Decadal-scale responses of larval fish assemblages to multiple ecosystem processes in the northern Gulf of Mexico

Abstract

Larval fish assemblages have been systematically sampled across the continental shelf of the northern Gulf of Mexico since the early 1980s. To date, these data have not been analyzed in terms of assemblage structure or variability, despite representing a highly valuable resource for examining decadal-scale change. In this study, multivariate statistical techniques were used to characterize temporal and spatial changes in abundances of the larvae of 20 common fish families from the early 1980s through to the late 2000s. The larvae of some pelagic and mesopelagic families showed marked increases in abundance over the survey time period, while the abundances of some benthic families decreased. Changes in assemblage structure were partially explained by changes in the Gulf of Mexico environment with respect to sea surface temperature and changes in shrimp trawling effort. Outflow from the Mississippi River was also influential on the interannual assemblage variability. However, the strong directional trends apparent in many family groups remained unexplained, and further research is required to discern the drivers of these patterns. © Inter-Research 2012.