Article

Ecosystem-based management for protected species in the North Pacific fisheries

Authors:
  • North Pacific Fishery Management Council
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

In the North Pacific Ocean, an ecosystem-based fishery management approach has been adopted. A significant objective of this approach is to reduce interactions between fishery-related activities and protected species. We review management measures developed by the North Pacific Fishery Management Council and the National Marine Fisheries Service to reduce effects of the groundfish fisheries off Alaska on marine mammals and seabirds, while continuing to provide economic op-portunities for fishery participants. Direct measures have been taken to mitigate known fishery impacts, and precautionary measures have been taken for species with potential (but no documented) interactions with the groundfish fisheries. Area closures limit disturbance to marine mammals at rookeries and haulouts, protect sensitive benthic habitat, and reduce potential competition for prey resources. Temporal and spatial dispersion of catches reduce the localized impact of fishery removals. Seabird avoidance measures have been implemented through collaboration with fishery participants and have been highly successful in reducing seabird bycatch. Finally, a comprehensive observer monitoring program provides data on the location and extent of bycatch of marine mammals and seabirds. These measures provide managers with the flexibility to adapt to changes in the status of protected species and evolving conditions in the fisheries. This re-view should be useful to fishery managers as an example of an ecosystem-based ap-proach to protected species management that is adaptive and accounts for multiple objectives.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

Article
Full-text available
Effective ecosystem-based management requires estimates of abundance and population trends of species of interest. Trend analyses are often limited due to sparse or short-term abundance estimates for populations that can be logistically difficult to monitor over time. Therefore it is critical to assess regularly the quality of the metrics in long-term monitoring programs. For a monitoring program to provide meaningful data and remain relevant, it needs to incorporate technological improvements and the changing requirements of stakeholders, while maintaining the integrity of the data. In this paper we critically examine the monitoring program for the Australian fur seal (AFS) Arctocephalus pusillus doriferus as an example of an ad-hoc monitoring program that was co-ordinated across multiple stakeholders as a range-wide census of live pups in the Austral summers of 2002, 2007 and 2013. This 5-yearly census, combined with historic counts at individual sites, successfully tracked increasing population trends as signs of population recovery up to 2007. The 2013 census identified the first reduction in AFS pup numbers (14,248 live pups, -4.2% change per annum since 2007), however we have limited information to understand this change. We analyse the trends at breeding colonies and perform a power analysis to critically examine the reliability of those trends. We then assess the gaps in the monitoring program and discuss how we may transition this surveillance style program to an adaptive monitoring program than can evolve over time and achieve its goals. The census results are used for ecosystem-based modelling for fisheries management and emergency response planning. The ultimate goal for this program is to obtain the data we need with minimal cost, effort and impact on the fur seals. In conclusion we identify the importance of power analyses for interpreting trends, the value of regularly assessing long-term monitoring programs and proper design so that adaptive monitoring principles can be applied.
Article
Full-text available
The North Pacific right whale (Eubalaena japonica) is among the most endangered of all great whales, having been subject to intensive commercial whaling in the 19 th century. All available 20 th century records of this species in the North Pacific were reviewed. There has been a total of 1,965 recorded sightings since 1900; of these, 988 came from the western North Pacific, 693 from the eastern No rth Pacific and 284 had no location specified. Thirteen strandings (all but one from the western North Pacific) were recorded. Known catche s for commercial or scientific purposes totalled 742 (331 in the western North Pacific, 411 in the eastern North Pacific). Most of th e reported Soviet 'sightings' in the eastern North Pacific were actually catches, as may be the case for Soviet sightings in the Okhotsk S ea. In addition, the impact of known Soviet illegal catches in the Okhotsk Sea may be reflected in an apparent decline in sightings after the 19 60s (although this may be partly explained by low observer effort). Overall, the data support the hypothesis that at least two stocks of righ t whales exist in the North Pacific. Any recovery in the western North Pacific population was compromised by the Soviet catches in the Okhotsk region, although recent sightings suggest that this population is still large enough to sustain reproduction. By contrast, Soviet catch es in the now-smaller eastern North Pacific population have severely reduced its prospects for recovery. Although the prognosis for this population is poor, a long-term monitoring programme is required to better understand its conservation status and to determine whether it may be affected by human-related problems that would require mitigation.
