Resource Ecology and Fisheries Management (REFM) Division
(cont.)

RESOURCE ECOLOGY AND
ECOSYSTEMS MODELING PROGRAM

Laboratory analysis was performed on 1,272 groundfish stomachs from the eastern Bering Sea and 3,173 from the Gulf of Alaska. Observers collected and returned 1,273 stomachs from their Bering Sea cruises.


Groundfishes in the Aleutian Islands Region

REFM scientists have completed a study describing the diets of the important groundfishes collected in the Aleutian Islands in 1994 and 1997. A total of 31 groundfish species were included in the investigation. The general diet, variations of the diet by different predator sizes, geographic distribution of main prey, and size of important prey consumed by each species were analyzed. When applicable, diets of certain species from 1994 and 1997 were compared with those from 1991 samples.

The study emphasized groundfish predation on commercially important fish, crab, and shrimp species. The data indicate that Atka mackerel was the dominant prey fish and was consumed by Pacific cod, arrowtooth flounder, Pacific halibut, Greenland turbot, Alaska skate, whiteblotched skate, great sculpin, and big mouth sculpin. Walleye pollock was another important prey and was consumed mainly by Pacific cod, arrowtooth flounder, Pacific halibut, Alaska skate, and whiteblotched skate. Pollock cannibalism was not found in this study. In the Aleutian Islands area, myctophids were important prey of many fish. The main predators of myctophids were arrowtooth flounder, Greenland turbot, Pacific ocean perch, pollock, giant grenadier, shortraker rockfish, and rougheye rockfish. Other forage fish such as Pacific herring, osmerids, and Pacific sand lance were consumed by Pacific cod, arrowtooth flounder, and Pacific halibut. However, each of these species comprised no more than 5% of the stomach contents weight. Some mesopelagic fish, like bathylagids and viperfish, were found in groundfish stomachs. Tanner crabs were mainly consumed by Pacific cod, Pacific halibut, and great sculpin, though they were also consumed by Alaska skate and flathead sole. Many predators preyed on pandalid shrimp, which includes all the Pandalus and Pandalopsis species. The diets of Pacific cod, arrowtooth flounder, shortspine thornyhead, rougheye rockfish, shortraker rockfish, Bering skate, darkfin sculpin, and Aleutian skate contained the most pandalids.

The study was published as AFSC Processed Report 2003-07.  (.pdf, 12MB)

By Mei-Sun Yang.


Ecosystem Indicators

Pat Livingston organized a meeting in May for researchers working on composite ecosystem indicators for the Ecosystem Considerations Chapter, which accompanies the annual stock assessment and fishery evaluation reports to the North Pacific Fishery Management Council. Participants came from the University of Washington (UW), University of Alaska, Pacific Marine Environmental Laboratory (PMEL), and AFSC. Attendees included: Wiebke Boeing, Jennifer Boldt, Janet Duffy-Anderson, Pat Livingston, Nate Mantua, Bern Megrey, Franz Mueter, Jim Overland, Sergei Rodionov, and Shannon Tribble.

The purpose of the Ecosystem Considerations Chapter is to provide scientists and fishery managers with information on the status and trends of various ecosystem components and to evaluate the effects of climate and fishing on the ecosystem. The use of aggregate indicators, which bring together time series data on climate, fishing, and biology, is an important part of the chapter but still is in early stages of development. Presently, the regime shift analysis pioneered by Steve Hare (International Pacific Halibut Commission) and Nate Mantua (UW) is part of the chapter. Future enhancements to this type of analysis could include time series of human influences on the system.

The meeting served to promote discussion among the different groups working on similar indicators, to determine what would be available for this year's ecosystem chapter, and to begin discussion about how to expedite these composite analyses to provide an annual aggregate assessment of the main climate drivers and human influences on historical ecosystem change.

PMEL is working on a web page to providing climate time series for the Bering Sea that will provide detailed information about the time series, such as geographic extent and how the index was actually calculated. A description of its relevance to the ecosystem will also be included along with information on recent trends and references used in interpreting the recent trends. The web page will make the physical time series data more available to biologists who have difficulty accessing and interpreting such time series. Some of these time series would also be presented in the Ecosystem Considerations Chapter. The Ecosystem Considerations Chapter will provide a structure for annually updating and reporting on individual ecosystem components and facilitating the aggregate analysis of these time series.

By Pat Livingston.


Arctic Climate Impact Assessment

REFM scientists Pat Livingston and Tom Wilderbuer are contributing to an effort to assess the effects of climate change on the Arctic. The Arctic Climate Impact Assessment (ACIA) (http://www.acia.uaf.edu) is an international project of the Arctic Council and the International Arctic Science Committee (IASC) to evaluate and synthesize knowledge on climate variability, climate change, and increased ultraviolet radiation and their consequences. The aim is to provide information to governments, organizations, and peoples of the Arctic on policy options to meet such changes. The National Science Foundation and NOAA are providing funding for the ACIA Secretariat, which is located at the International Arctic Research Center at the University of Alaska Fairbanks. Pat Livingston is contributing to the assessment on Marine Systems, and Tom Wilderbuer is contributing to the chapter on Fisheries and Aquaculture with focus on climate change in the Bering Sea.

