Full document / COSOC-W-86-002 - the National Sea Grant Library

In Louisiana, a computer simulation of a commercial alligator
harvest yieldod that proportional hunting rates (taking animals in
proportion to thoir relative abundance) would be more productive than
differential hunting (taking only certain size classes) In sustained
yield management (Nichols ot al., 1976). A night count on Rockefeller
Wildlife Refuge, in Louisiana, indicated the following size
distribution of the resident alligator population: 43.8% were 1.8 m long
(Chabreck, 1966; Nichols et al., 1976). Yet the commercial harvests in
Louisiana from 1972 to 1977, using daylight techniques, yielded an
average 26.7% from 1.2 - 1.8 m long and 73.3% >1.8 m long (Joanen and
McNease, 1980). Of the daylight techniques allowed during Louisiana's
fall season, shooting is seldom used and results in taking more smaller
alligators. Fishing tends to be much more bias toward the larger
animals and accounts for the high percentage of the alligators >1.8 m
long in the harvest (Palmisano et al., 1973). Increased use of
shooting would result in a greater harvest of smaller animals and would
make the size ratios more proportional to that in the population
(Nichols et al., 1976). Many subadults and juveniles arc in the marsh
and not in open water bodies and would ba loss frequently encountered
when hunting is done in the fall. A possible alternative for
correcting the size ratio problem might be to open a short spring
season, when the subadults are still active in the deeper water. Night
hunting methods might also be used In addition to a daylight program by
issuing to certain hunters or landowners "small-alligator" tags and
permitting them to use night methods (D. Taylor, pers. coranun.).
Hunting alligators at night by boat is a more selective harvest
method than setting fishing hooks. Eyeshine is an efficient method of
locating alligators; and, since snout length is related to total
length, size can be easily estimated (Chabreck, 1963; Dodson, 1975).
Therefore, night hunting is more flexible in achieving proportional
size ratios in tho kill. During the 1981 Florida commercial harvest,
only IS.3% of the kill was over 1.2 m. which was more proportional to
the size structure of natlvo alligator populations than the Louisiana
harvest (FGFC, 1982).
When dealing with nuisanco alligator control, the harvest size
ratio must be proportional to the size ratios received in the
complaints. In Louisiana, 7% of the nuisance alligator complaints in
1975 were of animals from 0.3 to 0.6 m, 60% were from 0.6 to 1.8 a and
only 33% of animals >1.8 n (Linscombe, 1976). During 1978, 12.5% of
those harvested in the Florida nuisance program were over 3.2 n long,
indicating that many of tho reported human/alligator confrontations
wore with very large animals (Hlnes and Woodard, 1980). The diversity
In size ratios in complaints of nuisance alligators points out a need
for flexibility in removing the specific nuisanco animals. Night
hunting has been shown to be the mora selective and provides less
public exposure than fishing, and so would probably be best suited for
taking most nuisance animals. However, cartain nuisance alligators may
become "light shy" and fishing may ba tho only logical removal method.
Night hunting methods are used in the Florida nuisance program, and tho
amount of complaints has decreased since the beginning of the statewide
program in 1978. This decrease has been attributed to water level
variations and to the fact that many of the "long-standing" nuisance
alligators ware dispatched in the beginning years of the program (Hinos
787