Article
Full-text available
DiCosimo, J., Methot, R. D., and Ormseth, O. A. 2010. Use of annual catch limits to avoid stock depletion in the Bering Sea and Aleutian Islands management area (Northeast Pacific). – ICES Journal of Marine Science, 67: 1861–1865. In total, 41 fish stocks in US ocean waters continue to be fished at unsustainable levels, and 46 fish stocks are overfished. In 2006, the US Congress required the implementation of annual catch limits (ACLs) and accountability measures by 2010 to prevent overfishing, and by 2011 to recover overfished stocks. These requirements were modelled on the existing management system for Northeast Pacific groundfish, where more than 20 fish stocks and assemblages have been managed sustainably for 30 years. Science-based overfishing levels and acceptable biological catches (ABCs) have been implemented for each stock or assemblage, with buffers between the two to avoid overfishing. Total allowable catches are set at or below the acceptable biological catch. Suballocations of quotas by season, area, and gear type, along with in-season fishery closures based on extensive observer coverage and vessel monitoring, ensure that quotas are not exceeded. To comply with ACL requirements, the North Pacific Fishery Management Council has defined ABC as an ACL. We demonstrate the effectiveness of ACLs for successful management of Northeast Pacific groundfish, suggesting that their use in other US fisheries might reduce the risk of overfishing and enhance the recovery of overfished stocks.
Article
Full-text available
A bstract The Pacific walrus (Odobenus rosmarus divergens) population is an important ecological and economic resource of the Bering Sea region. We describe population change, beginning with a low in 1950, through a high in about 1980, and ending in 1989. Estimates of abundance for the years after 1989 were not attempted due to the lack of harvest data and other population parameters. Selective hunting practices resulted in biased data regarding population composition and reproductive performance. Rates of reproduction had to be estimated from ovarian data, which indicated a dramatic drop in the 1980s. High harvests in the 1980s likely contributed to a decline in the population, but uncertainties as to accuracy of population estimates and other data raise reasonable doubts, especially with respect to the number of males, for which the most recent (1985) population estimate suggests a sharp decline. Past population estimates were revised upwards to compensate for walruses underwater and not seen in aerial surveys. The weaknesses in the available data make it clear that effective management of the population will require many improvements in collection of data regarding harvests, population structure, reproduction, and population trend.
Article
Full-text available
The Pacific walrus population has been depleted and subsequently allowed to recover three times in the past 150 yr. As we see it, the population has been made to fluctuate like an r-selected species, rather than being maintained at a high, stable level, as befits a K-selected species. The latest depletion began in the 1930s but was not recognized until 25 yr later, by which time the population had been reduced by at least half. Without benefit of communication, the U.S.S.R. and the State of Alaska put similar protective measures into place by 1960, and in the next two decades the walrus population recovered again, at least doubling in size. By 1980, it already was showing density-dependent signs of having approached or reached the carrying capacity of its environment. As productivity and calf survival declined sharply in the late 1970s and early 1980s the catches more than doubled. We believe that the combined effects of natural curtailment and human intervention may be bringing the population down again rather rapidly. With the present, crude monitoring methods, delayed management responses, and poor international communications, however, the downward trend may not be acknowledged for at least another decade, by which time the unilateral Soviet and American corrective measures are likely to be too much, too late. Walrus management needs to be based less on response to immediate crisis and more on long term prediction than it has been in the past. Because the U.S.A. and U.S.S.R. are trying to manage the same walrus population, without sufficient communication or consensus and sometimes to opposite ends, an international joint management program needs to be implemented.