A workshop was held in 2003 to bring chapter authors together and to provide a means for synthesizing results from the assessment. As a result of preliminary reviews and suggestions from the synthesis workshop, a revised draft of the assessment is being prepared and will be available for expert review around July 2003. The peer-reviewed scientific volume will be completed in 2004.

By Pat Livingston.


Climate / Fish Relationships Science Workshop

Jennifer Boldt and Anne Hollowed of the REFM Division participated in a climate/fish science workshop in San Jose, California, on 28-29 April 2003. The climate/fish science project is part of the NOAA-funded Marine Fisheries Stock Assessment Improvement Plan. The project consists of basinwide, coordinated research to improve stock assessments and other scientific evaluations needed for management. The goals of the project are to 1) deliver time series of ecological indicators to be used in assessment models, 2) develop climate-sensitive ecological indicators, 3) maintain time series, 4) examine them for climate trends, and 5) facilitate their incorporation into models used for fisheries and ecosystem management.

The purpose of the April workshop was to present and discuss progress on funded research projects. Jennifer presented 1) results of a study conducted by Tom Wilderbuer and others on flatfish recruitment response to decadal climatic variability and ocean conditions in the eastern Bering Sea, and 2) plans for developing an index of spawning pollock biomass anomalies, which incorporates water temperature and the amount and complexity of flow through Shelikof Strait. Other NOAA researchers presented progress on their indices/time series, and plans to incorporate these into stock assessments were discussed. The next workshop is planned for late September.

By Jennifer Boldt.


U.S. NORTH PACIFIC GROUNDFISH OBSERVER PROGRAM

During the second quarter of 2003, 165 observers were trained, briefed, and equipped for deployment to fishing and processing vessels and shoreside plants in the Gulf of Alaska, Bering Sea, and Aleutian Islands. They sampled aboard 205 fishing and processing vessels and at 16 shoreside processing plants for a total of 5,696 days. The observers were trained or briefed in three locations: the AFSC Observer Program in Seattle briefed 41 observers with prior experience and another 19 first-time observers were trained there; the University of Alaska Anchorage (UAA) Observer Training Center briefed 81 observers; 11 observers were briefed at the Observer Program's field office in Kodiak during the second quarter of 2003, and 13 observers were excused from briefing because they had just completed a cruise successfully and were returning immediately to the field. The second quarter 2003 observer workforce thus comprised 12% new observers and 88% experienced observers.

The Observer Program conducted a total of 221 debriefings during the second quarter of 2003. One debriefing was held in both Kodiak and Dutch Harbor, 76 in Anchorage, and 143 were held in Seattle.


Plans for Restructuring

At its April 2003 meeting, the North Pacific Fishery Management Council reviewed a draft schedule and analytical outline to restructure the design and funding mechanism of the Observer Program to address data quality and disproportionate cost issues resulting from the current program structure. The analytical outline contained a list of decision points that were reviewed by the Council and will become the basis for formal alternatives and options for analysis. The Council decided that the primary alternative would include a funding mechanism that combines a user fee-based system with Federal funding. This alternative would be developed for all vessels and processors operating in the Gulf of Alaska, with a suboption to extend the fee-based program to all vessels with currently less than 100% coverage requirements in the Bering Sea and Aleutian Islands. A preliminary analysis should be ready for Council review in October 2003, with initial review scheduled for February 2004 and final action in April 2004.


Deployments of NMFS Staff

With new regulations effective this year, NMFS was granted the authority to place NMFS staff and other authorized individuals as observers on fishing vessels that currently are required to carry observers. This will enable the Observer Program to deploy staff on two vessels during the third quarter 2003, with the purpose of developing vessel-specific sampling protocols. This will result in improved sampling conditions and support for observers, more effective observer sampling and catch and bycatch monitoring, and a better working relationship with vessel personnel. In addition, Observer Program staff already have been deployed to a catcher processor in the Pacific cod longline fishery to conduct research designed to evaluate the accuracy of catch accounting methods currently used by observers and longline catcher processor operators. Also, Observer Program staff trained and certified two NMFS staff members who were deployed to longliners that participate in fisheries with a high bycatch of shortraker and rougheye rockfish. The observers are attempting to develop new observer sampling protocols that will allow for more accurate differentiation of shortraker and rougheye rockfish.


Bill Karp Returns to Lead Observer Program

Dr. William Karp was chosen as the new Observer Program Leader in June 2003. He will be returning in August to a job he knows well, as he served in this position from 1993 to 1999. Dr. Karp served as leader of the RACE Division's Midwater Assessment and Conservation Engineering program from 1999 to July 2003.

By Bob Maier.

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AFSC Quarterly
Research Reports
April - June 2003