(Quarterly Report for Oct-Nov-Dec 1998)
AND ECOSYSTEMS MODELING PROGRAM
Activities and Research
A total of 295 fish stomachs were collected for the eastern Bering Sea and 667 for the Gulf of Alaska. Fishery observers performed 132 at-sea scans of stomach contents in the Bering Sea. Laboratory analysis was performed on 2,680 stomachs from the Bering Sea and 480 from the Aleutian Islands region. No observers were trained to collect stomachs.
ECOPATH/ECOSIM Models of the Eastern Bering Sea
Mass-balance models and simulations of the eastern Bering Sea ecosystem in the 1950s and 1980s have been developed in collaboration with researchers at the University of British Columbia. Some initial results of these models were recently presented in October at the 1998 Lowell Wakefield Symposium on Ecosystem Considerations in Fisheries Management held in Anchorage, Alaska. Over the past 10 years, there has been increasing criticism of management decisions that are based on single-species approaches and a call for the implementation of ecosystem approaches. The major criticism of single-species models is that they cannot predict changes in community structure. Unfortunately, our experience in modeling the Bering Sea shows that this same criticism can also be leveled against ecosystem models.
We employed trophic mass-balance models (ECOPATH and ECOSIM) to examine possible explanations for the changes that have occurred in the Bering Sea between the 1950s and 1980s. We removed fish and mammals from the modeled system and tracked how other components of the ecosystem responded. Our mass-balance models indicate that neither whaling nor commercial fisheries were sufficient to explain the possibility of a 400% increase in pollock biomass (and other changes) that may have occurred between the two time periods. The simulations further suggest that environmental factors affecting recruitment or primary production may be more important in determining the dynamics of the Bering Sea ecosystem than predator-prey interactions alone. These findings illustrate that mass-balance models that do not account for the impact of climate variability on year-class strength cannot provide reliable estimates of trends in marine fish production. The findings also highlight our lack of knowledge of the state of the eastern Bering Sea during the 1950s. We will be doing further work on these models to improve the parameters and processes modeled.
Climate Change and Carrying Capacity Program: 1998 Overview
The Climate Change and Carrying Capacity (CCCC) program of the North Pacific Marine Science Organization (PICES) was cochaired by Pat Livingston in 1998. This was an active year for the program with the formation of a new task team, continued activities of existing task teams, and advanced communicating our work not just within PICES but to the international scientific community as a whole. More information about the CCCC program has been organized on the PICES web site at http://www.pices.int/. For 1999 we anticipate new activities to aid research coordination in regions such as the subarctic North Pacific and the Japan-East Sea for a coordinated GLOBEC (Global Ocean Ecoystem Dynamics) program of research.
Task Team Activities of 1998 and Plans for 1999
The Basin Studies Task Team
coordinates biological and physical studies in the central subarctic Pacific. The team is
completing the review process for the papers from their 1997 BASS Symposium held in Pusan,
Korea. The papers will be published in a volume of Progress in Oceanography,
which will provide a summary of what is known about the eastern and western subarctic
North Pacific gyres at all ecosystem levels, as well as some initial guidance on research
gaps. BASS would like to build on this work by holding a workshop on the development
of a conceptual model of the subarctic North Pacific gyres. They hope to use the
information compiled in the BASS symposium volume to identify research questions and
opportunities, particularly with respect to physical structure of the gyres in relation to
climate change; long-term changes in plankton abundance and species composition; and
trophic relationships of fishes, birds, and mammals.
BASS is also planning to compile annually a comprehensive list of cruises in the subarctic North Pacific. The cruises and names of contact persons will be listed on the PICES web site to aid researchers interested in developing collaborative research efforts in this region.
MODEL has continued to facilitate
communication among modeling studies and field programs. They have expanded their
circulation models directory on the PICES web site to include biological models, and the
team plans to include a nutrient database directory on the web this year.
A small workshop was held just prior to the PICES VII meeting to deal with lower trophic level model comparison issues and gather information for nutrient databases. Proceedings of the workshop will be published later this year in the PICES Scientific Report series. Based on the discussions at the workshop, the team recommended that a prototype lower trophic level model with 12 compartments and executable on the World Wide Web be made available in 1999. Plans are developing to hold a workshop in the year 2000 to apply the model to two sites (Station P and Sanriku area), compare it with an existing Bering Sea model, and plan for its application to higher trophic level models, regional circulation models, and Joint Global Ocean Flux Study (JGOFS) models.
