NOAA logo AMJ 2001 Quarterly Rpt. AMJ 2001 sidebar

Resource Ecology &
Fisheries Management

(Quarterly Report for April-May-June 2001)

U.S. North Pacific Groundfish Observer Program:
Training, Briefing, and Debriefing

During the second quarter of 2001, 266 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 region.  They sampled aboard 208 fishing and processing vessels and at 18 shoreside processing plants.  These observers were trained or briefed in various locations.  The University of Alaska Anchorage (UAA) Observer Training Center trained 7 first-time observers, and another 123 observers with prior experience were briefed at this site.  The AFSC Observer Program in Seattle trained 35 first-time observers and briefed another 77 observers who had prior experience.  At the Observer Program’s field office in Kodiak, 8 observers were briefed, and 16 observers were excused from briefing because they had just completed a cruise successfully and were returning immediately to the field.  The second quarter observers workforce thus comprised 16% new observers and 84% experienced observers.

The Observer Program conducted a total of 237 debriefings during the second quarter.  One debriefing was held in Dutch Harbor, 2 in Kodiak, 70 in Anchorage, and 164 were held in Seattle.

Council Observer Advisory Committee
The Observer Advisory Committee (OAC) of the North Pacific Fishery Management Council met at the AFSC in late March to review options that would alleviate areas of concern with the present service delivery model for the North Pacific Groundfish Observer Program (NPGOP). At the meeting, Observer Program Leader Daniel Ito presented the idea of a pilot, no-cost contract approach in which NMFS would maintain a con tract with one or more observer companies to provide observer services to the American Fisheries Act (AFA) offshore fleet of vessels.  Under this approach, industry would still directly pay for observers, but observer companies that were awarded contracts with NMFS would have exclusive rights to provide observers to the offshore AFA fleet.  This would create an “arms length” relationship between industry and the observer companies and would also give NMFS more management control through a contractual agreement with the observer companies.

Members of the OAC expressed doubts and concerns about the no-cost contract approach. The committee agreed that the ideal, long-term approach would be to secure federal funding for the entire Observer Program. While the committee supported the overall goal of a federally-funded Observer Program, it recognized the short-term need to phase in changes to the Observer Program through other mechanisms such as regulatory changes.  Observer Program staff are now working with NMFS Alaska Region staff to move forward with various regulatory changes that will further the goals established by NMFS, industry, observer companies, and observers.

Insurance, Liability, and Labor Issues
Staff from the AFSC Observer Program participated in a 3-day conference in Silver Spring, Maryland, to discuss issues dealing with insurance coverage for observers.  Conference participants included representatives from all NMFS Regional Observer Programs, Department of Labor, Department of Commerce, NOAA General Counsel, insurance industry representatives, labor relation specialists, observers, observer providers, observer representatives, as well as other interested parties.  Topics of discussion at the conference included:

  • Defining insurance and labor terms as they relate to observer programs

  • Defining the roles of the insurance agent, underwriter and claims handler

  • Explaining the various types of liability and compensation coverage

  • Differentiating between coverage needs for land-based protection and seagoing protection

  • Definitions of seamen and nonseamen as they apply to observers under various insurance and labor laws

  • Implications of the Service Contract Act to contracted observers

  • Understanding the roles of base salary, overtime, and other supplemental pay (i.e., hazard pay) calculated under various labor laws for the purpose of insurance compensation

  • Providing sufficient compensation to injured observers so that their quality of life is not drastically diminished

  • Determining the feasibility of extending professional liability coverage to uninsured vessels that carry observers.

The conference was successful in providing all Observer Programs nationwide with guidance on how to better protect their observers with comprehensive insurance coverage plans.  It also provided insight into further study and analysis that will be needed in developing a risk management plan for observer programs and statutory amendments that will define observers and help to clarify their maritime (seaman) status.  The conference also underscored the need to inform observers of the various types of insurance currently available to them, specifically Federal Employee Compensation Insurance.

By Bob Maier.

Status of Stocks and Multispecies Assessment Program:
Fisheries Interaction Team

The Fisheries Interaction Team (FIT) conducts multidiscipline, process-oriented research activities that draw from the AFSC’s scientific expertise. The team investigates the potential impact of commercial fishing on the spatial distribution of marine fishes.  Of immediate interest is the impact of commercial fishing operations on the distribution and local abundance of species commonly consumed by Steller sea lions .

