SOUTHEAST BERING SEA CARRYING CAPACITY
A Concept Paper For A Coastal Ocean Program Regional Ecosystem Study
11 July 1995
G. Weller, Director
Cooperative Institute for Arctic Research
University of Alaska
W. Aron, Director E. Bernard, Director
Alaska Fisheries Science Center Pacific Marine
NOAA Environmental Laboratory
NOAACover: A Coastal Zone Color Scanner (CZCS) image of chlorophyll concentration in the southeastern Bering Sea on 7 June 1983. Land is masked in white and clouds are masked in greys. The two white islands in the middle of the figure are the Pribilof Islands. The shelf break runs to the northwest and southeast of the Islands with the shelf to the northeast. Elevated chlorophyll concentrations are seen on the shelf. A middle shelf front is visible as an area of high chlorophyll extending eastward from the Probilof Islands. Two eddies are seen to the south of the central cloud mass. Courtesy D. Eslinger. Executive Summary
There is a need for comprehensive research on the Bering Sea and adjacent waters. The rationale is simple and clear: these Alaskan waters are among the primary fishing grounds which still have the potential for remaining viable. Whereas several other major fisheries have very likely been irreversibly depleted, stocks in the Bering Sea are still undergoing variability due to cyclical trends, independent of harvesting. There may not be much time, however. Global processes and trends, pollution, and fishing pressure all continue to exert an influence. The interactions among these and other forcing factors must be understood to allow effective management.
There has been recent concern that the North Pacific Ocean appears to be showing signs of distress. Most dramatic are the precipitous declines in seabird and marine mammal populations in Alaskan waters. Recognizing that humans tend to consider peaks in populations to be normal and desirable for sustained population size, we have to admit that we do not know the normal fluctuations in these populations. Clearly, though, the intense fishing activity in the Bering Sea provides an additional factor which the ecosystem did not have to accommodate in the past. Large excess harvesting capacity exists, which places a stress on the Bering Sea, and requires management tuned to the system as a whole.
The ecosystem of the southeast Bering Sea contains two fairly distinct upper-trophic level species groups or guilds based on characteristics of feeding. The first group consists of an outer shelf pelagic group of fish, mammals and birds that consume small fish, primarily juvenile pollock, and euphausiids. The second group is an inshore group of fish, crab and other bottom dwelling fauna that consume mainly benthic infauna. These two groups represent a biomass of about 8-10 million metric tons each, making the southeast region the major commercial sector of the Bering Sea. Walleye pollock dominate the biomass of the outer shelf and the species diversity of the pelagic guild is low. This low diversity contributes to potential lack of stability in the present Bering Sea. If this hypothesis is true, research that elucidates processes that influence interannual to decadal scale changes in the production of walleye pollock provides an indicator of the health of the ecosystem.
We plan to examine juvenile pollock in terms of their linkages to other species. Production is influenced by their overlap in space and time with predators and the distribution of secondary productivity. The oceanography of the southeast Bering Sea consists of at least five distinct habitats which mediate this overlap. We propose a regional ecosystem study which will 1) conduct retrospective analyses of the role of pollock in the ecosystem since the 1960s, 2) characterize the fisheries biology and fisheries oceanography of the distinct habitats, and 3) develop spatially explicit models for the early life history of juveniles and upper-trophic level interactions. The project will be highly leveraged, including primary interactions with marine mammal studies and foreign research laboratories, and will provide products to the North Pacific Fishery Management Council.I. Introduction
The Bering Sea ecosystem is among the most productive of high-latitude seas, and as such produces large biomasses of fishes, birds and mammals. The Bering Sea is important to the U.S. economy. Fish and shellfish constitute almost 10% of the world and 40% of the U.S. fisheries harvest. Pollock, salmon, halibut, and crab generate over 2 billion dollars each year in fisheries revenue and provide a major source of protein. At present, some Bering Sea fisheries, such as pollock, appear not to be overexploited, although there have been major changes in abundance over the last thirty years. Populations of several species, such as king crab and greenland turbot, however, are at near historical lows. We do not know the fragility of the present ecosystem in which pollock plays a singularly important role, yet whose population historically has varied over a wide range.
The relative importance of natural cycles and exploitation in explaining variability in abundance is a key management issue for the Bering Sea. In addition to perturbations created by human activities, environmental factors are seldom stable and are subject to large scale fluctuations, at times of a regular nature. It is clear that the production of new organic matter, which provides the basis for exploitable fish populations and all other higher trophic level animals, is greatly affected by environmental factors. Questions remain, however, concerning the ecosystem dynamics of the vast Bering Sea shelf that supports this high productivity.
This concept paper presents a Coastal Ocean Program Regional Ecosystem Study in the southeastern Bering Sea (Figure 1). Our conceptual model proposes that juvenile pollock are a nodal species in the ecosystem in utilizing the high primary and secondary productivity and providing food for the pelagic upper trophic level species, including adult pollock. By nodal, we imply that a large fraction of the system energy flow passes through this species population. We plan to examine pollock in terms of their linkages to other species: to understand interspecific overlaps in feeding habits through various stages of life history, including energy flow into the pollock population and outward flow via predation by other species; to understand synchronized increases or decreases in biomass at different trophic levels that may indicate the co-influence of factors; to study changes in distribution and intensity of secondary productivity as one of the bases for change in year-class strength; and to examine pollock as a key to the large scale changes in productivity of the Bering Sea over the last three decades. As an abundant resource under stress, pollock provides an important measure of the health of the ecosystem.
Goal Statement - The goal of SE Bering Sea Carrying Capacity (SEBSCC) is to document the role of juvenile pollock in the eastern Bering Sea ecosystem, to examine the factors which affect their survival, and to develop and test annual indices of pre-recruit (age-1) abundance.
Relation to Bering Sea FOCI - Bering Sea FOCI has been a part of the Coastal Ocean Program from 1991-1995, with a one-year extension through FY1996. At the start of the project, the spatial distribution of pollock stock structure between the basin, and western and eastern shelves was uncertain. This uncertainty led to concern about conducting recruitment studies without the ability to distinguish between spawning populations. There is now sufficient evidence that the southeastern Bering Sea shelf is central and critical to the productivity of pollock. This motivates a SE Bering Sea Carrying Capacity project. Our goal statement is in accord with the recommendations of the National Research Council review of BS FOCI, and also with those emerging from the PICES-GLOBEC workshop held in April 1995.
By using the Coastal Ocean Program to support core projects, we plan an inclusive approach to implementing SEBSCC through engaging other agencies, groups, and investigators with broad ecological interest in the southeast Bering Sea. We plan to use the World Wide Web to exchange project information, preliminary results and data. With the advice and experience of the Technical Advisory Committee, we will assemble a core research team selected based on proposals solicited from the University of Alaska, other universities and agencies, the Alaska Fisheries Science Center, and the Pacific Marine Environmental Laboratory. The following concept paper is organized in accordance with COP guidelines, with sections: I) Project Management, II) Conceptual Model and Scientific Approach, III) Application to Management, and IV) Budget.
II. Project Management
A. Project Management Goals
1. Conduct a first-quality scientific program that supports a specific goal to provide critical knowledge needed for formulating policy and management of resources of the southeast Bering Sea ecosystem .
2. Build partnerships and encourage multidisciplinary cooperative efforts among research scientists within the academic community, NOAA, and other agencies interested in the SE Bering Sea.
3. Provide an open process in establishing research objectives and proposal selection to ensure quality and diversity.
B. Management and Review Structure
The project management structure consists of a Project Management Team (PMT), a Research Council (RC), a Technical Advisory Committee (TAC), and Coordination (Figure 2). This builds on successful structures of the Coastal Ocean Program, i.e. NECOP, SABRE and Bering Sea FOCI, and in addition provides a coordinated forum for marine ecological research in the SE Bering Sea.