The newly formed MONITOR task team
held a workshop just prior to PICES VII. Fifteen papers were presented at the
workshop and will be published in 1999 in the PICES Scientific Report series.
The task team has planned several projects for 1999. One project is to construct a table of present shipboard monitoring in the subarctic North Pacific by time and space to more clearly identify monitoring gaps and assist in the design of an improved monitoring system. They will also prepare a summary of the zooplankton sampling gear used in many of the long time-series of zooplankton observations in the North Pacific shelf and basin ecosystems and identify the most important intercalibration experiments needed in the near future. Another key project is to develop a white paper on the use of continuous plankton recorder (CPR) observations in the North Pacific. The task team also will develop recommendations about biophysical moorings and zooplankton production.
The Regional Experiments Task Team
identifies and carries out cooperative research experiments among PICES regions. The team
published the report of last years developmental workshop in PICES Scientific Report
No. 9, which forms the basis for their long- term work plan. A highly successful
topic session was held jointly with the PICES Fisheries Science Committee during PICES
VII, which highlighted the research findings of GLOBEC and GLOBEC-like programs. The
topic session will continue in future years to ensure a place for GLOBEC researchers to
present their findings at PICES scientific meetings. This is an important aspect of
scientific networking that provides rapid transfer of information to the GLOBEC research
The task team held an interesting and successful workshop on climate effects on small pelagic species just prior to PICES VII. Nine scientific papers were presented, and research programs on small pelagic species in each of the PICES nations were reviewed. A full workshop report will be published in 1999 in the PICES Scientific Report series. The task team plans to hold a workshop in 1999 just prior to PICES VIII in Vladivostok, Russia, on the comparative dynamics of herring and euphausiids. They also plan to compile a summary of the sampling strategies and methods used to assess the stocks of small pelagic species.
By Pat Livingston.
STATUS OF STOCKS AND MULTISPECIES ASSESSMENTS
The Status of Stocks and Multispecies Assessment Program (SSMA) completed stock assessments for major groundfish stocks in the Bering Sea (BS), Aleutian Islands (AI) region, and Gulf of Alaska (GOA). Stock assessments utilized information from a variety of sources including: survey biomass estimates provided by the RACE Division, fishery catch estimates from the Alaska Regional Office, and fishery-dependent biological samples from the REFM Observer Program and fishery and survey age composition data from the REFM Age and Growth Programs. Final Stock Assessment Fishery Evaluation (SAFE) reports were prepared for the North Pacific Fishery Management Council (NPFMC) Plan Team meetings. The assessments resulted in recommended levels of Acceptable Biological Catch (ABC), which were presented by the Plan Team chairpersons to the NPFMC Advisory Committees. Final ABC levels were set by the Council following the recommendations of its advisory committees.
In the Gulf of Alaska region, preliminary SAFE documents were prepared for the following species or species complexes: walleye pollock, Pacific cod, arrowtooth flounder, other flatfish, sablefish, slope rockfish, pelagic shelf rockfish, demersal shelf rockfish, thornyheads, and Atka mackerel. In the Bering Sea and Aleutian Islands region, preliminary SAFE documents were prepared for 13 species or species complexes including walleye pollock, Pacific cod, yellowfin sole, rock sole, flathead sole, Greenland turbot, arrowtooth flounder, other flatfish, BSAI Pacific ocean perch, BSAI other rockfish, sablefish, Atka mackerel, and squid and other species. Scientists from the SSMA Program participated in preparation of 8 of the 10 assessment chapters for the Gulf of Alaska, and all 13 assessment chapters for the BSAI region. Scientists from the ABL, RACE Division, and ADF&G also contributed to the development of SAFE chapters. Summaries of several ABC recommendations are presented below, grouped by species and management area.
It should be noted that final 1999 ABCs set in groundfish specifications of the NPFMC may differ from the ABC recommendations made by assessment authors. For information on final groundfish specifications, please consult the NPFMC web page at http://www.fakr.noaa.gov/npfmc/.
Gulf of Alaska:
New fishery data and results from
the 1998 echo integration trawl (EIT) survey in Shelikof Strait were used to update the
GOA pollock assessment. The biomass estimate from the EIT survey in 1998 was
489,900 metric tons (t), a 14% decrease from 1997. The length frequency data from the EIT
survey confirm the presence of a very large 1994 year class and a moderate to strong 1997
year class. Both the 1995 and 1996 year classes appear to be below average.
