CCCC -- Introduction

## Introduction

### U.S. GLOBEC Program

The U.S. GLOBal Ocean ECosystems Dynamics (U.S. GLOBEC) program has a goal of understanding how physical processes influence marine ecosystem dynamics in order to predict the response of the ecosystem and the stability of its food web to climate change. The program proposes to accomplish this goal by (1) undertaking field studies in several ocean ecosystem types, (2) developing models of the biological and physical systems, particularly focusing on the mechanistic coupling of the biology and physics, (3) developing improved technologies to sample the ocean environment, but more importantly encouraging wider application of existing, underutilized technologies to sample the ocean, and (4) examining or re-examining existing data sets in a retrospective fashion, to both guide future sampling programs and to document past variability due to both natural and anthropogenic factors.

U.S. GLOBEC's Initial Science Plan (U.S. GLOBEC, 1991a) identified specific criteria for the selection of field study sites. Those criteria include: a demonstrable linkage of the field program to climate change; a focus on secondary producers in the marine ecosystem, including zooplankton, fish and benthos; demographically and/or geographically distinct populations are to be the focus, since one must be able to define a population in order to study that population's fluctuations; the research must ultimately lead to better understanding of how the population dynamics of the target species are related to physical processes, many of which may be modified by climate change; ideally, U.S. GLOBEC study sites would have sufficient historical data on both physics and biology to provide a longer term context for field studies of 5-7 year duration, and to assist in planning the research and verifying models of the system; and finally, to the extent possible, U.S. GLOBEC field studies should be integrated both with other global change programs, and with international collaborators.

The Initial Science Plan identified several ecosystems that satisfied most of the criteria provided above: (1) Georges Bank, (2) a Pacific Basin study; (3) an Arabian Sea study; and, (4) a Southern Ocean study. The Georges Bank study was started in 1992. U.S. GLOBEC has funded planning meetings and developed, or assisted in the development, of GLOBEC science plans for studies in the Arabian Sea, the Southern Ocean, and the California Current.

U.S. GLOBEC's intent in all its field studies is to begin by funding modeling and retrospective projects before committing to large, and expensive, field programs. This plan was followed successfully in the Georges Bank program. In the spring of 1995 we began our Southern Ocean program similarly, by soliciting modeling proposals of relevance to Southern Ocean ecosystems. We expect that GLOBEC field studies in the Southern Ocean will commence several years from now.

The Initial Science Plan identified several regions in the eastern North Pacific that might be suitable sites for intensive U.S. GLOBEC field studies: (1) an eastern boundary current ecosystem as typified by the California Current; (2) a buoyancy-driven coastal current ecosystem as typified by the Pacific Northwest and Alaska continental margin, including the Bering Sea; and, (3) an open ocean ecosystem as typified by the Alaska Gyre. Of these, planning for a program in the California Current is advanced, with several meetings leading to the production of a report on the relation between climate and the ecosystem (U.S. GLOBEC, 1992) and a Science Plan for the California Current (U.S. GLOBEC, 1994). The California Current Science Plan identifies four major questions that GLOBEC should address. They relate to (1) seasonal-to-interannual variability in biological responses, (2) decadal and longer variability in biological responses, (3) mesoscale variability in biological responses, and (4) latitudinal gradients in biological responses. Details of the proposed U.S. GLOBEC California Current program can be obtained from the U.S. GLOBEC office in Berkeley, CA or from the World-Wide Web at URL:

http://www.usglobec.berkeley.edu/usglobec/globec.homepage.html

### PICES/GLOBEC CCCC Program

#### History of PICES-GLOBEC Climate Change and Carrying Capacity (CCCC) Initiative

PICES is an intergovernmental organization established in 1992 to promote and coordinate marine scientific research in the temperate and subarctic region of the North Pacific and its adjacent seas. PICES members are Canada, China, Japan, Korea, Russia, and the United States. At its First Annual Meeting in 1992 PICES created Working Group 3, on Dynamics of Small Pelagics in Coastal Ecosystems, and Working Group 6 (WG6), on the Subarctic Gyre (WG3). Terms of reference for WG3 included:

- Develop a program for a comparative study of the population dynamics and productivity of small pelagics (focusing on herring, sardine, anchovy, and mackerel) in the coastal ecosystems along the western and eastern continental margins of the North Pacific.

Terms of reference of WG6 included:

- Review existing information on the carrying capacity for salmon and other nektonic species in the subarctic, and what is known about variations in the carrying capacity of this region in response to climate change. Advise on how changes in carrying capacity could be quantified.

- Review existing level of knowledge of the processes affecting primary and secondary production in this region and identify information gaps. Advise on how these gaps could be studied.

- Identify key scientific questions, and propose collaborative programs which can be conducted to advance knowledge and test major hypotheses.

- Determine relationships to GLOBEC. Advise which PICES and GLOBEC objectives could be linked.

