Institute for Marine Mammal Studies Gulfport

Mississippi, Mississippi, United States

Institute for Marine Mammal Studies Gulfport

Mississippi, Mississippi, United States
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Coleman A.T.,Institute for Marine Mammal Studies Gulfport | Pitchford J.L.,Institute for Marine Mammal Studies Gulfport | Bailey H.,Chesapeake Biological Laborartory UMCES Solomons | Solangi M.,Institute for Marine Mammal Studies Gulfport
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2016

Seasonal movements and core habitat areas of immature Kemp's ridley sea turtles (Lepidochelys kempii) in the northern Gulf of Mexico were tracked via satellite telemetry. Tagged turtles were incidentally captured by recreational fishermen and rehabilitated at the Institute for Marine Mammal Studies in Gulfport, Mississippi. The average size of the core habitat areas (50% KDE (kernel density estimation)) was 1660.2km2±3438.2 SD. Turtles displayed strong intra- and inter-annual site fidelity to the Mississippi Sound during the spring, summer, and autumn months. During the winter months, most turtles, probably influenced by water temperatures, migrated to nearshore waters of Louisiana on either side of the Mississippi River Delta. However, other migration strategies were also observed. Overall, these data indicate that the Mississippi Sound is an important developmental habitat for this critically endangered species. In addition, their wintering grounds in Louisiana are utilized by adult Kemp's ridleys and other sea turtle species as foraging grounds and migratory corridors. The high use of these areas by sea turtle populations increases the potential for negative impacts from anthropogenic disturbances (e.g. shrimp trawling, oil production, hypoxia) that occur there. © 2016 John Wiley & Sons, Ltd.


Pitchford J.L.,Institute for Marine Mammal Studies Gulfport | Howard V.A.,Institute for Marine Mammal Studies Gulfport | Shelley J.K.,Institute for Marine Mammal Studies Gulfport | Serafin B.J.S.,Institute for Marine Mammal Studies Gulfport | And 2 more authors.
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2015

Spatial distribution models (SDMs) have been useful for improving management of species of concern in many areas. This study was designed to model the spatial distribution of bottlenose dolphins among seasons of the year in the Mississippi Sound within the northern Gulf of Mexico. Models were constructed by integrating presence locations of dolphins acquired from line-transect sampling from 2011-2013 with maps of environmental conditions for the region to generate a likelihood of dolphin occurrence for winter (January-March), spring (April-June), summer (July-September), and autumn (October-December) using maximum entropy. Models were successfully generated using the program MaxEnt and had high predictive capacity for all seasons (AUC (area under curve) > 0.8). Distinct seasonal shifts in spatial distribution were evident including increased predicted occurrence in deepwater habitats during the winter, limited predicted occurrence in the western Mississippi Sound in winter and spring, widespread predicted occurrence over the entire region during summer, and a distinct westward shift of predicted occurrence in autumn. The most important environmental predictors used in SDMs were distance to shore, salinity, and nitrates, but variable importance differed considerably among seasons. Geographic shifts in predicted occurrence probably reflect both direct effects of changing environmental conditions and subsequent changes in prey availability and foraging efficiency. Overall, seasonal models helped to identify preferred habitats for dolphins among seasons of the year and can be used to inform management of this protected species in the northern Gulf of Mexico. © 2015 John Wiley & Sons, Ltd.

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