Overestimating fish counts by non-instantaneous visual censuses: consequences for population and community descriptions.

ABSTRACT:

Background

Increasingly, underwater visual censuses (UVC) are used to assess fish populations. Several studies have demonstrated the effectiveness of protected areas for increasing fish abundance or provided insight into the natural abundance and structure of reef fish communities in remote areas. Recently, high apex predator densities (>100,000 individuals x km(-2)) and biomasses (>4 tonnes x ha(-1)) have been reported for some remote islands suggesting the occurrence of inverted trophic biomass pyramids. However, few studies have critically evaluated the methods used for sampling conspicuous and highly mobile fish such as sharks. Ideally, UVC are done instantaneously, however, researchers often count animals that enter the survey area after the survey has started, thus performing

SUBMITTER: Ward-Paige C 

PROVIDER: S-EPMC2908695 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature