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.