In the next 5 years, the FIT team will work with RACE and NMML to conduct research to evaluate the following questions:

  1. Are proposed or current Reasonable and Prudent Alternatives (RPAs) achieving their stated goals?  Specifically, is there a measurable impact of commercial fishing under proposed or current RPAs?  If so, are these impacts sufficiently small that they do not cause a change in the foraging success of a Steller sea lion or large enough to adversely impact the habitat of Steller sea lions?

  2. At what level are commercial fishing operations capable of eliciting a measurable impact on Steller sea lion foraging success?  What is the functional relationship between commercial fishing effort and foraging success of Steller sea lions? This research element will evaluate the relationship between the level of commercial harvest and the intensity and duration of the fishery response.

  3. What natural factors influence the functional relationship between commercial fishing and foraging success of Steller sea lions?  This research element will evaluate differences in fish response in different regions, seasons, and population structure (e.g., the role of age composition and fisheries oceanography).

  4. What human factors influence the functional relationship between commercial fishing and the foraging success of Steller sea lions?  This research element will examine how alternative methods of harvest influence the relationship between the commercial harvest and foraging success of Steller sea lions.  Alternative methods will include, but will not be limited to, studies of the influence of daily amount of fish removed from localized regions, the gear used to remove the fish, and the number of vessels participating in removing the fish.

In this quarter, FIT conducted a feasibility study for implementing an effects of fishing research project on Pacific cod (Gadus macrocephalus).  The REFM Division chartered the fishing vessel Big Valley from 13 to 22 June to evaluate pot fishing as a sampling method to be used in experiments on local relative abundance, distribution, and movement of Pacific cod.  Standardized trawling methods have been used in annual and semi-annual surveys to determine abundances of Pacific cod on a large scale.  However, trawling is not likely suitable for the smaller scale experiments being contemplated because of the high variances that will almost certainly accompany the necessarily smaller sample size.  Also trawls cannot be fished on the rough grounds that may comprise an important portion of cod habitat when viewed on a local scale.  Cod pots are a potential alternative sampling gear.  Pots are a proven fishing gear for Pacific cod, may produce catch data that does not suffer as high a variance, and can be deployed in all cod habitat.  As a sampling instrument, pot gear is not proven for cod, and a certain amount of preliminary experimentation is necessary before pots can be used as a rigorously applied sampling gear.  This cruise was the first step in developing pots as a sampling gear for cod.

The foci of the feasibility study were methods for handling fishing gear in a research context, deployment and retrieval of research instruments, data collection methods, maximizing the efficiencies of all operations, and data management.  Included among the goals were:

  1. Test and refine instruments that can measure times when fish entered the pot

  2. Determine best ways to attach and detach instruments during a deployment and retrieval of the pots

  3. Select among competing strategies for processing and managing a wide variety of data

  4. Determine time per pot for deployment and retrieval

  5. Determine time per pot invested in deploying, retrieving, and downloading catch timer instruments

  6. Determine the time per pot to process the catch for data.

The last three kinds of information were collected to determine how much sampling could be accomplished in a single sea day. A less rigorous definable goal was to acquire hands-on experience with this gear for those members of FIT who proposed to use the cod pot as a research instrument.

The goals of the study were all met.  Prototypes of the catch timers were tested extensively and, while refinements are necessary, the devices were shown to work and will produce data on when individual fish enter the pot.  The catch timers can also be deployed, retrieved, and downloaded without reducing the expected efficiency of a pot sampling operation.  The best strategy for collection and management of deployment, retrieval, and catch data clearly emerged as a consequence of the field work; future studies can be conducted with much greater efficiency as a result. The timing of the various aspects of research fishing with pots indicated that as many as 60 pot lifts can be accomplished in a single sea day, though 30 or 40 daily pot lifts is likely to be a more reasonable pace to expect during an extended voyage under fair conditions.  It is not yet known if 30 or 40 pot lifts per day will produce sample sizes that will yield reasonably low variances; the components of variance in cod pot data have yet to be assessed. However, 30 or 40 pot lifts per day will be ample to permit such sample size evaluations in a pilot project.  Based on the information gleaned from the cod pot feasibility cruise, we conclude that further development of this sampling instrument is well worth pursuing. Next steps include designing a research pot (including refining the catch timers), manufacturing enough research pots to conduct a pilot project, and conducting a pilot project to estimate as many components of variance as possible for standardized pot catch data collected for spawning populations.

