seasonal 

trends in stratification in the California Current, 1950-1993. Journal of Geophysical 

Research- Oceans 109 (C10): C10016, doi:10.1029/2004JC002380. 

Parrish, R. H., F. B. Schwing, and R. Mendelssohn. 2000. Midlatitude wind stress: the energy 

source for climatic regimes in the North Pacific Ocean. Fish. Oceanogr. 9: 224-238. 

Peterson, W. T. and F. B. Schwing. 2003. A new climate regime in Northeast Pacific ecosystems. 

Geophys. Res. Lett. 30(17), 1896. doi:10.1029/2003GL017528. 

Peterson, W. T., R. C. Hooff, C. A. Morgan, K. L. Hunter, E. Casillas and J. W. Ferguson. 2006a. 

Ocean conditions and salmon survival in the northern California Current. Web Document. 

http://www.nwfsc.noaa.gov/research/divisions/fed/ecosysrep.pdf

Peterson, W. T., R. Emmett, R. Goericke, E. Venrick. A. Mantyla, S. J. Bograd, F. B. Schwing, 

R. Hewitt, N. Lo, W. Watson, J. Barlow, M. Lowry, S. Ralston, K. A. Forney, B. E. 

Lavaniegos, W. J. Sydeman, D. Hyrenbach, R. W. Bradley, P. Warzybok, F. Chavez, K. 

Hunter, S. Benson, M. Weise, and J. Harvey. 2006b. The state of the California Current, 

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California Current. Science 267: 1324-1326. 

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64

Alaskan Ecosystem Complex 

Authors: 

Michael Sigler, Jeffrey Napp, and Anne Hollowed 

(Alaska Fisheries Science Center) 

Introduction 

 The Alaskan ecosystem 

complex is comprised of 

four large marine 

ecosystems (LMEs): Gulf 

of Alaska, East Bering 

Sea/Aleutian Islands, 

Chukchi Sea and Beaufort 

Sea. Marine fisheries of 

Alaska provide almost 50% 

of the nation’s seafood 

harvest, and this harvest is 

important to our balance of 

trade with other countries. 

The Bering Sea is directly 

or indirectly the source of 

over 25 million pounds of 

subsistence food for Alaska 

residents, primarily 

Alaska Natives in 

small coastal 

communities (Bering 

Ecosystem Study, 

2004). Alaska’s nearly 

44,000 miles of 

coastline constitute 

about two-thirds of the 

total U.S. coastline 

and support a wide 

variety of habitats and 

user communities. The 

region’s natural beauty 

and resident and 

migratory species are 

the basis of a billion 

dollar tourist industry. 

 Alaska’s marine 

ecosystems are highly 

responsive to shifts in 

Figure 1. Gray whale feeding grounds have changed. Feeding gray whale (top). 

Retrospective (left) and current (right) gray whale distribution in the northern Bering 

Sea. Colors indicate years (left) and days (right). (Moore et al., 2003)
65

climate (e.g. Hare and Mantua, 2000; Hollowed et al., 2001; Connors et al., 2002, Hunt et al., 

2002; Moore et al., 2003). As high-latitude, cold oceans, three of the issues highlighted in the 

Introduction are relevant to these ecosystems: climate regimes and ecosystem productivity, loss 

of sea ice and ocean acidification. Two of the four LMEs within the Alaskan complex (Bering 

Sea / Aleutian Islands and Gulf of Alaska) have experienced documented regime or phase shifts 

in community organization and productivity related to changing climate (Figure 1; Anderson and 

Piatt, 1999; Ciannelli et al., 2005; Grebmeier et al., 2006; Litzow et al., 2006; Litzow and 

Ciannelli, 2007; Mueter and Litzow, 2008). Three of the four LMEs are extremely susceptible to 

loss of sea ice and all four of the LMEs are susceptible to the impacts of ocean acidification. 

General circulation models predict that the largest changes in global temperatures will occur at 

high latitudes, and such change has already begun on both land and in the oceans surrounding 

Alaska (ACIA, 2004; Stabeno and Overland, 2001). At risk are Alaska’s seafood production, the 

recovery of endangered and threatened marine species, the living marine resources that nourish 

and provide continuity of Alaska’s native cultures, and natural resources that support Alaska’s 

large tourism industry. 

 It is imperative that we develop a mechanistic understanding of how ecosystems respond to 

climate change to apply in stewardship of our living marine resources. Climate shifts may cause 

changes in habitat suitability, trophic interactions and community composition through the 

disappearance or introduction of species. We must evaluate the sensitivity of our management 

strategies to climate change, mitigate unavoidable changes that adversely impact our 

stakeholders, and advise our stakeholders on the direction and rate of future changes (e.g. 

Jurado-Molina and Livingston, 2002). 

Climate Induced Ecosystem Concerns 

 Prudent and informed stewardship of Alaska’s living marine resources is challenging due to 

the high number of large marine habitats, the general remoteness of the region, the lack of 

knowledge of important factors influencing many of the commercial and subsistence species and 

the changing of climate conditions. The prioritized major climate related concerns for Alaska’s 

four large marine ecosystems are: 

I. Climate regimes and ecosystem productivity (Rank 1) 

II. Loss of sea ice (Rank 1) 

III. Ocean acidification (Rank 2) 

 All three concerns are potentially serious climate related threats to Alaska’s living marine 

resources. The magnitudes of these threats likely are similar, with major changes possible. 

However temperature-related effects are occurring sooner than anticipated ocean pH related 

effects (e.g., some species already have moved northward); thus we rank the first two concerns 

slightly ahead of the third concern.
66

I. Climate Regimes and Ecosystem Productivity 

Description

 Regional weather and 

climate patterns in Alaska 

are changing -- there has 

been an increase in the 

amount of heat flux to the 

ocean and land, and a 

decrease in the amount of 

wind energy. These two 

forces, heat and wind, are 

major structuring elements 

for our large marine 

ecosystems. Recent 

changes in Alaska’s coastal 

waters have been: general 

warming of ocean surface 

waters, warming of the 

southeast Bering Sea 

bottom waters over the 

continental shelf (Figure 2), 

a more strongly stratified 

ocean, hypothesized 

decrease in ocean 

productivity, alteration of 

pelagic ocean habitat, and changes in the distribution of species. In short, these changes have the 

potential to affect the structure, function, productivity, and composition of Alaska’s marine 

ecosystems. These changes may have large and irreversible impacts on our fin and shellfish 

harvests in the eastern Bering Sea / Aleutian Islands and Gulf of Alaska. In addition, changes in 

the structure, function, and productivity of these ecosystems may negatively impact the protected 

marine species that live or migrate through these ecosystems (e.g. North Pacific right whale). 

Current Activities

 North Pacific Climate Regimes and Ecosystem Productivity (NPCREP) is a partnership 

between the Alaska Fisheries Science Center (AFSC) and NOAA’s Pacific Marine 

Environmental Laboratory (PMEL) that focuses on how changing climate conditions affect the 

growth, survival, and recruitment of Alaska’s fin and shellfish species. Program goals are to 

reveal the mechanisms of how climate change impacts living marine resources and to provide the 

knowledge and insight to build models that accurately simulate how changing conditions impact 

populations. NPCREP is a small, but highly leveraged project begun in 2004. NPCREP 

contributes essential components of an observation backbone in the eastern Bering Sea. This 

observation network provides near-real-time observations of upper ocean and meteorological 

parameters. Data from its ship- and mooring-based observation network are reported in the 

Ecosystems Considerations chapter of the Stock Assessment and Fishery Evaluation (SAFE) 

reports (e.g. Boldt, 2006). NPCREP examines how ocean and atmosphere interact to determine 

Figure 2. Bering Sea bottom temperatures measured from a bottom 

trawl head rope. The middle shelf used to be covered with a pool of cold 

water (< 2°C) from seasonal ice. Now the bottom temperatures are > 2 

°C ). Courtesy of R. Lauth, AFSC. 
67

the transport of larvae of commercial 

flatfish species to their nursery grounds 

(Lanksbury et al., 2007) and collaborates 

with stock assessment modelers to 

incorporate climate variability into next 

generation stock assessment and 

ecosystem indicators and models. 

NPCREP supports retrospective studies 

of how groundfish distributions in the 

Bering Sea are changing in response to 

climate (Mueter and Litzow, 2008, 

Figure 3), and the use of indicators or 

metrics in an ecosystem approach to 

management. 

 Two other programs deserve mention: 

Fisheries-Oceanography Coordinated 

Investigations (FOCI, 1984-present) and 

Fisheries And The Environment (FATE). 

FOCI is a long-lived NOAA research 

program conducted jointly by the AFSC 

and PMEL primarily in the western Gulf 

of Alaska. FOCI’s goals are to 

understand the climate and ecosystem 

processes that affect the recruitment of 

walleye pollock, and to develop models 

and indicators that advise the Plan Teams 

and Management Council in setting catch limits (Kendall et al., 1996). FATE, a national program 

with regional components, applies conceptual models and mechanistic understanding to 

formulate models capable of predicting future trends in recruitment and stock size and increasing 

accuracy in assessments of target species. 

Research Needs

 NPCREP’s focus is currently limited to the eastern Bering Sea. The Alaska Fisheries Science 

Center is responsible for applying an ecosystem approach to management in four large marine 

ecosystems, and at present NPCREP’s funding limits our joint research with PMEL to only one 

of the four. NPCREP focuses on measuring physical and biological processes at lower trophic 

levels that affect fin and shellfish recruitment. 

 Priorities within the eastern Bering Sea ecosystem are: 

• Maintain/expand the observation system (moorings). The NPCREP Bering Sea 

observational network is anchored by (4) biophysical moorings along the 70 m isobath. 

We have begun to supply data from the moorings to our stakeholders in near real time 

and propose to expand this effort. 

• Expansion of process studies to include juvenile fish. The juvenile stage of fishes, 

particularly flatfish, can be a recruitment bottleneck. The eastern Bering Sea supports 

commercial fisheries for several flatfish species, some of which appear to respond to 

changes in climate (Wilderbeuer et al., 2002; Lanksbury et al., 2007). We need to 

Juvenile pollock survival is maximized when moderate spring and 

summer winds lead to a generally stable upper water column and 

periodic renewal of nutrients. Recruits (R) per spawning stock 

biomass (SSB) vs. May-Sep wind mixing. Mueter, F.J., C. Ladd, 

M.C. Palmer, B.L. Norcross. 2006. Prog. Oceanogr. 68: 152-183. log (R/SSB)

Juvenile pollock survival is maximized when moderate spring and 

summer winds lead to a generally stable upper water column and 

periodic renewal of nutrients. Recruits (R) per spawning stock 

biomass (SSB) vs. May-Sep wind mixing. Mueter, F.J., C. Ladd, 

M.C. Palmer, B.L. Norcross. 2006. Prog. Oceanogr. 68: 152-183. log (R/SSB)

Figure 3. Juvenile survival is maximized when moderate 

spring and summer winds lead to a generally stable upper 

water column and periodic renewal of nutrients. Recruits 

(R) per spawning stock biomass (SSB) vs. May-Sep wind 

mixing. (Mueter et al., 2006) 
68

understand if the recruitment bottlenecks are in the larval or juvenile phase. NPCREP and 

stock assessment scientists are collaborating to incorporate our knowledge of larval 

behavior and distribution into models that predict larval transport and whether transport 

will cross favorable nursery areas. 

• Full implementation of ecosystem modeling efforts. NPCREPs bottom up approach to 

climate-induced effects requires a full 3-D coupled biophysical model. NPCREP and 

North Pacific Research Board funding has been used to construct the initial model. 

Continued use and improvement (adding more trophic levels) will require additional 

funding. The next step is to introduce physical forcing consistent with IPCC projections 

into our models and observe the simulated effects on commercially important fish species. 

• Ability to support multiple extramural metrics/indices projects each year and hold annual 

synthesis meetings. The program has only been able to support one extramural 

metric/indices or modeling project in most years. We need to accelerate our progress in 

this area to develop new metrics that track the health and status of the eastern Bering Sea. 

In addition, we have plans to begin annual synthesis meetings to help bring panels of 

experts together each year to interpret and synthesize climate-induced changes in the 

eastern Bering Sea. These synopses will be reported in the Ecosystems Considerations 

Chapter of the Council’s SAFE document. 

 Missing is geographic expansion of NPCREP’s efforts to other Alaska LMEs. While the 

Bering Sea is the most productive Alaska ecosystem in terms of commercial fisheries, the Gulf 

of Alaska and Chukchi and Beaufort Seas have important living marine resources that respond to 

changes in climate. Addressing climate induced change in these other systems is a high priority, 

but must wait until we can fully implement NPCREP in the eastern Bering Sea. 

Resource Needs 

 NPCREP funding levels are well below what was originally proposed for a fully functional 

program in both the Bering Sea and Gulf of Alaska. While the program takes full advantage of 

resource leveraging with other NOAA programs (e.g. FOCI and FATE), and with outside 

funding sources (e.g. North Pacific Research Board and National Science Foundation), funding 

for this program must be increased to the full amount in the original funding profile ($6M) to 

reap all of the intended benefits. External funding currently is used to maintain the four 

biophysical moorings and process their data because of shortfalls in NOAA funding. Our major 

external partner, the North Pacific Research Board has notified us that they will stop funding this 

effort in 2010. In addition, the strong support of the Climate and Ecosystem Goal Teams for 

continued access to oceanographic and fisheries survey vessels is critical. Our data gathering, 

and hence efforts to achieve a mechanistic understanding, is hampered by lack of available 

NOAA ship time. Threatened decreases in the size of the NOAA Pacific fleet will make the 

shortage worse. 

 FOCI has been level funded since 1986. For it to play a major role in climate research, 

adjustments to base are necessary to account for the erosion of program funds by inflation. As 

with NPCREP, the strong support of the Climate and Ecosystem Goal Teams for continued 

access to oceanographic and fisheries survey vessels is critical. FATE has also been limited in 

the number of projects it can support. Increased funding to FATE would allow for more projects 

to occur simultaneously and would hasten the transformation of understanding and knowledge 

about individual species and multispecies assemblages into predictive capacity that would enable 
69

our assessment scientists to better advise resource managers and our stakeholders on future 

climate-induced changes on our ecosystems and their living marine resources. 

Climate Information Needs 

• Fine-scale (both time and space) surface and vertical temperature, salinity, oxygen, 

nitrate and chlorophyll fluorescence in the Gulf of Alaska and Bering, Chukchi and 

Beaufort Seas. Sea ice extent and thickness in the Bering, Beaufort, and Chukchi Seas. 

Sea level and 500 mb pressure maps, output from MM5 winds. Formats geographically 

indexed and compatible with GIS. 

• Downscaled IPCC climate scenarios resolved to drive kilometer and hourly-scale 

Regional Ocean Circulation Models (ROMS) with ice. Archived runs of ROMS from 

1900s to present. 

