Habitat Use and Movement of Tarpon In the Northern Gulf of Mexico

Abstract

Atlantic tarpon (Megalops atlanticus) are capable of long-distance migrations (hundreds of kilometers) but also exhibit resident behaviors in estuarine and coastal habitats. The aim of this study was to characterize essential habitat(s) and identify migration pathways of tarpon in the northern Gulf of Mexico. Habitat use by tarpon was investigated using gillnet data collected by Texas Parks and Wildlife Department (TPWD) over the past four decades. Generalized additive models (GAMs) were used to identify environmental factors that have a significant role in tarpon presence and assess temporal trends in the occurrence of tarpon in this region, which have increased over the past four decades. Adult tarpon caught off Texas and Louisiana were tagged with acoustic transmitters (n = 44) to characterize spatial and temporal trends in their movements and migrations, and two distinct migratory contingents were detected. Tarpon tagged west of the Mississippi River delta off Texas migrated south in the fall and winter into areas of south Texas and potentially into Mexico, while individuals tagged east of the delta migrated into Florida during the same time period, suggesting the presence of two unique migratory contingent or subpopulations in this region. An improved understanding of the habitat requirements and migratory patterns of tarpon inhabiting the Gulf of Mexico is critically needed by resource managers to assess the vulnerability of each stock to fishing pressure and guide multi-state and multi-national conservation efforts to rebuild and sustain tarpon populations.