By Anne Hollowed.

Age and Growth Program

Estimated production figures for 1 January to 30 June 2001.

Yellowfin sole: 302
Walleye pollock: 10,306
Sablefish: 3,700
Atka mackerel: 1,989
Pacific whiting: 1,913
Northern rockfish: 1,240
Light dusky rockfish: 186

Total production figures were 19,636 with 4,524 test ages and 148 examined and determined to be unreadable.


As part of the NMFS Rotational Assignment Program, Jim Ingraham visited the Southwest Fisheries Science Center’s Pacific Fisheries Environmental Laboratory (PFEL) from November to March in order to collaborate on the implementation of the Ocean Surface Current Simulations (OSCURS) model on PFEL’s Live Access Server (LAS).  The OSCURS numerical model is a research tool that allows oceanographers and fisheries scientists to perform retrospective analyses of daily ocean surface currents over the last several decades anywhere in the North Pacific Ocean and Bering Sea in a 90-km oceanwide grid from Baja California to China and from 10ºN to the Bering Strait.  OCSURS is used to measure the movement of surface mixed-layer water (trajectory) over time, as well as the movement of what was in or on the water.  Ocean surface currents affect organisms suspended and swimming in the water by determining their drift and affecting their destinations.  OSCURS has also gained visibility as an accidental debris tracker to analyze accidental at-sea events.  Investigation of events such as spills of cargo containers loaded with thousands of long-term floating objects such as shoes,  plastic bathtub toys, professional hockey gloves, thongs, or computer monitors have been used to fine-tune the OSCURS model and has drawn much public interest.

The upgraded OSCURS model software has been implemented on a separate version of PFEL’s LAS, available on the internet at  Users can input a location in the North Pacific and a start and ending time (1967–present), and get a plot or listing of the predicted daily trajectory.  Input to the model are daily values of gridded sea level pressure from the Fleet Numerical Meteorology and Oceanography Center’s 6-hourly 1 X 1 degree global files.  Prior to implementation on the LAS, a pressure extract was sent from PFEL by ftp each month to REFM.  OSCURS has now been updated to read netCDF pressure files created as part of PFEL’s monthly data processing.  This facilitated implementation on the LAS and also increased the speed of data access.  This automatic updating of the pressure fields makes the previous months data available only a few days after that month ends.  Future development will include an improved user interface, extension of the input data back farther in time, and integrating the OSCURS LAS with PFEL’s primary LAS. Monthly current charts of the North Pacific is one of the newly derived products.  Other products will be designed in response to user requests.  Contact Jim Ingraham (206-526-4241, or Lynn deWitt (831-648-0936 ).

Interannual variability of ocean currents can affect survival of both suspended and swimming marine species.  Implementation of OSCURS on PFEL’s LAS will provide access to a greater number of researchers in fisheries and related fields and could serve as a public relations tool for educators and the general public.

By James Ingraham.

Resource Ecology and Ecosystems Modeling Program

Stomachs collected totaled 486 from the eastern Bering Sea and 1,106 from the Gulf of Alaska. Laboratory analysis was performed on 1,618 groundfish stomachs from the eastern Bering Sea and 715 from the Washington-Oregon-California region. Nine observers returned groundfish stomach samples during the quarter.

Climate Forcing Effects on Trophically-linked Groundfish Populations

Commercially important groundfish populations in the eastern Bering Sea are connected to each other through the food web and act either as predators, prey, or both in the system.  Some species, such as walleye pollock (Theragra chalcogramma), are dominant in terms of biomass and may also dominate trophic dynamics.  In addition to having different trophic roles, the recruitment patterns of these species are variable and may be related to climate forcing on either interannual or interdecadal time scales.  We examined the possible future effects of four levels of fishing mortality (F30%, F40%, F50%, and no fishing) on trophically-linked species under two different scenarios of future climate regimes using both single-species and multispecies forecasting models of the eastern Bering Sea.  We used the eight-species system developed in the multispecies virtual population analysis (MSVPA) of the eastern Bering Sea by Livingston and Jurado-Molina.

Four species, walleye pollock, Pacific cod, Greenland turbot (Reinhardtius hippoglossoides), and yellowfin sole (Pleuronectes asper) played the role of both predator and prey.  Two species, rock sole (Lepidopsetta bilineata) and Pacific herring (Clupea pallasi), were considered only as prey.  Two species, arrowtooth flounder (Atheresthes stomias) and northern fur seal (Callorhinus ursinus), were considered “other predators,” whose populations are not estimated within the model but are provided externally from other sources.  The multispecies forecast model includes predation interactions and uses as input the predator-prey suitabilities which were derived from MSVPA.