II. Loss of Sea Ice 

Description 

 Bering Sea fisheries account 

for greater than 40% of the U.S. 

commercial catch. More than thirty 

Alaska Native communities depend 

on subsistence harvests of marine 

mammals. With increased average 

water temperatures there has been 

a loss of sea ice coverage and a 

northward shift of biological 

communities (Figure 4). Major 

food web pathways differ between 

different regions of the Bering Sea 

and the loss of sea ice may have 

different effects on the dominant 

biota in each region (pollock and 

other pelagic predators in the 

southern region, gray whales and 

other benthic foragers in the 

northern region). Some 

commercial fish and shellfish 

species have shifted outside areas 

NOAA currently surveys and thus 

are incompletely monitored, 

potentially aliasing population 

assessments. Some marine 

mammal species depend on the sea 

ice habitat that is disappearing, and 

these species are not monitored 

(Figure 5). At the end of 2007, the 

NMFS received its first petition to 

0 90 180 45 Km

Bering Sea Basin 

~ 3000 meters

5 0 0 meters

Alaska

2000

0 90 180 45 Km

Bering Sea Basin 

~ 3000 meters

5 0 0 meters

Alaska

1999

Pollock ( ) avoided the extensive cold pool (blue) in 1999, as 

did their predators, fur seals ( ), whereas both species spread out 

with warmer temperatures in 2000. Temperature range of -1.6 C 

(deep blue) to +4.0 C (yellow green). Courtesy of J. Sterling, 

AFSC.

0 90 180 45 Km

Bering Sea Basin 

~ 3000 meters

5 0 0 meters

Alaska

2000

0 90 180 45 Km

Bering Sea Basin 

~ 3000 meters

5 0 0 meters

Alaska

2000

0 90 180 45 Km

Bering Sea Basin 

~ 3000 meters

5 0 0 meters

Alaska

1999

0 90 180 45 Km

Bering Sea Basin 

~ 3000 meters

5 0 0 meters

Alaska

1999

Pollock ( ) avoided the extensive cold pool (blue) in 1999, as 

did their predators, fur seals ( ), whereas both species spread out 

with warmer temperatures in 2000. Temperature range of -1.6 C 

(deep blue) to +4.0 C (yellow green). Courtesy of J. Sterling, 

AFSC.

Figure 4. Pollock (gray circles) avoided the extensive cold pool 

(blue region) in 1999, as did their predators, fur seals (red circles), 

whereas both species spread out with warmer temperatures in 2000. 

Temperature range of -1.6 C (deep blue) to +4.0 C (yellow green). 

Courtesy of J. Sterling, AFSC. 
70

list one of the ice-dependent seal species as threatened or endangered. Increased temperatures 

and loss of sea ice have co-occurred with recent increases in piscivorous predators such as 

arrowtooth flounder in the southern Bering region, and an overall decline in benthic productivity 

in the northern Bering region. New biological communities are forming because species' 

population centers shift northward at different rates, thus affecting trophic interactions and the 

recruitment and biomass of renewable resources. Without improved stock assessment capability, 

fish harvests will be reduced owing to increased uncertainty, resulting in a substantial loss to the 

U.S. economy (e.g., 10% reduction in pollock harvest is worth $80M) and changes in some 

marine mammal populations due to the loss of sea ice will not be known. 

Current Activities 

 Current activities are limited. An NPCREP project demonstrated northerly movement of 

groundfish populations within the main survey area in the southern Bering region (Mueter and 

Litzow, 2008). Cooperative agreement funds were used in one year to extend the Bering Sea 

bottom trawl survey to more northern stations as a pilot study, but this effort was not continued 

due to lack of funding. The AFSC/National Marine Mammal Laboratory conducted aerial 

surveys of ice seal distribution during spring and tracking of ice dependent seals using satellite 

tags in 2006 and 2007; these studies depend on National Science Foundation provided helicopter 

and ship time which may not be available in the future. In the northern Bering region, dramatic 

declines in sea ice have resulted in a reduction of benthic prey populations, an increase in pelagic 

fish and a displacement in marine mammal populations. The National Marine Mammal 

Laboratory was able to conduct one survey in an area that was prime gray whale feeding habitat 

in 2002, but funds for follow-up investigations have not been available. 

Research Needs

• Expand existing surveys in the southeastern Bering Sea (bottom trawl, acoustic-midwater 

trawl surveys) to cover the current commercial fishery area and initiate routine gray 

whale (acoustic and 

visual surveys), ice 

seal (aerial survey and 

satellite tagging) and 

ocean temperature 

monitoring. 

• Conduct the processbased studies required 

to understand these 

changes. Assess the 

impacts of the loss of 

sea ice in the Bering 

Sea on vital rates 

(growth, maturity, and 

feeding) and 

movement. Assess 

whether spatial shifts 

are creating new 

biological 

M. Cameron, AFSC

Figure 5. Ribbon seal (Phoca fasciata) on an ice floe in the eastern Bering 

Sea. Current research on the distribution and abundance of ice seals is 

dependent on funding, ships, and aircraft provided by sources outside of 

NOAA. 
71

communities and altering food webs. Forecast distribution and abundance of managed 

species and the economic and sociological impacts on the commercial and subsistence 

fisheries of the Bering Sea. 

• Monitor fish, shellfish and marine mammal species in the northern Bering Sea where 

northward expansion of species is expected. 

Resource Needs 

 Funding is necessary to expand existing surveys in the southeastern Bering Sea to cover the 

current commercial fishery area and expand whale, seal and ocean temperature monitoring. 

Additional funding would support the process-based studies required to understand these 

changes and expand existing surveys to the northern Bering Sea. 

 

Climate Information Needs 

• Fine-scale (both time and space) surface and vertical temperature, salinity, oxygen, 

nitrate and chlorophyll fluorescence in the Gulf of Alaska and Bering, Chukchi and 

Beaufort Seas. Sea ice extent and thickness in the Bering, Beaufort, and Chukchi Seas. 

Sea level and 500 mb pressure maps, output from MM5 winds. Formats geographically 

indexed and compatible with GIS 

• Downscaled IPCC climate scenarios resolved to drive kilometer and hourly-scale 

Regional Ocean Circulation Models (ROMS) with ice. Archived runs of ROMS from 

1900s to present. 

III. Ocean Acidification 

Description 

 The North Pacific 

Ocean is a sentinel region 

for the biological impacts 

of ocean acidification. It 

will be one of the first 

regions affected by 

decreasing ocean pH 

because the depth below 

which the water is 

understaturated in calcium 

carbonate (the ‘calcium 

carbonate saturation 

horizon’) is relatively 

shallow in the North Pacific 

Ocean (Figure 6). For 

example, the aragonite (one 

of two major forms of 

CaCO3) saturation horizon 

is at about 200 m depth in 

the North Pacific Ocean 

Saturation depths (m) of aragonite (A) and calcite (B) (the two major forms 

of CaCO3) are much shallower in the North Pacific Ocean than in the North 

Atlantic Ocean. Feely et al. 2004. Science 305: 362-366.

Figure 6. Saturation depths (m) of aragonite (A) and calcite (B) (the two 

major forms of CaCO3) are much shallower in the North Pacific Ocean 

than in the North Atlantic Ocean. (Feely et al., 2004) 
72

compared to about 2500 m depth in the North Atlantic Ocean (Feely et al., 2004). In the North 

Pacific Ocean, the upward migration of the aragonite saturation horizon from pre-industrial times 

to present has been between 30 and 100 m (Feely et al., 2004). The saturation horizon is 

projected to reach the surface during this century (Orr et al., 2005). At that point, a wide range of 

North Pacific species will be exposed to seawater undersaturated with respect to calcium 

carbonate and may be unable, or have difficulty, forming the carbonate structures needed for 

their shells or other body components. 

Current Activities 

 Alaska Fisheries Science Center (AFSC) scientists have been conducting pilot ocean 

acidification research on shellfish since 2006. Their approach has included: 

• Identification of shellfish species that may be affected; 

• Development of laboratory studies to test hypotheses related to the direct effects of 

decreased pH and undersaturation of CaCO3 in seawater; 

• Identification of response variables that would be appropriate to assess ocean 

acidification impacts; 

• Development of in situ process studies to address the magnitude of importance that 

ocean acidification may have on coastally important shellfish species. 

AFSC scientists also have applied ecosystem modeling to forecast how reduced pteropod 

abundance (pelagic snails) could affect pink salmon abundance in the Gulf of Alaska; pteropods 

can be important prey for pink salmon. 

Research Needs

 The Alaska Fisheries Science Center (AFSC), as part of its integrated ecosystem approach to 

studying living marine resources from the North Pacific Ocean and Bering Sea, has plans for 

needed ocean acidification research to occur through a four-step progression from understanding 

species-specific physiological effects to applying this understanding to forecast population and 

economic consequences: 

• Conduct research targeted at understanding species-specific physiological responses to 

ocean acidification. 

• Develop models to forecast the population, community and ecosystem impacts of the 

physiological responses. 

• Develop scenarios to forecast economic consequences of these impacts. 

• Collaborate with NOAA’s Pacific Marine Environmental Laboratory to monitor ocean 

pH using AFSC’s NOAA and chartered shiptime. 

 We would focus on understanding effects of ocean acidification on coldwater corals and 

commercially important fish and shellfish species. Both direct (e.g. reduced survival) and 

indirect effects (e.g. reduced prey abundance) would be studied. 

 Focal species would be: 

• Commercially important crab species (king crab species) 

• Ecologically important prey of commercial fish species (pteropods, euphausiids) 

• Coldwater corals 

• Commercially important fish species (pollock, cod) 

 Climate change may affect both ocean pH and temperature, and to the extent practicable 

both factors would be integrated in our studies. We also would plan to collaborate with other 

Fishery Science Centers (PIFSC, SWFSC, NWFSC) in the first-affected region (Pacific Ocean). 
73

Resource Needs 

 Additional funding for the Alaska Fisheries Science Center is needed to support speciesspecific physiological experiments and population, ecosystem and economic models to forecast 

population and ecosystem effects and economic consequences. Also, additional funding and ship 

time are needed by the Pacific Marine Environmental Laboratory for ocean pH measurements 

that would be critically needed as part of the planned ocean acidification research. 

 

Climate Information Needs 

• Surface and vertical ocean pH and carbon species measurements in the Gulf of Alaska 

and Bering, Chukchi and Beaufort Seas, especially over the continental shelf and slope 

where fish, shellfish and marine mammal species are concentrated. 

• Fine-scale (both time and space) surface and vertical temperature, salinity, oxygen, 

nitrate and chlorophyll fluorescence in the Gulf of Alaska and Bering, Chukchi and 

Beaufort Seas. Sea ice extent and thickness in the Bering, Beaufort, and Chukchi Seas. 

Sea level and 500 mb pressure maps, output from MM5 winds. Formats geographically 

indexed and compatible with GIS 

• Downscaled IPCC climate scenarios resolved to drive kilometer and hourly-scale 

Regional Ocean Circulation Models (ROMS) with ice and CO2 chemistry. Archived runs 

of ROMS from 1900s to present. 

Program Integration 

 The proposed programs are highly integrated and matrixed within NOAA and between 

NOAA and the regional research community. First, Loss Of Sea Ice (LOSI), NPCREP, FOCI, 

and Ocean Acidification (OA) are all collaborative programs between NMFS and OAR. FOCI 

has a 22-year history as a successful matrixed program and the parties have been working 

together for 4 years in NPCREP. Plans for LOSI and OA have been jointly developed by AFSC 

and PMEL. These researchers have a strong history of working with other Federal, State, 

University and NGO researchers in the Bering Sea and the Gulf of Alaska. The AFSC and 

PMEL just successfully competed an Integrated Ecosystem Research Program proposal with the 

North Pacific Research Board (NPRB) for a vertically integrated study of the eastern Bering Sea. 

Included in the new program are scientists from the U.S. Fish and Wildlife Service (USF&WS), 

University of Alaska, University of Washington, and Oregon State University. The project will 

collaborate with the National Science Foundation (NSF) sponsored Bering Ecosystem Study 

(BEST) which has attracted scientists from around the U.S. and Canada. Prior to submission of 

these proposals, the AFSC, PMEL, NPRB, and NSF sponsored several workshops to begin 

coordination of climate change and loss of sea ice research activities in the Bering Sea (Bering 

Sea Interagency Working Group, 2006). Active in the group were the Alaska Ocean Observing 

System, USF&WS, U.S. Geologic Survey, U.S. Arctic Commission, NPRB, NSF and NOAA. 

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76

Pacific Island Ecosystem Complex 

Authors: 

Ellen Smith 

(Joint Institute for Marine and Atmospheric Research, Univ. of Hawaii) 

Jason Baker 

(Pacific Islands Fisheries Science Center) 

Introduction 

 The Pacific Islands region lies largely within the subtropical gyres of the North and South 

Pacific Oceans. These gyres are characterized by warm, vertically stratified, low nutrient and low 

surface chlorophyll waters. The resources of interest in the region can be grouped as either 

highly migratory species (HMS) or as insular and island associated species. The HMS species 

are treated in another section of this report so we focus on the insular species in this section. 

Within the insular species, management interests include the diverse coral reef ecosystem and 

marine mammals and turtles, including protected species such as green sea turtles and monk 

seals, which use the beaches for nesting or pupping and forage around the islands. Deepwater 

corals and deepwater snappers are also important components of the insular complex. 

 

Climate Induced Ecosystem Concerns 

 Prioritization of the climate related ecosystem concerns for the Pacific Islands is difficult 

because the region is vast and the biogeochemical conditions that exist in one region do not 

necessarily exist in another. In addition, climate related concerns may have different outcomes in 

different island regions of the Pacific. Rising sea level, for example, will likely affect the low 

lying atolls on the North Western Hawaiian Islands significantly more than the high islands in 

the Commonwealth of the Northern Marianas Islands. Links between climate events and insular 

species have been investigated in the Hawaiian Archipelago (Antonelis et al., 2003; Baker et al., 

2006; Polovina et al., 1994). The highest priority climate related ecosystem concerns in the 

Pacific Islands region are: 

I. Coral bleaching 

II. Sea level rise 

III. Ocean acidification 

IV. Changes in ENSO and ocean circulation patterns 

I. Coral Bleaching 

Description 

 Coral reef ecosystems are composed of a highly diverse assemblage of hundreds of 

thousands of plant and animal species, all existing in a very dynamic interaction with each other 

and the physical environment. These ecosystems are distributed throughout the tropical and 

subtropical surface waters of the Pacific Ocean between approximately 25°N and 25°S and 

coincide with water temperatures between 18°C and 30°C and salinities from 32-40 psu (HoeghGuldberg, 1999). The increase in water temperatures associated with global warming (1-2°C per 

century) and regionally specific ENSO events are leading to increased incidences of coral 
77

bleaching in the Pacific Islands region. Coral bleaching and subsequent mortality can lead to 

habitat phase shifts where corals are replaced by algal functional groups. Although recent 

research has documented algal-dominated areas to occur naturally on many healthy Pacific reef 

systems (Vroom et al., 2006), algal overgrowth of coral dominated areas as the result of 

anthropogenic climate change are indicative of decreased ecosystem health. This phase shift may 

result in decreased calcium carbonate accumulation, and impact the reef fauna that depend on the 

structural complexity provided by corals. The persistently increasing temperatures associated 

with global warming are likely to increase the frequency and magnitude of coral bleaching 

events in the Pacific Islands Ecosystem Complex. 

