Different surveys provide similar pictures of trends in a marine fish community but not of individual fish populations

摘要: Choice of sampling method and survey period can have an important impact on the perception structure dynamics ecological community. For Celtic Sea fish assemblage we compared data obtained by three different trawl surveys: autumn groundfish with a GOV trawl, spring survey, both carried out Portuguese high-headline trawl. Time-series abundance estimates were not consistent among surveys for all species generally very noisy. An analysis variance components showed that contributed more to in period, interannual variability, or even variance. Overall community assessments based indicators such as proportions non-commercial piscivorous species, proportion benthic similar trends series. The shape size spectrum abundances per length class summed over although stable time, was highly sensitive method. With exception spectra, marine assemblages monitored seem be robust trawling gear, but are dependent.