A statistical age-structured model was used in the GOA pollock assessment. The predicted biomass for ages 2 and above in for the Western-Central regulatory areas was 763,688 t. The recommended ABC for 1999 is 94,400 t in the Western-Central regulatory area and 8,620 t for the Eastern regulatory area. The ABC reflects a revision in the magnitude of incoming 1994 - 1997 year classes. The 1998 estimate of the incoming 1994 year class at age 2 dropped 34% from the 1997 estimate. The 5-year forecast is for a decrease in abundance. The ABC recommendation is based on a fishing mortality rate of 0.340 based on the NPFMC harvest guidelines (Tier 3b).
The BSAI SAFE document primarily
focused on the eastern Bering Sea. New data used in the assessment include the 1998
bottom trawl biomass estimate and 1997 catch-at-age data. The 1998 trawl survey
estimate was 2.21 million t, a 27% decrease from the 1997 survey estimate of 3.03 million
t. The data from the fishery and survey confirm the presence of a very large
1996 year class, although the estimate of the magnitude of this year class remains
uncertain. An analysis of average weight-at-age based on fishery data revealed that
lower than average growth occurred in 1997.
A statistical age-structured model was used to assess the eastern Bering Sea pollock resource. Changes from last years model included a computation of values related to MSY (FMSY BMSY etc.). This computation allows an evaluation of simple rates based on spawner biomass per recruit analyses and supplants previous estimates of FMSY. The ABC alternatives for 1999 are based on F40% (0.992 million t) or FMSY (1.45 million t). These alternatives bracket the level projected using the SAM model in last years assessment (1.211 million t). Under a median recruitment scenario, the 5-year forecast under a F40% harvest strategy is for an increase in yield, while under a FMSY harvest strategy yield is expected to remain fairly constant. The projected 1999 spawner biomass level is 1,585 million t which is below BMSY (1.738 million t) and B40% 2.063 million t.
The 1999 harvest levels for the
Aleutian Islands and Bogoslof regions were computed in the same way as last year.
An earlier age-structured analysis of the Aleutian Islands region highlighted
several problems with interpreting the available data. Foremost was a problem of stock
definition where, in the early 1990s, most of the catch was taken immediately adjacent to
the EBS. Also, commercial harvest data in the Aleutian Islands region is primarily
of older-age pollock. This indicated that since these fish had likely spawned
several times, the allowable harvests rates were quite high (since they were not
detrimental to replenishing the spawning stock). For this reason, a conservative
recommendation was made based on the most recent bottom trawl survey data (1997) for this
area resulting in an ABC value of 23,800 t with overfishing set at 31,700 t.
The AFSC conducted a survey of the southeastern Aleutian Basin near Bogoslof Island 1-10 March 1998. The pollock biomass for the entire Bogoslof survey area was 492,000 t: 59,000 t in the east area, and 433,000 t in the west. Because this stock is so far below its target biomass level of 2.0 million t, the ABC was based on a conservative fishing mortality rate giving a 1999 value of 15,300 t with corresponding overfishing limit (OFL) set at 21,000 t. As in past years, the Council is likely to recommend keeping the Bogoslof area closed to any directed pollock fishing.
Gulf of Alaska:
Size composition data from the 1997 and January-August 1998 commercial fisheries were incorporated into the Pacific cod assessment. There were no changes in the assessment model this year. The projected 1999 total age 3+ biomass was 648,000 t, down approximately 18% from last years F40% projection for biomass in 1999. The 1999 ABC recommendation of 90,900 t is based on a risk adverse procedure that considers uncertainty in survey catchability and the estimate of the natural mortality rate in the computation of the target harvest level.
The 1998 Pacific cod stock
assessment incorporated new information from three sources: a) size
composition data from the 1997 and January-August 1998 commercial fisheries; b) size
composition data from the 1998 EBS bottom trawl survey; and c) the biomass estimate from
the 1998 EBS bottom trawl survey. There were no changes in the assessment model this year;
however, three different configurations regarding natural mortality and survey
catchability were considered. The projected 1999 total age 3+ biomass was 1.21
million t, up approximately 3% from last years F40% projection for
biomass in 1999. The 1999 ABC recommendation of 177,000 t for BSAI Pacific cod
is based on a risk adverse procedure that considers uncertainty in survey catchability and
the estimate of the natural mortality rate in the computation of the target harvest level.
