Assessing southern flounder ( Paralichthys lethostigma) long-term population trends in the northern Gulf of Mexico using time series analyses

Abstract

A long-term fisheries independent data set (1975–2008) was used to assess population trends of juvenile and adult southern flounder ( Paralichthys lethostigma) along the Texas coast in the northern Gulf of Mexico, USA. The dataset contained a total of 46,784 sites that were sampled with bag seines to monitor small nekton abundance and 22,870 sites that were sampled with gill nets to assess adult fisheries trends. These data were examined for age-specific population trends using generalized least squares and extended with non-parametric bootstrapping to obtain interval estimates of regression parameters (juveniles) and linear regression (adults). These data showed long-term declines in juvenile southern flounder abundance (1.3% per year). For adult southern flounder, rate of decline was much more rapid (2.5% per year). Results suggest that survival of post-juvenile flounder has decreased during the time series. This precipitous decline has prompted increasingly stricter harvest restrictions along the Texas coast. However, these management measures have been insufficient to curb declines.