1. The Project Management Team (PMT)
The Project Management Team provides active leadership for the scientific conduct of SEBSCC, maintains financial and project accountability, and directs project administration. A primary function of the PMT is to assemble a multidisciplinary research team for a multi-year investigation of the SE Bering Sea ecosystem. The PMT will conduct a workshop early in FY1996 to define specific 2-year and 5-year research objectives for the three subprojects listed in the Approach Section. By that time, the NRC review of the Bering Sea ecosystem should be complete, and the PICES Workshop on the Bering Sea will have taken place. The SEBSCC workshop will attract a substantial group of potential PIs. Shortly thereafter, the PMT will conduct a competitive, peer-reviewed proposal process. Review by the Technical Advisory Committee will be based on scientific merit. The PMT will assure that balance and integration is maintained among subprojects, and that academic, NOAA, and resource manager viewpoints are included. The PMT, with guidance from the TAC and RC, will prioritize research. The PMT will adjust the mix of investigators during the progress of the study to reflect the evolving needs for observation, modeling, and synthesis. The PMT is responsible for ensuring that integrated results are passed to management organizations as discussed in the section on Application to Management.
The primary way for the PMT to achieve the SEBSCC research and management goals is through clear guidelines of accountability. The PMT will act as COTRs (monitors) on the accepted proposals. The expertise within the PMT includes integrative approaches to modeling fisheries stock structure, lower trophic process-oriented research, and a regional oceanographic approach. The PMT also balances a research orientation with a NOAA perspective of providing scientific products to the North Pacific Fishery Management Council. The PMT members will not directly compete for funds from the program, and will receive one month of salary compensation. The composition of the team is as follows:
Vera Alexander, University of Alaska
Dr. Alexander is Dean of the School of Fisheries and Ocean Sciences. She has a long career of studying the Bering Sea, specializing in physical influences on lower trophic level processes. She is one of the two U.S. delegates to PICES and has served on numerous research and review boards. The North Pacific Marine Science Organization (PICES) was established to promote scientific coordination among Pacific rim nations. Dr. Alexander is a Fellow of the American Association for the Advancement of Science, the Arctic Institute of North America and the Explorers Club.
Anne Hollowed, Alaska Fisheries Science Center
Dr. Hollowed provides scientific advice to the North Pacific Fishery Management Council for the Gulf of Alaska fisheries. She works with population models and has published on the connectivity between strong year classes throughout the North Pacific Basin. She serves on the steering committee for U.S. GLOBEC and is leading PICES-GLOBEC planning to address the issue of carrying capacity and climate change in the North Pacific and Bering Sea.
Jim Overland, Pacific Marine Environmental Laboratory
Dr. Overland has published research on the Bering Sea for fifteen years. He was co-director
of the Bering Sea FOCI project for the previous five years and conducted two proposal solicitations. He has just completed a five-year term as an editor for the Journal of Geophysical Research-Oceans and serves on the National Research Council Committee for the Coastal Ocean and the PICES Bering Sea Working Group. Dr. Overland will provide the primary contact with the Coastal Ocean Program Office.
All members of the Management Team agree to undertake the following:
a) Actively manage the scientific conduct of this research.
b) Participate in meetings for planning and coordination of the program.
c) Evaluate and report on interim progress and steps required to meet the project objectives.
d) Prepare annual implementation plans.
e) Ensure that quality-controlled data are made available to other investigators in a timely manner.
f) Participate in synthesis and interpretation of research results and the development of products of value to environmental and scientific communities.
g) Participate in selected fora to encourage communication between the resource management and scientific communities.
h) Encourage the publication of research results in the peer-reviewed literature for the benefit of the marine scientific community.
i) Prepare a data management plan and schedule.
2. Technical Advisory Committee (TAC)
The TAC provides independent oversight to the PMT. Members review the science implementation plan and suggest how to better coordinate the program to meet its goal and objectives. They also provide peer-review of proposals. The following members have agreed to serve:
Dr. Michael J. Dagg is Professor, Louisiana Universities Marine Consortium, Chauvin, Louisiana. He was Interim Director during 1990-1991. Dr. Dagg was a participant in PROBES and NECOP. His specialty is secondary production.
Mr. D. Bart Eaton is Vice President of Alaska Operations with Trident Seafoods Corporation. He has been active in the commercial fishing industry for 30 years and is currently partner in two state-of-the-art catcher/processors operating in the Bering Sea and Gulf of Alaska. Mr. Eaton is a past member of the North Pacific Fishery Management Council and a current Technical Advisor to Bering Sea FOCI.
Dr. Eileen E. Hofmann is Associate Professor at the Center for Coastal Physical Oceanography, Old Dominion University, in Norfolk, Virginia. Her primary interest is marine ecosystem models.
Dr. Thomas C. Royer is Professor of Marine Science at the University of Alaska Fairbanks. His specialties are coastal boundary currents and mesoscale ocean circulation with emphasis on the sub-polar gyre. He is a member of the National Academy of Science Ocean Studies Board and Committee on the Bering Sea Ecosystem. Dr. Royer has served as an Associate Editor of the Journal of Geophysical Research.
Dr. Albert V. Tyler is Associate Dean and Professor of Fisheries at the School of Fisheries and Ocean Sciences, University of Alaska, Fairbanks, Alaska. Dr. Tyler has served as a Research Scientist with the Fisheries Research Board of Canada, Professor at Oregon State University, and Research Scientist with the Canada Department of Fisheries and Oceans. Dr. Tyler is active in developing models of stock assessment in multi-species fisheries and at-sea surveys of groundfish assemblages. Dr. Tyler is chair of the PICES Bering Sea Working Group.
Dr. Warren S. Wooster is Professor Emeritus of the School of Marine Affairs, University of Washington, Seattle, Washington. He has held positions as Research Oceanographer and Professor at the Scripps Institution of Oceanography, Director of UNESCO's Office of Oceanography, and Dean of the Rosenstiel School of Marine and Atmospheric Sciences at the University of Miami. A current Technical Advisor to the Bering Sea FOCI, Dr. Wooster is Chairman of PICES and a member of the National Research Council Committee on the Bering Sea Ecosystem. He is a Fellow of the American Geophysical Union and a Fellow of the American Meteorological Society. His main area of scientific interest is the relationship between climate and large marine ecosystems.
3. Research Council
The Research Council will consist of project-funded Principal Investigators (the science team) and Associate PIs. The Council provides a forum for exchange of information on the multidisciplinary aspects of the SE Bering Sea. Several smaller interdisciplinary scientific working groups are expected to evolve from the Research Council. A representative subgroup will work with the PMT and the coordinators on field operations. The continuity of the Council will provide for extensive cross-disciplinary cooperation. The early workshop will encourage the development of interdisciplinary research proposals.
The Associate PIs, although not directly funded through the Coastal Ocean Program, will be scientists with a major interest in the SE Bering Sea ecosystem. Some potential Associate PIs are the following:
*NMFS Marine Mammal Laboratory (G. Antonelis and C. Fowler).
*State of Alaska - salmon (G. Kruse).
*University of Washington - salmon (D. Rodgers).
*University of California - birds (G. Hunt).
*NMFS/RACE Division - acoustic surveys of pollock abundance (J. Traynor).
*NMFS Kodiak Laboratory - crabs (R. Otto).
*EPA - dispersion near Pribilof Islands.
*Office of Naval Research/University of Alaska - basin-wide circulation.
*Tokai University, Japan - fishery oceanography (Nishiyama).
*Hokkaido University - HUBEC program on pollock recruitment, salmon.
*Institute of Marine Biology, Far East Branch, Russian Academy of Sciences.
*Japan Marine Science and Technology Center - physical processes/circulation.
SEBSCC will not be able to fund all potential PIs. The Associate PI opportunity will allow individual investigators funded from other sources to coordinate research activities with SEBSCC.
4. Project Coordination and Communication
SEBSCC will support a small office to coordinate communication among 1) project investigators, 2) other agencies and researchers studying the SE Bering Sea ecosystem, and 3) NOAA's Coastal Ocean Program and National Marine Fisheries Service. Products provided are data management, World Wide Web theme page, personnel directories, seminar series and announcements, publication and presentation lists, reports and documents, minutes of meetings, production of conferences and workshops, a graphic archive, and cruise plans and schedules. This office will maintain a catalog of investigators, and encourage interdisciplinary contact among investigators. The Project Coordinators will be Mr. Allen Macklin in Seattle, with the support of two NOAA Corps Officers, and Dr. Joseph Niebauer at the University of Alaska, Fairbanks.