Monte Carlo simulations for each level of fishing mortality and each assumption on mean recruitment level associated with each regime shift were performed using the single-species and multispecies forecasting models.  We took a simple approach for recruitment by assuming that the climate regime shift produced a change in the variability and mean level of this parameter. Two hypotheses were examined.  One hypothesis was that the eastern Bering Sea is still responding to the 1977 climate regime; the second hypothesis was that the species are responding to a possible new regime shift that occurred in 1989. Mean and variance in recruitment for each species used in the forecast models were calculated from historical recruitment estimates corresponding to a particular regime shift. The ratio of spawning biomass in the forecast of year 2015 relative to the starting year of 1998 was used as indicator of performance.  The temporal trend of the median spawning biomass ratio of pollock was also tracked in the long term.

In the single-species context, fishing mortality in conjunction with the regime shift assumption was the most important factor driving the dynamics of the species.  The regime shift assumption produced important effects in only three species in a single-species context.  The three species, Pacific cod, Greenland turbot, and rock sole, were the species in which the regime shift assumption changed the mean (Pacific cod and rock sole) or had a larger change in the variance of recruitment (Greenland turbot).  The observed changes in spawning stock biomass (SSB) ratios of these species were a direct result of the changes in recruitment assumptions for the two  regime shift scenarios.  Thus, forecasts of single-species dynamics can be influenced if regime shifts changes in recruitment can be estimated and incorporated into the projections.

In the multispecies scenario, the results showed greater complexity. Fishing was an important factor driving the dynamics of all species. An increase in fishing mortality produced a decrease in the mean spawning biomass in the majority of the species. For Pacific herring, in which fishing mortality was held constant at the 20% harvest rate policy presently used in its management, an opposite trend was observed.  This tendency was due to predation interactions.   As the fishing mortality of Pacific herring predators increased, their abundance decreased, producing a reduction in Pacific herring predation mortality and thus an increase in its mean SSB ratio.  This shows how fishing changes on predator populations in combination with predation interactions have the potential to cause unintended changes in prey populations.

The cumulative frequency distributions of some species’ SSB ratios were also affected by predation.  Within a no-fishing scenario, the single-species simulation of both assumptions of climate regime shift suggested an increase in the spawning biomass of most species.  Different results were seen in the multispecies forecasts, which included predation interactions.  For walleye pollock, the multispecies no-fishing simulation suggested an increase in the SSB ratio in the medium-term projections.  However, this increase was smaller than the multispecies simulations of the F40% and F50% levels of fishing mortality.  These differences are due to the cannibalistic interactions that increase the complexity of the dynamics of walleye pollock.

Charts of walleye pollock juvenile median biomass trajectories.

Figure 1.  Median biomass trajectories of walleye pollock juveniles (age 0-2) and adults (age 3+) from the multispecies scenario of the 1977 regime shift under two different levels of fishing (F30% - top and F=0 - bottom).

If predation interactions are taken into account in models of walleye pollock, the absence of fishing mortality produces an increase in the survival of adult walleye pollock and consequently an increase in the predation mortality of juvenile pollock. This result is also seen in our simulations (Figure 1 above) in which the initial effect of a no-fishing regime on pollock in the multispecies forecast is a strong build-up of adult biomass and the depression of juvenile pollock biomass.  Therefore, results of the multispecies forecast suggest that cannibalism is an important factor influencing the amplitude and frequency of biomass oscillations in walleye pollock in this model.  The lack of an explicit stock recruitment function in generating recruitment values in this model is also likely responsible for the strong depression of juveniles at high, adult walleye pollock stock sizes.  Future refinements for this model should include derivation of functional stock-recruitment relationships for walleye pollock under different climate regimes.  However, there are not yet enough historical observations of stock and recruitment to derive these for different climate regimes.