Current Activities 

 During the 2007 U. S. Coral Reef Task Force meeting a new climate change working group 

was formed and an action plan for the International Year of the Reef 2008 involving government 

and non-government partners in conservation was endorsed. The new climate change working 

group is charged with developing best practices to help local resource managers minimize the 

impact of climate-induced stresses like coral bleaching, while better educating the public about 

the impacts of climate change on the health and survival of reef resources. Components of the 

decision called for developing bleaching response plans for each U.S. state and territory with 

reefs, and assessing what expertise and resources federal agencies have to mitigate risk and 

damage. The Task Force also hosted a special session on the health of coral reef ecosystems in a 

changing climate, drawing from the regional and international expertise to highlight common 

challenges and management needs. The Task Force further called on members and partners to 

reduce greenhouse gas emissions and affirmed the role that regional networks of marine 

protected areas can play in protecting ecological connectivity among islands in the face of 

potential future losses that may result due to climate change. The creation of the climate change 

group is considered a major new step for the Task Force, but one that builds on several past 

resolutions and the 2006 release of The Reef Manager’s Guide to Coral Bleaching (Marshall and 

Schuttenberg, 2006). The Reef Manager’s Guide provides information on the causes and 

consequences of coral bleaching, and helps managers understand and plan for bleaching events. 

 Currently the Coral Reef Ecosystem Division (CRED) of NMFS Pacific Islands Fisheries 

Science Center (PIFSC) has Coral Reef Early Warning System (CREWS) buoys deployed 

throughout the Pacific Islands Ecosystem Complex which provide high resolution telemetered 

data and long-term monitoring of sea surface temperature (SST), barometric pressure, wind 

speed and direction, salinity, UV-B, and PAR. Extended periods of low winds, increased 

temperatures and downwelling light signatures are indicative of potential bleaching events. 

Research Needs 

• Share strategies and tools that predict where coral bleaching will occur. 

• Measure coral reef resilience. 

• Assess the socioeconomic impacts of damage related to climate change. 

• Advance our understanding of the links between bleaching events and the impacts to the reef 

fish community. 

• Use coupled ocean-climate models to better understand the spatial and temporal patterns of 

ocean warming. 

• Enhance and integrate in situ and satellite-based coral bleaching and alert systems. 
78

II. Sea Level Rise 

Description 

 Rising sea level is a concern for terrestrial habitats and the biological community that 

depends on them, as well as for shallow water coral reef communities. Depending on the rate of 

the sea level increase, reef-building corals may be unable to accrete at a rate that maintains close 

enough proximity to the surface to sustain the nutritional needs of the ecosystem. Rising sea 

levels will overwhelm coastlines around the Pacific affecting human life and increasing the 

amount of both sediment and nutrient pollutants that reach the ocean. Nesting sites for marine 

turtles and other species will be impacted due to the alteration of shore lines and other low-lying 

areas. The reduction in nesting and pupping beaches in the Northwestern Hawaiian Islands for 

the Hawaiian Monk Seal and Green Sea turtle are of primary concern. Increased sea level 

combined with less effective barrier reefs will allow greater energy to reach the shoreline in the 

forms of waves and currents, thereby altering coastal ecosystems. Many of the low-lying atolls in 

the Pacific Islands Ecosystem Complex are forecasted to be completely submerged by rising sealevels and will have to be evacuated. 

 Terrestrial habitats in the Northwestern Hawaiian Islands (NWHI) consist largely of lowlying oceanic sand islands (cays) and atolls which support a spectacular biological community, 

including numerous terrestrial species which are only found on these islands (Conant et al., 

1984). The NWHI are also important for large marine vertebrates including sea birds, green sea 

turtles and Hawaiian monk seals, all of which feed at sea but require terrestrial habitat with few 

or no predators to either nest or raise offspring. The Hawaiian monk seal, listed as endangered 

under the U.S. Endangered Species Act (1973), has a population of less than 1300 individuals, 

primarily in the NWHI (Baker and Johanos, 2004; Antonelis et al., 2006; Carretta et al., 2006). 

Female seals typically give birth on sandy beaches adjacent to shallow waters, which offer 

neonates access to the sea while providing some protection from large waves and the approach of 

predatory sharks (Westlake and Gilmartin, 1990). Hawaiian green sea turtles, listed as threatened 

under the Endangered Species Act, range over the entire Hawaiian archipelago, but over 90% of 

breeding females nest at one NWHI atoll, French Frigate Shoals, where their number has been 

increasing for the past 30 yr (Balazs and Chaloupka, 2004). The NWHI are also habitat for 14 

million seabirds of 18 species (Harrison, 1990). The islands are particularly important nesting 

habitat for Laysan and black-footed albatross, the sooty, or Tristram’s, storm petrel, and Bonin 

petrels (Fefer et al., 1984; Harrison, 1990). 

 Despite the NWHI’s high conservation value, the impacts of sea-level rise on terrestrial 

habitats in the region have been largely overlooked until recently. The low-lying land areas of 

the NWHI are highly vulnerable to sand erosion due to storms and sea-level rise. Sea-level rise 

reduces cays by passive flooding, active coastal erosion, and in concert with seasonal high swell. 

As a result, these important littoral and coastal ecologies are at risk. Demonstrating this, islands 

at French Frigate Shoals have been greatly reduced in size during roughly the past 40 years for 

reasons not well understood, as this occurred during a period when sea level rose relatively little 

(Antonelis et al., 2006). Another example of this is the effective disappearance of Whaleskate 

Island, which had been important habitat for turtles and seals (Fig. 1). 
79

Figure 1. Whaleskate Island at French Frigate Shoals, NWHI. Once an important nesting island for Hawaiian green 

sea turtles and a primary pupping site for endangered Hawaiian monk seals, pictured from the air in 1963 (left) and 

in 2002 (right). 

Current Activities 

 Concerns about sea level rise in the NWHI motivated a study to project what might happen 

as global sea level increases in the future. Baker et al. (2006) produced the first NWHI 

topographic maps in three locations (Lisianski Island, Pearl and Hermes Reef, and French 

Frigate Shoals). They then used passive flooding scenarios to estimate the area that would be lost 

if islands maintained their current topography and the sea were to rise by various amounts within 

the range predicted by the 2001 Intergovernmental Panel on Climate Change (IPCC). The 

projected effects of sea level rise on surface area varied considerably among the islands 

examined (Fig. 2). For example, Lisianski Island is projected to be the least affected of the 

islands surveyed, losing only 5% of its area with an 88 cm rise in sea level. In contrast, the islets 

at French Frigate Shoals and Pearl and Hermes Reef are projected to lose between 15 and 65% of 

their area with a 48 cm sea level rise. 

 The uncertainty of predictions increases over time, but the expectation is that sea level will 

continue to rise beyond 2100 (Church et al., 2001). Moreover, recent evidence suggests that sea 

level may rise more rapidly than previous models have predicted, due in part to an accelerated 

rate of ice loss from the Greenland Ice Sheet (Rignot and Kanagaratnam, 2006). 

Research Needs 

• High resolution mapping of all islands (preferably using Light Detection and Ranging, 

LIDAR) including characterization of the extent and thickness of erodable substrate is 

required. 

• Modeling of shoreline evolution under higher sea level with elevation, bathymetric, 

hydrodynamic and geologic substrate data inputs, to indicate the effects of sea-level rise on 

sediment transport and resulting evolution of sandy cays and impacts on terrestrial habitats. 

• Development of strategies for mitigating hazards posed by sea-level rise using, for example, 

beach nourishment (Hanson et al., 2002). 
80

 

Figure 2. Current and projected maps of four Northwestern Hawaiian Islands at mean low water 

(MLW) with minimum (9 cm), median (48 cm) and maximum (88 cm) predicted sea-level rise 

by 2100. The median scenario at spring tide is also shown. A) Lisianski Island; B) East Island, 

French Frigate Shoals; C) Trig Island, French Frigate Shoals; D) Southeast Island, Pearl and 

Hermes Reef. (Baker et al., 2006) 
81

III. Ocean Acidification 

Description 

 A coral reef represents the net accumulation of carbonate minerals produced by reef-building 

corals and other calcifying organisms. The living component of the reef is the uppermost layer of 

the limestone foundation formed by calcifying organisms dating back to millions of years. This 

living layer of the coral reef offers a highly 3-dimensional environment to all of the living 

organisms that call the reef ecosystem home. Coral reefs are susceptible to ocean acidification 

because reef calcification depends on the saturation state of carbonate minerals in surface waters 

which decrease with increasing levels of carbon dioxide and the concomitant decrease in pH. By 

the middle of this century, an increased concentration of CO2 will decrease the saturation state 

with respect to carbonate minerals in the tropics by 30 percent and biogenic carbonate 

precipitation by 14 to 30 percent (Kleypas et al., 1999). 

Current Activities 

 Approximately 150 water samples have been collected for sea water chemistry analysis from 

approximately 25 sites around the American Samoa region in two separate years as part of 

ongoing CRED Reef Assessment and Monitoring Program biennial cruises. For increased 

temporal resolution of carbonate chemistry, research and development is continuing on sensor 

systems for in situ metabolic monitoring of the carbonate system in coral reef environments. 

Research Needs 

 To date, efforts to examine the response of marine calcifying reef organisms to future 

changes in carbonate chemistry have been mostly limited to controlled laboratory experiments 

and models, with little research examining the impacts of ocean acidification on the community 

structure of coral reef ecosystems in the real ocean. 

• Understanding the biological responses to ocean acidification is critical for predicting and 

conserving reef ecosystem health in the face of climate change. Biological calcification 

processes and seawater carbonate chemistry need to be assessed and monitored at strategic 

near-shore coral reef sites in the U.S.-affiliated Pacific Islands, thereby providing an 

improved understanding of ecosystem level responses to ocean acidification. 

• Development and implementation of methodologies to describe the spatial structure of the 

carbonate system from a variety of reef zones and habitat types is needed to insure proper 

utilization of the metabolic monitoring stations currently being developed by Feely, Sabine 

and Wanninkhof (PMEL/AMOL) to gauge the system response to increases in CO2. 

• Coral cores need to be collected to examine long-term changes in biological response to 

increases in CO2. Development and testing of promising new technologies, specifically the 

use of underwater ultrasound (and other acoustic tools), to examine recent calcification rate 

changes of a broad spectrum of the coral community would allow an unprecedented ability to 

monitor ecosystem level responses to ocean acidification. 

• A program to collect long-term records of carbon cycle parameters and analyze the impacts 

of changing carbonate equilibrium on coral reef ecosystems needs to be developed, and 

historical records of coral reef environmental variability using paleo-climatic records of SST 

and other parameters from coral skeletons needs to be reconstructed. 
82

IV. Changes in ENSO and Ocean Circulation Patterns 

Description 

 El Niño-Southern Oscillation (ENSO), resulting from the large-scale global coupling of 

atmospheric and oceanic circulation, is an inter-annual climatic phenomenon (approximately 3 – 

8 years) that creates significant temperature fluctuations in the tropical surface waters of the 

Pacific Ocean. ENSO events can have a significant impact on coral reef ecosystems due to 

changing surface winds, storm events, ocean currents, water temperatures, nutrient availability, 

storm frequency and magnitude, etc. ENSO is a naturally occurring phenomenon, however, there 

is uncertainty regarding how global warming and the associated climate changes will impact the 

frequency, magnitude and importantly the duration of this cycle and how that will in turn affect 

coral reef ecosystems. Changes to established ocean circulation patterns can have significant 

effects on biological connectivity, distribution of species, biological productivity, and marine 

debris issues. Changes in storm events can impact corals directly from wave damage or more 

indirectly from runoff and sediment deposition. 

Current Activities 

 The Tropical Atmosphere Ocean/Triangle Trans-Ocean Buoy Network array consists of 

approximately 70 moored buoys all over the Pacific basin designed for the study of year-to-year 

climate variations related to ENSO. This array is geared towards improved detection, 

understanding and prediction of El Niño and La Niña. Correlations between physical and 

ecological parameters during the fluctuating ENSO forced conditions are starting to be studied 

more carefully as time series data sets are continuing to grow, covering a temporal range that 

encompasses many of these varying phases.

Research Needs 

• Use output from coupled ocean-climate models (IPCC models) to examine how ENSO 

dynamics might change in the future and where these changes might have the greatest 

impacts on coral reefs. 

• Develop models that downscale the IPCC model output that have specific relevance to coral 

reefs. 

Resource and Climate Information Needs 

 Due to the similarities of these needs for all Pacific Island climate induced ecosystem 

concerns, these needs are just provided here. 

Resource Needs

 For coral reef ecosystems research on impacts from climate change needs funds to maintain 

and expand long term field monitoring programs. Further, support is required to develop models 

of bleaching, disease, and coral growth driven from output from IPCC climate models. For 

NWHI habitat loss from sea level rise, funds to conduct aircraft-based LIDAR surveys and create 

high resolution maps of islands (and nearshore shallow bathymetry) are needed to characterize, 

forecast and mitigate sea level rise effects in the Northwestern Hawaiian Islands. Having these 

data would also be of great use to the co-trustee agencies (NOAA, USFWS, State of Hawaii) 

charged with managing the new NWHI Marine National Monument. 
83

Climate Information Needs 

• Improved spatial and temporal estimates for the Pacific of future changes in key physical and 

chemical parameters, including temperature, ocean pH, sea level rise, storm intensity, and 

ENSO dynamics. 

• Better tools (models) that permit downscaling from basin-scale IPCC output to islands and 

atolls. 

References 

Antonelis, G. A., J. D. Baker, and J. J. Polovina. 2003. Improved body condition of weaned 

Hawaiian monk seal pups associated with El Nino events: potential benefits to an endangered 

species. Marine Mammal Science 19(3): 590-598. 

Antonelis, G. A., J. D. Baker, T. C. Johanos, R. C. Braun, and A. L. Harting. 2006. Hawaiian 

monk seal (Monachus schauinslandi): status and conservation issues. Atoll Res. Bull. 543: 

75-101. 

Baker, J. D. and T. C. Johanos. 2004. Abundance of the Hawaiian monk seal in the main 

Hawaiian Islands. Biological Conservation 116(1): 103-110. 

Baker, J. D., C. L. Littnan, and D. W. Johnston. 2006. Potential effects of sea level rise on the 

terrestrial habitats of endangered and endemic megafauna in the Northwestern Hawaiian 

Islands. Endangered Species Res. 2: 21-30. 

Balazs, G. H., and M. Chaloupka. 2004. Thirty-year recovery trend in the once depleted 

Hawaiian green sea turtle stock. Biol. Conserv. 117: 491-498. 

Carretta, J. V., K. A. Forney, M. M. Muto, J. Barlow, J. Baker, B. Hanson, and M. Lowry. 2006. 

U.S. Pacific Marine Mammal Stock Assessments: 2005. NOAA-TM-NMFS-SWFSC-388. 

Church, J. A., J. M. Gregory, P. Huybrechts, M. Kuhn, K. Lambeck, M. T. Nhuan, D. Qin, and P. 

L. Woodworth. 2001. Changes in Sea Level in Climate Change 2001: The Scientific Basis. In: 

Houghton J. T., Y. Ding, D. J. Griggs, M. Noguer, P. van der Linden, X. Dai, K. Maskell, 

and C. I. Johnson (eds) Contribution of Working Group I to the Third Assessment Report of 

the Intergovernmental Panel on Climate Change. Cambridge University Press Cambridge, p 

641-693. 

