radio's life span. The hypothesized "extended herd honne range" boundaries 

 in this study correspond well with those of Gruber (1981:52). Individually 

 preferred areas were also hypothesized by Shane (1977) and Price-May (1993) 

 for the Port Aransas, Texas area. 



Bottlenose dolphins in Matagorda Bay show intriguing parallels to the 

 Sarasota Bay connmunity. The mean 140 ± 90.7 (SD) km^ range size for 

 individuals in the present study is similar to ranges in the Sarasota area. The 

 Sarasota community is composed, in part, of several "bands" of females and 

 their calves. Some bands contain more than one matriline. In the Matagorda 

 Bay area, evidence of several "extended herd home ranges" within at least 312 

 km^ overlapping near Port O'Connor, could correspond to the adjacent 

 communities hypothesized to reside along the Florida west coast, or to the 

 matrilineal bands seen within the Sarasota dolphin community. Dolphin 

 movement ranges in Matagorda, as revealed by radio-tracking, appeared very 

 similar to early radio-tracking results in Sarasota Bay (Irvine et al. 1981). In 

 both studies, individual dolphins used separate but somewhat overlapping 

 regions of the bays, and individual ranges were on the order of 100 km^. The 

 radio-tracked ranges in Irvine et al. (1981) for Sarasota Bay corresponded 

 generally to what, with more data, came to be recognized as female band 

 ranges, shown in Wells (1991). Wells et al. (1993) reported a "mosaic of 

 overlapping home ranges" for individuals in Sarasota and neighboring 

 communities. 



A "dual home range", similar to that of FB501, was described by Caldwell 

 and Caldwell (1972:64) for an albino bottlenose dolphin known from Saint 

 Helena Sound, South Carolina (Essapian 1962) and Georgia waters, a 

 minimum 60-km-traveling range. 



Shane (1977), Gruber (1981), and McHugh (1989) report very limited 

 movement in either direction through passes linking Texas bays with the 

 Gulf of Mexico. Wiirsig (unpublished data) indicates that this type of 

 movement by "resident" dolphins may be more frequent for Galveston Bay. 

 Data from the present study suggest that such movement by these apparently 

 resident dolphins does occur, but infrequently, lasting on the order of several 

 hours, and to an unknown distance offshore (but probably within a few 

 kilometers). The radio tracked dolphins of the present study were not 

 observed to leave the bay system to feed (for example) in oceanic waters. This 

 is an imjX)rtant finding, for it indicates that — if true for a large part of the 

 inshore animals — these dolphins are potentially susceptible to localized toxin 

 input from agricultural runoff or industry. If ongoing studies indicate that the 

 35 freeze-branded dolphins have long-term (across year) site fidelity for all 

 activities, including feeding, this potential habitat influence may be judged to 

 be even greater. 



23 



