Short-term survival and movements of Atlantic sharpnose sharks captured by hook-and-line in the north-east Gulf of Mexico

Ultrasonic telemetry was used to compare post-release survival and movements of Atlantic sharpnose sharks Rhizoprionodon terraenovae in a coastal area of the north-east Gulf of Mexico. Ten fish were caught with standardized hook-and-line gear during June to October 1999. Atlantic sharpnose sharks were Continuously tracked after release for periods of 0(.)75 to 5(.)90 h and their positions recorded at a median interval of 9 min. Individual rate of movement was the mean of all distance and time measurements For each fish. Mean +/- S.E. individual rate of movement was 0(.)45 +/- 0(.)06 total lengths per second (L-T s(-1)) and ranged from 0(.)28 to 0(.)92 L-T s(-1) over all fish. Movement patterns did not differ between jaw and internally hooked Atlantic sharpnose sharks. Individual rate of movement was inversely correlated with bottom water temperature at capture (r(2) = 0(.)52, P < 0(.)05). No consistent direction in movement was detected for Atlantic sharpnose sharks after release, except that they avoided movement towards shallower areas. Capture-release survival was high (90%), with only one fish lot Surviving, i.e. this particular Fish stopped movement for a period of 10 min. Total rate of movement was total distance over total time (m min(-1)) for each Atlantic sharpnose shark. Mean total rate of movement was significantly higher immediately after release at 21(.)5m min(-1) over the first 1(.)5 h of tracking, then decreased to 11(.)2m min(-1) over 1(.)5-6h, and 7(.)7m min(-1) over 3-6h (Pless than or equal to0(.)002), Which Suggested initial post-release stress but quick recovery front capture. Thus, high survival (90%) and quick recovery indicate that the practice of catch-and-release would be a viable method to reduce capture mortality for R. terraenovae. (C) 2004 The Fisheries Society of the British Isles.