SS1.10 Marine Protected Areas: Critical tools for Marine Biodiversity Conservation
Date: Monday, June 10, 2002
Time: 2:00:00 PM
Location: Esquimalt
WillisTJ, Leigh Marine Lab, University of Auckland, Warkworth, New Zealand,
The implementation of marine reserves has been frequently touted as a useful means for conservation of habitat, or a potential tool for replenishment of fished stocks. However, the most useful function they may serve is as undisturbed baselines for the study of ecological processes and the estimation of population parameters. No-take reserves provide the opportunity to determine the state of marine ecosystems in the absence of fishing. Specifically, they allow assessment of the effects of not fishing on the local density of exploited species. For example, traditional estimates of fishing mortality are obtained from historical catch records or from trawl survey data used to model stock dynamics and hence such estimates are made at the stock scale. Here, I use three coastal marine reserves to make direct estimates of fishing mortality of an intensively fished sparid (Pagrus auratus) that consists of (at least) two behavioural subsets: those exhibiting long-term site fidelity, and those that undertake seasonal onshore/offshore migrations. Fishing mortality was estimated by the difference in seasonal density increases between reserve and fished areas. These comparisons indicate that at local scales, fishing mortality may be as high as 97%.