Status of white croaker Micropogonias furnieri exploited in southern Brazil according to alternative hypotheses of stock discreetness

The exploitation status of white croaker Micropogonias furnieri in southern Brazil is assessed using a production model constructed according to three hypotheses of stock discreetness: an isolated stock in southern Brazil; a straddling stock shared between Brazil and Uruguay; and a straddling stock shared among Brazil, Uruguay and Argentina. Estimates of virgin stock size and maximum sustainable yield were more sensitive to the hypothesis assumed correct, the posterior means varying respectively from 177,648 to 1,007,256 tonnes and from 7459 to 38,677 tonnes. Estimates of stock status in relation to management reference points were more robust to the uncertainties in stock discreetness and indicate that the species in currently overfished (biomass at 60% of Bmsy) and under heavy overfishing (F between approximately 2 and 6 times higher than Fmsy). Results suggest that the relative stability of catches in the region occurs at the expense of a steady decline in stock abundance and that concerted management actions by the three countries are needed to bring the stock to safer levels of exploitation.