Gulf of Alaska:
New information used in the GOA arrowtooth flounder assessment included revised catch statistics and estimated age compositions for the 1993 and 1996 triennial trawl surveys. A length-based stock assessment was utilized to assess the arrowtooth flounder stock. Estimated 1999 age 3+ biomass was 2.127 million t, making arrowtooth flounder the dominant species in the GOA in terms of weight. Acceptable biological catch in 1999 was 217,100 t based on a F40% fishing mortality rate (Tier a). An alternative assessment model was introduced as an appendix to the arrowtooth flounder assessment. This model predicted slightly lower 1999 harvest levels of 180,120 t.
Although research is being conducted
on the commercial utilization of arrowtooth flounder, the species currently has a low,
perceived commercial value and is captured primarily as bycatch and is usually
New information used in the BSAI arrowtooth flounder assessment included revised catch statistics, results of the 1998 Bering Sea shelf trawl survey, and survey and fishery size compositions adjusted for the appropriate sex ratio. Examination of the shelf and slope survey population estimates indicated that females were consistently more abundant than males. Possible explanations for the higher abundance of females in the commercial catch and survey include: 1) spatial separation of males and females, such that males are less available; 2) differential natural mortality; 3) sampling problems; and 4) a genetic predisposition to produce more females than males. Adjusting the sex ratio resulted in a 30% increase in biomass relative to previous assessments. Above average recruitment occurred in 1981, 1984, 1986, 1987, and 1992. These year classes should maintain the overall population abundance at a relatively stable level for the near future (with continued light harvest).
A length-based stock model was used to assess the status of the BSAI arrowtooth flounder stock. The predicted biomass of arrowtooth flounder in 1999 was 1,188,800 t. The recommended ABC of 162,400 t was estimated by applying a F40% rate of 0.19.
Yellowfin sole are caught with
bottom trawls on the Bering Sea shelf. New information used in the EBS yellowfin
sole assessment included revised catch statistics, results of the 1998 Bering Sea shelf
trawl survey, 1997 survey and fishery age compositions, and estimates of discard and
retained portions of the catch. The 1998 total trawl survey biomass estimate was
2.330 million t. Above average recruitment occurred in 1981, 1983, 1988, and
1991. These year classes should maintain the overall population abundance at a relatively
stable level for the near future under current harvest levels.
An age structured stock model was used for to assess the status of the EBS yellowfin sole stock. The predicted age 2+ biomass of yellowfin sole in 1999 was 3,179,200 t. The recommended ABC of 212,000 t was estimated by applying a F40% rate of 0.11.
In recent years, Greenland turbot
have been primarily captured using long-line gear. New information used in the
EBS Greenland turbot assessment included revised catch and discard statistics by gear
type, and length frequency and biomass data from the 1998 eastern Bering Sea shelf survey.
Due to limited vessel time, deep water stations have not been sampled since 1991.
The 1998 trawl survey biomass estimate for the shelf region was 28,126 t.
Recruitment of Greenland turbot has been poor since the early 1980s. Consequently,
the stock is expected to continue to decline in the near future.
An age structured model was used to assess the status of the EBS Greenland turbot stock. The target stock size (B40%, female spawning biomass) is estimated at about 139,000 t, while the projected 1999 spawning biomass is about 110,000 t. The adjusted yield projection from F40% computations is estimated at 20,000 t for 1999, an increase of 5,000 t from last years ABC. Given the continued downward abundance trend and no sign of recruitment to the EBS shelf, stock assessment authors recommended that the ABC be set equal to the 1998 level of 15,000 t.
Rock sole are an important target of
a high value roe fishery that typically occurs between February and March. New
information used in the EBS rock sole assessment included revised catch and discard
statistics, 1997 fishery age composition data, age composition data from the 1998
EBS shelf survey, and biomass estimates from the 1998 EBS shelf survey. The 1998
trawl survey biomass estimate was 2.169 million t. Recruitment of rock sole was
strong between 1980 and 1988; since then, above-average year classes were only observed in
1990 and 1993. Consequently, the stock is expected to decline in the near future.