Data Management
SEBSCC's data management plan ensures that all data are processed, validated, and made available to other investigators. Included are those documents that describe the data, how they were collected, processed and analyzed. Retrospective data sets, numerical experiments, and field data are included in the database.
SEBSCC follows the lead of the U.S. GLOBEC data policy (U.S. Global Ocean Ecosystems Dynamics Report Number 10, February 1994). SEBSCC maintains that the intellectual investment and time committed to the collection and processing of a data set entitles an investigator to the fundamental benefits of the data set. Initial publication of descriptive or interpretive results derived immediately and directly from the data is the privilege and responsibility of the investigators responsible for each collection. Accordingly, SEBSCC will generally allow exclusive use of data for one year from the completion of data processing, which will be established for each data type by the Research Council. Data must be released for collaboration among scientists to promote interdisciplinary and comparative interpretation, development of collaborative approaches, and development and testing of new theories. Any scientist making substantial use of a data set is obligated to communicate with the investigators who acquired the data and should anticipate that these scientists will be co-authors of published results.
We will develop proposed data quality and timeliness standards prior to the workshop. In its request for proposals, SEBSCC's PMT will require a data management plan from each investigator. This will include documentation of adequate methods and equipment to meet the quality standards established for SEBSCC. As part of an interdisciplinary study, each plan should show coordination with other elements. Investigators will submit a schedule for collecting, processing, analyzing, archiving, and sharing data with other investigators consistent with SEBSCC standards. The investigators are responsible for archiving data with appropriate agencies and maintaining data for project sharing, preferably by on-line electronic means; SEBSCC will facilitate data sharing. Applicants shall agree to the following conditions: At least three months prior to execution of field sampling or scientific cruises, investigators will submit a plan to the SEBSCC data management office which documents the procedure to be used to collect, process, and analyze samples and data. SEBSCC will then derive a single plan for each cruise. From the collection of cruise summaries, SEBSCC will publish an annual data report describing its field operations.
SEBSCC Informational Data Base
The SEBSCC Office of Coordination will manage a Southeast Bering Sea theme page on the World Wide Web (Figure 3). This page will exploit existing home page developments to create a single, hyper-linked resource that enables any user to browse the most recent observational data, scientific analyses, model animations, management and proposal information, and historical perspectives. The goal is to provide a virtual network for the SE Bering Sea, with participation based on common interest and easy access to information.
III. Conceptual Model and Scientific Approach
The high productivity of the Bering Sea which leads to the large biomasses of birds, mammals and fishes has long been an ecological enigma. The Bering Sea supports over 50 commercially important species and at least 50 species of marine mammals. The reasons for the consistently high productivity, even though the waters of the Bering Sea shelf are seasonally ice-covered and are cold and light limited for much of the year, have been investigated by several research programs such as PROBES, ISHTAR, BS FOCI, and marine mammal studies. The findings of PROBES (Processes and Resources of the Bering Sea Ecosystem) are particularly relevant to this proposed work, in that the emphasis was on the roles of physical oceanography and nutrient supply in regulating primary and secondary production on the southeast Bering Sea shelf (Continental Shelf Research, 5, No. 1/2, 1986). Primary productivity on the southeast Bering Sea shelf appears to be spatially variable and is highly episodic. Spring blooms associated with the ice edge and with thermal stratification are important, and the approximately 200 g C m-2 annual production remains available to the higher trophic levels, both pelagic and benthic. A limiting factor in the productivity of the southeastern Bering Sea shelf is the transport of nutrients onto the shelf.
Upper trophic level species of the SE Bering Sea can be divided into three fairly distinct species groups or trophic guilds based on characteristics of feeding (Livingston et al., 1994). The first guild consists of an outer shelf group of fish, mammals, and birds that consume small pelagic fish, primarily juvenile pollock, and euphausiids. The second guild is an inshore group of fish, crab and other epibenthic fauna that consume mainly benthic infauna. These two groups represent a biomass of about 8-10 million metric tons each. The third guild is a smaller (~1.2 million tons), more ubiquitous group, dominated by cod and skates that feed on crab and fish. Walleye pollock dominate the biomass of the outer shelf pelagic guild and the species diversity of the guild is very low (Figure 4). For the pelagic guild a biomass-weighted effective number of species, or species diversity index (Suchanek, 1994), was nearly constant (1.0 - 1.2) between 1979 and 1993. In contrast, the benthic guild had a species diversity near 5.1.
Some ecologists speculate that a low species diversity within a guild could result in less year to year stability of the guild (Wilson et al., 1991, 1994). The instability results from interannual variations in the dominant species of the guild without compensation from other guild members. Given that walleye pollock represent a dominant species in a guild with low diversity, one might expect that pollock are a nodal or focal species in the outer shelf feeding guild and would play a central role in determining the general health of the Bering Sea ecosystem (Springer 1992; Livingston, 1993). If this hypothesis is true, then research that elucidates processes that influence interannual to decadal scale changes in the production of walleye pollock in the Bering Sea (Figure 5) provide information to the status of the outer shelf guild of the Bering Sea as well. This lack of ecological stability based on adult pollock and their primary food sources, juvenile pollock and euphausiids, is a major issue in understanding the present Bering Sea ecosystem.
Production of juvenile pollock is influenced by upper trophic level predation and by the spatial and temporal distribution of secondary productivity. We believe that density-dependent predation and environmental factors have influenced pollock recruitment since the 1960s. Contrast the low recruitment years 1986, 1987, 1988 in Figure 6 with the high recruitment years 1982, 1984 and 1989; all occurred at historical highs for population biomass. It is clearly necessary to move away from simple single species spawner-recruit models to view fisheries in an ecological context and to consider the full complexity of this approach (Ludwig et. al., 1993). Both the predator and food environment are important. These co-factors interact in unclear ways. Spatial overlap or lack of overlap is a clear issue.
The dominance of pollock shown in Figure 4 suggests that predation by marine mammals and birds on juvenile pollock is overshadowed by cannibalism by older pollock. There is evidence that pollock year class survival may be enhanced by separation of juveniles from adults. About 64% of the above average 1982 year class was found in the middle shelf regime at age 1, whereas only 15% of the below average 1987 year class was located in the middle shelf (Figure 7). Both these year classes were produced from similar spawning stock sizes (Wespestad, 1994). Simulated drifter tracks started in the outer shelf region in April go to inner and middle shelf areas in 1982, but are retained in the outer shelf region in 1987 (Ingraham and Miyahara, 1988).
Changes in availability of juvenile pollock and other forage fish to upper trophic level predators may also be the result of variations in environmental conditions among various habitats in the eastern Bering Sea (Quinn and Niebauer, 1995). Temperature has a profound impact on time to hatch and growth rate of larval pollock, and influences the amount of energy available to the pelagic and benthic guilds. Mortality estimates from FOCI research suggest a decrease of larval abundance by a factor of twenty for a temperature decrease of 4[[ring]]C; growth rate for the prey of larval pollock is also temperature-dependent. In the middle domain (50-100 m water depth), a cold pool exists in the bottom layer as a remnant of previous year's ice cover. The heat content and horizontal extent of this pool vary greatly each year with minimum temperature between -1.5 to 3.0[[ring]]C. Over the outer shelf (100-180 m water depth) the intrusion of warm slope waters limits extremes in temperature. Thus, while temperature variations could limit survival in the middle domain, the outer domain probably provides a more stable environment. Data suggests that cold waters resulted in the small 1976 year class (Bailey et al., 1986), and will similarly influence the 1995 year class. Analysis of water temperatures in the period after spawning indicate that the largest year-classes of pollock occurred during the first year of a warm period (Bulatov, 1989).
It is also possible that transport along and onto the shelf encourages juvenile pollock to migrate in a westerly direction passing through areas of particularly high primary, and presumably, secondary productivity; compare the location of age-0 juveniles (Figure 8) with that of age-1 (Figure 7). One high productivity area extends south from St. Matthews Island toward Cape Navarin (Sobolevski, et al., 1991). This region receives high concentrations of nutrients from the Bering Sea basin, in some cases probably via canyon upwelling. Juveniles that successfully transit the Bering Sea shelf westward can reach regions of high productivity.