Article
Full-text available
During 1991-2000, the western stock of Steller sea lions, Eumetopias jubatus, declined at 5.03% (SE = 0.25%) per year, statistically significant rates (P < 0.10) in all but the eastern Aleutian Islands region. The greatest rates of declines occurred in the eastern and central Gulf of Alaska and the western Aleutian Islands (> 8.2% per year). Using a published correction factor, we estimated the total non-pup population size in Alaska of the western stock of Steller sea lions to be about 33,000 animals. Based on a published life table and the current rate of decline, we estimate that the total number of mortalities of non-pup Steller sea lions during 1991-2000 was about 6,383 animals; of those, 4,718 (74%) are mortalities that would have occurred if the population were stable, and 1,666 (26%) are additional mortalities that fueled the decline. We tabulated the levels of reported anthropogenic sources of mortality (subsistence, incidental take in fisheries, and research), estimated another (illegal shooting), then approximated levels of predation (killer whales and sharks). We attempted to partition the various sources of "additional" mortalities as anthropogenic and as additional mortality including some predation. We classified 436 anthropogenic mortalities and 769 anthropogenic plus some predation mortalities as "mortality above replacement"; this accounted for 26% and 46% of the estimated total level of "mortality above replacement", respectively. The remaining mortality (74% and 54%, respectively) was not attributed to a specific cause and may be the result of nutritional stress.
Article
Full-text available
North Pacific right whales (Eubalaena japonica) were extensively exploited in the 19 th century, and their recovery was further retarded (severely so in the eastern population) by illegal Soviet catches in the 20 th century, primarily in the 1960s. Monthly plots of right whale sightings and catches from both the 19 th and 20 th centuries are provided, using data summarised by Scarff (1991, from the whale charts of Matthew Fontaine Maury) and Brownell et al. (2001), respectively. Right whales had an extensive offshore distribution in the 19 th century, and were common in areas (such as the Gulf of Alaska and Sea of Japan) where few or no right whales occur today. Seasonal movements of right whales are apparent in the data, although to some extent these reflect survey and whaling effort. That said, these seasonal movements indicate a general northward migration in spring from lower latitudes, and major concentrations above 40°N in summer. Sightings diminished and occurred further south in autumn, and few animals were recorded anywhere in winter. These north-south migratory movements support the hypothesis of two largely discrete populations of right whales in the eastern and western North Pacific. Overall, these analyses confirm that the size and range of the right whale population is now considerably diminished in the North Pacific relative to the situation during the peak period of whaling for this species in the 19 th century. For management purposes, new surveys are urgently required to establish the present distribution of this species; existing data suggest that the Bering Sea, the Gulf of Alaska, the Okhotsk Sea, the Kuril Islands and the coast of Kamchatka are the areas with the greatest likelihood of finding right whales today.
Article
Full-text available
Industrial longline fishing has been suspected to impact upon black‐footed albatross populations Phoebastria nigripes by increasing mortality, but no precise estimates of bycatch mortality are available to ascertain this statement. We present a general framework for quantifying the relationship between albatross population and longline fishing in absence of reliable estimates of bycatch rate. We analysed capture–recapture data of a population of black‐footed albatross to obtain estimates of survival probability for this population using several alternative models to adequately take into account heterogeneity in the recapture process. Instead of trying to estimate the number of birds killed by using various extrapolations and unchecked assumptions, we investigate the potential relationship between annual adult survival and several measures of fishing effort. Although we considered a large number of covariates, we used principal component analysis to generate a few uncorrelated synthetic variables from the set and thus we maintained both power and robustness. The average survival for 1997–2002 was 92%, a low value compared to estimates available for other albatross species. We found that one of the synthetic variables used to summarize industrial longline fishing significantly explained more than 40% of the variation in adult survival over 11 years, suggesting an impact by longline fishing on albatross’ survival. Our analysis provides some evidence of non‐linear variation in survival with fishing effort. This could indicate that below a certain level of fishing effort, deaths due to incidental catch can be partially or totally compensated for by a decrease in natural mortality. Another possible explanation is the existence of a strong interspecific competition for accessing the baits, reducing the risk of being accidentally hooked. Synthesis and applications. The suspicion of a significant impact of longline fishing on the black‐footed albatross population was supported by the combination of a low estimate of adult survival for the study period, and a significant relationship between adult survival and a synthetic measure of fishing effort. This study highlights the sensitivity of the black‐footed albatross to commercial longline fishing, and should exhort fishery management authorities to find adequate seabirds avoidance methods and to encourage their employment.
