Population dynamics of Pacific herring and humpback whales, Sitka Sound, Alaska 1981-2011
Dissertation (Ph.D.) University of Alaska Fairbanks, 2015 Humpback whales are a major predator in Sitka Sound, possibly consuming as much as a half-ton of Pacific herring per day. These large migratory baleen whales congregate in Sitka Sound to feed on schools of Pacific herring which spawn in April...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/6099 2023-05-15T15:37:12+02:00 Population dynamics of Pacific herring and humpback whales, Sitka Sound, Alaska 1981-2011 Liddle, Joseph B. Quinn, Terrance II Hillgruber, Nicola Adkison, Milo Straley, Janice 2015-08 http://hdl.handle.net/11122/6099 en_US eng http://hdl.handle.net/11122/6099 Graduate Program in Fisheries Dissertation phd 2015 ftunivalaska 2023-02-23T21:36:34Z Dissertation (Ph.D.) University of Alaska Fairbanks, 2015 Humpback whales are a major predator in Sitka Sound, possibly consuming as much as a half-ton of Pacific herring per day. These large migratory baleen whales congregate in Sitka Sound to feed on schools of Pacific herring which spawn in April. In recent decades humpback whale abundance has increased tremendously in Sitka Sound after recovering from near extinction due to commercial whaling. In order to assess the long-term impact on herring by humpback whales, I estimated humpback whale abundance from 1981 to 2011. To do so I developed a Bayesian mark-recapture method for small sample sizes. I also modified a multi-strata Hilborn model to account for sporadic availability of whales in Sitka Sound. The multi-million dollar sac roe fishery in Sitka Sound is managed by the Alaska Department of Fish and Game (ADF&G) with an Age-Structured Assessment model (ASA). I modified the standard ASA model by including the humpback whale abundance estimates as a covariate for herring natural mortality. I found that there is no significant effect of humpback whales on herring mortality. In fact, both Pacific herring and humpback whale abundance have increased together, reaching their maximum values in 2011. This suggests that some other factor, perhaps better marine survival for both species, is driving their upwards trend. Doctoral or Postdoctoral Thesis baleen whales Humpback Whale Alaska University of Alaska: ScholarWorks@UA Fairbanks Pacific |
institution |
Open Polar |
collection |
University of Alaska: ScholarWorks@UA |
op_collection_id |
ftunivalaska |
language |
English |
description |
Dissertation (Ph.D.) University of Alaska Fairbanks, 2015 Humpback whales are a major predator in Sitka Sound, possibly consuming as much as a half-ton of Pacific herring per day. These large migratory baleen whales congregate in Sitka Sound to feed on schools of Pacific herring which spawn in April. In recent decades humpback whale abundance has increased tremendously in Sitka Sound after recovering from near extinction due to commercial whaling. In order to assess the long-term impact on herring by humpback whales, I estimated humpback whale abundance from 1981 to 2011. To do so I developed a Bayesian mark-recapture method for small sample sizes. I also modified a multi-strata Hilborn model to account for sporadic availability of whales in Sitka Sound. The multi-million dollar sac roe fishery in Sitka Sound is managed by the Alaska Department of Fish and Game (ADF&G) with an Age-Structured Assessment model (ASA). I modified the standard ASA model by including the humpback whale abundance estimates as a covariate for herring natural mortality. I found that there is no significant effect of humpback whales on herring mortality. In fact, both Pacific herring and humpback whale abundance have increased together, reaching their maximum values in 2011. This suggests that some other factor, perhaps better marine survival for both species, is driving their upwards trend. |
author2 |
Quinn, Terrance II Hillgruber, Nicola Adkison, Milo Straley, Janice |
format |
Doctoral or Postdoctoral Thesis |
author |
Liddle, Joseph B. |
spellingShingle |
Liddle, Joseph B. Population dynamics of Pacific herring and humpback whales, Sitka Sound, Alaska 1981-2011 |
author_facet |
Liddle, Joseph B. |
author_sort |
Liddle, Joseph B. |
title |
Population dynamics of Pacific herring and humpback whales, Sitka Sound, Alaska 1981-2011 |
title_short |
Population dynamics of Pacific herring and humpback whales, Sitka Sound, Alaska 1981-2011 |
title_full |
Population dynamics of Pacific herring and humpback whales, Sitka Sound, Alaska 1981-2011 |
title_fullStr |
Population dynamics of Pacific herring and humpback whales, Sitka Sound, Alaska 1981-2011 |
title_full_unstemmed |
Population dynamics of Pacific herring and humpback whales, Sitka Sound, Alaska 1981-2011 |
title_sort |
population dynamics of pacific herring and humpback whales, sitka sound, alaska 1981-2011 |
publishDate |
2015 |
url |
http://hdl.handle.net/11122/6099 |
geographic |
Fairbanks Pacific |
geographic_facet |
Fairbanks Pacific |
genre |
baleen whales Humpback Whale Alaska |
genre_facet |
baleen whales Humpback Whale Alaska |
op_relation |
http://hdl.handle.net/11122/6099 Graduate Program in Fisheries |
_version_ |
1766367658110877696 |