We are now in a position to make the following assertions for a Southeast Bering Sea Regional Ecosystem Study:
*The southeast Bering Sea shelf is a major region for groundfish, other commercial species, and marine mammals, containing as much as 50-85% of the pollock biomass in the Bering Sea, depending on authors' estimates. For 1994 this pollock biomass estimate for the SE Bering Sea is ~8 million metric tons (mmt), compared to 0.7 mmt for the Gulf of Alaska.
*Walleye pollock is a nodal species in the Bering Sea ecosystem, i.e., it dominates the pelagic guild and in its juvenile stage it serves as a major forage fish. Adult pollock are a major commercial asset for the United States.
*Because population dynamics processes that determine abundance appear to be chaotic, they are especially sensitive to initial conditions. The success of age structured models for pollock in the Bering Sea shows that much variability in year class abundance is established by age two. There appears to be top-down predation control of pollock recruitment, spatial and temporal variability in food supply, and variability in transport processes affecting larval and juvenile pollock. The sequence of survival processes is non-linear.
Southeast Bering Sea Carrying Capacity will test the hypothesis that interannual ocean variability influences the availability of prey, growth rate, predation, and distribution of juvenile pollock and higher trophic level species. Although we already know that ocean
variability can influence fisheries, what is not known is how these factors specifically co-occur in the Bering Sea. We use the phrase "carrying capacity" in a general context as to what limits the potential size of the pelagic guild. From the results of testing these hypotheses we will develop annual recruitment indices for pre-recruit pollock.
RESOURCES: This proposal requests $500K for a start-up year in FY1996 and $1.5 M per year for five years beginning in Fiscal Year 1997. We also will request 50 days of NOAA Ship Miller Freeman and 30 days Class I vessel time per year.
SCIENTIFIC APPROACH: The approach is interdisciplinary and balances time-series measurements, process studies and models, phased over the life of the project. Modification of the emphases and details suggested in these approaches will depend on the outcome of the workshop and will be presented in the implementation plan.
1. Time Series. We will maintain a spring larval survey and autumn juvenile survey over the shelf and shelf break. We plan to maintain moored biophysical platforms in several habitats over a six-year period. They will track important changes in the ecosystem and the climate system forcing these changes, and provide data for model studies.
2. Process and Retrospective Studies. We will ask such questions as: 1) how do horizontal and vertical physical dynamics influence the separation and overlap of aggregations of predators and prey, 2) what is the feeding and switching behavior of juvenile pollock and their predators, 3) what influences nutrient transport onto the shelf, and 4) how did pollock become established as the dominant species in the 1960s?
3. Model-Based Research. We plan to implement 1) a three-dimensional physical model coupled to an individual-based model (IBM) for larval/juvenile processes and a trophic dynamics model, and 2) a spatially dependent model of pollock, their predators, and alternate food sources similar to the Multispecies Virtual Population Analysis (MSVPA) model. The former model will be used to support early life history studies and the later will support ecosystem stability studies and be used to assess alternate management strategies.
The following table provides a timeline for major components of the program. We have an investigative stage, a hypothesis development phase, and a synthesis stage.
Table 1 - Proposed Timeline
FISCAL YEAR
96 97 98 99 00 01
Workshop * * * * * *
Proposal Cycle* *
Exploratory
Hypothesis Testing I------------------------I
Develop Survival Index I----------------------I
Validate Survival Index I-------------I
Measurement Program
Biophysical Platforms I----I I----I I----I I----I I----I I----I
Larval Ecology
Cruises I--I I--I I--I I--I I--I I--I
Juvenile Ecology
Cruises I--I I--I I--I I--I I--I I--I
The following sections outline three subprojects that comprise SEBSCC: 1) characterization of five biophysical domains, 2) studies of juvenile pollock in the ecosystem, and 3) a physical/IBM model and a MSVPA model of the shelf and slope.
1. Biophysical Domains
The eastern shelf is partitioned into biophysical domains (Figure 1) that delineate habitats for many species. The habitats are differentiated along the shelf by latitude and, across the shelf, by hydrographic domains: the outer shelf with well-mixed upper and lower layers separated by continuous stratification (bottom depth between 100 and 180 m), the middle shelf with two layers (bottom depth between 50 and 100 m), and the vertically mixed inner shelf (bottom depth less than 50 m). Characteristics such as currents, temperature, dispersion, timing of the spring bloom, community structure of plankton, and carbon flux differ among domains. These differences influence hatching time, larval growth rate, and predator and prey availability, all affecting the survival of young pollock. Apparently separate aggregations of adult pollock are found southeast and northwest of the Pribilof Islands (Hinckley, 1987; Mulligan et al., 1989). Two regions, the Pribilof Islands and Unimak Island, are unique in having all three shelf domains within a limited area. Near the Pribilofs, extensive bird and marine mammal populations rely on young pollock for food. The Unimak region is different from adjacent shelf habitats because of the influence of both the Alaska Coastal Current and the North Aleutian Slope Flow.
The transport of new nutrients needed to support the lower trophic level productivity, and ultimately the juvenile pollock growth and survival, must flow from the deep basin onto the shelf. Temporal and spatial variations in such transport are poorly known, as are primary and secondary productivity during the late summer and early fall, at the time juveniles are present in the Bering Sea. The Pervenets Canyon along the central Bering Sea slope may be a particularly good source of nutrients as it differs from the other canyons along the shelf break by being wide with gently sloping walls. Most of the work done previously, particularly during the PROBES study, emphasized the early spring dynamics when only pollock larvae are present. Juvenile pollock in late summer feed on larger zooplankton and micronekton (Merati and Brodeur, 1995). Juvenile pollock undergo a diel vertical migration pattern that apparently follows that of euphausiids, their principal prey (Bailey, 1989). This pattern places them in the more productive surface waters at night when the risk of predation to visually-feeding marine birds and mammals is reduced.
We propose to contrast the temporal and spatial variability of the biological, nutrient and physical conditions between habitats. We will ask questions such as: What are the spatial distributions of larval, juvenile and adult pollock? What are the influences of sea ice and its conditioning of bottom temperature? What controls the variability of source waters in slope/shelf nutrient flux? What maintains the different stratification between the habitats?
Concept for a Field Program - We will sample the habitats in Figure 1. Observations will be made between April (ice permitting) and September. Sampling (Table 1) will include annual distribution surveys of spawning adults, larvae, and juvenile pollock; determination of primary and secondary productivity; assessment of prey and predators; measurement of the physical environment and nutrients; and study of important frontal regions which lie between habitats, to determine scales of variability. We will monitor seasonal predator food habits and energetics with index sites at the Pribilof Islands, outer shelf domains, and the middle shelf. From 1996 through 2001 we propose to maintain several moored biophysical platforms. Each moored platform will record meteorological (wind, temperature, irradiance, pressure), oceanographic (current, salinity, temperature), and biological (chlorophyll) data. A subset of sites will have ADCPs to measure ocean currents and indicate zooplankton biomass. Both shipboard surveys and platforms will continue time series begun in 1995 as part of BS FOCI. Other chemical-water column measurements will include d13C and d15N isotope content of phytoplankton, zooplankton, fishes and other higher animals. The d13C and d15N of zooplankton collected over deep basin pelagic waters appear to be lower than those collected from on shelf and continental slope waters (D. Schell, pers. comm.) The elevated ratios on the shelf may be the result of a vigorous supply of deep nutrients onto shelf waters via upwelling, and this may offer a useful signal to determine the importance of deep basin nutrients to shelf productivity.
2. Juvenile Productivity
We hypothesize that survival of juvenile pollock is increased when predator-prey overlap is decreased via the horizontal and vertical separation of juvenile pollock from their upper trophic level predators, particularly adult pollock, marine mammals, and birds. Bottom-up effects are seen if changes decrease the availability of juvenile pollock to top level predators with limited foraging ranges or depths. Several key questions result from these hypotheses:
*What is the ecological role of forage fish and euphausiids in the Bering Sea and what is their linkage to apex species, including fisheries?
*How do oceanographic conditions in the different domains and frontal boundaries affect the seasonal and interannual predation-induced mortality on juvenile pollock?
*How does larval and juvenile growth relate to temporal and spatial characteristics in primary and secondary production?