For rock sole, predation interactions were also important.  The multispecies forecast of the no-fishing level under the 1989 regime shift assumption predicted a decreasing spawning biomass ratio compared with the no-fishing scenario under the 1977 regime shift assumption, which predicted an increasing biomass ratio.  The decreasing trend of the spawning biomass ratio is likely due to increased predation mortality caused by an increase in the population of rock sole’s predators (walleye pollock and Pacific cod) when fishing is stopped, together with the reduced recruitment in rock sole assumed under the 1989 regime relative to the 1977 regime.  The single species forecast for rock sole under the 1989 regime shift scenario predicted an increased SSB trend.  Thus, predation interactions can influence not only the magnitude of population change but also the direction of change.

The displacement of the frequency distributions produced by the different combination of assumptions of climate regime and fishing mortality in the single-species and  multispecies forecasts produced an overlap of some cumulative frequency distributions of the SSB ratio of some species such as  Pacific cod and rock sole.   In the case of Pacific cod, a more conservative policy (F40%) under recruitment assumptions of a 1989 regime shift could produce similar effects to those produced by a less conservative policy (F30%) under the assumptions of the 1977 regime shift in the medium term (Figure 2 below).

Graph of Pacific cod spawning biomass distribution.

Figure 2.  Cumulative distributions of the spawning biomass (SSB) ratio of Pacific cod in 2015 relative to 1998 estimated with two levels of fishing mortality (F30% and F40%) and two assumptions of climate regime shift in the single-species forecast.

In the case of walleye pollock, there was overlap among scenarios in the cumulative frequency distributions in both the medium-term and the long-term multispecies projections.  For this species, the addition of strong cannibalistic interactions in combination with fishing and changes in recruitment variability produce oscillations in the medium term that have a different amplitude and frequency for each scenario.  There is overlap at various short and long time intervals of the median biomass estimates from different scenarios.  Discriminating among environment, predation, and fishing effects on this species will continue to be a challenge.  Similarly, the design of multispecies or ecosystem-based management strategies that attempt to balance human and predator needs for walleye pollock are complicated by these cannibalistic interactions that are confounded with fishing and environmental factors.

In summary, the effects of fishing, predation interactions, and climate could be considered similar because they produce changes in the SSB ratios of species of the same order of magnitude.  The effect of fishing is always to reduce the biomass of the target species in single-species forecasts.  On the other hand, the effects of predation and fishing in multispecies forecasts cannot be generalized and depend on the species, the complexity, and magnitude of the predation interactions and the species’ position in the food web and its response to climate variability.

The MSVPA and the multispecies forecast models are a first step in taking a more holistic approach in providing advice for fisheries management.  However, some aspects in this approach can be improved.  The incorporation of climate regime shifts in the model will require a better understanding of the mechanisms involving changes in physical environment and their effects on recruitment success during a particular climate regime.  The recognition of the 1977 regime shift was made in the early 1990s, and there is a belief that this event was not exceptional but the latest in a sequence of regime shifts. Therefore, it is necessary to develop a reliable way to identify regime shifts based on biological and physical indices.   Monitoring these indices in the North Pacific and the Bering Sea ecosystems might allow for an earlier identification of regime shifts.  This identification, in combination with a sufficient number of stock and recruitment data points in different regimes, will allow a more detailed functional specification of recruitment of the Ricker or Beverton-Holt form for each regime shift.  Long-term monitoring is required in order to recognize and quantify the effects of regime shifts on marine ecosystems.  This recognition and  the improved understanding of the influence of multispecies interactions will help resource management better adapt to current or future environmental conditions.

By Pat Livingston.

Socioeconomic Assessments Program:
Alaska Marine Sport Fishing Economic Survey

The Center received $95,000 from the NMFS Headquarters  to estimate the economic value of sport halibut fishing trips in Alaska, including estimating attributes of a recreational fishing trip and how those attributes affect participation rates.  The attributes include fish size, number of fish caught, and harvest regulations.  A key component of the research will be estimating the value of fish that are caught and retained versus fish that are caught and released.  Todd Lee is responsible for directing the project, designing the study and angler questionnaire, and completing the econometric analysis.  The survey will be administered through a contracted survey research firm.

Alaska Halibut Charter Boat Operator Economic Survey

In cooperation with the Pacific States Marine Fisheries Commission (PSMFC), the AFSC is engaged in a project to collect economic data from halibut charter boat operators.  The purpose of the survey is to provide information about the economic performance of the halibut charter fleet. It is expected that the survey will be repeated every few years. The project will provide baseline data that can be used to evaluate some of the economic effects of management proposals, such as an IFQ program and guideline harvest levels, if and when they take effect.

By Joe Terry.