Trawl Fishing Fleet Operations Used to Illustrate the Life Cycle of the Southern Brown Shrimp: Insights to Management and Sustainable Fisheries

The purpose of this study was to better understand the life cycle of brown shrimp along the Amazon Continental Shelf by using spatial and temporal trawl fleet activities. A total of 208,121 specimens and 1281 trawls were studied throughout the course of 13 years of shrimp size composition. To investigate differences in length composition between fishing grounds, months, and depth, a PERMANOVA analysis was employed. A geographic information system was developed for environmental characterisation and spatiotemporal trawl fleet distribution. Our findings show that the industrial trawl shrimp fleet has a close relationship with shrimp biological characteristics, following shrimp migration patterns in different months, locations, and depths during different stages of their life cycle, and that this fleet acts on two-yearly cohorts. The management measures of limiting effort (number of vessels) appear enough to avoid overcapitalisation, but the closed period and a proposed no-take fishing zone appear insufficient for what was originally proposed. Ecosystem-based management strategies should be addressed immediately because they would be far more effective than traditional fishery-based management measures in promoting sustainable fishing.

Automated summary

The purpose of this study was to understand the life cycle of brown shrimp along the Amazon Continental Shelf by studying the spatial and temporal trawl fleet activities. The findings suggest that the industrial trawl shrimp fleet closely follows shrimp migration patterns during different stages of their life cycle in terms of months, locations, and depths.