We presently have a limited understanding of how pollock eggs spawned elsewhere in the Bering Sea end up as juveniles near and to the northwest of the Pribilof Islands (Dell'Arciprete, 1992). Satellite-tracked drifters placed on the southeast Bering shelf are generally transported toward the northwest and some have become entrapped around the Pribilofs. After being transported as larvae, the juvenile pollock may remain to capitalize on enhanced feeding conditions, despite the increased risk to predation. Juvenile pollock residence time on the southeast Bering Sea shelf is not known, but it appears that by the second year of life, food production in the region is insufficient or unsuitable and the juveniles move, partly by swimming and partly via currents to a more northwesterly location (Figures 7).
Mortality estimates are used to examine the role of environmental conditions on larval survival, to construct life history models, and to evaluate hypotheses concerning the relationship of larval size and survival rates. We believe that combining otolith (Bailey and Macklin, 1994) methods to determine cohorts, with Lagrangian methods of marking a patch of larvae and monitoring changes in abundance as it drifts, offers an accurate estimate of mortality (Talbot, 1977; Yoklavich and Bailey, 1990; Hill, 1991). Field results indicate that retention mechanisms operate to maintain larval patches (Hinckley et al., 1993).
We hypothesize that the unique physical and biological conditions associated with the frontal regions around and to the northwest of the Pribilof Islands provide a rich nursery habitat for juvenile pollock. Further, we hypothesize the importance of intermittent advection of nutrient-reach deep Bering basin slope water onto the shelf leading to intense new summer production. To test this, we will compare the abundance, size composition, growth, and condition of juvenile pollock at these fronts compared with those on either side of the fronts.
A factor in the survival of age-0 pollock in the Bering Sea may be the high abundance of large medusae in the summer. There is some evidence that the largest medusae are capable of feeding on small age-0 pollock (Hamner, 1983). At the very least, the high biomass and prodigious feeding capability of these medusae make them potential competitors with juvenile pollock and other small fishes for the available food. There is also some evidence that juvenile pollock may derive benefit by associating commensally with these abundant medusae, obtaining shelter from predators and possibly food from these hosts (Van Hyning and Cooney 1974, Hamner 1983).
Research Activities
Retrospective Analyses
*Determine the extent that pollock has historically been a dominant species, and investigate the species biomass shift during the 1960s.
*Conduct spatial distribution studies linking predator distribution, environmental variables (fronts, ice, lagged wind) and juveniles.
*Summarize the Bering Sea weather climatology since the 1940s and investigate possible causal mechanisms between the known weather shift in the mid-1970s and the strong 1978 year class.
Bio-Physical Oceanography
*Determine relative contribution of sub-stocks to pollock recruitment into the fishery noting the location of spawning sub-stocks, and the fate of spawning products in terms of location and survival; this analyses will make use of hatch date distribution, otolith analysis and molecular genetics of juvenile pollock from various subareas and seeding late-larval and early juvenile patches with satellite-tracked drifters to determine where these patches are advected. Assimilate such data into the modeling activity.
*Examine seasonal variations in location and intensity of the nearshore fronts near the Pribilofs and compare these to the other middle shelf fronts. Determine where elevated food, juvenile and predator concentrations co-occur and whether these are the result of local production, advection, or convergence.
*Determine the strength of the linkage between the spring bloom, wind mixing, and the fall concentration of meso- and macrozooplankton biomass.
Juvenile Pollock Distribution, Mortality, Feeding, Growth and Condition
*Assess small-scale vertical and horizontal distribution and behavior of juvenile pollock and alternate prey of top level predators by using acoustics, nets, and insitu video. How are different food sources utilized by predators (prey switching/selectivity)?
*Obtain information on diet and growth patterns relative to prey abundance from contrasting habitats. Use these data to determine feeding selectivity and to parameterize a bio-energetics model of feeding and growth.
Role of Gelatinous Zooplankton
*Examine distribution, stomach contents, species, and size composition of medusae around the Pribilof Islands. Determine if an association exists between juvenile pollock and medusae, with regard to enhanced food or predator avoidance, using underwater video and shipboard mesocosms.
3. Bering Sea Modeling
We propose the development of a coupled, spatially explicit, biophysical model of the eastern Bering Sea, driven by wind, tides, upwelling, insolation and temperature, to explore the growth and mortality of young pollock from the various spawning sites through the juvenile stage, and the mixing among these subpopulations (Figure 9). The spatially explicit nature of this model will allow for realistic interaction with the ecosystem by the incorporation of density dependent predation and spatially variable food sources, both of which can be badly misrepresented in spatially aggregated models.
Individual Based Models (IBM) have been successful in the OPEN, Georges Bank and Shelikof Strait FOCI programs (Werner et al., 1994; Hinckley et al., 1995; Hermann and Stabeno, 1995). We propose including lower trophic level interaction (NPZ). The IBM follows the trajectories through space of individual fish using the hydrodynamic model flow fields. The IBM is a probabilistic and mechanistic model which includes development, behavior, feeding, bioenergetics, growth and mortality for each life stage. Processes are driven by physical factors (temperature, salinity and turbulence) derived from the hydrodynamic model, and by prey levels derived from the NPZ model. The addition of the NPZ model will help address issues of match/mismatch of larval feeding to the timing of the spring phytoplankton bloom. Predation pressure exerted by other species will be incorporated into the IBM. Circulation of the Bering Sea shelf and slope should be calculated using an eddy resolving, free surface, hydrostatic primitive equation model which accurately resolves mixed layers and shelf break processes. Model hindcasts can include assimilation of data from cruises, the biophysical platforms and drifters.
We will ascertain the most important parameters that govern the year-to-year variability of food and predation relative to physical processes and the location of shelf fronts. We intend to establish links between success of the juvenile pollock, interannual variability, and spatial and temporal shifts in forcing. Combined observations and simulations will suggest which pollock spawning sites yield lowest mortality for present and projected physical forcing. Sensitivity analyses will yield insights into the fundamental predictability of pollock dynamics in this region.
We will use the output of the IBM/trophodynamic model to parameterize a spatially explicit model of upper-trophic level predators and their predation on juvenile pollock and alternate sources of prey. This second model, known as MSVPA (multispecies virtual population analysis) will include pollock and major predators of pollock and will be used to address ecological stability issues and assess the influence of various management schemes on long-term species abundances. Questions that we can ask are: What is the importance of juvenile pollock versus euphausiids in the diet of the pelagic guild based on different food switching scenarios? Can we quantify predation pressure on juvenile pollock? What is the stability of the present ecosystem? We will make use of the facilities at the University of Alaska Arctic Region Supercomputer Center. As the causal mechanisms are determined as a basis for survival, statistical models (Megrey et al., 1995) will be used to assess the robustness of the SEBSCC indices to biological and physical environmental fluctuations.
4. Leverage and Collaboration
Southeast Bering Sea Carrying Capacity will be a highly leveraged program. It plans to work collaboratively with ongoing research by other National Marine Fisheries Service (NMFS) programs examining pollock resources and ecology of the Bering Sea (fishery acoustics group, stock assessment group, and Marine Mammal Protection Act Studies), programs at the University and State of Alaska, EPA, Shelikof Strait FOCI, Japan Far Seas Fisheries Laboratory, Ocean Research Institute of Tokyo University, Faculty of Fisheries, Hokkaido University, the Japanese Marine Science and Technology Center, Tokai University in Sapporo, Tohoku National Fisheries Institute, Korean Ocean Research and Development Institute and the Institute of Marine Biology, Far East Branch of the Russian Academy of Sciences. We will also coordinate with the inhabitants of St. Paul Island. We will promote collaborative research with the ONR, NSF, and NASA. Marine mammalogists from the AFSC, ornithologists from the University of California-Irvine, and bioacousticians from the Southwest Fisheries Science Center (NMFS) and Scripps Institute of Oceanography are collaborating on ecosystem studies as part of the current BS FOCI project. An example of existing leverage is that Japanese researchers are providing facilities for BS FOCI aboard two cruises in the early summer of 1995; future collaborative work is being planned for SEBSCC in 1997. When combined with NOAA cruises, this will allow several larval cohorts to be followed through their period of maximum mortality. Japanese researchers (JAMSTEC) also are cooperating with University of Alaska scientists in research on the northern Bering Sea and Chukchi Seas in consort with Russian participants, and are providing financial support for ship time. Southeast Bering Sea Carrying Capacity will be considered a component in the PICES-GLOBEC Climate Change and Carrying Capacity (CCCC) Program.
