ESR 32:321-332 (2017)  -  DOI: https://doi.org/10.3354/esr00817

Sighting demographics of the West Indian manatee Trichechus manatus in the north-central Gulf of Mexico supported by citizen-sourced data

Elizabeth E. Hieb1,*, Ruth H. Carmichael1,2, Allen Aven1,2, Courtney Nelson-Seely1, Nicole Taylor1

1Dauphin Island Sea Lab, Dauphin Island, Alabama 36528, USA
2University of South Alabama, Mobile, Alabama 36688, USA
*Corresponding author:

ABSTRACT: Traditional research methods are often limited in their ability to capture broad spatial and temporal changes in species distribution that affect global patterns of biodiversity. To provide range-wide demographic data needed to quantify and evaluate changes in habitat use and support ongoing recovery efforts for the endangered West Indian manatee Trichechus manatus, we analyzed data from a formal manatee sighting network that uses citizen-sourced data for the understudied north-central Gulf of Mexico region. Although historically considered to be outside manatees’ typical US range, more than 1700 opportunistic, publicly reported manatee sightings and 23 mortalities have been documented in Alabama and Mississippi since the early 1900s. Live manatee sightings have occurred primarily during warmer months in rivers and subembayments. Manatee mortalities have significantly increased since the mid-1980s and have most often been attributed to cold stress, with 2 known mortalities due to vessel strikes in recent years. Sightings of individual manatees were most common, but group sizes of up to 17 were reported, typically in late summer. Decadal-scale trends in opportunistic sighting records demonstrate persistent spatial and temporal patterns of manatee occurrence in the north-central Gulf of Mexico and suggest greater use and importance of the region as seasonal manatee habitat than previously documented. If applied appropriately, citizen-sourced data have the potential to enhance targeted research efforts, significantly contribute to ecological datasets for a number of species, and provide a useful tool to enhance conservation and management.


KEY WORDS: Manatee · Gulf of Mexico · Distribution · Citizen science · Opportunistic data


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Cite this article as: Hieb EE, Carmichael RH, Aven A, Nelson‑Seely C, Taylor N (2017) Sighting demographics of the West Indian manatee Trichechus manatus in the north-central Gulf of Mexico supported by citizen-sourced data. Endang Species Res 32:321-332. https://doi.org/10.3354/esr00817

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