Squid catches (Mollusca: Cephalopoda) by industrialfishing landed in Santos: comparison after 4 decades.

Abstract

Analysis of the temporal variation of fishery resources’ landed catch is essential to monitor changes and alterations inthe fisheries and related aquatic ecosystems. Thus, analyzing catches after 4 decades represents a comparisonbetween an initial industrial fishing off Southeastern Brazil and a present exploitation phase, considered as decline, andis particularly uncommon due to the atypical data availability. Through the analysis of 1959 and 1999 Santos landing data,this study aims to identify: (a) fleets and gears where squids occurred, with related proportions, (b) differences in thesquid’s fishery between the two periods, and (c) squids fishing grounds used by the industrial fleets in both periods.Squids were caught by pink-shrimp bottom-trawlers, but also occurred in the sea-bob shrimp fleet, pair-bottom trawlersand purse-seiners, especially in 1959. Differences between both periods can be clearly seen. In 1959, squid fishingareas were more restricted and in lower depths, and in 1999, the areas were broader and deeper. The decrease offishing boats, and the significant increase of squids catch volume can be verified, where its relative abundance (kg/tow)was 400 times greater in 1999, showing a great availability increase of those resources in the later period or differenceson exploitation technology between periods. The existence of both “bottom-up” control mechanism (oceanographicvariation-recruitment-fishery production) within the fishery ecosystem, and “top-down” control (fishermen-fisheries-structure of marine communities) should be taken into account in the interpretation on the squids abundance variation.