IV. Application to Management - Pathway to a New Product
The 1970s and the 1980s were marked by dramatic changes in abundance for many groups of upper-trophic level species. Populations of piscivorous seabirds, such as murres and kittiwakes, underwent significant declines (Hatch, 1993). Similarly, estimates of steller's sea lion and northern fur seal pup production show a declining trend, particularly in the 1970s (NMFS 1993). Biomass of adult walleye pollock decreased during the 1970s, increased in the 1980s, and has approached a median value in the 1990s (Wespestad and Terry, 1984; Wespestad, 1994). The common link between these upper-trophic level predators is their reliance on juvenile walleye pollock as a food source (Livingston 1993). One needs to look no further than the Georges Bank fishery closure (Sinclair and Page, 1995; Kunzig, 1995) to see the impact of the physical/biological variability of the ecosystem.
EXPECTED RESULTS/MANAGEMENT ACTIVITY: Information on eastern Bering Sea pollock and its interactions with the remaining ecosystem will include population estimates and time series of regional biophysical parameters and research results. The program goal for the end of six years (five years plus a start-up year) is to develop and test annual indices of survival for pre-recruit pollock in the eastern Bering Sea. The FOCI program has successfully provided such indices for Shelikof Strait for the previous three years. As intermediate results become available, they will be forwarded to appropriate management and policy groups. Specification of these intermediate objectives will be a result of the 1996 workshop.
Information from SEBSCC will increase the ability of the North Pacific Fishery Management Council (NPFMC) and International Convention on Conservation and Management of Pollock Resources in the Central Bering Sea to improve the reliability of traditional fisheries assessment methods, evaluate alternate management approaches, anticipate changes in the environment, and balance fisheries and other environmental/economic concerns. The research results involving short-term forecast of walleye pollock recruitment will be incorporated into stock assessments used by AFSC to recommend allowable biological catch (ABC) estimates to the Council (Figure 10). Other research results involving factors influencing horizontal and vertical distribution of juvenile walleye pollock to upper trophic level predators would assist Council decisions regarding restriction of fishing around marine mammal rookery areas. Results on the relative contributions of various pollock sub-stocks to successful recruitment into the eastern Bering Sea fishery could also be useful in formulating management options for the timing and location of pollock fishing. The NPFMC is attempting to move in the direction of ecosystem management and information provided by SEBSCC will lead in this effort by improving knowledge of the role of pollock in the SE Bering Sea ecosystem.
Sustainable Fisheries is the first goal listed in NOAA's Strategic Plan. Southeast Bering Sea Carrying Capacity meets the requirement of the Advance Fisheries Prediction element of the Strategic Plan: The Bering Sea is a major ecosystem and economic resource where there is a large year-to-year pollock recruitment and upper-trophic level variability which is not well understood. SEBSCC's proposed management structure is a proven NOAA-academic-international partnership, effective in providing scientific leadership and subsequent transition to management. V. Budget
FY1996 FY1997 FY1998 FY1999 FY2000 FY2001
Research Program
Process Studies
Modeling
Synthesis
Science/Policy and Management Interactions
Project Management
Totals: $500K $1.5M $1.5M $1.5M $1.5M $1.0M
References
Bailey, K. M., 1989. Interaction between the vertical distribution of juvenile walleye pollock Theragra chalcogramma in the eastern Bering Sea, and cannibalism. Mar. Ecol. Prog. Ser., 53, 205-213.
Bailey, K. M., R. Francis, and J. D. Schumacher, 1986. Recent information on the causes of variability in recruitment of Alaska pollock in the eastern Bering Sea: physical conditions and biological interactions. In: International North Pacific Fisheries Commission, Bull. 47, 155-166.
Bailey, K. M., and S. A. Macklin, 1994. Analysis of patterns in larval walleye pollock Theragra chalcogramma survival and wind mixing events in Shelikof Strait, Gulf of Alaska. Mar. Ecol. Prog. Ser., 113, 1-13.
Bulatov, O. A., 1989. The role of environmental factors in fluctuations of stocks of walleye pollock (Theragra chalcogramma) in the eastern Bering Sea. In: Effects of Ocean Variability on Recruitment and on Evaluation of Parameters Used in Stock Assessment Models. R. J. Beamish and G. A. McFarlane (eds.) Can. Spec. Publ. Fish. Aquat. Sci., 108.
Dell'Arciprete, P., 1992. Growth, mortality, and transport of walleye pollock larvae (Theragra chalcogramma) in the eastern Bering Sea. M.S. Thesis, University of Washington, 105 pp.
Hamner, W., 1983. Gelatinous zooplankton of the Bering Sea. In: Processes and Resources of the Bering Sea Shelf, Final Report Vol. II, Nat. Sci. Foundation, pp. 211-229.
Hatch, S. A., 1993. Population trends of Alaskan seabirds. Pacific Seabird Bulletin, 20, 3-12.
Hermann, A. J., and P. J. Stabeno, 1995. An eddy resolving model of circulation on the western Gulf of Alaska Shelf, I, Model development and sensitivity analyses. J. Geophys. Res., in press.
Hill, A. E., 1991. Advection-diffusion-mortality solutions for investigating pelagic larval dispersal. Mar. Ecol. Prog. Ser., 70, 117-128.
Hinckley, S., 1987. The reproductive biology of walleye pollock in the Bering Sea with reference to spawning stock structure. Fish. Bull., 85, 481-498.
Hinckley, S., A. J. Hermann, and B. A. Megrey, 1995. Development of a spatially explicit, individual-based model of marine fish early life history. Mar. Ecol. Prog. Ser., submitted.
Hood, D. W., 1994. Processes and Resources of the Bering Sea Shelf (PROBES). Continental Shelf Research, 5, no. 1/2 special issue.
Ingraham, W. J., Jr., and R. K. Miyahara, 1988. Ocean surface current simulations in the North Pacific Ocean and Bering Sea. NOAA Tech. Memo. NMFS F/NWC-130.
Kunzig, R., 1995. Twilight of the cod. Discover, April 44-58.
Livingston, P. A., 1993. Importance of predation by groundfish, marine mammals and birds on walleye pollock Theragra chalcogramma and Pacific herring Clupea pallasi in the eastern Bering Sea. Mar. Ecol. Prog. Ser., 102, 205-215.
Livingston, P. A., L-L. Low, and R. J. Marasco, 1994. Eastern Bering Sea Ecosystem Trends. Symposium on Large Marine Ecosystems of the Pacific, Qingdau, China, 8-11 October 1994.
Ludwig, D., R. Hilborn, and C. Walters, 1993. Uncertainty, resource exploitation and conservation: lessons from history. Science, 260, 17, 36.
Megrey, B. A., S. J. Bograd, W. C. Rugen, A. B. Hollowed, P. J. Stabeno, S. A. Macklin, J. D. Schumacher, and W. J. Ingraham, Jr., 1995. An exploratory analysis of associations between biotic and abiotic factors and year-class strength of Gulf of Alaska walleye pollock (Theragra chalcogramma). In: Climate Change and Northern Fish Populations, Can. Spec. Publ. Fish. Aquat. Sci., 121, R. J. Beamish, Ed., 227-243.
Merati, N., and R. D. Brodeur, 1995. Feeding habits and daily ration of juvenile walleye pollock in the western Gulf of Alaska. NOAA Tech. Rep. In press.
Mulligan, T. J., K. M. Bailey, and S. Hinckley, 1989. The occurrence of larval and juvenile walleye pollock in the eastern Bering Sea with implications for stock structure. In: Proc. Int. Symp. Biol. Mgmt. Walleye Pollock, Alaska Sea Grant Report, 89-1, 471-489.
Nishimura, A., 1995. Preliminary results (and updated results) of larval pollock survey conducted by the Kaijo Maru in 1993. Unpubl. manuscript, Far Seas Fisheries Institute, Japan.
NMFS, 1993: Final conservation plan for the northern fur seal. Prepared by the National Marine Mammal Laboratory/Alaska Fisheries Science Center, Seattle, Washington, and the Office of Protected Resources/National Marine Fisheries Service, Silver Spring, Maryland. 80 pp.
