SHANE: OCCURRENCE AND DISTRIBUTION OF BOTTLENOSE DOLPHIN 



Table 3. — Relationship between direction of dolphin movement and time of day was significant (chi- 

 squareP<0.01) in four sections of the Port Aransas, Texas, study area during a few tidal stages. Numbers 

 in the table represent frequency of individual dolphin sightings. Cramer's V indicates the strength of 

 the relationship between the two variables, and each V is comparable with every other V. 



' Insufficient data in a given case made chl-square test potentially invalid. 



study area. Thick Fin and Raggedy Ann used 

 separate but adjacent portions of the study area 

 (Figure 3). Teaser used a portion of the study area 

 which included most of Thick Fin's portion and all 

 of Raggedy Ann's portion (Figure 3). 



The portions of the study area used by Thick Fin 

 and Raggedy Ann were designated Region A and 

 Region B. Region A encompassed Aransas Pass, 

 the Confluence, Lydia Ann Channel, and Corpus 

 Christi Channel. Five dolphins, including Thick 

 Fin, were sighted 80% or more of the time in this 

 region (Table 4). Region B covered Morris and 

 Cummings Cut, and three dolphins, including 

 Raggedy Ann, were seen SS'Ji or more of the time 

 there (Table 4). These three Region B dolphins 

 consistently traveled in a large group of usually 20 

 or more dolphins which moved into and out of the 

 study area through Corpus Christi Bay. Two dol- 

 phins. Teaser and Cloud, were observed often in 

 both Regions A and B, and their sightings covered 

 20 km2 and 25 km^. 



In addition to the 19 identifiable dolphins in the 

 study area, two recognizable individuals, South- 

 paw and Half Fin, were sighted only in the Gulf of 

 Mexico. Other dolphins with unique dorsal fins 

 were seen in the gulf whenever observations were 

 made there. These T. truncatus from the Gulf of 

 Mexico were sometimes seen within meters of 



Aransas Pass, but they entered the study area 

 only rarely and briefly. 



As discussed earlier, many dolphins inhabited 

 the study area on a seasonal basis. Observations of 

 some individuals indicated their possible locations 

 when they left the study area. On 22 February 

 1977 I saw Short Triangle traveling up Aransas 

 Pass toward the bays at 11:07 a.m. and traveling 

 down the Pass to the Gulf at 12:35 p.m. Although I 

 made continuous observations for the remainder 

 of the day from the shoreline of the Pass, I did not 

 resight Short Triangle. On 18 October 1976 I saw 

 Thick Fin entering the Gulf of Mexico; after that 

 and until mid-March 1977,1 saw Thick Fin only on 

 18 November 1976 and 25 January 1977. On 29 

 June 1979, Gruber^ sighted Thick Fin 50 m off the 

 Port O'Connor, Texas, jetties in the Gulf of Mexico, 

 100 km northeast of Port Aransas. I was able to 

 confirm the sighting from photographs taken by 

 Gruber. Port Aransas ferry operators, familiar 

 with Thick Fin, reported to Gruber that they had 

 seen Thick Fin on 24 June and again on 22 July. 

 Bent Fin entered and left the study area through 



^J. Gruber, graduate student. Department of Wildlife and 

 Fishery Sciences, Texas A&M University, College Station, TX 

 77843, pers. commun. July 1979. 



597 



