Dolphins in Matagorda Bay (but not necessarily other Texas bays) may 

 show less offshore movement than in Sarasota, Florida, where the 

 community home range is considered to extend 1 km offshore. Dolphins in 

 the Indian/ Banana River system on the Florida east coast showed no 

 movement offshore in surveys conducted between August 1979 and October 

 1981 (Odell and Asper 1990). 



There was a greater geographic spread of male dolphin sightings (variance 

 ratio F-test). If we assume capture and sampling biases were small between 

 the sexes, this pattern might arise from two different behavioral traits: 



(1) males have larger ranges than females (not supported statistically) or 



(2) range sizes are similar for both sexes but males visit more of their range 

 more frequently or for longer periods, and are therefore more likely to be 

 found in a wider distribution. Male dolphins in Sarasota Bay have shown 

 both traits (Wells et al. 1987, Wells 1991). The "resident male pattern" was 

 typified by lone males associating frequently with females and remaining i n 

 the relatively limited area within which females ranged. The "roving male 

 pattern" was characterized by males who roamed throughout the community 

 home range. The "resident males " were seen with reproductively receptive 

 females more than the "roving males" (Wells et al. 1987). It is possible that 

 the patterns have to do with sexual maturity and obtaining mating 

 opportunities. 



We believe that most of the marked dolphins were resident to the area 

 during the major study, and sporadic sightings throughout the year and from 

 unanalyzed surveys through August 1994 indicated longer term residency as 

 well. However, a bias may exist if the 35 marked animals were not collected at 

 random from the jX)pulation. Certain biases were inherent in the dolphin 

 capture procedures. All amimals were caught in or very near water shallow 

 enough for humans to stand, a requisite for the surround-net capture method 

 (Asper 1975). For dolphin and human safety, the capture effort avoided 

 dolphin groups of greater than five individuals and grouf>s containing 

 dolphins less than one year old (Sweeney 1992). It is possible that these 

 shallow-water dolphins displayed more site fidelity than dolphins fotmd in 

 deeper waters of the bay, and that interchange with other bay systems and 

 with the open ocean may be greater than indicated by this subsample. Such 

 biases may also explain why we apparently captvired older females than 

 males. 



Coastal bottlenose dolphins appear to have "home ranges". Range size 

 and dolphin movement patterns have been hypothesized to be dependent 

 upon reproductive (Scott et al. 1990a) and/or forage (Scott et al. 1990a, Weller 

 1991, Balance 1992, Bearzi and Notarbartolo di Sciara 1993) resources. All 

 coastal studies using some form of individual identification show resighting 



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