Quinn, II, T. J., and H. J. Niebauer, 1995. Relation of eastern Bering Sea walleye pollock recruitment to environmental and oceanographic variables. In: Climate Change and Northern Fish Populations, Can. Spec. Publ. Fish. Aquat. Sci., 121, R. J. Beamish, Ed., 497-507.
Sinclair, M., and F. Page, 1995. Cod fishery collapses and North Atlantic GLOBEC. U.S. GLOBEC News, No. 8, 1-3 and 16-20.
Sobolevski, E. I., K. V. Cheblykova, and V. I. Rodchenko, 1991. Distribution of first-year pollock, Theragra chalcogramma, in the western Bering Sea. Voprosy ikhtiologii, 31, 766-775.
Springer, A. M., 1992. A review: walleye pollock in the North Pacific - how much difference do they really make? Fish. Oceanogr., 1, 80-96.
Suchanek, T. H., 1994. Temperate coastal marine communities: biodiversity and threats. Amer. Zool., 34, 100-114.
Talbot, J. W., 1977. The dispersal of plaice eggs and larvae in the southern bight of the North Sea. J. Cons. int. Explor. Mer., 37, 221-248.
Van Hyning, J. M., and R. T. Cooney, 1974. Association of walleye pollock, Theragra chalcogramma, with the jellyfish, Cyanea. Copeia 1974, 791.
Werner, F. E., R. I. Perry, R. G. Lough, and D. R. Lynch, 1994. A coupled individual-based-trophodynamics and circulation model for studies of larval cod and haddock on Georges Bank. U.S. GLOBEC News, No. 7, 1-3 and 14-15.
Wespestad, V. G., 1994. Walleye pollock. In: Stock assessment and fishery evaluation report for the groundfish resources of the Bering Sea/Aleutian Islands regions as projected for 1995. North Pacific Fishery Management Council, P.O. Box 103136, Anchorage, AK, 99510.
Wespestad, V. G., and J. M. Terry, 1984. Biological and economic yields for eastern Bering Sea walleye pollock under differing fishing regimes. N. Amer. J. Fish. Manage., 4, 204-215.
Wilson, J. A., J. M. Acheson, M. Metcalfe, and P. Kleban, 1994. Chaos, complexity and community management of fisheries. Marine Policy, 18, 291-305.
Wilson, J. A., J. French, P. Kleban, S. R. McKay, and R. Townsend, 1991. Chaotic dynamics in multiple species fishery: a model of community predation. Ecological Modelling, 58, 303-322.
Yoklavich, M. M., and K. M. Bailey, 1990. Hatching period, growth and survival of young walleye pollock Theragra chalcogramma as determined from otolith analysis. Mar. Ecol. Prog. Ser., 64, 13-23.VITA
Vera Alexander
School of Fisheries and Ocean Sciences
University of Alaska Fairbanks
Fairbanks, Alaska 99775-7220
Education: University of Wisconsin - B.A. (Zoology) - 1955 (Honors)
University of Wisconsin - M.S. (Zoology) - 1962
University of Alaska - Ph.D. (Oceanography) - 1965
Memberships: American Society of Limnology and Oceanography
(professional) The Arctic Institute of North America (Fellow)
American Association for the Advancement of Science (Fellow)
The Oceanography Society
American Geophysical Union
Sigma Xi
Phi Kappa Phi
Explorers Club (Fellow)
Professional Dean, School of Fisheries and Ocean Sciences, University of Alaska
Employment: Fairbanks, 1989-Present
Professor of Marine Science, 1974-present
Director, Institute of Marine Science, University of Alaska Fairbanks, 1980-1993
Dean, College of Environmental Sciences, University of Alaska Fairbanks, 1977-1978; 1983-1984
Visiting Professor, National Institute of Polar Research, Tokyo, Japan, Fall 1981
Visiting Professor, University of Turku, Finland, Spring 1976
Assistant/Associate Professor, University of Alaska Fairbanks, 1965- 1974
Selected Activities: U.S. Delegate to North Pacific Marine Science Organization (PICES), 1992-present
Member, Committee on Geophysical and Environmental Data, Board on Earth Science and Resources, National Research Council, 1993-present
Alaska State Secretary, Rhodes Scholar Selection Committee
Research Nutrient cycles in aquatic systems, primary productivity, arctic and Interests: subarctic limnology; biological oceanography with special emphasis on low trophic level biology; aquatic and terrestrial nitrogen fixation; dynamics of marine marginal ice zone ecosystems.
Relevant Experience in arctic and Antarctic sea-ice areas, with emphasis on ice Research biology, primary production and nitrogen dynamics; has been involved Experience: in the Arctic Research Vessel Design over the past five years; more than 70 papers published in the refereed literature, authored or co-authored.
Selected Niebauer, H. J. and V. Alexander. 1985. Oceanographic frontal structure
Publications: and biological production at an ice edge. Cont. Shelf Res. 2:367-88.
Müller-Karger, F. and V. Alexander. 1987. Nitrogen dynamics in a marginal sea-ice zone. Cont. Shelf Res. 7:805-823.
Alexander, V. and H. J. Niebauer. 1989. Recent studies of phytoplankton blooms at the ice edge in the Southeast Bering Sea. Rapp. P.-v. Reun. Cons. Int. Explor. Mer 188:98-107.
Niebauer, H. J., V. Alexander, and S. Henrichs. 1990. Physical and biological oceanographic interaction in the spring bloom at the Bering Sea marginal ice zone. J. Geophys. Res. 95:22229-22241.
Gu, B., D. M. Schell, and V. Alexander. 1994. Stable carbon and nitrogen isotope analysis of a plankton food web in a subarctic lake. Can. J. Fish. Aquat. Sci. (in press)
Niebauer, H. J., V. Alexander, and S. Henrichs. 1994. Time series of the spring bloom from the Bering Sea ice edge in spring. Cont. Shelf Res. (in press)
Graduate Ph.D.
Students: Binhe Gu
Robert Paul Marshall (Co-chairman)
John C. Mellor
Stephen Charles Whalen
M.S.
Kristin Teje Bezdek (Co-chairman)
Margaret Mary Billington
Robert C. Clasby
Katherine M. Klingensmith
Binhe Gu
Frank Müller-Karger
VITA
Dr. Anne Babcock Hollowed
Alaska Fisheries Science Center
National Marine Fisheries Service
7600 Sand Point Way NE, Seattle, WA 98115
Education
Ph.D. Fisheries, University of Washington, Seattle, WA 1990
M.S. Biological Oceanography, Old Dominion University, Norfolk, VA 1981
B.A. Biology and Geology, Lawrence University, Appleton, WI 1978
Professional Experience
1982 - Present. Supervisory Fisheries Biologist, National Marine Fisheries Service, Alaska Fisheries Science Center, Seattle, WA 98115. Responsible for the Gulf of Alaska sub-task of the Resource Ecology and Fisheries Management Division. Members of this task conduct annual assessments of groundfish stocks in the Gulf of Alaska. Together with members of this task, Anne conducts research on population dynamics of groundfish stocks, develops bio-physical models, and designs and implements experiments to improve estimates of stock abundance, stock distribution and life history parameters such as growth, mortality, or maturity. Conducts research on the response of the groundfish complex to multi - year to decadal scale changes in ocean climate.
1982. Research Biologist. University of Washington, Seattle, WA. Conducted multivariate assemblage analysis of groundfish complexes in the Bering Sea.
Professional Memberships
1994 - Present. Affiliate Professor, University of Washington, College of Fisheries and Ocean Sciences, School of Fisheries, Seattle, WA. Serves on graduate student committees, cooperates on research projects at the University of Washington, and conducts guest lectures.
1993 - Present. Member of the U.S. GLOBEC Steering Committee.
1994. Member of the PICES Steering Committee responsible for development of the PICES GLOBEC Science Plan for research on Climate Change and Carrying Capacity.
1995. Member of the Executive Committee of the PICES Implementation Group responsible for development of an implementation plan for the Climate Change and Carrying Capacity research program.
1993-1994. Chairperson of the Groundfish Management Plan Team of the North Pacific Fisheries Management Council.