A separable catch-at-age analysis was used to assess the status of the EBS rock sole stock. The projected 1999 spawning biomass (663,300 t) is well above the target stock size (B40%, female spawning biomass). The 1999 yield projection from F40% computations is estimated at 299,900 t.
New information used in the EBS
flathead sole assessment included revised catch and discard statistics, 1997 fishery size
composition data, and the 1998 trawl survey biomass estimate.
The 1998 trawl survey biomass estimate was 692,200 t, down from the 1997 estimate of 807,800 t. Sustained strong or average recruitment was observed from 1977 to 1989; since that time, recruitment has been average or below average. Consequently, the stock is expected to decline in the near future if fished to full potential. However, if present levels of light exploitation continue, the stock should remain stable at a high level of abundance in the near future.
A length-based assessment model was used to assess the status of the EBS flathead sole stock. This was the first year that assessment model results were used as the basis for harvest recommendations. The projected 1999 age 3+ female spawning biomass (290,400 t) was well above the target B40% equilibrium biomass level of 127,900 t. The 1999 yield projection from F40% computations was 77,300 t down from last years recommendation of 131,900 t.
Gulf of Alaska:
1999 ABC in metric tons (t)
Deep water flatfish
Shallow water flatfish
Revised catch estimates were provided in
the 1997 other flatfish assessments. The ABC recommendations were
unchanged from last year. The other flatfish resource remained
lightly to moderately harvested in 1997 as the shallow and deep water,
flathead sole, and rex sole ABC apportionments were 18%, 51%, 9%, and 36%
harvested, respectively. In 1997 and 1998, the shallow and
deep water fisheries were closed prematurely to prevent exceeding the
halibut bycatch limits.
Gulf of Alaska flatfish trends in abundance, status of stocks, and estimates of exploitable biomass are completely reliant upon the triennial demersal trawl surveys. Life history information is limited for many flatfish species. ABC recommendations are based on F40% for rock sole, constant catch for deep-sea sole and Greenland turbot, for all others, FABC was set equal to 0.75 * M. The 1999 recommended ABCs for other flatfish were the same as those projected in 1998.
Changes to the input data used to
assess the BSAI other flatfish stocks included catch estimates, fishery length frequency
data, the 1998 EBS bottom trawl survey biomass estimate, and the size composition data
from the 1998 EBS bottom trawl survey. Historically, the biomass of flatfish in the
Aleutian Islands region has been small relative to the eastern Bering Sea. Alaska
plaice dominates the other flatfish complex. In the most recent EBS bottom trawl
survey, the biomass of Alaska plaice (452,600 t) represented 86% of the other flatfish
An age-structured model was used to assess the Alaska plaice stock. The estimated exploitable biomass of Alaska plaice in 1999 was 491,300 t. The ABC recommendation was based on the F40% projection of 142,500 t. Projections show that poor recruitment during the past decade will lead to a declining stock condition.
Estimates of the exploitable biomass of species in the BSAI other flatfish complex other than Alaska plaice are based on the combined biomass estimate of other flatfish in the most recent Aleutian Islands and EBS surveys. The ABC recommendation was calculated assuming that the F40% rate for flathead sole was applicable to all other flatfish in the complex. This method produced a recommended combined catch of 11,800 t for the other flatfish species other than Alaska plaice.
New information incorporated in the model included 1997 age data, 1998 relative abundance and length data from the sablefish longline surveys, and length data from the 1997 longline fishery.
A statistical age-based stock assessment was utilized to assess the sablefish stock. This year the stock assessment model was improved by distinguishing the individual fishing quota (IFQ) fishery from the earlier fishery. Separate fishery selectivities were estimated for the IFQ fishery and the early fishery. Estimated 1999 exploitable biomass was 155,000 for the Aleutian Islands region, eastern Bering Sea, and Gulf of Alaska combined. The stock is projected to decline in the near future. Acceptable biological catch in 1999 was 15,900 t for the combined regions based on an adjusted F40% fishing mortality rate (Tier 3b).
PACIFIC OCEAN PERCH
Gulf of Alaska:
A statistical age-based stock assessment was utilized to assess the Pacific ocean perch stock. New information incorporated in the model included updated catch and age composition data and the 1996 trawl survey age composition. Stock assessment authors explored the implications of different assumptions regarding trawl survey catchability. Survey catchability was estimated by the model used as the basis for the harvest recommendations. Estimated 1999 female spawner biomass (101,530 t) fell below the target B40% level of 126,850 t. The adjusted yield projection from F40% computations is estimated at 13,120 t for 1999.
A statistical age-based stock
assessment was utilized to assess the AI Pacific ocean perch stock. The time series
of commercial catch was updated in the model. ABC recommendations were based on a
target rate of F40%. Estimated 1999 Aleutian Islands female spawner
biomass (122,200 t) fell below the target B40% level of 124,800 t. The
adjusted yield projection from F40% computations was 13,500 t for 1999.
Short-term spawning biomass projections show the stock will decline at present
A statistical age-based stock assessment was utilized to assess the BS Pacific ocean perch stock. ABC recommendations were based on a target rate of F40%. Estimated 1999 Bering Sea female spawner biomass (24,800 t) fell below the target B40% level of 34,400 t. The adjusted yield projection from F40% computations was 1,900 t for 1999. Short-term spawning biomass projections show the stock will stabilize under present harvest rates.
Gulf of Alaska:
Northern rockfish are managed as part of the slope rockfish complex in the Gulf of Alaska. Age-or length-based models have not been developed for this stock. Reliable point estimates of stock biomass, F30% and F40% are available for northern rockfish (Tier 4). The most recent trawl survey point estimate of biomass was 83,367 t, down slightly from the 1993 estimate (109,835 t). The recommended ABC for northern rockfish was 5,002 t.
Northern rockfish are managed under
Tier 5 of Amendment 44 of the NPFMC fisheries management plan. The 1997 point
estimate of biomass in the Aleutian Islands region was 80,706 t, which was down from peak
biomass levels observed in 1986 (133,662 t) and 1991(181,613 t), similar to the 1994
level (81,183 t). The recommended ABCs were 537 t and 4,230 t for the eastern Bering
Sea and Aleutian Islands region, respectively.
SHORTRAKER/ ROUGHEYE ROCKFISH
Gulf of Alaska:
Shortraker and rougheye rockfish are managed as part of the slope rockfish complex in the Gulf of Alaska. Age- or length-based models have not been developed for this stock. Reliable point estimates of stock biomass, F30% and F40%, are available for rougheye rockfish (Tier 4), whereas, only reliable point estimates of stock biomass and natural mortality rate are available for shortraker rockfish (Tier 5). The exploitable biomass estimates of shortraker and rougheye rockfish were 16,673 t and 48,709 t, respectively. The recommended ABCs for shortraker and rougheye rockfish were 375 t and 1,218 t, respectively.
Bering Sea-Aleutian Islands
shortraker and rougheye rockfish are managed under Tier 5 of Amendment 44 of the NPFMC
fisheries management plan. Both stocks are more abundant in the Aleutian Islands
region. In the Aleutian Island region, the recommended ABCs for shortraker and
rougheye were 560 t and 405 t, respectively. For the eastern Bering Sea region, the
ABC recommendations for shortraker and rougheye were 185 t and 51 t, respectively.
Gulf of Alaska:
This year the model was updated with
available recent catch data. A size-based age-structured model was developed and applied
to the thornyhead resource in the GOA. This original model was rewritten in C++
computer language in order to take advantage of analytical software designed for building
large, complex models. Assessment authors evaluated uncertainties in the estimate of
natural mortality by selecting a prior distribution rather than assuming a fixed value.
They used a relatively informative prior on M with an expected value of 0.05 and a
coefficient of variation equal to 10% . Model results show that several strong year
classes were apparent, but the ability to resolve the precise recruitment year was poor.
The ABC, based on F40% computations for shortspine thronyheads in the
GOA, was 1,990 t, a value nearly identical to last years recommendation.
The current estimate of female spawning biomass (23,100 t) was above the
long-term expected value of spawning biomass with fishing held at F40% (16,300
Gulf of Alaska:
Bottom trawl surveys do not provide a reliable estimate of the biomass of Atka mackerel in the GOA. Because there is no reliable estimate of current Atka mackerel biomass in the Gulf of Alaska, harvest recommendations are based on Tier 6 of Amendment 44. Tier 6 defines the overfishing level as the average catch from 1978 to 1995 and the ABC level cannot exceed 75% of the overfishing level. Based on these guidelines, 1999 Atka mackerel ABC could not exceed 4,700 t. The stock assessment authors recommend a lower ABC that was sufficient to satisfy the bycatch needs of other trawl fisheries 600 t. This recommendation was based on the following concerns: a) when ABCs were lower than 4,700 t, the fishery may have created localized depletions; b) analysis of catch-per-unit-effort (CPUE) data suggests that Atka mackerel populations at Unimak and Shumagin Islands declined between 1992 and 1994; and c) the GOA Atka mackerel stock is vulnerable to local depletion because it is at the eastern boundary of its typical range.
The 1998 Atka mackerel stock
assessment incorporated new information from four sources: a) size composition from
the 1997 commercial fishery, b) 1998 age composition data, c) 1997 Aleutian Islands trawl
survey age composition, and d) 1998 catch. Four alternative models were considered.
The ABC recommendations are based on assumptions of constant natural mortality (0.3)
and survey catchability of 1.0. The 1999 estimated age 3+ biomass of Atka mackerel
is 595,000 t with a spawner biomass of 193,700 t. The 1999 recommended ABC for
BSAI Atka mackerel is 73,000 t based on a fishing mortality rate less than F40%.
A harvest rate more conservative than the maximum level under Amendment 44 was
warranted because of concerns regarding future trends in female spawning stock size.
Under the recommended harvest rate F52%= 0.23, the female spawner stock
biomass is projected to be within 3% of B40% within 5 years. The
recommended 1999 ABC represents a 14% increase relative to the 1998 harvest level.
An increase in yield is justified because the 1992 year class is above average.
By Anne Hollowed.
U.S. GROUNDFISH FISHERIES OBSERVER PROGRAM
During the fourth quarter of
1998, 167 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 223 fishing and processing vessels and at 14 shoreside
processing plants. These observers were trained or briefed in various locations. The
AFSC Observer Program in Seattle trained 25 first-time observers, and another 18 observers
with prior experience were briefed at this site. The University of Alaska Anchorage
(UAA) Observer Training Center briefed 44 observers, and another 39 were trained. At
the Observer Programs field offices in Dutch Harbor and Kodiak, 10 observers were
briefed, and 31 were excused from briefing because they had just completed a cruise
successfully and were returning immediately to the field. The fourth quarter 1998
observer workforce thus comprised 38% new observers and 62% experienced observers.
The Observer Program conducted a total of 207 debriefings during the fourth quarter of 1998. Three debriefings were held in Kodiak, 9 in Dutch Harbor, 28 in Anchorage, and 167 were held in Seattle.
The statistics for the entire year of 1998 are shown below.
HIGHLIGHTS OF 1998
The Observer Program developed a computer software application (ATLAS) which allows groundfish observers to enter and send data directly from their vessels and plants to the NMFS office in Seattle. The implementation of this data-reporting system benefits NMFS and the fishing industry in numerous ways. It reduces the data processing time considerably, and the error-checking functions of the software provide all users with higher quality data. Using this application also benefits the observer. It has markedly reduced debriefing time and the time required to complete paperwork at sea. The reduction in paperwork allows observers to focus more of their time and energy on collecting data. Electronic reporting of observer sampling data from sea using ATLAS is now occurring on about 76 at-sea processing vessels, 11 shoreside plants, and 7 shoreside delivery vessels.
Further expansion of the Community
Development Quota (CDQ) program occurred in 1998. This quota system was developed
for the purpose of allocating fishery resources to eligible western Alaska communities to
provide the means for starting or supporting commercial fishery activities that would
result in ongoing, regionally-based, commercial fisheries or related businesses. The CDQ
program was initiated in 1992 for the walleye pollock resource and was expanded to include
fixed gear halibut and sablefish in 1995. In 1998, the program was further expanded
to include other groundfish and crab resources. In 1999, NMFS will be responsible
for monitoring and enforcing the groundfish (including pollock and sablefish) and halibut
CDQs and the state of Alaska will be responsible for monitoring and enforcing the crab
The MSCDQ catch-accounting for catcher/processor vessels will be based entirely on data collected by observers, and unlike the open access fisheries where observer data is used to manage a fleet-wide quota, industry participants in the MSCDQ fisheries will require individual accounting of fish harvested in each haul or set. This change in expectations placed on observers, their data, and the program in general has required much staff effort in developing special selection criteria and training requirements for MSCDQ observers, developing new sampling strategies and regulations to enhance the observers working environment, and changing the data collection and data management software systems.
