592 



Fishery Bulletin 93(3), 1995 



Channel use 



During our study, turtles remained primarily near 

 the jetties, probably because food was abundant there 

 and virtually absent in the channel and barren bot- 

 tom areas. Turtles were found in the channel <0.3% 

 of the time. They appeared to use the channel for 

 transit to other areas or as presumed escape cover. 



Conclusions 



Our data, combined with numerous sightings of 

 turtles at the jetty 3 and with the fact that there was 

 no appreciable movement away from the jetties by 

 tracked turtles, support the hypothesis that juvenile 

 green turtles in Brazos-Santiago Pass, south Texas, 

 selected for jetty habitat over other habitats avail- 

 able. If this pattern is consistent for all times that 

 green turtles inhabit the pass, then it would indi- 

 cate that potential harm from hopper dredging or 

 channel boat traffic would be minimal. Our study 

 included only nine turtles and was limited to August- 

 September 1992. Therefore, caution should be used 

 in extrapolating our results to other years or times 

 of the year. The study was timed to coincide with the 

 period of highest turtle abundance in the pass. Data 

 gathered by TAMU indicate that use of the pass by 

 green turtles increases during June-September. 13 

 Turtles appear to be rare from December to March 

 and gradually begin to increase in numbers starting 

 in April. We were unable to monitor turtle behavior 

 during dredging, because no dredging was done dur- 

 ing the study; therefore, we do not know how dredg- 

 ing of the channel may affect behavior of turtles oc- 

 cupying the jetty habitat. 



Because green turtles are herbivorous, there is very 

 little danger of hook and line captures from jetty fish- 

 ing. The greatest impact on turtle behavior may be sim- 

 ply that of human activity on the jetties. The level of 

 that impact is currently unknown. We encourage fur- 

 ther study, particularly during other times of the year. 



Acknowledgments 



We would like to acknowledge several organizations 

 and their personnel for assistance in making this 

 work possible: the U.S. Army Corps of Engineers 

 (Galveston and New Orleans Districts) for funding 

 the research, Texas A&M University for capturing 

 sea turtles and characterizing habitats in the lower 

 Laguna Madre, the University of Texas Pan Ameri- 

 can Coastal Studies Laboratory for making their fa- 

 cility available to hold turtles, and the U.S. Coast 



Guard Station at South Padre Island for use of their 

 base to store our tracking vessel. Special thanks go 

 to Gregg Gitschlag for development of the turtle 

 monitoring system along the jetties. 



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