Conant, S., C. C. Christensen, P. Conant, W. C. Gange, and M. L. Goff. 1984. The unique 

terrestrial biota of the Northwestern Hawaiian Islands. In: Grigg, RW and Tanoue, KY (eds) 

Proceedings of the second symposium on resource investigations in the northwestern 

Hawaiian Islands. Volume 1 Sea Grant Miscellaneous Report UNIHI-SEAGRANT-MR-84-

01, Honolulu p. 77-94. 

Fefer, S. I., C. S. Harrison, M. B. Naughton, and R. J. Shallenberger. 1984. Synopsis of results of 

recent seabird research conducted in the Northwestern Hawaiian Islands. In: Grigg, RW and 

Tanoue KY (eds) Proceedings of the second symposium on resource investigations in the 

northwestern Hawaiian Islands, Volume 1. Sea Grant Miscellaneous Report UNIHISEAGRANT-MR-84-01, Honolulu p. 9-76. 

Hanson, H., A. Brampton, M. Capobianco, H. H. Dette, L. Hamm, C. Laustrup, A. Lechuga, and 

R. Spanhoff. 2002. Beach nourishment projects, practices, and objectives - a European 

overview. Coastal Engineering 47: 81– 111. 
84

Harrison, C. S. 1990. Seabirds of Hawaii: Natural history and conservation. Cornell University 

Press, Ithaca. 

Hoegh-Guldberg, O. Climate change, coral bleaching and the future of the world’s coral reefs. 

1999. Marine and Freshwater Research 50: 839-866. 

Kleypas, J. A., R. W. Buddemeier, D. Archer, J. Gattuso, C. Langdon, and B. N. Opdyke. 1999. 

Geochemical Consequences of Increased Atmospheric Carbon Dioxide on Coral Reefs. 

Science 284: 118-120. 

Marshall, P. A., and H. Z. Schuttenberg. 2006. A Reef Manager’s Guide to Coral Bleaching. 

Great Barrier Reef Marine Park Authority, Australia (ISBN 1-876945-40-0). 

Polovina, J. J., G. T. Mitchum, N. E. Graham, M. P. Craig, E. E. Demartini, and E. N. Flint. 

1994. Physical and biological consequences of a climate event in the central North Pacific. 

Fish. Oceanogr. 3(1), p. 15-21. 

Rignot, E., and P. Kanagaratnam. 2006. Changes in the velocity structure of the Greenland Ice 

Sheet. Science 311: 986-990. 

Vroom, P. S., K. N. Page, J. C. Kenyon, and R. E. Brainard. 2006. Algae-Dominated Reefs. 

American Scientist 94: 430-437. 

Westlake, R. L., and W. G. Gilmartin. 1990. Hawaiian monk seal pupping location in the 

Northwestern Hawaiian Islands. Pac. Sci. 44: 366-384. 
85

Eastern Tropical Pacific 

Authors: 

Lisa T. Ballance, Paul Fiedler, and George Watters 

(Southwest Fisheries Science Center) 

Introduction 

 

 The eastern tropical Pacific (ETP) is comprised of approximately 21 million km2

 of ocean 

between the U.S.-Mexico border, Hawaii, and Peru, and includes a number of oceanographically 

distinct regions, including the Equatorial Cold Tongue, and the eastern Pacific Warm Pool 

(between Central America and 120o W, and between 25o N and 5o N, Figure 1). The predominant 

variability in the ecosystem, both physical and biological, appears to be associated with El NiñoSouthern Oscillation events (ENSO; Ballance et al., 2002; Fiedler, 2002; Fiedler and Philbrick, 

2002; Gerrodette and Forcada, 2002; Pitman et al., 2002; Reilly et al., 2002a, b). Underlying this 

ENSO-scale variability are longer-period physical changes, often labeled “climate shifts”. These 

have been detected throughout the north Pacific, including the ETP. 

Figure 1. Oceanographic 

depiction of the eastern 

tropical Pacific (modified 

from Wyrtki) and eastern 

spinner (upper right) and 

pantropical spotted (lower 

left) dolphins, two of the 

stocks depleted through 

incidental mortality from 

the yellowfin tuna purse 

seine fishery.

 

 NOAA Fisheries has been conducting research in this ecosystem since the late 1970s 

because incidental mortality of northeastern offshore spotted and eastern spinner dolphins due to 

the yellowfin tuna purse seine fishery resulted in these stocks being designated as “depleted” 

under the Marine Mammal Protection Act. Despite changes in fishing practices in the early 

1990s which reduced observed dolphin mortality to very low levels, it is uncertain whether these 

stocks are recovering (e.g., Wade et al., 2007; Figure 2). Scientists at the Southwest Fisheries 

Science Center (SWFSC) have been mandated by Congress under the International Dolphin 

Conservation Program Act (IDCPA) to conduct research to try to understand the reasons for this 

lack of recovery. 

 
86

Figure 2. Model-averaged estimated population 

trajectories for depleted spotted dolphin stocks, 

1958 – 2002. (Wade et al., 2007) 

Climate Induced Ecosystem Concerns 

 

 While there are other climate induced ecosystem concerns in the ETP (e.g. ocean 

acidification), the highest priorities for NOAA Fisheries are focused on ecosystem concerns as 

they relate to the lack of recovery of depleted dolphin stocks. Within this framework, the major 

climate induced ecosystem concerns in order of importance are: 

I. The biological effects of ENSO cycles 

II. The biological effects of climate shifts, particularly the late 1970s climate shift 

I. The biological effects of ENSO cycles 

Description 

 The dominant variation in the ecosystem appears to occur at a two to seven-year periodicity, 

corresponding to ENSO-scale variation. This variation is evident in both physical (Figure 3) and 

biological components (reviewed in Fiedler 2002), but the specific relationships between many 

of the ecosystem components remain largely unquantified. Additionally, there is an indication 

that El Niño events may be occurring at more frequent intervals or with greater intensity (Miller 

and Cayan 1994, Stephens et al. 2001). The need to understand specific effects of these cycles on 

dolphins, and their prey, predators, competitors, and commensals, is great. 

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

-2

-1

0

+1

+2

+3 NINO3

Warm Pool

) y p y,

Figure 3. Monthly sea surface temperature anomalies for the equatorial region and Eastern Pacific Warm 

Pool, 1900-2000. (Fiedler, 2002.) 

Current Activities 

 Current research has focused on a multi-year cetacean and ecosystem assessment survey 

(Figure 4). A series of research vessel cruises began in the 1970’s and are repeated periodically. 

A five-year series was conducted during 1986-1990, a three-year series was completed from 

1998 through 2000, two cruises were conducted in 2003 and 2006; and future monitoring cruises 

are planned at three year intervals. These surveys utilize two vessels, NOAA ships David Starr 

Jordan and McArthur II. Each survey covers approximately 100,000 linear km of trackline. 
87

 The surveys use a multidisciplinary approach. Data used to support estimates of stock 

abundance are collected using state of the art line-transect methods and wide-format photographs 

of dolphin schools taken from a helicopter or fixed-wing aircraft. Research on cetacean biology 

provides additional critical information for stock assessment. This includes analysis of skin 

biopsy samples collected with biopsy darts, acoustic recordings, and lateral photographs to 

provide information on population structure, use of biopsy samples and aerial photographs to 

investigate pregnancy rates and demographic composition of schools, and studies to determine 

how dolphin behavior influences ship-based detection. Ecosystem assessment provides a context 

in which to place abundance and assessment results and is a critical means of separating fisheryfrom non-fishery effects on dolphin abundance. Cetacean habitat is characterized through 

collection of physical and 

biological oceanographic data, 

cetacean prey through collection 

of mid trophic-level fishes and 

invertebrates, and cetacean 

predators, competitors, and 

commensals through studies of 

other apex predators in the 

system. These data form the 

basis for investigations into the 

effects of ENSO cycles on the 

ecosystem. 

 Figure 4. Survey effort in the eastern tropical Pacific, 2006. 

Research Needs 

 Analyze existing ecosystem data to clarify species-habitat relationships, to identify links 

(direct and indirect) between trophic levels, and to quantify effects of ENSO-scale variation 

on the ecosystem. 

 Develop ecosystem models to investigate ecosystem structure, function, and responses to 

ENSO variability (and longer-period climate change). 

Resource Needs 

Resources needed for these activities primarily consist of additional technicians and postdoctoral level investigators for sample processing and data analysis. Continuation of monitoring 

activities and undertaking process-oriented research cruises are also important activities and have 

the added resource need of research vessel days at sea. Monitoring cruises, conducted at least 

once every three years, will allow documentation of long-term environmental and ecosystem 

changes and are crucial for understanding long-term population changes. Process research 

cruises will be valuable to test hypotheses developed as a result of the other investigations. 

Climate Information Needs 

 U. S. and international agencies maintain databases of ETP climate variables including 

temperature, winds, and precipitation. We will rely on continued archival of oceanographic data 
88

from ships and buoys, development of data-assimilation models to cover gaps in observational 

data, and continued funding and renewal of satellite temperature, wind, and ocean color 

programs to ensure continuous time series of physical and biological variables. 

II. The biological effects of climate shifts, particularly the late 1970s climate shift 

Description 

One hypothesis put forward to explain the lack of recovery of ETP dolphin stocks to preexploitation levels focuses on regime shifts as a cause. Specifically, a climate-induced shift may 

have altered the ecosystem so as to prevent recovery of depleted dolphin stocks to preexploitation levels (Figure 5). Biological responses to the 1976-1977 climate shift have been well 

documented in many areas of the North Pacific (Venrick et al., 1987; McGowan et al., 1998; 

Hare and Mantua, 2000; Napp et al., 2002). In the ETP, temporal and spatial scales of climateocean coupling differ from those in other parts of the Pacific; hence the biological response to 

climate shifts is also likely to differ. While biological data that represent the ecosystem prior to 

1976 are rare, a few historical datasets offer the opportunity to compare patterns pre- and postshift in order to obtain insight into climate impacts on the ecosystem. 

Figure 5. Cumulative sums of monthly sea surface temperature anomalies for four regions in the Pacific. 

Gray bars identify years in which climate shifts have been detected. The late 1970s shift is evident in the 

four regions shown in the figure, including the “Warm Pool” which encompasses the eastern tropical 

Pacific between Central America and 120oW, and between 25oN and 5oN. (Fiedler, 2002.) 

Current Activities 

 There is little current activity focused on these types of investigations due to lack of 

resources. 

Research Needs 

• Compare distribution and abundance of zooplankton and micronekton from net samples 

collected in the late 1960s with samples collected in the late 1980s and 1990s. 

Data available to address this question span the years 1967-1968 (EASTROPAC expeditions) 

and 1986-2006. During these expeditions, two types of net sampling were used: oblique 

tows, providing an index of zooplankton abundance and distribution in the upper 200 m of 

the water column; and horizontal, surface tows, providing an index of zooplankton 

abundance and distribution at the surface. 

• Compare stable isotope signatures from marine turtle, seabird, and cetacean museum 

specimens with specimens collected more recently to investigate potential diet shifts 

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

-200

-150

-100

-50

0

ETP

NINO3

Warm Pool

North Pacific

California Current

Central N. Pacific

b) Cu u a e su s o y sea su ace e pe a u e a o a y, C
89

Stable isotope analysis has become a common tool to answer questions about the trophic 

ecology of a variety of marine vertebrates, including cetaceans (Ruiz-Cooley et al., 2004), 

pinnipeds (Kurle and Worthy, 2002), seabirds (Hobson, 1993), marine turtles (Godley et al., 

1997), sharks (Estrada et al., 2003) and bony fishes (Thomas and Cahoon, 1993). These 

inferences are possible because the isotope compositions of a consumer’s body tissues are 

ultimately derived from those in its diet (DeNiro and Epstein, 1978; 1981; Miniwaga and 

Wada, 1984; Michener and Schell, 1994). By providing information on nutrients assimilated 

over extended periods, this technique is much less subject to temporal bias that may result 

from the ‘snapshot’ that comes from conventional diet analyses (Peterson and Fry, 1987; 

Hobson et al., 1996). 

• Compare tissue samples from dolphins killed in the purse-seine fishery pre- and post-regime 

shift to investigate potential changes in demographic parameters 

Biological samples collected from dolphins incidentally killed in the fishery from 1968 

through 1994 have provided material to estimate birth rates and other parameters that are 

used to describe life history characteristics (e.g. average age at weaning and at attainment of 

sexual maturity, breeding season, calving interval, adult length, longevity). Most studies 

conducted to date using these samples have focused on producing stock-specific estimates of 

vital rates, while few studies have considered spatial/temporal variability in estimates. 

Analysis of these samples can provide insight into spatial/temporal variability in these life 

history characteristics coincident with the 1976-1977 climate shift. 

Resource Needs 

 Resources needed for these activities primarily consist of additional technicians and postdoctoral level investigators for sample processing and data analysis. 

Climate Information Needs 

 U. S. and international agencies maintain databases of ETP climate variables including 

temperature, winds, and precipitation. We will rely on continued archival of oceanographic data 

from ships and buoys, development of data-assimilation models to cover gaps in observational 

data, and continued funding and renewal of satellite temperature, wind, and ocean color 

programs to ensure continuous time series of physical and biological variables. 

References

Ballance, L. T., R. L. Pitman, L. B. Spear, and P. C. Fiedler. 2002. Investigations into temporal 

patterns in distribution, abundance and habitat relationships within seabird communities of 

the eastern tropical Pacific. SWFSC Admin. Rep., La Jolla, LJ-02-17, 79 p. 

DeNiro, M. J., and S. Epstein. 1978. Influence of diet on the distribution of carbon isotopes in 

animals. Geochimica Cosmochimica Acta 42: 495-506. 

DeNiro, M. J., and S. Epstein. 1981. Influence of diet on the distribution of nitrogen isotopes in 

animals. Geochimica Cosmochimica Acta 45: 341-331. 

Estrada, J. A., A. N. Rice, M. E. Lutcavage, and G. B. Skomal. 2003. Predicting trophic position 

in sharks of the north-west Atlantic Ocean using stable isotope analysis. J Mar Bio Ass UK

83: 1347-1350. 
90

Fiedler, P. C. 2002. Environmental change in the eastern tropical Pacific Ocean: Review of 

ENSO and decadal variability. Marine Ecology Progress Series 244: 265-283. 

Fiedler, P. C., and V. A. Philbrick. 2002. Environmental change in the eastern tropical Pacific 

Ocean: Observations in 1986-1990 and 1998-2000. SWFSC Admin. Rep., La Jolla, LJ-02-15, 

16 p. 

Gerrodette, T., and J. Forcada. 2002. Estimates of abundance of Western/Southern spotted, 

whitebelly spinner, striped and common dolphins, and pilot, sperm and Bryde's whales in the 

eastern tropical Pacific Ocean. SWFSC Admin. Rep., La Jolla, LJ-02-20, 24 p. 

Godley B. J., D. R. Thompson, S. Waldron, and R.W. Furness. 1997. The trophic status of 

marine turtles as determined by stable isotope analysis. Marine Ecology Progress Series 166: 

277-284. 

Hobson, K. A. 1993. Trophic relationships among high Arctic seabirds: insights from tissuedependent stable isotope models. Marine Ecology Progress Series 95: 7-18. 

Hobson, K. A., D. M. Schell, D. Renoug, and E. Noseworthy. 1996. Stable carbon and nitrogen 

isotopic fractionation between diet and tissues of captive seals: implications for dietary 

reconstructions involving marine mammals. Can. J. Fish. Aqua.t Sci. 53: 528–533. 