The Observer Program has been working with the North Pacific Fishery Management Council (Council) for several years to resolve major issues associated with observer procurement and contracting, observer-associated fishing industry costs and cost distribution, observer working conditions, and Observer Program goals and objectives. A joint partnership agreement (JPA) between NMFS and the Pacific States Marine Fisheries Commission (PSMFC) was under development in 1998 to establish the PSMFC as the sole source for the fishing industry to obtain observers. The goal of the JPA was to establish a single point of contact (PSMFC) for fishing companies seeking to procure observers, thus avoiding the conflict of interest which arises when companies are permitted to negotiate with multiple observer companies.Unfortunately, unresolvable legal issues pertaining to contracting and liability prevented the JPA from being put in place. NMFS and the Council must now examine alternative approaches for resolving potential conflict of interest and other major challenges confronting the Observer Program. NMFS has advised the Council that it expects to make recommendations regarding the future of the Observer Program by late next year.
The Observer Program added eight new
employees to its ranks in 1998 and opened a new field office in Anchorage. The new
staff members will aid in the accomplishment of MSCDQ-related duties and implementation of
the ATLAS communications system. Two have been assigned full-time to the Anchorage
office, and staff based in Seattle will be rotating to Dutch Harbor and Kodiak on a
regular basis, thus expanding the Observer Program presence in the Alaska field offices.
In addition, staff in the Anchorage Observer Program office will provide liaison
between the Observer Program and the University of Alaska Anchorage Observer Training
By Bob Maier.
During the past quarter, program members have been heavily involved in activities in support of the Pacific and North Pacific Fishery Management Councils (PFMC and NPFMC) and other cooperative efforts.
Cost Recovery Program for the IFQ and CDQ Programs: The proposed individual fishing quota (IFQ) cost recovery program was revised and a draft economic analysis was prepared for the revised program. The development of a separate CDQ cost recovery program was initiated.
Supplemental Environmental Impact Statement (SEIS): Staff members assisted in responding to comments on the draft SEIS and in preparing the Final SEIS for the BSAI and GOA groundfish fisheries.
Reasonable and Prudent Alternatives for the Alaska Pollock Fisheries: An economic analysis was prepared for the emergency actions the Council proposed to prevent the BSAI and GOA pollock fisheries from jeopardizing Steller sea lion stocks and adversely impacting their critical habitat.
NPFMC Socioeconomic Data Committee: Staff members assisted the Committee in identifying the following: 1) the types of economic data to be collected, 2) data collection methods, 3) measures of economic performance that would assist the Council and NMFS in meeting their fishery conservation and management responsibilities, and 4) changes in record keeping and reporting requirements that would assist in obtaining economic data.
PFMC Groundfish Management: A staff member: 1) prepared and presented at the Councils November meeting an analysis of bocaccio-lingcod allocation and total allowable catch (TAC) options for 1999 and proposed allocations and trip limits for other groundfish species for 1999; 2) began a project to evaluate the effects of the factory trawler cooperative in the Pacific whiting fishery; 3) started to develop computer programs to apply rockfish species-composition percentages to west coast fish ticket-level data for use in modelling fishery landings for upcoming allocation issues; and 4) provided support for several projects under way at the Northwest Regional Office.
Staff members helped to develop
programs to collect and model economic data for Alaska commercial fisheries. Center
economists met with several industry members (owners, managers, controllers, and
association representatives) to discuss the collection of economic data and review draft
surveys. Second drafts of five industry sector surveys were completed. Center economists
met with bankers and vessel brokers to discuss measures of profitability and capital
valuation. A question-and-answer sheet that motivates and explains to industry the Alaska
groundfish fishery cost, earnings, and employment data-collection program was prepared and
given to industry members and others for comment before a final draft is created. Staff
economists developed and revised a written summary of the economic measures that may be
calculated or statistically estimated from the survey data and toured several processing
vessels currently moored in Seattle to learn about their operations and production
By Joe Terry.
AGE AND GROWTH PROGRAM
Estimated releases of production ages for January to December 1998 were 789 flathead sole, 336 rock sole, 729 Dover sole, 466 yellowfin sole, 660 arrowtooth flounder, 9,992 walleye pollock, 1,936 sablefish, 999 Atka mackerel, 4,253 Pacific whiting, and 780 Pacific ocean perch for a total of 20,940. Also, 5,689 were tested, 3,126 were updated, and 455 were examined and determined to be unreadable.
By Dan Kimura.