Prenatal stress from trawl capture affects 1 mothers and neonates: a case study using the 2 southern fiddler ray (Trygonorrhina dumerilii)

Abstract

Assessing fishing effects on chondrichthyan populations has predominantly focused on 15 quantifying mortality rates. Consequently, sub-lethal effects of capture stress on the 16 reproductive capacity of chondrichthyans are largely unknown. We investigated the 17 reproductive consequences of capture on pregnant southern fiddler rays (Trygonorrhina 18 dumerilii) collected from Swan Bay, Australia, in response to laboratory-simulated trawl 19 capture (8 h) followed immediately by air exposure (30 min). Immediately prior to, and for 20 up to 28 days post trawling, all females were measured for body mass (BM), sex steroid 21 concentrations (17-β estradiol, progesterone, testosterone) and granulocyte to lymphocyte 22 (G:L) ratio. At parturition, neonates were measured for total length (TL), BM and G:L ratio. 23 Trawling reduced maternal BM and elevated the G:L ratio for up to 28 days. Trawling did not 24 significantly affect any sex steroid concentrations relative to controls. Neonates from trawled 25 mothers were significantly lower in BM and TL than control animals, and had an elevated 26 G:L ratio. Our results show that capture of pregnant T. dumerilii can influence their 27 reproductive potential and the fitness of neonates. We suggest other viviparous species are 28 likely to be similarly affected. Sub-lethal effects of capture, particularly on reproduction, 29 require further study, particularly reproduction, to improve fisheries management and 30 conservation of chondrichthyan species.