Case Studies: A Closer Look
Bluefin Tuna
Bluefin tuna’s essential habitat lies in the northern Gulf of Mexico, from southern Texas across to the Florida Keys. Within this habitat, the main occurrence hotspots are in the western Gulf, south of the Louisiana-Texas continental shelf. Adult bluefin migrate here to spawn every year. The most important portion of this migratory pathway is around the tip of Florida, but another critical portion of the pathway exists between the Yucatan Peninsula and the mouth of the Mississippi River. The most severe threats to bluefin tuna in the Gulf are in the northeast, just south of the Florida Panhandle, and on the northwest coast of Cuba—areas that align with critical habitats and migratory corridors. These locations should be managed more carefully to reduce the present threats to bluefin tuna habitats and migrations.
Green Sea Turtle
Green sea turtles have clear migratory corridors along the coastlines of the Gulf, as well as south of Cuba near the Yucatan Peninsula. The portion of the pathway between south Florida and the northern Yucatan Peninsula is the most densely traveled. Major threats to sea turtles are present halfway along the route, in the middle of this major corridor, and likely interfere with their migration. Planning of coastal and marine activities in this region should carefully consider impacts on green sea turtle migration when regulating human activity.
Sperm Whale
Sperm whale habitat largely consists of the northwest Gulf of Mexico. A clear pathway between southern Texas and the mouth of the Mississippi River sustains the semi-resident population in the Gulf. The bulk of available sperm whale animal tracking data is biased toward the northern Gulf; there is much less migration data available for areas near Mexico and Cuba. Because of that, there may be migration pathways in the southern Gulf that simply cannot be analyzed now.
Nevertheless, all data shows the northern Gulf migration pathway is densely traveled. It is also threatened by a shipping lane that intersects it and leads to the Port of Houston. This location should be a conservation priority for sperm whales, and shipping vessels should take extra precautions not to disrupt the species’ migration.
Wood Thrush
Wood thrushes migrate regularly between the northern U.S. and Central America using two major pathways. They fly south in the fall across the East Coast through Florida and return north across the Gulf and through the southeastern United States. Threats to these birds include tall buildings and towers, which are plentiful in Florida throughout the fall migratory pathway and in Louisiana and Mississippi throughout the spring pathway. Cities within these migratory pathways should be marked as conservation priorities for the wood thrush.