Article
Full-text available
In spring 2006, we conducted a collaborative U.S.–Russia survey to estimate abundance of the Pacific walrus (Odobenus rosmarus divergens). The Bering Sea was partitioned into survey blocks, and a systematic random sample of transects within a subset of the blocks was surveyed with airborne thermal scanners using standard strip-transect methodology. Counts of walruses in photographed groups were used to model the relation between thermal signatures and the number of walruses in groups, which was used to estimate the number of walruses in groups that were detected by the scanner but not photographed. We also modeled the probability of thermally detecting various-sized walrus groups to estimate the number of walruses in groups undetected by the scanner. We used data from radio-tagged walruses to adjust on-ice estimates to account for walruses in the water during the survey. The estimated area of available habitat averaged 668,000 km2 and the area of surveyed blocks was 318,204 km2. The number of Pacific walruses within the surveyed area was estimated at 129,000 with 95% confidence limits of 55,000–507,000 individuals. Poor weather conditions precluded surveying in other areas; therefore, this value represents the number of Pacific walruses within about half of potential walrus habitat.
Article
Full-text available
Spectacled eiders (Somateria fischeri) winter among leads in the Bering Sea pack ice, where they dive 40-70 m for benthic prey. During the first icebreaker cruises into that area, esophagi of collected eiders contained only clams, mostly Nuculana radiata, with no trace of the once-dominant Macoma calcarea. Alternative prey used elsewhere (snails, amphipods, other bivalves) were available but not eaten. Eiders ate mainly N. radiata 18-24 mm long, although M. calcarea of this length contained 62% more energy. Percent body lipid of eiders averaged 12&#453% (SD) for 26 adult males and 14&#453% for 12 adult females. Mean body mass (&#45SE) of these males in late March (1,688ᆩ g) was higher than reported for 53 males after arriving at breeding areas in late May (1,494ᆢ g). Body mass of these females (1,550ᆷ g) was lower (but not significantly) than reported for 11 females upon arrival at breeding sites (1,623ᇂ g). In 1999, the last spectacled eiders left the wintering area on 21 April, 4-8 weeks before their typical arrival at breeding sites. Their location is unknown in the interim, when habitats used appear critical to acquiring reserves for reproduction.
Article
Full-text available
Effective mitigation measures were developed to reduce high levels of seabird mortality due to warp strikes in southern hemisphere trawl fisheries. However, in northern hemisphere trawl fisheries, little is known about the extent of cable strike seabird mortality or techniques to mitigate it. We compared the rate of heavy seabird strikes by third-wire cables and warps, using three mitigation measures compared to a control of no mitigation. Experiments were conducted aboard two catcher-processor vessels targeting walleye pollock (Theragra chalcogramma) in the eastern Bering Sea: one that rendered offal into fish meal and fish oil (Vessel R) and one that minced offal prior to discharge (Vessel M). More birds attended Vessel M, but the rate of seabird cable strikes was higher on Vessel R due to the greater aerial extent of its cables. Streamer lines significantly reduced heavy seabird strikes by both cable types regardless of discharge characteristics. Reducing the aerial extent of third wires also reduced third-wire strike rates, but this method was less effective than streamer lines. Warp booms designed to divert seabirds from warps failed to reduce seabird warp strikes, but this technique could be improved. These results show for the first time that seabird strikes with modern third-wire trawl sonar cable systems can be reduced through mitigation or gear modification and that warp strikes can be mitigated with techniques similar to those found successful in southern hemisphere fisheries. Mitigation measures and concepts identified in this study should be widely applicable. KeywordsSeabird bycatch–Trawl fisheries–Walleye pollock–Trawl seabird mitigation–Collaborative research
Article
Full-text available
"Fisheries managers have established many marine protected areas (MPA’s) in the Federal and state waters off Alaska to protect ecological structure and function, establish control sites for scientific research studies, conserve benthic habitat, protect vulnerable stocks, and protect cultural resources. Many MPA’s achieve multiple objectives. Over 40 named MPA’s, many of which include several sites, encompass virtually all Federal waters off Alaska and most of the state waters where commercial fisheries occur. All of the MPA’s include measures to prohibit a particular fishery or gear type (particularly bottom trawls) on a seasonal or year-round basis, and several MPA’s prohibit virtually all commercial fishing. Although the effectiveness of MPA’s is difficult to evaluate on an individual basis, as a group they are an important component of the management program for sustainable fisheries and conserving marine biodiversity off Alaska."