Kurle C. M., and G. J. Worthy. 2002. Stable isotope assessment of temporal and geographic 

differences in feeding ecology of northern fur seals (Callorhinus ursinus) and their prey. 

Oecologia 126: 254-265. 

McGowan, J. A., D. R. Cayan, and L. M. Dorman. 1998. Climate-ocean variability and 

ecosystem response in the northeast Pacific. Science 281: 210-217. 

Michener, R. H., and D. M. Schell. 1994. Stable isotope ratios as tracers in marine aquatic food 

webs. In: Latja K, Michener RH (eds) Stable isotopes in ecology and environmental science. 

Blackwell, Oxford. Pp 138-157. 

Miller, A. J. and D. R. Cayan. 1994. The 1976-77 climate shift of the Pacific Ocean. 

Oceanography 7: 21-26. 

Miniwaga, M., and W. Wada. 1984. Stepwise enrichment of d15N along food chains: further 

evidence of the relation between d15N and animal age. Geochimica Cosmochimica Acta 48: 

1135-1140. 

Napp, J. M., C. T. Bair, R. D. Brodeur, K. O. Coyle, N. S. Shiga, and K. Mier. 2002. Interannual 

and decadal variability in zooplankton communities if the southeast Bering sea shelf. DeepSea Research II 49: 5991-6008. 

Peterson B. J., and B. Fry. 1987. Stable isotopes in ecosystem studies. Annual Review of Ecology 

and Systematics 18: 293-320. 

Pitman. R. L., L. T. Ballance, and P. C. Fiedler. 2002. Temporal patterns in distribution and 

habitat associations of prey fishes and squids. SWFSC Admin. Rep., La Jolla, LJ-02-19, 52 p. 

Reilly, S. B., P. C. Fiedler, T. Gerrodette, L. T. Ballance, R. L. Pitman, J. M. Borberg, and R. C. 

Holland. 2002a. Eastern tropical Pacific dolphin habitats - Interannual variability 1986-2000. 

SWFSC Admin. Rep., La Jolla, LJ-02-21, 44 p. 

Reilly, S. B., L. T. Ballance, P. C. Fiedler, T. Gerrodette, R. L. Pitman, H. G. Moser, L. B. Spear, 

and J. M. Borberg. 2002b. Recent information to aid in detecting regime shifts in the eastern 

tropical Pacific Ocean. SWFSC Admin. Rep., La Jolla, LJ-02-22, 21 p.

Ruiz-Cooley, R. I., D. Gendron, S. Aguíñiga, S. Mesnick, and J. D. Carriquiry. 2004. Trophic 

relationships between sperm whales and jumbo squid using stable isotopes of C and N. 

Marine Ecology Progress Series 277: 275-283. 
91

Stephens, C., S. Levitus, J. Antonov, and T. Boyer. 2001. On the Pacific Ocean regime shift. 

Geophysical Research Letters 28(19): 3721-3724. 

Thomas, C. J., and L. B. Cahoon. 1993. Stable isotope analyses differentiate between different 

trophic pathways supporting rocky-reef fishes. Marine Ecology Progress Series 95: 19-24. 

Venrick, E. L., J. A. McGowan, D. R. Cayan, and T. L. Hayward. 1987. Climate and chlorophyll 

a: long-term trends in the central north Pacific Ocean. Science 238: 70-72. 

Wade, P.R., G. M. Watters, T. Gerrodette, and S. B. Reilly. 2007. Depletion of spotted and 

spinner dolphins in the eastern tropical Pacific: modeling hypotheses for their lack of 

recovery. Marine Ecology Progress Series 343: 1-14. 
92

North Pacific Highly Migratory Species 

Authors: 

Sam McClatchie, Heidi Dewar, Suzanne Kohin, and Steven Bograd 

(Southwest Fisheries Science Center) 

Evan Howell 

(Pacific Islands Fisheries Science Center) 

Introduction 

Under Article 64 of the United Nations Convention on Law of the Sea highly migratory 

species (HMS) are specifically defined. Based on this definition, the Pacific Fishery Management 

Council’s (PFMC) HMS Management Plan specifies active management of the following species: 

Tunas [North Pacific albacore (Thunnus alalunga), yellowfin (T. albacares), bigeye (T. obesus), 

skipjack (Katsuwonus pelamis) and northern bluefin (T. thynnus orientalis)], pelagic sharks 

[common thresher (Alopias vulpinus), pelagic thresher (A. pelagicus), bigeye thresher (A. 

superciliosus), shortfin mako (Isurus oxyrinchus) and blue (Prionace glauca)], billfish [striped 

marlin (Tetrapturus audax) and Pacific swordfish (Xiphias gladius)] and dolphinfish 

(Coryphaena hippurus). Although the PIFSC FMP includes additional species, this section, 

which includes work of the SWFSC and PIFSC, focuses on the above species.

 One of the greatest challenges facing fisheries biologists is predicting how long-term climate 

change will impact the distribution and abundance of marine organisms, including highly 

migratory species (HMS). Climatic impacts on HMS occur on a variety of space and time scales. 

These scales can be classified as long-term climate trends like global warming, multi-year 

climate cycles like the Pacific Decadal Oscillation (PDO), climate pulses such as ENSO, and 

higher frequency inter-annual and seasonal variability. While efforts to integrate oceanographic 

information with fisheries data or biological studies have illuminated climate impacts over 

shorter time-scales, impacts over longer time-scales have been more challenging to address. 

Even for variations such as regime shifts, there are few data with sufficiently long time series to 

accurately determine their effects. For taxa such as some pelagic fish or foraminifera that leave 

abundant scales or tests in the sediment, long-term variability can be deduced from sedimentary 

records (Soutar and Issacs, 1969; Baumgartner et al., 1992). Long-term fluctuations in other 

species can only be inferred from more recent correlations among species. Unfortunately, for the 

HMS defined by the management plan little or no information can be obtained from the paleooceanographic records, and therefore the effects of climate change may best be understood by 

studying the effects of higher frequency climate variability (eg. El Niño) on key habitats. 

Climate Induced Ecosystem Concerns 

 The impacts of long-term climate change will undoubtedly be apparent at a number of 

different levels. Three important areas where substantial impacts are expected based on 

experience over shorter-time frames include recruitment, geographic range, and response to 

meso-scale features such as eddies and fronts that are a key determinant in distribution patterns 

within a region. Hence, the major climate induced ecosystem concerns for North Pacific HMS 

are: 
93

I. Effect of climate variability on recruitment 

II. Effect of climate variability on HMS habitats – changes in range and abundance 

III. HMS responses to mobile oceanic gradients: fronts and meso-scale features 

I. Effect of climate variability on recruitment 

Description 

 Recruitment is one critical aspect of HMS biology that will likely be impacted by climate 

change regardless of life history strategies. A broad range of oceanographic and climactic factors 

can impact recruitment including temperature, wind shear, meso-scale features, temporal or 

spatial shifts in optimal habitat, upwelling, and salinity to name a few. The forcing mechanisms, 

however, will likely differ between sharks that bear few relatively large young, and broadcast 

spawners like tuna and billfish. 

 The majority of research conducted to date has examined the recruitment of broadcast 

spawners, and some insights into the potential impacts of climate change are available. The 

recruitment of relatively closely related species can respond differently to climate pulses or 

trends. For instance, temperate and tropical tuna appear to respond differently to pulsed climate 

variability. Temperate albacore recruitment was enhanced when La Niña conditions were 

dominant and the PDO was negative, with a two-year lag. In contrast, the tropical skipjack and 

yellowfin tuna showed enhanced recruitment when El Niño dominated (and the PDO was 

positive) with a one-year lag (Lehodey et al., 2003). Forcing mechanisms that impact the 

recruitment of one species may vary between locations. Modeling results indicate that the 

positive effects of El Niño on skipjack recruitment differ between the central and western Pacific. 

In the central region, the main factor is the westward extension of the equatorial warm pool. In 

the western region, the positive effect on recruitment is due to enhanced primary production in 

warmer water, and subsequent development of improved tuna forage conditions (Lehodey et al., 

2003). 

 An example suggesting climatic effects on the northern bluefin tuna population is a positive 

correlation between the winter North Pacific Index (NPI) and bluefin recruitment for the period 

1952-1998. The NPI provides a measure of the intensity of the mean wintertime Aleutian Low 

that influences both oceanography and climate. The mechanisms underlying the correlation 

remain unknown (Uehara et al., 2002). 

Current Activities 

 1) Tunas and billfishes are broadcast spawners with extremely high egg production and 

repeated spawning activities that rely on quasi-permanent oceanographic features conducive to 

larval development. For both of these HMS groups, shipboard molecular identification of eggs 

and larvae is being conducted annually off Hawaii resulting in the characterization of spawning 

areas and spawning times. A better understanding of the oceanographic and climactic conditions 

conductive for spawning and larval recruitment is critical to understanding how these may 

change in time or space with climate change. 

 2) In the Southern California Bight annual fisheries independent surveys are being conducted 

to estimate the abundance of juvenile blue, mako and thresher sharks. Current efforts are focused 

on determining how environmental conditions influence catch per unit effort. Over the long-term, 

this will provide important insight into the impact of climate and oceanography on shark 

recruitment, a topic for which little is known. 
94

Research Needs

 Efforts to predict climate impacts on recruitment first require basic information about 

temporal and spatial patterns in spawning and recruitment and second, an understanding of how 

these are dependent on environmental conditions. Priority research needs to accomplish this are: 

1) Increase efforts to examine the recruitment of pelagic sharks, which are managed under 

the HMS FMP and under international treaties. This should include fishery-independent 

surveys as well as more extensive use of Pacific wide-observer programs to examine the 

spatial distribution and relative abundance of neonates and juveniles and the reproductive 

biology of incidentally caught adult sharks. Far less is known about shark recruitment 

than broadcast spawners. 

2) More comprehensive surveys of early life history phases of all HMS North Pacific-wide 

are required. This will require coordination among international management agencies 

and research institutions, but is required to obtain more comprehensive and systematic 

coverage over the Pacific. 

3) Results from surveys need to be coupled with information on oceanography to understand 

the essential habitat of HMS during all life history phases. 

4) Linking understanding of the essential habitat of pre-recruit HMS to predictions of how 

global climate change will impact physical and biological oceanography is needed to 

predict the future effects on recruitment. 

5) Conduct research necessary to quantify the impact of atmospheric effects, such as 

weather and wind shear, on the recruitment of HMS. These are known to vary under 

different climate regimes. 

6) While temperature is often considered an important determinant of spawning and 

recruitment due to correlations between spawning locales and temperature, other climate 

related features such as the oxygen minimum zone, thermocline depth, salinity, ocean 

circulation and possibly ultraviolet penetration also may impact recruitment. Additional 

research is required to determine the interplay between the different environmental 

factors in their impact on recruitment. 

Resource Needs 

1) Funding to further develop the tuna/billfish molecular ID protocol is needed. The 

methods were initially developed at SWFSC and are currently being employed on a 

limited basis. 

2) Provide additional resources to conduct more comprehensive Pacific-wide surveys of 

shark reproductive biology using observer programs and fisheries independent sampling 

programs. This is currently conducted on a small-scale in the California Swordfish Drift 

Net Fishery. 

3) Additional ship-time and personnel are needed to conduct larval surveys. This will 

complement existing surveys that are limited in both time and space. 

4) More advanced models to forecast recruitment based on predicted changes in 

oceanography and climate are needed. 

5) Additional resources to conduct focused studies on of the impact of a range of 

oceanographic and climate driven factors on recruitment are needed. 

6) Expanded capability in the use of conventional and molecular identification methods for 

eggs and larvae of tunas, billfishes and tuna-like species managed under the HMS FMP 
95

and under international treaties. This will dramatically improve the ability to conduct 

surveys for both eggs and larvae. 

Climate Information Needs 

• Increase ability to predict the impact of climate change on regional climate and 

oceanography in 4 dimensions. 

• Additional information on regional weather and wind shear to incorporate into 

recruitment models. 

II. Effect of climate variability on HMS habitats – changes in range and abundance 

Description 

 Changes in the geographic range and abundance of HMS populations can be expected with 

climate change based on experience with other organisms and communities as well as 

documented responses to shorter-scale climate fluctuations like ENSO. The list of factors that are 

known to influence the range and abundance of marine organisms is quite long and likely varies 

throughout the life history of the animal. One of the most important environmental factors is 

temperature; others include prey availability, water column profiles of oxygen, and meso-scale 

features (see below). Of these, the one that has received the most attention in a climate change 

context is temperature. Tropical oceans have warmed by 1-2°C over the past 100 years (HoeghGuldberg, 1999) and climate predictions suggest that this is likely to continue for at least another 

50 years (Hoegh-Guldberg, 1999). Such warming will likely lead to poleward shifts in the 

distribution of many HMS. The geographic range of HMS and/or their population sizes could 

either expand or contract. 

 Concurrent with the warming of the subtropical gyres we are seeing changes in ocean 

biology. A recent study using a 9-year time series of SeaWiFS ocean color found that the least 

productive oligotrophic gyres, those with surface chlorophyll is less than 0.07 mg/m3

, have 

expanded in area in the North Pacific, North Atlantic, South Pacific and South Atlantic by an 

average of 1-4%/yr (Polovina et al., 2008). 

 The long-term increase in temperature is overlain by ENSO effects that may produce 

additional temporary changes in the range of HMS. For example, skipjack dominate tuna catches 

in the western Equatorial Pacific warm pool. El Niño events produce a large zonal displacement 

of the warm pool that was linked to shifts in the skipjack population, with major implications for 

the fishery (Lehodey et al., 1997) as well as its effects on recruitment as noted above. Bigeye 

tuna in the central Tropical Pacific are also observed to respond to this ENSO-driven 

displacement of the warm pool. An increase in bigeye catch rates in the Hawaii-based longline 

fishery corresponding to an increase in eastward advection of the warm pool was observed 

during the winter months of El Niño events (Howell and Kobayashi, 2006). This eastward 

advection of warm pool waters, coupled with vertical changes in habitat, appeared to increase the 

availability of bigeye tuna to the longline fishery. This variability in bigeye availability is 

important as the central tropical Pacific represents only a small area fished by the Hawaii 

Longline Fishery, yet accounts for a large percentage of the total bigeye landings. 

 Shifts in the range of species can also lead to changes in community structure. HMS can 

leave areas that are no longer suitable habitat and some species change their range more quickly 

than others. Therefore, the community composition both in the historic and invaded range may 

evolve as a result of population movements. HMS can be impacted by temporal and spatial 
96

changes in community structure. For example, if migrations are timed to take advantage of a 

specific pulse of production that is shifted in time or space, expected prey may not be available. 

As mentioned above, similar scenarios could impact recruitment. 

 As top predators in the marine environment, pelagic sharks are likely to be greatly affected 

by changes in the distribution or abundance of their prey. Based on electronic tagging data, adult 

and sub-adult blue, mako and thresher sharks all have fairly wide thermal ranges suggesting that 

they may be able to change their vertical or horizontal distribution in response to climate induced 

changes in water temperatures (Weng and Block, 2004; Weng et al., 2005; S. Kohin, personal 

communication). Most also feed on a wide variety of prey and therefore may be able to shift their 

diet if some prey becomes unavailable. However, many of these species have discrete pupping 

areas, and neonates may be more susceptible to changes in water temperatures or oceanographic 

conditions. 