Reports of the two Working Groups are contained in PICES Scientific Report No. 1 (PICES, 1993) which includes WG6's review of the Subarctic Pacific, with summaries of its physics and biology (phytoplankton, zooplankton, and fish). Recommendations to the Science Board included two that are particularly relevant to the current workshop:

- PICES should support GLOBEC activities in the North Pacific region, especially those directed towards understanding the physical and biological oceanographic linkages to long term variations in zooplankton and fish populations.

- A scientific workshop should be organized in 1994 on a "PICES-GLOBEC Program for the North Pacific Ocean. The purpose would be to develop and plan further collaborative research programs between PICES and International GLOBEC for the North Pacific Ocean.

The PICES Second Annual Meeting (fall 1993) authorized preparation of a draft Science Plan for what was called the PICES GLOBEC-International Program on Climate Change and Carrying Capacity (CCCC). The Plan was then discussed at a workshop and approved at the PICES Third Annual Meeting (fall 1994) where it was agreed to establish a Scientific Steering Committee (now called Implementation Group) to initiate development of an implementation plan. An Executive Committee of that Group met in May 1995 to prepare a draft for review and revision during the summer (a preliminary draft was available at the Seattle Workshop in April 1995).

#### Central Questions

The CCCC Science Plan emphasizes that research activities are anticipated on two spatial scales:

1. Basin-scale studies to determine how plankton productivity and the carrying capacity for highÐtrophic level pelagic carnivores in the North Pacific change in response to climate variations.

2. Regional scale ecosystem studies comparing how variations in ocean climate affect species dominance and fish populations at the coastal margins of the Pacific Rim.

The Key Scientific Questions postulated in the Science Plan have since been consolidated into the set of so-called Central Scientific Issues presented on page 1. Key research activities related to these issues will include retrospective analyses, development of models, process studies, development of observational systems, and data management. The next steps in developing the CCCC implementation plan on the regional scale are expected to include efforts to design the proposed comparison of ecosystem properties and responses to climate variability in cooperation with national GLOBEC programs. On the basin scale, a more comprehensive effort to develop an international cooperative program will be required.

### Program Rationale

The North Pacific is an attractive site for a U.S. GLOBEC program for several reasons. Many commercial industries in the Pacific Northwest and Alaska are heavily dependent on natural resources. For example, approximately half of the total U.S. fisheries catch is removed from waters off the coast of Alaska (Anon. 1993). Many studies have shown a strong connection between climatic variables and indices of fish abundance and distribution in the North Pacific (see collection of papers Beamish 1995, and Beamish and McFarlane 1989). These strong responses to climatic change translate into direct impacts on the efficiency and sustainability of the region's fishing industry. Elucidation of long term influences of climate change on these natural resources could have important benefits to the nation by improving our knowledge of functional relationships between climatic conditions and biological production that would allow for the development of long range plans for resource conservation and management.

The North Pacific is the location of one of the major storm tracks in the northern hemisphere. Simulation models suggest that the southern side of the Arctic front will be the region of greatest alteration due to global climate change. The storm track responds to two global teleconnection patterns, 1) the West Pacific oscillation that influences the location of storm generation and 2) the Pacific-North American (PNA) pattern that influences the track of storms across the Subarctic Pacific. The PNA pattern is often considered the major mode of planetary variability of the atmosphere. We can hypothesize the shift in storm frequency and track due to climate change, and its potential impact on the physical environment (see Climate Change scenarios). Any systematic shifts that occur will be modulated by the large natural variability that exists on time scales from seasonal to millennia. This variability has a profound impact on circulation, mixed layer depths and the extent of ice coverage, all of which influence the rich biological resources of the Subarctic Pacific and Bering Sea.

At the present time, we are poised to take advantage of newly developed tools that will enable us to address the questions of carrying capacity of the Subarctic Pacific. These include measurement technologies and complex computer models. The vast time-space scope of the environmental questions requires application of technologies such as remote sensing via aircraft and satellite, shipboard data acquisition systems such as those employing acoustic sampling of currents and biota, and moored platforms to collect high resolution time series of biological and physical observations. Advances in computer technology now permit using large-scale models that assimilate field observations and integrate biological and physical processes. Even over remote regions like the North Pacific Ocean, the atmosphere can be monitored and modeled operationally well enough that the largeÐscale forcing of the ocean can be specified. For example, The TOGA-TAO array in the South Pacific will provide excellent coverage of the development of El Niño Southern Oscillation events, which can be related to processes in the North Pacific. In addition, once underway the ATOC (Acoustic Thermography of the Ocean Climate) program will provide ocean basin scale information on temperature variations and the heat budget of the North Pacific Ocean.