1995. Chairperson of the organization committee responsible for convening and documenting the U.S. GLOBEC planing workshop for scientific research on Climate Change and the Carrying Capacity, held at Battelle Laboratory, Seattle, WA, April 19-20, 1995.
Selected Publications
Hollowed, A. B., and W. S. Wooster, 1995. Decadal-scale variations in the eastern subarctic Pacific: 2. Response of northeast Pacific fish stocks. In: R. J. Beamish (editor) Climate Change and Northern Fish Populations. Can. Spec. Publ. Fish. Aquat. Sci., 121, 000-000.
Woodbury, D., A. B. Hollowed, and J. A. Pearce, 1995. Interannual variation in growth rates and back-calculated spawn dates of juvenile Pacific hake (Merluccius productus). pp. 481-496. In: D. H. Secor, J. M. Dean, and S. E. Campana (editors) Recent Developments in Fish Otolith Research. University of South Carolina Press, Columbia, SC.
Wooster, W. S., and A. B. Hollowed, 1995. Decadal-scale variations in the eastern subarctic Pacific. 1. Winter ocean conditions. In: R. J. Beamish (editor) Climate Change and Northern Fish Populations. Can. Spec. Publ. Fish. Aquat. Sci., 121, 000-000.
Hollowed, A. B., and B. A. Megrey, 1993. Evaluation of risks associated with application of alternative harvest strategies for Gulf of Alaska walleye pollock. pp. 291-320. In: Proceedings of the International Symposium on Management Strategies for Exploited Fish Populations.
Hollowed, A. B., 1992. Spatial and temporal distributions of Pacific hake, Merluccius productus, larvae and estimates of survival during early life stages. California Cooperative Oceanic and Fisheries Investigations Reports 33, 100-123.
Hollowed, A. B., and W. S. Wooster, 1992. Variability of winter ocean conditions and strong year classes of northeast Pacific groundfish. ICES Mar. Sci. Symp., 195, 433-444.
Wooster, W. S., and A. B. Hollowed, 1991. Decadal scale changes in the northeast Pacific ocean. Northwest Environmental Journal, 7, 361-363.
Hollowed, A. B., 1990. Recruitment of marine fishes in the northeast Pacific ocean in relation to interannual variations in the environment. Dissertation, University of Washington, Seattle, WA 98195.
Megrey, B. A., and A. B. Hollowed, 1990. Integrated analysis of Gulf of Alaska walleye pollock catch-at-age and research survey data using two different stock assessment procedures. International North Pacific Fisheries Commission Bull., 50.
Hollowed, A. B., and K. M. Bailey, 1989. New perspectives on the relationship between recruitment of Pacific hake (Merluccius productus) and the ocean environment. In: Beamish, R.J. and G.A. McFarlane (eds.) Effects of ocean variability on recruitment and an evaluation of parameters used in stock assessment models. Can. Spec. Publ. Fish. Aquat. Sci., 108, 207-220.
Hollowed, A. B., K. M. Bailey, and W.S. Wooster, 1987. Patterns in recruitment of marine fishes in the Northeast Pacific Ocean. Biological Oceanography, 5, 99-131.
VITA
James E. Overland
Pacific Marine Environmental Laboratory/NOAA
7600 Sand Point Way NE, Seattle, WA 98115
ACADEMIC TRAINING
Ph.D. New York University, Physical Oceanography and Meteorology, 1973.
M.S.University of Washington, Physical Oceanography, 1971.
B.S.University of Washington, Physical Oceanography, 1970.
PROFESSIONAL EXPERIENCE
1979-present GM-15 Division Leader, Coastal and Arctic Research Division, Pacific
Marine Environmental Laboratory, NOAA.
Dr. Overland heads one of the three Research Divisions of the Laboratory, consisting of seven principal scientists and ten support personnel. The goal of the Division is to conduct research to improve the scientific base of NOAA in fisheries oceanography.
1977-79 Oceanographer, PMEL.
1973-76 Physical Scientist, National Meteorological Center, National Weather
Service.
SELECTED MEMBERSHIPS
1991-present Affiliate Professor, Department of Atmospheric Sciences, University
of Washington.
1983-1991 Affiliate Associate Professor, Department of Atmospheric Sciences,
University of Washington.
Editor, JGR-OCEANS, 1990-1994
Committee on the Coastal Ocean, National Academy of Sciences, 1990-
Panel on Marine Meteorology, National Academy of Sciences 1990-1991, 1993-1994
AMS Committee on Meteorology and Oceanography in the Coastal Zone, 1988-1992, 1994-
PICES Committee on Physical Oceanography and Climate 1992-
Interagency Taskforce on Ice and Weather Dynamics, 1986-1988
Santa Barbara Channel Review Board (BLM), 1983-1986
Co-Editor, Nansen Centennial Volume, AGU, 1994
The Outstanding Reviewer for J. Geophysical Research-OCEANS, 1986.
SELECTED PUBLICATIONS
Overland, J.E., and N.A. Bond, 1995: Observations and scale analysis of coastal wind jets. Mon. Weather Rev., 123, in press.
Overland, J.E., P. Turet, and A.H. Oort, 1995: Regional variations of moist static energy flux into the Arctic. J. of Climate, 8, in press.
Bond, N.A., J.E. Overland, and P. Turet, 1994: Spatial and temporal characteristics of the wind forcing of the Bering Sea. J. of Climate, 7, 1119-1130.
Overland, J.E., M.C. Spillane, H.E. Hurlburt, and A.J. Wallcraft, 1994: A numerical study of the circulation of the Bering Sea basin and exchange with the North Pacific Ocean. J. Phys. Oceanogr., 24, 736-758.
Stabeno, P.J., R.K. Reed, and J.E. Overland, 1994: Lagrangian Measurements in the Kamchatka Current and Oyashio. J. of Oceanogr., 50, 653-662.
Overland, J.E., and N. Bond, 1993: The influence of coastal topography: The Yakutat storm. Mon. Weather Rev., 121, 1388-1397 .
Overland, J.E., 1990: Prediction of vessel icing at near-freezing sea temperatures. Weather and Forecasting, 5, 62-77.
Overland, J.E., and C.H. Pease, 1988: Modeling ice dynamics of coastal seas. J. Geophys. Res., 93, 15619-15637.
Overland, J.E., and A.T. Roach, 1987: On northward flow in the Bering and Chukchi Seas. J. Geophys. Res., 92, 7097-7105.
Overland, J.E., 1984: Scale analysis of marine winds in straits and along mountainous coasts. Mon. Weather Rev., 112, 2530-2534.
Overland, J.E., H.O. Mofjeld, and C.H. Pease, 1984: Wind-driven ice drift in a shallow sea. J. Geophys. Res., 89, 6525-6531.
Cavalieri, D.J., J.E. Overland, C.H. Pease, R.M. Reynolds, J.D. Schumacher, et al., 1983: MIZEX-West Bering Sea marginal ice zone experiment. EOS Transactions, 64, 578-579.
Overland, J.E., R.M. Reynolds, and C.H. Pease, 1983: A model of the atmospheric boundary layer over the marginal ice zone. J. Geophys. Res., 88, 2836-2840.
Overland, J.E., and C.H. Pease, 1982: Cyclone climatology of the Bering Sea and its relation to sea ice extent. Mon. Weather Rev., 110, 5-13.
Overland, J.E., and R.W. Preisendorfer, 1982: A significance test for principal components applied to a cyclone climatology. Mon. Weather Rev., 110, 1-4.
Schumacher, J.D., C.A. Pearson, and J.E. Overland, 1982: On exchange of water between the Gulf of Alaska and Bering Sea through Unimak Pass, Alaska. J. Geophys. Res., 87, 5785-5795.
Overland, J.E., 1981: Marine climatology of the Bering Sea. In: The Eastern Bering Sea Shelf: Oceanography and Resources, D. Hood and J. Calder, eds., University of Washington Press, 15-22.
Overland, J.E., and T.R. Hiester, 1980: Development of a synoptic climatology for northeast Gulf of Alaska. J. Appl. Meteorol., 19, 1-14.
Bishop, J.M., and J.E. Overland, 1977: Seasonal drift on the Middle Atlantic Shelf. Deep Sea Res., 24, 161-169.