Acoustic assessment of trophic dominance in a marine ecosystem

R. E. Thorne, G. L. Thomas

Research output: Contribution to journalConference article

Abstract

The results from sixteen years of acoustic surveys suggest that Prince William Sound (PWS), Alaska, functions as a wasp-waist ecosystem. The planktivorous fishes that dominate the wasp waist are Pacific herring (10-100 thousand tons) and walleye pollock (10-50 thousand tons). The dominant macrozooplankton prey are the large-bodied copepods (Neocalanus spps., 50 thousand tons), and comparable sized abundances of pteropods, and euphausids, which are also the primary forage of juvenile fishes such as pink salmon. The herring and pollock consume the bulk of the spring macrozooplankton, so they are major competitors as well as predators of juvenile fishes. Their individual abundances also affect the composition and production of the top piscivores in the ecosystem. The near-shore and near-surface distribution of herring in the winter makes them the most available forage for surface-oriented marine mammal and seabird predators. In contrast, the deep, off-shore distribution of pollock favours large benthic predators, such as arrowtooth flounder and large sharks. The acoustic surveys demonstrated that high abundance of copepods, pteropods, and euphausids distract the wasp-waist fishes in the spring, creating possible loopholes in predation for nearshore juvenile fishes like pink salmon, allowing them to have a successful recruitment year. An additional outcome of the long-term database on Pacific herring was the discovery of linkages between the 1989 "Exxon Valdez" oil spill and a subsequent collapse of the herring along with associated predators.

Original languageEnglish (US)
Pages (from-to)729-734
Number of pages6
JournalProceedings - European Conference on Noise Control
StatePublished - Dec 1 2008
Event7th European Conference on Noise Control 2008, EURONOISE 2008 - Paris, France
Duration: Jun 29 2008Jul 4 2008

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ASJC Scopus subject areas

  • Acoustics and Ultrasonics
  • Public Health, Environmental and Occupational Health
  • Building and Construction
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Automotive Engineering
  • Aerospace Engineering

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