A U.S. GLOBEC program in the North Pacific would benefit from parallel development of complementary research programs of other nations through the PICESÐGLOBEC Climate Change and Carrying Capacity program. International cooperation on a common research program will inevitably enhance our national research efforts. In the case of coastal programs, Japanese and Russian studies in the Bering Sea, and Canadian research off British Columbia will augment U.S. investigations of ecosystem responses to climate variability.

U.S. GLOBEC research programs in the North Pacific would complement proposed research for the California Current (U.S. GLOBEC 1994). Coordination with the California Current program is highly desirable because large scale forcing for both regions could be modeled simultaneously.

### Linkages to Other Field Programs

The North Pacific is a desirable region for U.S. GLOBEC research efforts partially because of the potential for coordination with five existing process oriented programs. A short description of each of these programs follows.

1. Fisheries Oceanography Coordinated Investigations (FOCI): FOCI focuses research on biological and physical processes that influence survival of walleye pollock (Theragra chalcogramma). FOCI is comprised of scientists at the Pacific Marine Environmental Laboratory, the Alaska Fisheries Science Center, and several other institutions who have been studying both the biotic and abiotic environment, including processes within larval patches through integrated field, laboratory and modeling studies. The original focus of FOCI was recruitment to the pollock population spawning in Shelikof Strait.

2. Bering Sea FOCI: Bering Sea FOCI, a component of NOAA's Coastal Ocean Program has been studying production of walleye pollock in the Bering Sea since 1991. The Bering Sea FOCI program is a six year research program that ends in 1996. The Bering Sea FOCI program has two main thrusts: investigation of stock structure of pollock in the Bering Sea, and investigation of recruitment of walleye pollock in the southeast portion of the Bering sea, where significant spawning takes place.

3. Southeast Bering Sea Carrying Capacity (SEBSCC): SEBSCC is a new regional study funded through NOAA's Coastal Ocean Program. Southeast Bering Sea Carrying Capacity will focus resources during each of the next five years to improve our understanding of the Bering Sea ecosystem. This program begins in 1996 and will continue through 2001.

4. Exxon Valdez Oil Spill Trustees (EVOS): The EVOS Trustees support research programs that will guide the development of an integrated science plan for restoration of species potentially injured by oil spills in Prince William Sound, Gulf of Alaska. These programs include the Sound Ecosystem Assessment (SEA) program, and the Apex Predator Ecosystem Experiment (APEX) . SEA is an interdisciplinary, multiÐcomponent program designed to understand factors constraining pink salmon and herring production in Prince William Sound, Alaska.

5. NMFS Ocean Carrying Capacity studies (OCC). The NMFS Auke Bay laboratory initiated the OCC study on Pacific salmon in the Gulf of Alaska in 1995. The OCC study is focused around cooperative Canada-U.S. research surveys on the marine life history of Pacific salmonids and will include studies of: age-at-maturity, modeling and diet studies, and retrospective studies of salmon growth. These process oriented research programs will provide: a) estimates of many of the critical biological parameters required to develop a coupled bio-physical model, and b) spatially explicit physical models for the region.

Canadian scientists also have a long history of fisheries oceanographic research. The Canadian La Perouse program provides a continuous time series of biological and physical oceanographic conditions off the outer coast of Vancouver Island since 1985.

The FOCI and the Canadian La Perouse Programs are among the most mature fisheries oceanography programs in the world. Few fisheries oceanography programs have been able to maintain continuous coordinated research for more than a decade. The findings from these two programs provide many of the critical parameters for the development of larger scale ecosystem models necessary to study climate change and carrying capacity of the North Pacific and Bering Sea. For example, the FOCI program has enumerated abundance trends at various life stages of early development; examined processes affecting life stages; mapped horizontal, vertical, and temporal distributions; described the oceanic and atmospheric environment; developed coupled bioÐphysical models of the Gulf of Alaska, and developed techniques to examine recruitmentÐ process hypotheses.

### Regional Boundaries

The geographic boundary between the coastal regions of the Gulf of Alaska and the open subarctic has not been defined by the PICES/CCCC/SSC. The following working definition is offered by GLOBEC:

1. The open subarctic region will include Pacific Waters north of the position of the isohaline of 34.0 psu in the upper mixed layer with the exception of the coastal regions over the continental shelf and slope (to depths of 1000 m).

2. The Bering Sea includes all oceanic waters north of the Aleutian Islands but south of the Chukchi Sea.

3. The coastal regions of the Subarctic Pacific will include all waters over the continental shelf and slope to depths of 1000 m. This coastal region will include areas south of the Aleutian Islands to the western boundary of U.S. waters at 173°E.

Some species, such as salmon, undertake seasonal migrations that cross both the coastal Gulf of Alaska and the open subarctic. It is recognized that processes in the subarctic gyre would be extended where necessary to include all areas and species of the North Pacific and marginal seas which currently are known to, or potentially could, significantly affect the physics, chemistry or biology of the subarctic gyre.