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AFSC Seminar Series No. 9
 


Scheduled Seminars

Subject: Fish ecology plays a key role in understanding the potential for commercial fishing to impact prey fields of endangered Steller sea lions

Speaker: Libby Logerwell, Interaction Team (FIT), REFM Division
When: Friday, 19 May 2006, 10:00 am
Where: Bldg. 4, Traynor Seminar Room, Rm. 2076,  AFSC, Sand Point Campus, Seattle, Washington

Dear Colleagues,

Libby Logerwell from AFSC Sand Point is our next speaker. A Seattle native and expert in the North Pacific and Alaska aquatic ecosystems, Libby joined AFSC in 2001 and currently leads the Fisheries Interaction Team (FIT) - “a cozy group of six researchers (give or take a post-doc or intern)” in the Status of Stocks and Multispecies Assessment Program, REFM Division.

FIT was formed in 2000 to study the potential conflict between Steller sea lions and commercial fisheries, but its research interests extend beyond sea lions into all the ways that fishing interacts with the local ecology of fished populations. Please join us at the seminar to discover the intrigues behind that fortunate acronym.

The seminar will be transmitted live to Auke Bay and Newport (BF201) Labs, and recorded on tape/disk.

Fish ecology plays a key role in understanding the potential for commercial fishing to impact prey fields of endangered Steller sea lions

Libby Logerwell et al
Fisheries Interaction Team (FIT), REFM
Seattle, Washington
Libby.Logerwell@noaa.gov

Abstract:

The Fishery Interaction Team (FIT) at the Alaska Fisheries Science Center (National Marine Fisheries Service, USA) was formed in 2000 to investigate the potential ecosystem effects of commercial fishing. FIT researchers are presently interested in interactions between commercial fisheries and endangered Steller sea lions.

The objectives of our current research projects are to: 1) test the hypothesis that commercial fishing results in localized depletion or disruption of sea lion prey fields, and 2) evaluate the efficacy of trawl exclusion zones designed to mitigate competition between commercial fishing and sea lions. The research activities of FIT currently focus on three commercially fished groundfish species in Alaska: Pacific cod, Atka mackerel and walleye pollock.

To investigate whether fishing impacts prey fields, we conducted at-sea experiments that used a before-after, treatment-control type design to compare the change in fish abundance within heavily-trawled areas during the fishing season to the change within adjacent no-trawl zones. These studies focused on Pacific cod and walleye pollock. To evaluate the efficacy of trawl exclusion zones at maintaining sufficient quantities of prey for sea lions, we used tag release-recovery methods to estimate local fish abundance and movement rates inside and outside the zones. This study focused on Atka mackerel. In addition, fish food habits, reproductive biology and pelagic habitat selection were studied during field research experiments.

Results to date indicate that fish ecology (movement, feeding, habitat selection and reproduction) plays an important role in understanding the potential for commercial fishing to cause localized depletions of fish. Fish ecology is also key to assessing the role of trawl exclusion zones at maintaining local concentrations of fish for foraging sea lions.


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