Article
Full-text available
The North Pacific right whale (Eubalaena japonica) was heavily exploited by both nineteenth century whaling and recent (1960s) illegal Soviet catches. Today, the species remains extremely rare especially in the eastern North Pacific. Here, we use photographic and genotype data to calculate the first mark-recapture estimates of abundance for right whales in the Bering Sea and Aleutian Islands. The estimates were very similar: photographic = 31 (95% CL 23-54), genotyping = 28 (95% CL 24-42). We also estimated the population contains eight females (95% CL 7-18) and 20 males (95% CL 17-37). Although these estimates may relate to a Bering Sea subpopulation, other data suggest that the total eastern North Pacific population is unlikely to be much larger. Its precarious status today-the world's smallest whale population for which an abundance estimate exists-is a direct consequence of uncontrolled and illegal whaling, and highlights the past failure of international management to prevent such abuses.
Article
Satellite radio-location data from 57 adult male Pacific walruses (Odobenus rosmarus divergens) were used to estimate haul-out fidelity, broadly describe seasonal foraging distributions, and determine the approximate timing of autumn migration from Bristol Bay, Alaska. Data were collected intermittently during 1987-91 and 1995-2000, primarily during the period from May to October. Transmitter longevity ranged from less than 1 day to 560 days (median 75 d). The four tagging sites were the only haul-outs that were commonly used in the bay from spring through autumn. Mean fidelity, defined as the chance that an animal will return to an area where it previously hauled out, was 0.56 (SE = 0.09). However, small sample sizes precluded comparisons of fidelity among years and among haul-outs by season. No tagged animals migrated out of the bay between spring and early autumn. Combined monthly locations suggest that foraging occurred primarily in the southern and eastern areas of the bay in spring and gradually shifted towards northwestern areas in late autumn and winter. Ninety-eight percent of the in-water locations were in waters under 60 m deep, which account for 76% of the study area. Some animals migrated out of the bay in late autumn and winter; others remained within the bay throughout the year. Those making long-range migrations departed the bay during November and December.
Article
We conduct a decision analysis that explores the effects of trawl-related fishery mortality on achieving the population recovery goals for the US federally-endangered short-tailed albatross (Phoebastria albatrus), proposed by the US Fish and Wildlife Service. A population model is constructed and its parameters estimated using data on counts of the numbers of albatross chicks and eggs at Torishima Island, Japan, where 83% of the world’s population of this species is found. Bayesian inference is used to assign probabilities to alternative plausible rates of fishing mortality and as the basis for population projections with different levels of trawl mortality to determine their effects on achieving the population recovery goals. The analyses of the impact of trawl mortality on the Torishima short-tailed albatross population suggests that exceeding the current expected incidental take in the Alaskan groundfish trawl fishery, two in any 5-year period, by as much as a factor of 10 would have little impact on when the proposed recovery goals for the species are achieved. A quantitative approach that addresses uncertainty, such as that outlined in this study, could aid the process to evaluate allowable limits in light of species recovery goals by addressing both take limits and recovery goals within the same framework.
