Reproductive Consequences of Fisheries Capture in the Southern Fiddler Ray

AWRUCH C. A.; GUIDA, L.; REINA. R.; WALKER, T.

Conferencia; American Elasmobranch Society Conference; 2016

Assessingfisheries impacts on elasmobranch populations has largely focused onquantifying both immediate and delayed mortality rates. However, very little isknown about the sub-lethal effects of capture stress, particularly in reproductivelyactive females. Our study is the first to investigate the consequences ofcapture on a pregnant elasmobranch species, the southern fiddler ray (Trygonorrhina dumerilii). Nineteen pregnantfemales were collected by hand in Swan Bay, Australia, and transported toaquaria where nine females were subjected to trawl capture (8 hr) followed immediatelyby air exposure (30 min). Immediately prior to, and for up to 28 days posttrawling, all females were routinely sampled to monitor changes in total bodymass (TBM), sex-steroid levels (estrogen, progesterone, testosterone) andgranulocyte to lymphocyte ratio (G:L). At parturition, neonates were measuredfor total length (TL), TBM and where possible, G:L was also calculated.Trawling reduced maternal TBM and elevated the G:L for up to 28 days posttrawling. Trawling did not significantly affect any sex-steroid titers, howeverall females reported lower than expected concentrations in all sex-steroids at28 days post trawling. Neonates who experienced pre-natal stress were lower inTBM and TL, and had an elevated G:L. Our results suggest that depending on themagnitude of environmental stress experienced by a pregnant female, a singlecapture event (or multiple) is sufficient to influence current and futurereproductive efforts.