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Manatee behavioral response to boats
Author(s) -
Rycyk Athena M.,
Deutsch Charles J.,
Barlas Margaret E.,
Hardy Stacie K.,
Frisch Katherine,
Leone Erin H.,
Nowacek Douglas P.
Publication year - 2018
Publication title -
marine mammal science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.723
H-Index - 78
eISSN - 1748-7692
pISSN - 0824-0469
DOI - 10.1111/mms.12491
Subject(s) - manatee , seagrass , home range , habitat , environmental science , geography , fishery , ecology , biology
The long‐term viability of the Florida manatee is threatened in part by mortality from boat collisions. This study investigated manatee behavior during boat approaches to better understand factors that lead to manatee–boat collisions. Digital acoustic recording tags (DTAGs) and Argos‐linked GPS tags were deployed on 18 manatees in southwest Florida, and boat traffic around them was mapped. Suites of manatee behavioral, environmental, and boat‐related factors were recorded during opportunistic boat passes. We built generalized linear mixed models to determine which factors accounted for variation in occurrence, number, and timing of manatee behavioral changes during boat passes. Manatees responded to boats, changing their orientation, depth, and fluking behavior most often when a boat approached closely (<10 m). Manatees were also more likely to change their depth when not on a seagrass bed and when actively fluking before a boat pass. Boat speed did not affect the occurrence or intensity of manatee response. Compared to fast approaches, however, slower passes allowed the manatee more time to respond, and behavioral change occurred earlier relative to the time of the boat's closest point of approach. We conclude that faster boats likely pose a greater risk of collision with manatees than do slower boats.