 Some of the best data available for examining interannual variability in migratory patterns of 

these pelagic sharks comes from ongoing electronic tagging studies. NMFS and the Tagging of 

Pacific Pelagics (TOPP) program have been studying movements of blue, mako and common 

thresher sharks since 2002. While the data are still being analyzed, some patterns have emerged. 

Shortfin mako sharks, for example, are strongly associated with the California Current and 

migrate along the U.S. and Baja California, Mexico coast. Sharks tagged during the summers of 

2003, 2005 and 2006 migrated along the coast for the subsequent year, generally remaining 

within 100 miles of shore. However, sharks tagged in 2004 and tracked through summer 2005 

tended to migrate farther from the coast and in a more dispersive manner than during the other 

years (S. Kohin, personal communication). A similar pattern was observed for the California sea 

lion which also forages within the California Current (Weise et al., 2006). Behavior of the mako 

sharks and sea lions may have been altered during 2004-2005 in response to the changes in the 

timing of coastal upwelling and a decrease in prey availability (Weise et al., 2006; Brodeur et al., 

2006). Examinations of inter-annual variability in migratory patterns for blue and thresher sharks 

are currently underway. 

 Availability of North Pacific bluefin tuna to U.S. fishers in the eastern North Pacific has 

declined dramatically in recent decades. One possible explanation is that the portion of bluefin 

that migrate to the eastern Pacific has declined in response to shifts in prey abundance. Decadal 

scale variation in population abundance of Japanese sardine has been linked to the Pacific 

Decadal Oscillation (PDO). In the 1980s and early 1990s the availability of Japanese sardine 

(Sardinops melanosticta), an important prey of bluefin tuna in the western Pacific, was high due 

to favorable environmental conditions. Consequently, during the 1980s and early 1990s, bluefin 

tuna may have remained in western Pacific waters rather than migrating into the eastern Pacific 

(Polovina, 1996). More recently, the abundance of sardines off Japan has declined, but whether 

bluefin tuna availability in the eastern Pacific has increased has not been quantitatively examined. 

 Bigeye tuna is another important species which is targeted by commercial fisheries in the 

Pacific Ocean. When used together, data from fisheries logbooks and archival/satellite tags 

provide information on the movement, migration, and vertical behavior patterns of bigeye tuna. 

Musyl et al. (2003) used data collected from archival tags on bigeye around the Hawaiian 

archipelago to uncover differences in vertical behavior. In this study large differences in bigeye 

depth distibutions were found between day and night periods, as well as in times when animals 

associated with fish aggregating devices (FADs) or in varying oceanic environments. Using 

these same archival tags Sibert et al. (2003) were able to estimate horizontal movement patterns 

for this area close to the Hawaiian Archipelago. From these tagging studies, as well as ongoing 
97

research, a more precise habitat description for bigeye tuna will be possible. A better 

understanding of the preferred habitat of bigeye tuna will aid in understanding the effects of 

changing climate conditions. For example, an increase in surface temperatures and stratification 

may affect both the horizontal and vertical distribution patterns of this species in the central 

North Pacific. 

 The distribution of striped marlin (Tetrapturus audax), like many of the HMS, is apparently 

related to temperature. While a few studies have reported changes in catch rates of striped marlin 

during El Niño events, the results differ depending on the area examined. Off Southern 

California and Baja California, Mexico, recreational catch of striped marlin increased during the 

1983 and 1992 El Niños (Squire, 1987; Hammann et al., 1995). In contrast, a preliminary 

analysis of data from the east coast of Australia indicated increased catch rates during La Niña 

conditions (Wise and Bromhead, 2004). Differences may depend on whether the area under 

consideration is at the colder extreme or warmer extreme of the species range. Near the colder 

extreme, El Niño may cause an increase in abundance as the fish range into the transiently 

warmer waters, whereas at the warmer extreme, fish may move out of the area as waters become 

too warm. Recent electronic tracking data also show that striped marlin are predominately 

epipelagic, spending most of their time in the mixed layer, so climatic changes that affect the 

depth of the thermocline may also affect their distribution and behavior. 

Current Activities 

 To understand how the geographic range or abundance of HMS might shift due to climate 

change requires an understanding of their current and historic range and abundance. Much of the 

work conducted by the HMS groups at NOAA focuses on these issues as well as linking results 

to environmental conditions to distinguish between human and environmental impacts on 

populations. 

1) NOAA Fisheries routinely maintains long and short-term time-series of fisheries catch 

data for both target and non-target species, of data from fishery independent surveys, and 

of recreational catch and effort. Activities are ongoing to improve, standardize and 

modernize the acquisition of fisheries data. These data are all critical for defining stock 

structure and conducting assessments that provide insight into abundance and distribution. 

2) Both electronic and conventional tagging programs to define essential habitat are ongoing. 

Electronic tagging studies of a number of North Pacific HMS have now been conducted 

for over five years, allowing for analysis of inter-annual differences linked to changes in 

environmental conditions. The PIFSC has an ongoing research project to tag bigeye tuna 

in the central North Pacific. Data has been transmitted from 45 popup satellite archival 

tags that were deployed on bigeye in locations within the extent of the Hawaii Longline 

fishery. Work is being done now to quantify the regional and seasonal variation in 

horizontal and vertical behavior for these animals. An examination of seasonal climactic 

shifts can also provide insight into the impacts of climate change. 

3) Trophic studies are being conducted to establish the links between HMS and prey and 

how distribution of HMS might be linked to prey. Samples are being obtained from both 

commercial and recreational fisheries from a number of HMS in U.S. waters.

4) Additional efforts are ongoing to conduct stock assessments for many of the HMS 

species. For those species, recruitment strength is estimated based on virtual population 

analyses, or length/age structured stock assessments. Recruitment trends can be examined 

with respect to short and long-term climate changes.
98

Research Needs 

Priority research needs are: 

1) Identify and characterize essential habitat of HMS by combining satellite and in-situ

oceanographic data with conventional tagging data, electronic tagging data, fishery data 

and fishery-independent resource surveys. This will help us to understand how 

environmental variability affects the distribution and abundance of selected HMS 

especially over longer time scales. To obtain Pacific-wide data will require better 

international coordination of fisheries databases and observer programs. 

2) Expand the above analyses to include additional data sources for key prey species to 

better understand links between predator and prey abundance and distribution. This 

should include more comprehensive studies of the deep scattering layer (DSL), which is 

poorly understood especially in the context of environmental variability. The DSL is a 

critical food source for many HMS species. This effort would be advanced by improved 

communication and data sharing between groups working on HMS and mid-trophic level 

organisms. 

3) Link defined essential habitat to predictive models of how climate change will impact 

oceanography including the abundance and distribution of both predator and prey. 

4) Develop more complex tags that measure a range of environmental variables such as 

oxygen concentrations or behaviors like feeding or spawning. Efforts are ongoing at 

SWFSC to develop an acoustic tag that will measure prey fields. This will provide more 

comprehensive data on what is essential habitat. 

5) Develop predictions of how longer term climate change will influence the timing and 

intensity of shorter-term events, including seasonal processes such as coastal upwelling 

and ENSO. 

Resource Needs 

 Additional resources and personnel are required to enhance the current studies identified 

above and obtain a more comprehensive understanding of essential habitat and of the links 

between the environment and the abundance and distribution of predator and prey. This is a 

necessary precursor to predicting how abundance and distribution will be impacted by climate 

change. Specific needs are: 

1) Better software and models to allow for quantitative analysis of fisheries and tagging data 

(historical and more recent) in relation to environmental conditions, both surface features 

and water column profiles. This is currently not readily available and hampers efforts to 

quantify relationships and link the diverse datasets. Current efforts are time consuming 

and less quantitative than will be required to predict the impacts of climate change. This 

will require additional qualified personnel. 

2) Additional funding for more comprehensive surveys of mid trophic level organisms that 

are prey for HMS including the DSL. This ties in well to recent efforts to enhance 

acoustic sampling methods for the California Current region. What is needed is multifrequency acoustics (12, 38, 120 and 200 kHz) capability on the new research vessels 

(with transducers mounted in a drop keel or in a tow-body). 

3) Additional resources to maintain ongoing deployments of conventional and electronic 

tags on targeted HMS species. Tagging studies are among the most effective in 
99

monitoring changes in species range and distribution in relation to environmental 

variability. 

4) To complement acoustic surveys, better in-situ sampling methods are required. For 

example a high-speed, opening-closing trawl capable of sampling micronekton could be 

used for acoustic target identification. This would be of great value especially for efforts 

to sample the DSL. No similar net is currently available at the SWFSC for work in the 

eastern North Pacific, however some DSL sampling has been done by the PIFSC on the 

south Pacific albacore fishing ground near American Samoa. 

5) There is currently a large archive of historic data that is not in electronic format and 

consequently cannot be easily accessed. This includes acoustic survey data collected by 

CalCOFI. Funding is required to process this type of data so that it can be distributed and 

analyzed in relation to environmental conditions. 

6) More complex stock assessments to incorporate both electronic tagging data and 

environmental conditions to help distinguish between the impact of environment and 

human activity and identify which environmental factors influence the abundance of 

HMS. This will require additional staff for the stock assessment group. 

7) Additional funding to improve and standardize the collection of fisheries data from 

around the globe. Current efforts are slowed by too few qualified staff. 

Climate Information Needs 

• As with recruitment, we need better information on how climate change will influence 

regional climactic and oceanographic conditions including water column profiles of key 

parameters. Coastal regions, especially in the California Current, are of particular 

importance. Collection of core oceanographic variables would require a sustained ocean 

observing network, such as that planned for the Pacific Coastal Ocean Observing System 

(PaCOOS). 

III. HMS responses to mobile oceanic gradients: fronts and meso-scale features 

Description 

 Marine organisms are not randomly distributed throughout the world’s oceans but instead are 

uneven and patchy. This patchy distribution is often driven by meso-scale features. Very small 

gradients can be associated with major changes in the distribution of HMS. Small changes in 

oceanic conditions forced by climate variability at all temporal scales (trend, regime shift, pulses 

and interannual) will likely affect the location, intensity and persistence of oceanographic 

features over a range of spatial scales. Any such changes can impact the suitability of these 

features as habitat for organisms at all life history stages. For example, modeling suggests that 

the recruitment of sardines in the California Current can be both positively and negatively 

affected by the abundance of meso-scale eddies (Logerwell and Smith, 2001). It is likely that 
100

 Figure 1: from Polovina et al., 2001: The meandering solid line shows the TZCF (0.2 mg m-3) chlorophyll a and dots show the 

spatial distribution of albacore CPUE from the U.S. troll fishery for May – September 1998. Note how the albacore seasonal 

migration follows the TZCF. 
101

other small pelagics would show similar responses, changing the available forage for HMS. 

Climate forced changes in the North Pacific Transition Zone Chlorophyll Front, a basin-wide 

feature which moves between about 35o

N in summer and 45oN in winter, would be expected to 

have a significant impact on the foraging of loggerhead turtles, as well as on the seasonal 

migration and distribution of albacore, bluefin tuna and other HMS which follow the front as 

they migrate (Polovina et al., 2001) (Figure 1). Similarly, the location of biological hotspots such 

as that observed off southern Baja California (Etnoyer et al., 2004) could change, affecting the 

catch rates of billfish and the location where whales stop to feed during their long-distance 

movements. Etnoyer et al. (2004) compared the frontal energy during El Niño and La Niña in the 

North Pacific, revealing some interesting differences under the two climactic conditions. The 

annual frontal energy was lower both off the Channel Islands and southern Baja California, 

Mexico during the El Niño and higher during La Niña, with the reverse being the case in the 

North Pacific Transition Zone (Figure 2). Whales tracked off the U.S. West Coast spent less time 

off southern Baja during the El Niño, suggesting a reduction in local productivity during this 

climactic event. 

 Because swordfish (Xiphias gladius) are targeted by commercial fisheries throughout the 

Pacific Ocean, the most complete information on climate effects comes from analysis of fisheries 

data. In the central North Pacific, highest catch rates occur in association with the frontal zones 

bounding the North Pacific transition zone, even when gradients in temperature are very slight 

(Bigelow et al., 1999). In this study, frontal energy was also an important predictor of catch rate, 

but not as important as SST. In the coastal regions around the Pacific, catch is highest in areas 

with high frontal energy (Sakagawa, 1989). Patterns in one of these frontal areas off California 

illustrate that temperature also plays a role in distributions. Here, swordfish fisheries are seasonal, 

with the highest catch rates in the summer and fall when temperatures are the warmest. In 

addition, during El Niño years, the distribution of swordfish extends to higher latitudes in both 

the northern and southern hemisphere (Caviedes, 1975; Brosnan and Becker, 1998). One 

challenge in linking swordfish abundance and distribution to climate has to do with their 

Figure 2: from Etnoyer et al., 2004: Persistence, in months per year, for concentrations of sea surface temperature fronts in the 

Northeast Pacific. Red values indicate exceptional densities of temperature gradients: 12 months per year. Green values indicate 

seasonal concentrations. The years defined are June 1997-1998 (El Niño) and June 1998-1999) (La Niña). 
102

foraging behavior. Swordfish forage largely on the DSL, spending the majority of their day at 

depths between 300 and 600 m. Their focus on this subsurface layer may limit the utility of using 

surface ocean features to understand their distributions and highlights the need to learn more 

about the links between surface features and the DSL. 

 Another species for which abundance is linked to meso-scale features is the North Pacific 

albacore. This stock ranges from 10-50°N latitude between Japan and the North American coast. 

A number of studies have demonstrated the dependence of albacore tuna on specific water 

temperatures and oceanographic conditions. In general, albacore show a preference for transition 

zone waters where SST, chlorophyll and salinity gradients tend to be high (Laurs and Lynn, 1991; 

Polovina et al., 2001). Surface mixing in transition zone areas creates meso-scale features that 

are thought to concentrate prey. The North Pacific Transition Zone (NPTZ), in addition to being 

important habitat for albacore, is also important for a number of other pelagic predators 

including seabirds, turtles, swordfish and bluefin tuna. Temporal changes in the location and/or 

strength of the frontal areas in the NPTZ or in association with El Niño conditions is highly 

correlated with changes in albacore migrations and distribution (Laurs and Lynn, 1991; Polovina 

et al., 2001; Kimura et al., 1997) and will likely affect the other predators as well. 

Current Activities 

 As mentioned, the presence of meso-scale features can significantly impact regional 

abundance of HMS creating “hotspots” where either single or multiple species aggregate. Much 

of the current work to understand the impact of meso-scale features centers on the study of 

hotspots. Once hotspots have been characterized, analyses using archived oceanographic data 

will enable quantification of their climate driven variability. 

1) In collaboration with the Tagging of Pacific Program, SWFSC is using electronic tagging 

data in combination with remote sensing and in-situ oceanographic observations to locate 

biologically important HMS hot spots, describe their physical characteristics, quantify 

their temporal persistence, and understand their impact on species behavior and 

interactions. Initial efforts are in the California Current where more than 23 species 

covering diverse taxanomic groups (birds, turtles, fish, and marine mammals) are being 

electronically tagged. Tagging spanned a mild ENSO event that should provide some 

insight into the potential implications of climate change. 

