Meeting Abstract

P2.76  Jan. 5  Correlations of Bite Performance with Body and Head Morphometrics in Juvenile Loggerhead Sea Turtles (Caretta caretta): Preliminary Data SALAZAR, A.*; MARSHALL, C.D.; Texas A&M University; Texas A&M University at Galveston asalazar@tamu.edu

Incidental bycatch of loggerhead sea turtles from the pelagic longline fishery is a serious concern due to recent data that demonstrates a greater than predicted turtle bycatch globally. Little is known about loggerhead bite performance, but the propensity of loggerheads to bite forcefully may make them vulnerable to becoming hooked in the mouth or throat. The mechanics of hooking by loggerheads on longline fishing gear is not well understood. Bite force measurements were taken from juvenile captive-reared loggerheads at the NOAA/NMFS sea turtle facility in Galveston, TX using a bite force transducer customized for a loggerhead mouth. Morphometric measurements including straight carapace length (SCL), straight carapace width (SCW), head width (HW), head height (HH), head length (HL) and body-mass were recorded from individuals of the 2004 (n=180) and 2005 (n=29) age classes. The mean maximum bite force was 140 N for the 2004 age class and 24 N for the 2005 age class. Mean morphometric values for the 2004 age class were 30.7 cm SCL, 25.5 cm SCW, 62.3 mm HW, 53.9 mm HH, 93.5 mm HL and mass 4032 g. Mean values for the 2005 age class were 12.0 cm SCL, 9.7 cm SCW, 28.3 mm HW, 24.7 mm HH, 45.0 mm HL and mass 266 g. Maximum and mean bite force measurements are positively correlated to all body and head morphometrics (p<0.001). Head width is the best predictor of maximum (adjusted R²= 0.899; maximum bite force=3.481(HW) � 76.497) and mean bite force (adjusted R²= 0.893; mean bite force=3.215(HW) � 71.158) in these juvenile loggerheads. Investigations of loggerhead bite performance may provide data that can be used to modify longline fishing gear and diminish sea turtle bycatch.