A new publication in the journal Frontiers in Marine Science tracks West Indian manatee movements through nearshore and offshore ship channels in the north-central Gulf of Mexico. The publication, "Linking Use of Ship Channels by West Indian Manatees (Trichechus manatus) to Seasonal Migration and Habitat Use", provides new fundamental knowledge on movement ecology of a large, protected marine species and important information to guide future conservation practices.
The work synthesizes 10 years of data collected by researchers at the Dauphin Island Sea Lab from satellite tracking, citizen-sourced sightings, and environmental attributes linked to manatee movements.
During migration, manatees have the potential to travel through a wide range of channel types and are exposed to a diversity of vessel types, including recreational boats, shrimp trawlers, barges, and large container ships. By understanding manatee movement patterns, we can better aid risk assessment for vessel collision and other shipping related activities for migratory marine species globally.
"More and more manatees are coming up from Florida during the summer time and using these ship channels as travel corridors. This means there's more of a chance they'll cross paths with a vessel of some kind, which makes them more vulnerable to boat strikes," said post-doctoral researcher Carl Cloyed. "By knowing when they are using these channels the most, we can suggest the best times for channel maintenance and give recreational and commercial boaters a better idea of when they may encounter a manatee during the year."
Manatees travel in both nearshore boat channels (i.e. rivers, canals, and estuaries) and open water fairways (i.e. Mobile Bay Ship Channel), but were found to use nearshore channels more frequently. Satellite-tracked manatees swam faster and moved more directly in all channel types, indicating these channels as migratory and travel corridors. In estuaries and rivers, manatees traveled north and south, consistent with movement among foraging habitats and other essential resources.
The approach used in this study can be applied to a wider range of species among locations to help predict when and how marine megafauna use ship channels and to evaluate risks associated with channel use.
This work was supported by the National Science Foundation, the State of Alabama, and other independent agencies.
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About the Manatee Sighting Network:
The Dauphin Island Sea Lab's Manatee Sighting Network (DISL's MSN) is the only formal network to receive and track manatee sightings in the northern Gulf of Mexico. MSN research focuses on defining where manatees go and what they eat while visiting Alabama and surrounding waters. The network is dedicated to sharing data with other researchers, managers, and the public. MSN was founded in 2007 as a collaboration among researchers at the Dauphin Island Sea Lab and Sea to Shore Alliance in Florida. Since it started, the network has successfully processed more than 2,000 manatee sightings in Alabama and nearby waters. The program has processed additional sightings in each of the southeastern United States and now serves as the sighting clearinghouse from western Florida through Mississippi. MSN currently partners with the AL Marine Mammal Stranding Network, Sea to Shore Alliance in Florida, the Florida Fish and Wildlife Conservation Commission, USFWS, ADCNR, ALDWFF, the Mobile Bay NEP, the Northern Gulf Institute, and others. Report manatee sightings in Mississippi or Alabama by visiting manatee.disl.org, calling 1-866-493-5803 (toll-free), or emailing email@example.com. In Louisiana call, 1-800-442-2511. In Texas, call 1-800-9-MAMMAL.