Article
Terrestrial haul-out of Atlantic walruses (Odobenus rosmarus (L.)) was studied in relation to temporal, weather, and disturbance factors at a site on Bathurst Island, N.W.T., from 24 July to 23 August 1977. Counts at 6-h intervals showed that up to 129 walruses occupied the site between 25 July and 19 August, with strong fluctuations in numbers during this period. Both sexes and various age classes were represented. Numbers hauled out were weakly correlated with ambient temperature, precipitation, and possibly with wind. Walruses on land spent over 90% of their time recumbent and apparently sleeping during ten 24-h watches. There were no consistent patterns of diel variation in percentage of walruses engaged in broadly scaled activities, with the possible exceptions of suckling by young walruses and near-shore feeding by older animals. Walruses on land responded to 27% of 71 local flights by helicopters, to 35% of 31 flights by fixed-wing aircraft, and to none of 6 approaches by boats. Responses recognized were head-lifting, orientation toward the sea, and retreat into the sea; the level of response depended upon distance and altitude of disturbance approach.
Article
We consider the question of which quantitative modelling tools can be used to support an ecosystem approach to management (EAM), with a focus on evaluating the implication of decisions on the biological system being managed. Managers of federal fisheries in the eastern Bering Sea, USA, have adopted an EAM. The tools used to support EAM in the eastern Bering Sea serve as a guide to what types of models could be used elsewhere. A review of the role of natural science in the implementation of EAM shows that scientific advice enters into decision-making at a variety of steps. Single-species stock assessment and projection models are the most commonly used tools employed to inform managers. Comprehensive assessments (e.g. management strategy evaluation) are emerging as a new and potentially valuable analysis technique for use in assessing trade-offs of different strategic alternatives. In the case of management in the eastern Bering Sea, end-to-end models and coupled biophysical models have been used primarily to advance scientific understanding, but have not been applied in a management context. This review highlights that implementation of an EAM in a management environment such as eastern Bering Sea requires substantial commitments to the collection and analysis of data and support for a group of analysts with interdisciplinary training in population dynamics, oceanography and ecology. This review supports the growing recognition that a diverse suite of modelling tools is needed to address tactical and strategic management issues germane to the adoption of the ecosystem approach to fisheries management.
Article
A bstract Pacific walruses ( Odobenus rosmarus divergens ) make trips from ice or land haul‐out sites to forage for benthic prey. We describe dive and trip characteristics from time‐depth‐recorder data collected over a one‐month period during summer from four male Pacific walruses in Bristol Bay, Alaska. Dives were classified into four types. Shallow (4 m), short (2.7 min), square‐shaped dives accounted for 11% of trip time, and many were probably associated with traveling. Shallow (2 m) and very short (0.5 min) dives composed only 1% of trip time. Deep (41 m), long (7.2 min), square‐shaped dives accounted for 46% of trip time and were undoubtedly associated with benthic foraging. V‐shaped dives ranged widely in depth, were of moderate duration (4.7 min), and composed 3% of trip time. These dives may have been associated with navigation or exploration of the seafloor for potential prey habitat. Surface intervals between dives were similar among dive types, and generally lasted 1–2 min. Total foraging time was strongly correlated with trip duration and there was no apparent diel pattern of diving in any dive type among animals. We found no correlation between dive duration and postdive surface interval within dive types, suggesting that diving occurred within aerobic dive limits. Trip duration varied considerably within and among walruses (0.3–9.4 d), and there was evidence that some of the very short trips were unrelated to foraging. Overall, walruses were in the water for 76.6% of the time, of which 60.3% was spent diving.
Article
We conducted a satellite tracking study of the endangered short-tailed albatross (Phoebastria albatrus) to determine post-breeding season distribution, the amount of time spent within exclusive economic zones of Pacific Rim countries, and assess factors affecting spatial and temporal overlap with commercial fisheries in Alaska. We obtained 6709 locations for 14 albatrosses (131–808 locations and 51–138 days of tracking per bird). Albatrosses ranged widely throughout the North Pacific Rim, spending the majority of time within the exclusive economics zones of Japan, Russia (Kuril Islands and Kamchatka Peninsula), and the United States (Aleutian Islands and Bering Sea, Alaska). We found evidence for gender and age-related differences in distribution and, therefore, potential interaction with regional fisheries. Overall, albatrosses spent the greatest proportion of time within the Alaska exclusive economic zone. Within Alaska, albatrosses occurred most frequently in fishery management zones that encompassed the Aleutian Islands, Bering Sea, and south of the Alaska Peninsula. Short-tailed albatrosses had the greatest potential overlap with fisheries that occurred along continental shelf break and slope regions, e.g., longlining for sablefish (Anoplopoma fimbria), where albatrosses occurred most often. Some birds, however, also made frequent excursions onto the extensive Bering Sea shelf, suggesting significant potential for interactions with the large-scale walleye pollock (Theragra chalcogramma) and Pacific cod (Gadus macrocephalus) fisheries. Alaskan longline fishing fleets have been proactive in using seabird deterrent devices, however, our data further emphasize that such efforts beyond the Alaska exclusive economic zone would provide a greater conservation benefit for this species.