2) Ultimately efforts at the SWFSC and PIFSC will be expanded to describe, and possibly 

forecast, oceanographic features, both physical and biological, that are associated with 

high concentrations of albacore and bluefin tuna in the central North Pacific (Kuroshio 

Current extension and sub-arctic transition zone). In the long-term these predictions can 

be linked to climate models. 

Research Needs 

 A problem with predicting how HMS respond to climate change is our poor understanding of 

HMS habitat, especially in relation to dynamic ocean processes. Areas that are ripe for additional 

analyses include examining the electronic tagging datasets being collected for a range of HMS 

species, as well as the archives of fisheries data. These data should be examined with a focus on 

characterizing climate impacts on seasonal to decadal scales. This approach should be taken with 

the first three points listed below.
103

1) Expand efforts to quantify the links between meso-scale features and tracks obtained 

from electronic tags over long time frames. This is currently occurring on a limited basis. 

2) Begin to examine long-term archives of fishery-dependent and -independent data in 

relation to meso-scale features 

3) Additional information on how the abundance and distribution of HMS, their prey and 

the DSL varies in relation to fronts and meso-scale features is needed. This will require 

focused field and modeling studies. 

4) Before we can accurately predict how climate change will impact HMS in the North 

Pacific we need a better understanding of how the environment responds to climate 

forcing over a range of spatial and temporal scales. Critical questions include how the 

major current systems might shift or change in intensity as well as how the processes 

driving meso-scale features, including fronts and eddies, will change. 

Resource Needs 

1) Staff to develop the software to rapidly integrate oceanography and atmospheric data 

with fisheries and electronic tracking data. Currently these efforts are labor intensive and 

developing quantitative relationships across a range of environmental variables is 

complicated. This is especially the case when it comes to meso-scale features and fronts 

where the persistence and intensity are both important. A further complication is that 

there often exists a lag between the time a front is created and when it becomes habitat 

for a given HMS. Quantifying these relationships will require complex software. This 

software should be developed such that it can be broadly distributed to the scientific 

community to make quantitative analysis more accessible. 

2) Additional ship-time, personnel and equipment will be required for focused studies to 

establish the relationship between surface features and the abundance and distribution of 

the DSL.

Climate Information Needs 

• Better information on how climate change will impact meso-scale features as well as 

large-scale current patterns. Critical information includes the intensity, persistence and 

temporal and spatial patterns of key oceanographic processes and features. 

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106

Antarctic 

Author: 

Christian Reiss 

(Southwest Fisheries Science Center) 

Introduction 

 NOAA Fisheries has conducted annual biological and oceanographic monitoring in the South 

Shetland Islands region of the Antarctic Peninsula, since 1986. Data collected as part of the 

monitoring effort is used to advise CCAMLR (the Convention for the Conservation of Antarctic 

Marine Living Resources) in setting catch limits of Antarctic krill (Euphausia superba), as well 

as several species of finfish, squid, and crab populations within the framework of this 

international harvesting Convention. Land-based predator population dynamics (three species of 

penguins and Antarctic fur seals) are also monitored, using a standardized series of biological 

measurements (CCAMLR Environmental Monitoring Program). CCAMLR employs an 

ecosystem-based approach to management and specifically requires that ecological relationships 

among harvested, dependent and related species be maintained. Thus, separating the effects of 

fishing from climate driven environmental variability is a critical component of the monitoring 

conducted by the Southwest Fisheries Science Center, U.S. Antarctic Marine Living Resources 

program (U.S. AMLR). This program is also timely, as the Antarctic peninsula area (Fig. 1), 

including the South Shetland Islands, is one of three regions on the planet that has experienced 

the most rapid and pervasive environmental changes over the last 50 years (Vaughan et al., 2003). 

This summary focuses on data from the south Atlantic sector of the Southern Ocean; the area in 

which the U.S. AMLR program has monitoring and scientific programs. 

Figure 1. Bathymetric chart of the Antarctic 

Peninsula region including the West Antarctic 

Peninsula and the South Shetland Islands. Black 

dots represent fixed sample sites during U.S. 

AMLR acoustic biomass surveys. Open red 

circles represent locations of the Cape Shirreff 

and Copacabana field stations operated by U.S. 

AMLR and the U.S. NSF. Solid black lines 

represent prevailing flows, and blue lines 

represent surface counter current circulation. 

Depth contours are 500, 750, 1000, 1250, 2500, 

>2500 m. 

Climate Induced Ecosystem Concerns 

 Within the U.S. AMLR area of the 

Southern Ocean the 

atmosphere/ocean/ecosystem is very 

tightly coupled and climate forcing 

impacts all trophic levels. Atmospheric 

climate scale variability drives air and 

sea temperature patterns (Turner et al., 2005; Sprintall, 2003), sea-ice dynamics (Zwally et al., 

2002), variability in the Antarctic Circumpolar Current (ACC) strength (Meredith et al., 2004), 

Longitude

Antarctic Peninsula

South Shetland

Islands

Bransfield

Strait

Weddell Sea

Drake

Passage

Scotia

Sea

Latitude

ACC

Longitude

Antarctic Peninsula

South Shetland

Islands

Bransfield

Strait

Weddell Sea

Drake

Passage

Scotia

Sea

Latitude

ACC
107

the position of frontal features and the outflow from the Weddell Sea (Conil and Menendez, 

2006) and influences Upper Circumpolar Deep Water (UCDW; Klinck, 1998). Winter ocean 

conditions are also important although much less is known about winter variability. Other 

atmospheric phenomena will impact the pH of the ocean, potentially impacting physiological 

calcium carbonate pathways in a variety of animals. 

 The major climate induced ecosystem concerns in order of importance are: 

I. Ocean temperature, sea ice extent, and Weddell outflow variability 

II. Circumpolar Current variability and Upper Circumpolar Deep Water movement 

III. Winter ocean environment and its climatic variability 

IV. Ocean acidification 

I. Ocean temperature, sea ice extent, and Weddell outflow variability 

Description 

 Both sea and air temperatures have experienced substantial changes over the short time that 

records exist (Gille, 2002; Turner et al., 2005). Within the open ocean environment, deep water 

temperatures appear to have increased ~0.2 oC over the last 40 years (Gille, 2002). Winter and 

summer air temperatures along the coast of the Antarctic Peninsula have also increased (Turner 

et al., 2005). No significant long term trends in sea surface water temperature have been 

observed, although considerable variability in sea surface temperatures are associated with El 

Niño – La Niña events. Small deviations in water temperature have important impacts on 

biological processes in the Antarctic. For example, small changes in temperature and salinity 

have large impacts on water column stability and therefore primary productivity. In addition, 

enzymatic activities of many invertebrate species (including krill) are adapted to low 

temperatures, so water temperature increases are likely to impact energetic and physiological 

conditions at the base of the food chain. 

Figure 2. Time series plots of the proportional recruitment 

of Antarctic krill (upper panel; yellow), the abundance of 

salps (middle panel; red) and extent and duration of sea ice 

(bottom panel; blue high ice concentration). High 

proportional recruitment follows years of high ice extent 

and duration and salps increase during periods of low ice 

extent and duration. 

 Sea-ice is perhaps the most conspicuous 

physical feature of the oceanic environment that 

directly affects organisms in the Antarctic. Sea-ice 

provides habitat for ice dependent animals, serves 

as refuge from predation for some fish species, 

and contains algal communities that serve as 

nourishment during the over-wintering phase of 

juvenile krill (see review Garrison, 1991). Variability in the extent and duration of sea-ice, and 

it’s relation to atmospheric events like El-Niño or other atmospheric forcing directly impacts a 

variety of species and communities. 

 U.S. AMLR studies (Loeb et al., 1997; Hewitt et al., 2003) have directly related recruitment 

variability of krill to amount of sea ice, with high recruitment following years of high sea ice 

Year

1

2

3

4

5

6

7

8

9

10

11

12

79 81 83 85 87 89 91 93 95 97 99 01 03

Month

Sea ice extent

10^6 km^2

0

875

1750

2625

3500

Salp density 

(no. m^-2 0.2

0.4

0.6

Krill proportional 

recruitment 0.8

Year
108

extent and duration (Fig. 2). Additionally, the ecosystem switches from being krill dominated to 

salp dominated when sea ice concentrations are low. Since the late 1980s, sea ice duration has 

declined, and this has resulted in a corresponding increase in the number of salp dominated years. 

 Changes in the frequency of krill recruitment events are likely to greatly impact the 

populations of land based predators. In particular, strong correlations between indices of penguin 

and krill recruitment suggest that penguins in the South Shetland Islands may live under an 

increasingly krill-limited system that has disproportionate effects on the survival of juvenile 

penguins (Hinke et al., 2008) 

 In the West Antarctic Peninsula and South Shetland Islands (SSI) region sea ice duration has 

varied considerably, and the extent has generally declined over the last thirty years (Zwally et al., 

2002). These changes may be associated with ambient environmental conditions, as sea ice 

extent is highly correlated with annual air temperatures (Turner, 2005; Fig. 3). Sea Ice (10^6 km^2)

Mean temperature (C)

0.2

0.3

0.4

0.5

0.6

-3.0 -2.0 -1.0 0.0

-9

-7

-5

-3

-1

1940 1960 1980 2000 2020

Temperature (C)

0

0.1

0.2

0.3

0.4

0.5

0.6

Sea ice (10^6 km^2)

Air temperature

Sea Ice extent

Year

Figure 3. Relationship between air temperature and sea ice extent in the West Antarctic Peninsula and South 

Shetland Islands. A) Secular trends in air temperature and sea ice are significant (p<0.05); B) Sea-ice extent is 

highly (p<0.001) negatively correlated with air temperature over the period 1979 to 2005.

The effects of sea surface temperature variability are not limited to the effect on sea ice and 

krill productivity. Other atmospheric forcing mechanisms are associated with variability in 

phytoplankton biomass and the development of the spring bloom. Over the last 17 years U.S. 

AMLR has monitored the phytoplankton productivity of this area as krill are dependent upon 

phytoplankton for food, and for reproductive energy. El Niño is a major factor influencing 

phytoplankton productivity and the development of the spring bloom in the South Shetland 

Islands (Reiss, unpublished data.). Elevated indices of El Niño (the EN34 index) are associated 

with low chl a in the waters around the South Shetland Islands. Thus, broad scale climate 

variability critically impacts the structure and function of the Antarctic ecosystem, and ensures 

that separating the effects of climate variability from fishing will be complicated without detailed 

study and enhanced cooperation with climate programs. 

The outflow and circulation of the Weddell Sea, which is adjacent to the South Shetland 

Islands, is directly impacted by global climate variability (Martinson and Ianuzzi, 2003; Conil 

and Menendez, 2006). U.S. AMLR has found that the balance between Weddell outflow and 

ACC influence may also impact the productivity of the waters around the South Shetland Islands 

(Reiss, unpublished data). During periods of low phytoplankton productivity, the water around 
109

Elephant Island is slightly cooler and more saline, indicative of a Weddell source. Thus, 

understanding the variability in the outflow of the Weddell is critical to understanding the bottom 

up processes in this area. 

Modeling studies indicate that over the next 20-30 years the Western Weddell Sea area, 

including the South Shetland Islands area, will encounter consistent increases in air temperature, 

coupled with increases in sea surface salinity. Such differences may impact the productivity of 

the SSI region by changing the outflow of the Weddell and by altering the stratification of the 

water column around the South Shetland Islands. 

In addition to the pelagic environment, finfish populations monitored by the U.S. AMLR 

program are also likely affected by climate. However, in contrast to krill, most populations for 

which significant data exist show that populations that have been overfished have not increased 

greatly since the cessation of harvesting (Jones et al., 2000; Kock and Jones, 2005). There is little 

information about the effects of climate on most Antarctic fish stocks and species. The paucity of 

time series data reflects the huge area of the Southern ocean, and the relatively recent nature of 

most finfish fisheries in the region. 

Some species of non-fished finfish show declines that may indicate changes in productivity 

associated with changing environments. For example, the notothenoid Gobionotothen 

gibberifrons, has demonstrated consistent declines in abundance and recruitment in the South 

Shetland Islands (Barrera-Oro et al., 2000; Barrera-Oro and Marschoff, 2007), which has been 

closed to commercial fishing since 1989/90 and is not being impacted by harvest. The conclusion 

is that some environmental change is responsible. This could be climate related, but may also 

represent changes in competition for resources among species. 

Current Activities 

 In order to monitor and assess the impact of remote forcing of broadscale climatic variability 

on ocean temperature, sea ice extent and decline, and Weddell outflow variability, the U.S. 

AMLR program monitors summer surface and sub-pycnocline water properties at ~100 stations 

twice each summer. The nearly 20 year record of summer water temperature are approaching a 

sufficient length to resolve correlations with atmospheric teleconnections (ENSO), but are still 

too short to resolve decadal scale variability. However, no consistent monitoring of the western 

Weddell Sea is conducted by the U.S. AMLR program. Ice conditions and limitations of the 

chartered vessel have precluded establishment of long term monitoring stations from which to 

infer the strength of the Weddell outflow. 

 The U.S. AMLR program develops annual and seasonal sea-ice extent indices for the South 

Shetland Islands area for use in statistical models relating ice variability to recruitment of krill 

(Loeb et al., 1997; Hewitt et al., 2003). Additionally, we monitor air temperature from existing 

sites along the western Antarctic Peninsula, in order to extend time series of sea ice into the past. 

Research Needs 

 The U.S. AMLR program continues to monitor summer water temperatures, and is 

developing indices of variability that may be useful in separating effects of in situ warming from 

water mass effects. Better automated sea surface and sub surface water temperature (i.e. of the 

top few hundred meters) would be extremely valuable to understand interannual variability in the 

water column temperature. 

 As satellite data recorders are placed on over-wintering seals and penguins, U.S. AMLR will 

develop and acquire a variety of remotely sensed indices of the environment. Satellite based sea 
110

surface temperature, chlorophyll and sea ice concentration and distribution as well as current 

velocities will provide the means to analyze these overwintering behaviors. 

Further development of predictive models of the effects of sea-ice variability on biological 

populations will require significant resources. Our current vessel is incapable of operating within 

the ice thereby limiting our inferences about the importance of ice to krill and other organisms to 

an examination of variability as inferred from space. Outside line offices that model sea-ice 

dynamics for input into Global Circulation models (GCM) are critical partners in extending our 

program and understanding the biological and ecosystem consequences of sea-ice loss and 

variability. 

 One factor necessary for the interpretation of the data collected by U.S. AMLR is a 

quantitative ecosystem model to investigate the impact of climate variability on the whole 

ecosystem. Currently ecosystem models are being used to investigate options for the 

implementation of small-scale management units to the krill fishery. Models that examine the 

impact of climate variability across intermediate and long-term management timescales have not 

been developed. 

Climate Information Needs 

 The U.S. AMLR program sees a number of opportunities to team with the climate program to 

better understand ecosystem variability attributed to these factors. Simple increases in the level 

of observation are critical. For example, fully autonomous weather stations within Bransfield 

Strait, at both the Copacabana, and Cape Shirreff field stations as well as at Elephant Island 

would be extremely important in understanding regional weather and climate impacts. Currently, 

the U.S AMLR program relies on data collected at weather stations farther to the southwest. 

