Decline of the Steller Sea Lion in Alaskan Waters Untangling Food Webs and Fishing Nets (2003) / Chapter Skim
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1. Introduction
1. Introduction
Pages 14-25
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From page 14... ...
These included drift gillnet fleets for Pacific salmon; tangle net fisheries for crabs; longline fisheries for Pacific halibut, Pacific cod, sablefish, and Greenland turbot (Reinhardtius hippoglossoides) in the Bering Sea; and trawl fisheries for groundfish, unscientific names for species mentioned in the text are given in Appendix H
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From page 15... ...
In the l990s the Alaska groundfish fishery became fully "Americanized." The current domestic groundfish fisheries target walleye pollock (67% of total groundfish catch in 2000) , Pacific cod, Atka mackerel (Pleurogrammus monopterygius)
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From page 16... ...
It is not possible to determine whether the 1960s sea lion counts assessed the population above, at, or below the long-term average because reliable population data are not available to establish this type of baseline. A l9th-century description of Steller sea lions suggests that the population previously experienced large fluctuations in abundance, although again the cause is unknown but could be partially the result of human disturbance and hunting (see Appendix D)
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From page 17... ...
The hypothesized factors include changes in the species composition and abundance of Steller sea lion prey, disease, toxins, killer whale predation, intentional and incidental (or illegal) killing of Steller sea lions, and regime shifts in the physical environment.
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From page 18... ...
Complex systems, by definition, are not amenable to simple description and analysis. Not only is the Steller sea lion situation complex, there is a dearth of information about both the ecosystem and the sea lions before and during the decline that could be used to reduce uncertainty about the cause or causes of the population decrease.
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From page 19... ...
While these legislative mandates approach protection from different perspectives, careful management of human use of living marine resources remains their overarching goal.
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From page 20... ...
On the basis of this information, the federal action agency (NMFS Office of Sustainable Fisheries) will determine whether or not to proceed with the proposed action (in this case the groundfish fishery in the Bering Sea/Aleutian Islands and the Gulf of Alaska (Figure 1.3~.
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From page 21... ...
they must be economically and technically feasible; and (4) they must be actions that the agency believes will ameliorate the original finding of jeopardy to the listed species or its habitat.
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From page 22... ...
The purpose of the biological opinion is to ascertain if the groundfish fisheries, as prosecuted under the fishery management plans, are likely to imperil the continued existence of Steller sea lions (and other listed species) or are likely to destroy or adversely modify critical habitat.
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From page 23... ...
NMFS released the revised biological opinion on November 30, 2000 (BiOp #3~. It concluded that Steller sea lion populations are jeopardized by the Alaska groundfish fisheries, including Atka mackerel, Pacific cod, and pollock, due to competition for prey and modification of prey distribution in critical habitat.
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From page 24... ...
In August 2001, NMFS released BiOp #4, which evaluates the new RPA measures and includes a supplemental environmental impact statement that compares the various RPA measures. NMFS concludes in BiOp #4 that the tune 2001 RPAs provide adequate protection for Steller sea lions with regard to the groundfish fisheries.
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From page 25... ...
Readers unfamiliar with Steller sea lion biology may prefer to consult the review of sea lion biology presented in Chapter 4 prior to reading the modeling discussion in Chapter 3. Chapter 5 describes the North Pacific commercial fisheries in reference to potential interactions with Steller sea lions.
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