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Bioenergetic and Economic Impacts of...

Chenoweth, Ellen M.

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Bioenergetic and Economic Impacts of Humpback Whale Depredation at Salmon Hatchery Release Sites.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Bioenergetic and Economic Impacts of Humpback Whale Depredation at Salmon Hatchery Release Sites./
作者:	Chenoweth, Ellen M.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2018,
面頁冊數:	164 p.
附註:	Source: Dissertations Abstracts International, Volume: 80-02, Section: B.
Contained By:	Dissertations Abstracts International80-02B.
標題:	Ecology. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10840955
ISBN:	9780438274594

Bioenergetic and Economic Impacts of Humpback Whale Depredation at Salmon Hatchery Release Sites.
Chenoweth, Ellen M.

Bioenergetic and Economic Impacts of Humpback Whale Depredation at Salmon Hatchery Release Sites. - Ann Arbor : ProQuest Dissertations & Theses, 2018 - 164 p.

Source: Dissertations Abstracts International, Volume: 80-02, Section: B.

Thesis (Ph.D.)--University of Alaska Fairbanks, 2018.

This item must not be sold to any third party vendors.

Since 2008, humpback whales have been documented depredating hatchery-produced juvenile salmon, a novel prey, at points of their release in Southeast Alaska. The objectives of this dissertation are to determine the spatial distribution, seasonal distribution, and frequency of humpback whale foraging at release sites, determine whether whale presence is affecting the economic productivity of hatchery operations, and compare the bioenergetic benefits for whales feeding on juvenile salmon at hatchery release sites relative to typical prey. Five hatchery release sites were monitored over six years during the spring release season for whale presence/absence, numbers, and behaviors. Linear models were used to determine that for coho salmon, cohorts with frequent humpback whale presence had lower marine survival than cohorts with less or no humpback whale presence, but this was not seen for chum or Chinook salmon. Over six years, these sites lost an estimated 23% of revenue from coho salmon totaling almost a million dollars per year in addition to increased rearing costs to mitigate whale predation. A process model was developed to compare the net energy gain for humpback whales foraging on krill, herring and juvenile salmon. Whales were found to feed profitably on krill and chum salmon where they occurred in dense enough distributions and on herring when large coordinated groups impeded the escape of prey. Coho salmon typically distributed too diffusely for humpback whales to recuperate the full energetic costs of engulfment, indicating that behaviors such as bubble net feeding may be essential for increasing prey aggregation to an energetically profitable level, or humpback whales may be feeding to mitigate energetic losses. As intraspecific competition increases due to recovery and or changes to prey resources, generalist humpback whales may expand feeding to exploit new and less profitable prey resources.

ISBN: 9780438274594Subjects--Topical Terms:

516476
Ecology.

Bioenergetic and Economic Impacts of Humpback Whale Depredation at Salmon Hatchery Release Sites.
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