Past Awards

FY 2005 | 1 – Understand | 5/10/07

Biological Monitoring of Spring Zooplankton and Nekton in PWS

Richard Thorne, Prince William Sound Science Center
Contract Term: 1/1/05-12/31/05
Award: $75,000

Scope of Work:

Publications: Assessment of the Spring Zooplankton and Nekton in Prince William Sound 2005, R. E. Thorne

Deliverables: quarterly and annual reports

Project Summary: Studies had shown that juvenile pink salmon survival depends on available food supply, primarily the large-bodied copepods of the genus Neocalanus and levels of predators, especially walleye Pollock. The overall goal of this project was to develop and apply a cost effective approach to estimation of the pink salmon food supply and predator abundance.

The project was initiated in spring of 2000 and has consisted of three surveys between the latter half of April and early June, a period anticipated to encompass the Neocalanus spring bloom and early marine entry of juvenile pink salmon. The surveys simultaneously assess the abundance of zooplankton production and timing. Results from the early years of the program have verified the effectiveness of the assessment system for both the large-bodied copepods and the predator fishes and have shown that pink salmon returns are impacted by the supply of large-bodied copepods. In addition, the study has confirmed hypotheses from previous research that the fishes, mainly Pollock and herring, switch from feeding on zooplankton to feeding on juvenile fish when large copepod abundance drops below 10g/m2.

One objective will be to obtain long-term support for the assessment program and to recruit and train personnel for future assessments.


Download Report: 05-10-0712.pdf