Atlantic tarpon (Megalops atlanticus) nursery habitats: evaluation of habitat quality and broad-scale habitat identification

Abstract

Coastal habitats are threatened worldwide by habitat loss and degradation. These habitats play a crucial role as fish nurseries. Unfortunately, it is difficult to determine the impact of habitat degradation for many species because data are lacking on early life history metrics including growth (0.07 ± 0.04 SE mm/day in this study), survival (apparent annual survival 0.007 (95% CI: 0.001–0.033 in this study), emigration (27% in this study) and the spatial extent and condition of these habitats. The juvenile life stage of Atlantic tarpon (Megalops atlanticus), an economically important species in the Caribbean, sub-tropical and tropical Atlantic, and Gulf of Mexico, depends upon wetlands and marshes. A mark-recapture study designed to measure juvenile tarpon growth in an altered mangrove habitat in Florida (USA) found that juvenile tarpon exhibited slow growth and emigrated at small sizes. The low scores on these metrics, in combination with a broad knowledge gap on the extent and condition of juvenile tarpon habitats in Florida, caused concern about the conservation prospects for tarpon and the fishery it supports. To provide information necessary to formulating an effective conservation plan for tarpon, we used citizen science to identify juvenile tarpon habitats and to characterize them as natural or altered (a first-level measure of direct, physical habitat change). A comparison of angler reports and habitat assessments with scientific field assessments showed that using anglers is an efficient and effective means of identifying juvenile tarpon habitats and providing a first-level assessment of habitat condition. This study provides a baseline for ongoing and future habitat conservation and restoration efforts for juvenile tarpon and other species that also use these habitats as nurseries.