Article
We integrated satellite-tracking data from black-footed albatrosses (Phoebastria nigripes; n = 7) and Laysan albatrosses captured in Alaska (Phoebastria immutabilis; n = 18) with data on fishing effort and distribution from commercial fisheries in the North Pacific in order to assess potential risk from bycatch. Albatrosses were satellite-tagged at-sea in the Central Aleutian Islands, Alaska, and tracked during the post-breeding season, July–October 2005 and 2006. In Alaskan waters, fishing effort occurred almost exclusively within continental shelf and slope waters. Potential fishery interaction for black-footed albatrosses, which most often frequented shelf-slope waters, was greatest with sablefish (Anoplopoma fimbria) longline and pot fisheries and with the Pacific halibut (Hippoglossus stenolepsis) longline fishery. In contrast, Laysan albatrosses spent as much time over oceanic waters beyond the continental shelf and slope, thereby overlapping less with fisheries in Alaska than black-footed albatrosses. Regionally, Laysan albatrosses had the greatest potential fishery interaction with the Atka mackerel (Pleurogrammus monopterygius) trawl fishery in the Western Aleutian Islands and the sablefish pot fishery in the Central Aleutian Islands. Black-footed albatrosses ranged further beyond Alaskan waters than Laysan albatrosses, overlapping west coast Canada fisheries and pelagic longline fisheries in the subarctic transition domain; Laysan albatrosses remained north of these pelagic fisheries. Due to inter-specific differences in oceanic distribution and habitat use, the overlap of fisheries with the post-breeding distribution of black-footed albatrosses is greater than that for Laysan albatrosses, highlighting inter-specific differences in potential vulnerability to bycatch and risk of population-level impacts from fisheries.
Article
Stram, D. L., and Evans, D. C. K. 2009. Fishery management responses to climate change in the North Pacific. – ICES Journal of Marine Science, 66: 1633–1639. In the North Pacific, warming trends, coupled with declining sea ice, raise concerns about the effects of climate change on fish populations and ecosystem dynamics. Scientists are only beginning to understand the potential feedback mechanisms that will affect everything from plankton populations to major commercial fish species distributions, yet fishery managers have a responsibility to prepare for and respond to changing fishing patterns and potential ecosystem effects. There are ways for fishery managers to be proactive, while waiting for better information to unfold. The North Pacific Fishery Management Council (Council) and the National Marine Fisheries Service have jurisdiction over offshore fisheries in Alaska, USA. Recently, the Council has undertaken risk-averse management actions, in light of uncertainty about the effects of warming trends (and loss of sea ice) and resulting changes to fishing activities in the North Pacific. The Council has assessed whether opportunities for unregulated fishing could result from changes in fish distribution, has closed the Arctic Ocean to all commercial fishing pending further research, and has established extensive area closures where fishing with bottom-trawl gear is prohibited to protect vulnerable crab habitat and to control the northern expansion of the trawl fleet into newly ice-free waters. In cases where linkages between climate variables and fish distributions can be identified, the Council is developing adaptive management measures to respond to varying distributions of fish and shellfish. Finally, the Council has also tried to re-examine existing information to gain a better understanding of climate and ecosystem effects on fishery management. The pilot Fishery Ecosystem Plan for the Aleutian Islands maps interactions among climate factors and ecosystem components and suggests indicators for the Council to monitor.