Could capture stress affect future reproductive outcomes in elasmobranch species? A case study: the southern fiddler ray, Trygonorrhina dumerilii.

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

Conferencia; Australian Society for Fish Biology conference; 2016

Assessing fisheriesimpacts on elasmobranch populations has largely focused on quantifying bothimmediate and delayed mortality rates. However, very little is known about thesub-lethal effects of capture stress, particularly in pregnant females. Ourstudy is the first to investigate the consequences of capture on a pregnantelasmobranch species, the southern fiddler ray (Trygonorrhina dumerilii). Nineteen pregnant females were collectedby hand in Swan Bay, Australia, and transported to aquaria where nine femaleswere subjected to trawl capture (8 hr) followed immediately by air exposure (30min). Immediately prior to, and for up to 28 days post trawling, all femaleswere routinely sampled to monitor changes in total body mass (TBM), sex-steroidlevels (estrogen, progesterone, testosterone) and granulocyte to lymphocyteratio (G:L). At parturition, neonates were measured for total length (TL), TBMand where possible, G:L was also calculated. Trawling reduced maternal TBM andelevated the G:L for up to 28 days post trawling. Trawling did notsignificantly affect any sex-steroid titers, however all females reported lowerthan expected concentrations in all sex-steroids at 28 days post trawling.Neonates who experienced pre-natal stress were lower in TBM and TL, and had anelevated G:L. Our results suggest that depending on the magnitude ofenvironmental stress experienced by a pregnant female, a single capture event(or multiple) is sufficient to influence current and future reproductiveefforts.