Sea otter (Enhydra lutris) perspective: Part B. Food limitation and the recovery of sea otters following the Exxon Valdez oil spill

By: , and 
Edited by: Leslie E. Holland-Bartels

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Abstract

We examined the potential role of food limitation in constraining recovery of sea otters in Prince William Sound, Alaska, following the <i>Exxon Valdez</i> oil spill. The spill resulted in the removal of a large number of sea otters in 1989, and as of 1998, the portion of the population in the heavily oiled northern Knight Island region had not fully recovered. Between 1996 and 1998, prey consumption rate was higher and the condition of sea otters was better at northern Knight Island than in an unoiled area of the sound (Montague Island). Estimates of prey energy available per unit mass of sea otter were about 4 times higher at Knight than Montague Island, albeit not significantly different between the two areas. Over this same period, the number of sea otters remained constant at northern Knight Island but increased at Montague Island. These data suggest that food was at least as abundant at Knight than at Montague Island, and that recovery of sea otters via intrinsic population growth was limited by factors other than food. However, the availability of food, the prey consumption rate, and the condition of sea otters were all much lower at both Knight and Montague Islands than in areas newly occupied by sea otters where the population growth rate was near the theoretical maximum. It is possible that the relative short supply of food (compared to areas where sea otter population growth rate was high) may have inhibited immigration or interacted with other factors (e.g., oil-induced mortality or predation) to restrict sea otter population growth. Nonetheless, these data suggest that impacts of anthropogenic disturbances on large, often food-limited vertebrate predators can persist in spite of the availability of food resources that are sufficient for intrinsic population growth.

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Additional publication details

Publication type Report
Publication Subtype Other Report
Title Sea otter (Enhydra lutris) perspective: Part B. Food limitation and the recovery of sea otters following the Exxon Valdez oil spill
Chapter 3B
Year Published 2002
Language English
Publisher Exxon Valdez Oil Spill Trustee Council
Publisher location Anchorage, AK
Contributing office(s) Alaska Science Center
Description 30 p.
Larger Work Type Report
Larger Work Subtype Other Report
Larger Work Title Mechanisms of impact and potential recovery of nearshore vertebrate predators following the 1989 Exxon Valdez oil spill
First page 3B.1
Last page 3B.30
Country United States
State Alaska
Other Geospatial Prince William Sound
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