Local conditions, including precipitation and incident PAR and surface water temperature, need 

to be measured locally and are critical to understanding the development of the spring bloom, 

and for the examination of energetics and reproductive success of krill dependent predators. 

II. Circumpolar Current variability and Upper Circumpolar Deep Water movement 

Description 

The strength and variability of the prevailing Antarctic Circumpolar Current (ACC) is 

impacted by climatic forcing (Meredith et al., 2004). Meridional variability in winds originating 

from the Pacific basin drives the Southern Annular Mode of atmospheric variability which 

creates variability in the strength of the ACC. The strength of the ACC controls the amount of 

upwelling that occurs in response to the geostrophic adjustment. South of the Polar front, this 

upwelling may control the upward flux of limiting nutrients potentially impacting bottom up 

ecosystem functions like primary productivity. Additionally, due to the prevailing eastward flow 

of the ACC, local krill abundance downstream from the South Shetland Islands likely results 

from transport variability within the ACC (Loeb et al., 1997). Penguins and seals variously use 

the ACC to transit between feeding and reproductive sites, and may use the prevailing currents or 

eddies to minimize energy use, and travel time. Thus, understanding the variability in the 

strength of the ACC is likely to increase our knowledge of the interaction between advection and 

the abundance and distribution of krill and larger predators. 
111

Current Activities 

Currently, the U.S. AMLR program monitors the upper water column summer temperature of 

the ACC to 850m, between two and four times each summer. Additionally, the U.S. AMLR 

program in conjunction with the NOAA Vessel of Opportunity Program and the National Drifter 

Program at AOML, releases between 10 and 20 sea surface temperature drifters each summer, on 

transits across the Drake Passage. 

Research Needs 

Future integration into the 

large scale modeling programs 

within NOAA and especially the 

Geophysical Fluid Dynamics 

Laboratory, and outside 

ecosystem and climate programs 

including NASA and NSF will be 

critical to model the dynamics of 

the ACC and the Weddell 

outflow, and the interactions 

within the South Shetland Islands. 

Figure 4. Population trends of Chinstrap and Adelie penguins at Copacabana, King George Island, 1978 - 1999. 

Black lines represent the linear regressions solid grey line represents the piecewise linear regression with breakpoint. 

Trends have continued through the present.

Climate Information Needs 

 Coupled atmosphere ocean models at appropriate spatial resolution (<<1km near coast) are 

required. No local scale models such as those developed for other areas of US interest have been 

developed. However, the NOAA climate program and OAR have the capacity and modeling 

expertise to develop these models in cooperation with U.S. AMLR. 

III. Winter ocean environment and climatic variability 

Description 

Over the past 30 years, Gentoo penguin populations have remained fairly constant, while 

Chinstrap penguins have shown a long-term downward trend, and Adelie penguins have shown a 

step wise decline in abundance (Fig. 4). Different trends in abundance and recruitment indices 

for each species, despite generally similar indices of summer performance, suggest that winter 

conditions contribute to the divergent responses among the penguin species (Hinke et al., 2008). 

Moreover, recent data, based on satellite tagged animals, suggest that each species has 

7.5

8

8.5

9

1977 1980 1983 1986 1989 1992 1995 1998

Year

Log of the number of pairs

8.50

8.75

9.00

9.25

1977 1980 1983 1986 1989 1992 1995 1998

Ad elie

C hinstrap
112

distinctively separate wintering areas, further supporting the hypothesis that overwinter survival 

is likely the critical factor affecting population trends in these three species (Trivelpiece et al., 

2007). 

Juvenile survival of Antarctic fur seals, particularly during the first winter at sea, is a critical 

factor determining population growth (Goebel et al., 2006b). Mark-recapture data from fur seals 

at Cape Shirreff, Livingston Island from 1997 to present show highly variable cohort success 

(Goebel et al., 2006a). Two factors appear to be critical to juvenile survival in their first year: 

pre-weaning predation by leopard seals and the post-weaning environment. Leopard seals exert a 

strong top-down influence on fur seal populations and may be controlling population growth 

(Boveng et al., 1998). Leopard seals are ice dependent predators, and their local abundance in the 

South Shetland Islands is correlated with ice dynamics (Goebel, pers. comm.). During 

intermediate ice years, the local abundance of leopard seals is elevated, as the ice edge is in close 

proximity to the South Shetland Islands. However, preliminary studies by the U.S. AMLR 

program of post-weaning dispersal and survival indicate that the environment young fur seals 

wean into also has a strong influence on overall cohort success (Goebel, unpublished data). 

However little is known about the mechanisms responsible for the variability in over winter 

survival. 

U.S. AMLR is currently involved in collaborations with UCSC (University of CaliforniaSanta Cruz) and the SMRU (Sea Mammal Research Unit, St. Andrews, Scotland) to use southern 

elephant seals (SES) as oceanographic sampling platforms. These wide ranging very deep diving 

mammals can carry instruments over winter that measure temperature and salinity continuously 

and to depths of up to 1,000 meters. SES are circumpolar and these data are providing 

temperature-salinity throughout the southern ocean and winter months (Biuw et al. 2007, ). 

The combined information from both seal and penguin studies shows that the largest gap in 

our knowledge of the life history of higher trophic levels is in understanding the environmental 

determinants overwinter survival. Given the dispersion of animals during winter, it is not feasible 

or necessary to establish a winter field monitoring component. It is necessary however, to track 

the spatio-temporal dispersion of animals in relation to currents, temperature and other biological 

properties. Much of this can be accomplished using satellite based tracking of animal movements. 

This task will require significant resources for satellite tags. 

Current Activities 

While biological data collected as part of the environmental monitoring program in 

CCAMLR provides important information during the summer reproductive season, quantifying 

mortality, diet and habitat use during the winter is clearly an important and unresolved issue for 

penguins and seals. Recent advances in technology for satellite tracking of penguins and seals 

over winter and remote sensing of the southern ocean using satellites will be crucial in 

understanding the links between healthy ecosystems, commercial fisheries, and climate 

variability. 

Research Needs 

Remote sensing of climate and weather parameters (sea level, winds, temperature and 

chlorophyll) and integration of these data into statistical models of habitat use will help to 

identify likely scenarios controlling overwinter survival. Cooperation with the NOAA climate 

program in the development and testing of remote measures to examine habitat use under 
113

different winter conditions should provide a framework to understand climate impacts on the 

overwinter distribution and survival of seabirds and mammals. 

Climate Information Needs 

 U.S. AMLR will require basic weather and climatological data of the winter months, across 

the Southern Ocean. Recent data from chinstrap penguins show that their winter migrations can 

exceed several thousand kilometers in lineal distance. Thus near real time forecasting of weather, 

current and sea ice conditions are critical to understanding overwinter survival of penguins and 

seals. Such data will allow U.S. AMLR to conduct re-analysis of ocean conditions from 

returning seals and penguins. 

IV. Ocean acidification 

Description 

 Antarctic marine organisms may be particularly susceptible to the effects of ocean 

acidification. The Southern Ocean is predicted to be among the first areas to have its surface 

waters become undersaturated with respect to aragonite, a form of calcium carbonate utilized by 

some marine organisms, potentially by the year 2050 (Orr et al., 2005). Changes in ocean pH 

over the next 20 years are likely to impact species that inhabit subpycnocline waters. For 

example, the Blackfin icefish (Chaenocephalus aceratus), which is in the group of Antarctic 

fishes that are the second most valuable commercially (following Dissostichus spp.) in the 

Antarctic is a benthic egg brooder (Detrich et al., 2005). Changing pH and aragonite and calcite 

compensation depths (below the mixed layer) may greatly impact egg-mass integrity through the 

dissolution of the mucous bonds which maintain nest integrity. This could have significant and 

widespread impact on the population dynamics of this and similar species. It would also have 

implications to trophic connection within the Antarctic foodweb. 

Current Activities 

U.S.AMLR has begun collaborating with NOAA OAR and California State University San 

Marcos to monitor the total alkalinity, and dissolved inorganic carbon concentration in the South 

Shetland Islands. This effort is currently supported by CSU and NOAA-OAR. 

Research Needs 

 The U.S. AMLR program continues to develop the monitoring capacity to examine the likely 

influence of changes in ocean acidity on the marine resources and marine sentinels of the 

Southern Ocean. Future work requirements include experimental studies to investigate the likely 

impact of changing ocean pH, expanded monitoring of pCO2, and other chemical indicators of 

the carbonate system state. 

Climate Information Needs 

U.S. AMLR currently is working to develop a structure to ensure monitoring of ocean pH, 

and dissolved inorganic carbon can be integrated into the US AMLR programs sampling scheme. 

We collaborate with researchers at PMEL, and this collaboration needs to be enhanced. 

Where the NOAA climate program develops indicators, products or models reflecting the 

carbonate system of the ocean, U.S. AMLR would use such data in interpreting biological data 
114

collected within South Shetland Islands region. This would help U.S. AMLR to properly 

structure future data collection and interpretation of this important issue. 

Resource Needs 

 The U.S. AMLR Program consists of 9 FTEs and 1 NOAA Corp Rotational officer. The 

Program maintains two field camps in the South Shetland Islands, and conducts oceanographic 

surveys during austral summer. Program PI’s are in the field between 2 and 3.5 months each year. 

Thus, in order to address many of the research and management challenges regarding the impact 

of climate change, additional FTEs, instrumentation, and ship time will be required. 

• Ship time: To address many of the questions regarding the monitoring of ocean resources, 

additional ship time will be required. The U.S. AMLR Program currently uses 70 days of 

ship time in the austral summer. A minimum of 30 additional sea days is required to 

develop programs to survey other areas, deploy and recover gear, and to extend the length 

of research activity at field camps. The lack of knowledge regarding the winter 

distributions of predators and krill will require additional winter ship time in ships with 

ice breaking capacity. Additionally, increasing the depth (to >2000m) to which 

oceanographic information will be collected could dramatically alter the allocation of 

ship time. 

• Meteorological data: Increased support to develop self supporting automated weather 

stations is necessary. 

• Ecosystem modeling: While current FTE composition is sufficient to provide support to 

contemporary modeling efforts, increased use of climate models and the development of 

decision support tools will require additional ecosystem modeling expertise. Moreover, 

inclusion of large-scale GCM output or modeling investigations will necessitate increases 

in the oceanographic component of the U.S. AMLR Program to validate the projections 

from these models. 

• Over winter biological observations: Increased funding for the deployment of satellite 

instrumentation on fur seals, penguins, and southern elephant seals is necessary to 

quantify patterns of habitat use during the overwinter period. Current deployment levels 

are too low to statistically validate population level habitat preferences. Moreover, 

considerable development through the Advanced Survey Technologies Initiative or other 

funding is necessary to engineer small, light, and hydrodynamically neutral instruments 

for deployment on marine mammals and seabirds that can monitor the entire winter time 

period (8 months). 

• Physiological observations: Resolving the importance of ocean acidification will require 

additional resources. In addition to chemists that can monitor the acidity of the ocean 

from current sampling locations, physiologists will be necessary to understand the likely 

impact of the pH changes on the physiology of calcium pathways in a variety of single 

and multicellular organisms. This will require the development of an experimental 

physiology group or partnership to investigate these issues. 
115

 

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Appendix A - List of Acronyms 

ACC - Antarctic Circumpolar Current 

AFSC - Alaska Fisheries Science Center 

AMO - Atlantic Multidecadal Oscillation 

AOML – Atlantic Oceanographic and Meteorological Laboratory 

CalCOFI – California Coordinated Oceanic Fisheries Investigations 

CCAMLR - Convention for the Conservation of Antarctic Marine Living Resources 

CeNCOOS - Central and Northern California Ocean Observing System 

CCE - California Current Ecosystem 

CODAR – Coastal Ocean Dynamics Applications Radar 

COOS – Coastal Ocean Observing System 

CPC – Climate Prediction Center 

CRED - Coral Reef Ecosystem Division 

CREWS - Coral Reef Early Warning System 

CTD – Conductivity, Temperature, Depth 

DSL - Deep Scattering Layer 

EFH - Essential Fish Habitat 

EKE – Eddy Kinetic Energy 

EMAX - Energy Modeling and Analysis Exercise 

ENSO - El Niño-Southern Oscillation 

ESRL – Earth System Research Laboratory 

ETP – Eastern Tropical Pacific 

FADs - Fish Aggregating Devices 

FATE – Fisheries And The Environment 

FMP – Fisheries Management Plan 

FOCI - Fisheries-Oceanography Coordinated Investigations 

FP – fibropapilloma 

GCM - Global Circulation Model 

GFDL – Geophysical Fluid Dynamics Laboratory 

GLOBEC – Global Ocean Ecosystems Dynamics 

GPS – Global Positioning Satellite 

HMS – Highly Migratory Species 

IEA - Integrated Ecosystem Assessment 

IOOS – Integrated Ocean Observing System 

IPCC - Intergovernmental Panel on Climate Change 

LIDAR - Light Detection and Ranging 

LME – Large Marine Ecosystem 

LOSI – Loss Of Sea Ice 

MACOORA - Mid-Atlantic Coastal Ocean Observing Regional Association 

MARMAP – Marine Resources Monitoring, Assessment and Prediction 

MPA – Marine Protected Area 

NANOOS - Northwest Association of Networked Ocean Observing Systems 

NAO - North Atlantic Oscillation 

NASA – National Aeronautics and Space Administration 

NCDC – National Climatic Data Center 
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NCEP – National Centers for Environmental Prediction 

NEFSC - Northeast Fisheries Science Center 

NERACOOS - Northeastern Regional Association of Coastal Ocean Observing Systems 

NGO – Non-Governmental Organization 

NMFS – National Marine Fisheries Service 

NODC – National Oceanographic Data Center 

NOAA – National Oceanic and Atmospheric Administration 

NPCREP – North Pacific Climate Regimes and Ecosystem Productivity 

NPI - North Pacific Index 

NPRB – North Pacific Research Board 

NPTZ - North Pacific Transition Zone 

NPZ – Nutrient-Phytoplankton-Zooplankton 

NSF – National Science Foundation 

NWFSC - Northwest Fisheries Science Center 

NWHI – Northwest Hawaiian Islands 

NWS – National Weather Service 

OA – Ocean Acidification 

OAR – Office of Oceanic and Atmospheric Research 

PaCOOS – Pacific Coastal Ocean Observing System 

PAR – Phytosynthetically Active Radiation 

PFMC – Pacific Fishery Management Council 

PIFSC – Pacific Islands Fishery Science Center 

PDO - Pacific Decadal Oscillation 

PMEL – Pacific Marine Environmental Laboratory 

psu – practical salinity units 

RAs - Regional Associations 

ROMS - Regional Ocean Circulation Models 

SAFE - Stock Assessment and Fishery Evaluation 

SCOOS - Southern California Ocean Observing System 

SEFSC – Southeast Fisheries Science Center 

SOI – Southern Oscillation Index 

SSI - South Shetland Islands 

SST – Sea Surface Temperature 

STSSN - Sea Turtle Stranding and Salvage Network 

SWFSC – Southwest Fisheries Science Center 

TOPP - Tagging of Pacific Pelagics 

TZCF - Transition Zone Chlorophyll Front 

UCDW - Upper Circumpolar Deep Water 

U.S. AMLR - U.S. Antarctic Marine Living Resources program 

YOY – Young of Year