Age, growth, and biomass projections of red porgy Pagrus pagrus (Teleostei, Sparidae) after the fishery collapse in southern Brazil

Abstract

A formerly unexploited stock of red porgy that was intensely fished along southern Brazil in the 1970s collapsed in less than a decade. Subsequently, population dynamics or stock status has not been reported, so we updated growth parameters by analysis of otolith annual‐increments and micro‐increments. Growth did not change after the stock collapsed, which suggested no density‐dependent effect. Given the lack of growth changes and data‐limitation, we used an age‐structured assessment model set until 1984 to forecast relative spawning biomass and assess recovery possibilities. Projections showed that a 19 years moratorium would have been necessary for the stock to rebuild. The model suggested an annual catch of at least 170 t in the post‐collapse period because the stock did not recover, and a small‐scale hand‐line fishery with unreported landings continued fishing. Our results reinforced the need for more curated and up‐to‐date data collection to properly assess and manage this formerly abundant stock.