MARINE MAMMAL COMMISSION - Annual Report for 1995 



In May 1995 both orphaned calves were released. 

 One that was originally captured in the St. Johns 

 River was tagged and released directly back into the 

 St. Johns River. He was tracked until late September, 

 when the tag fell off. He appeared to be adapting 

 well, but had not been resighted at the river's major 

 warm-water refuge, Blue Spring, as of the end of 

 1995. The second orphaned animal was released 

 through the soft-release pen on 1 June with an older 

 animal captured for rehabilitation early in 1995. The 

 second orphaned animal was also tagged and appeared 

 to be adapting well as of the end of 1995. In mid- 

 January 1996, however, he was struck by a boat and 

 killed in a high-traffic canal near the release pen. 



After these animals were released, three other 

 long-term captive animals were introduced into the 

 pen in early June. Because of weight loss and some 

 blood chemistry analyses suggesting possible dehydra- 

 tion, the animals were not released but instead were 

 returned to their respective captive facilities late in 

 June. In mid-July 1995 three other animals, all born 

 in captivity since 1990, were introduced into the soft- 

 release pen. By early in August, all three appeared to 

 be ajusting well, and they were released together late 

 in August. In mid-November, however, one of the 

 three was struck by a boat and killed in Biscayne Bay 

 in southeastern Florida. A second animal was tracked 

 through 1995 but was recaptured at a warm-water 

 refuge on 3 January 1996 because he appeared to be 

 underweight and disoriented, swimming in tight 

 circles. Upon examination, he was found to be 

 emaciated and to have ingested some debris, but he 

 soon began eating normally and is being maintained in 

 captivity. Subsequently, the third animal was recap- 

 tured in a severely emaciated condition and died 

 during transport to a rehabilitation facility. 



In review, of the four young manatees raised in 

 captivity and released through the soft-release pen in 

 1995, one was recaptured in poor condition and 

 recovered, one was recaptured in very poor condition 

 and died, and two appeared to have been adjusting 

 well but were struck and killed by boats. The status 

 of the fifth animal raised in captivity and released 

 directly into the St. Johns River is uncertain. He may 

 be using one of the area's small, infrequently moni- 

 tored warm- water refuges. 



In addition to these difficult release cases, 13 

 successfully rehabilitated were released at various 

 locations along the east and west coasts of Florida, 

 usually near their capture sites. Because of past 

 success with such releases, released animals are not 

 usually tagged for satellite tracking. In 1995 three 

 adult females that had been rehabilititated and released 

 in recent years were resighted with new calves con- 

 ceived and born in the wild. 



Manatee Stock Assessments 



As part of efforts to reduce incidental take of 

 marine mammals in commercial fisheries, the Marine 

 Mammal Protection Act was amended in 1994 to 

 require, in part, that stock assessments be prepared 

 for all U.S. marine mammal stocks. The assessments 

 are to include estimates of population size and maxi- 

 mum net productivity, a determination of the potential 

 biological removal rate (other than natural mortality) 

 that would allow the stock to reach or remain at its 

 optimum sustainable population level, information on 

 fishery interactions, and a determination as to whether 

 the stock should be considered strategic and possibly 

 require establishment of an incidental-take reduction 

 team and preparation of an incidental-take reduction 

 plan. 



In October 1995 the Service released final stock 

 assessments for marine mammal stocks under its 

 jurisdiction, including the Florida manatee and a 

 population of Antillean manatees in Puerto Rico. The 

 assessment for Florida manatees noted that the popula- 

 tion numbered at least 1,856 animals and that the best 

 estimate of maximum net productivity was four 

 percent per year. Using this and other information, 

 the potential biological removal level was determined 

 to be three animals per year. Between 1975 and 1994 

 it noted that 17 deaths had been attributed to interac- 

 tions with fishing gear, principally shrimp nets, and 

 that a number of injuries and some mortality also had 

 been attributed to entanglement in crab trap lines, 

 hoop nets, trot lines, and monofilament line. 



For the Antillean manatee population in Puerto 

 Rico, the assessment estimated a population size of at 

 least 86 animals and a maximum productivity of four 

 percent per year. The potential biological removal 

 level was determined to be zero. The assessment also 



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