Studies of the West Indian Manatee: Anna Maria to Venice (Florida)
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Authors
Kreckman, Todd A.
Issue Date
1988
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
West Indian manatees (Trichechus manatus) typically depart
the waters extending from Anna Maria Island, Florida, to Venice,
Florida, when the water temperature reaches 16º C and return in
the spring when the water temperature rises in the bays of this
area. Attempts to accurately determine the population size and
distribution of these animals have only recently been initiated
(Hartman, 1984). Three manatee programs using aerial surveys
conducted in the study area during the 1970's compiled non-winter
sightings of only twenty animals. Twenty-five flights averaged
21.5 manatee sightings (n=314) per survey in 1985 (Patton, 1985).
From January-December 1985, 138 sighting events occurred in 81
hours of active surveying; manatees were sighted in groups of 1-12 animals, of which 8% were calves. Continued studies were
needed to provide data for determination of the stability and
actual size of this manatee population. The present study is
intended as a follow-up to the 1985 Patton study prepared for the
Florida Department of Natural Resources. Twenty flights from
March-December 1986 averaged sightings of 13.5 animals (n=269)
per survey. In 95 hours of active surveying 136 sighting events
were recorded. Numbers of manatees in each sighting event ranged
from 1-10 animals; 6.7% were calves. The decrease in the average
number of manatees seen per flight from the 1985 study to the
1986 study may be a result of poorer sighting conditions
experienced in 1986, but a reduction in the number of large
groups (mating herds) may be a significant factor. Five areas of
regular or recurring non-winter sightings identified in 1985 were
comparably important in 1986: the southeast corner of Anna Maria
sound; a large area between Tidy Island and Longboat Pass; the
Buttonwood Harbor area; inside Midnight Pass; and the Roberts
Bay, situated east of Siesta Key.
Description
v, 52 p.
Citation
Publisher
Kalamazoo College
License
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