Little Thrift Harbor Cay 



07 



Appro*. ,„ 



water ,A/ i 



depth 15 



at 



mean 2.0- 



high «e 



tide " 



ao 



Distonce (meters) 350 



700 



Figure 2.— Movements of a 61.0 cm FL bonefish in Big Creek Lake during 1981. The solid line denotes move- 

 ment during falling tides, and the dashed line movement during a rising tide. The Arabic numerals denote the 

 starting point and day of track, with '/ 2 -h intervals and direction of movement indicated by arrows. The time 

 periods and dates of the individual tracks are: 1)1630-1700, 14 April; 2) 0855-0925, 1615-1650, 15 April; 3) 1350- 

 1435, 16 April; 4) 1557-1640, 18 April; 5) 1600-1700, 21 April; 6) 1200-1300, 22 April; 7) 1500-1530, 16 May; 

 8) 1200-1300, 20 May; 9) 0900-1000, 20 June; 10) 1200-2400, 23 June; 11) 1220-2420, 23 July. 



from 0.1 to 4 m. Tracking occasionally extended 

 into areas of <0.1 m depth, at which times move- 

 ments were visually monitored by observing the 

 exposed dorsal and caudal fins. Visual observa- 

 tions indicated that the fish generally remained 

 near the substrate (<1 m). The range of water 

 temperatures measured during a single track of 

 any fish was no more than 8°C, with a low of 24°C 

 and a high of 32°C. 



The general pattern of daily movements was a 

 retreat to deeper water on an ebbing tide and a 

 movement into shallow water on a rising tide. 

 This pattern can be clearly seen in the track of 

 the fish from Big Creek monitored for 100d(Fig. 

 2). A similar pattern was obtained by tracking 

 the other two fish for 5 d each at McLean's Town. 

 However, some variability was noted in the 

 observed depth of fish movements as compared 

 with the depth range available at the two 

 locations. The fish at Big Creek was observed to 

 move consistently into very shallow water (<1 m) 

 with the rising tide. In contrast, the McLean's 



Town fish showed a variable response in depth- 

 related movement. Also, "mudding" (a common 

 term used to describe the turbidity resulting 

 from fish feeding in bottom sediments) was ob- 

 served only during low tide at Big Creek, but 

 throughout the tidal cycle at McLean's Town. 

 Nocturnal movements closely followed the same 

 pattern. 



From January 1980 through December 1981, 

 214 bonefish were tagged with Monel metal or 

 dart tags and released in the same channels, 

 bays, and flats of Deep Water Cay as they were 

 captured. None of these fish were recaptured 

 more than 24 h from time of release. Only a single 

 collection resulted in recapture of tagged fish; 

 this was made 4 h after the fish had been tagged. 



Collection data provided a record of fish 

 lengths and weights for each month (excluding 

 September 1980) over a 19-mo period (June 1980- 

 December 1981). The proportion of large fish 

 (>55.5 cm FL) in these collections showed a pro- 

 nounced regular seasonal change, with a strong 



151 



