Manatee response to boating activity in a thermal refuge

Thermal refuges are important for the endangered Florida manatee (Trichechu s manatus latirostris) during winter cold periods in temperate latitudes. H owever, little research has examined impacts on manatees from human disturb ance during these critical periods. We studied the effect of recreational b oating activity on manatee use of established sanctuaries in the natural th ermal refuge created by warm-water springs in Kings Bay, Crystal River, Flo rida. We examined the relationship among manatee use of the study area and sanctuaries, temperature, and level of boating activity. Manatees continued to use the Bay regardless of the number of boats present; however, their u se of sanctuaries in the southern portion of the Bay increased (P<0.001) as number of boats increased. Temperature, as expected, was inversely related to manatee use of the study area. Human activity patterns were variable, w ith significantly greater numbers of boats in the study area on weekends (( x) over bar=32.7, SE=2.71) than on weekdays ((x) over bar=10.7, SE=1.23). W e concluded that recreational boating influenced manatee distribution, sanc tuaries are important to manatees in Kings Bay, and sanctuaries are an effe ctive management tool to reduce the impact of boating activities on manatee s.