Dead tired: evaluating the physiological status and survival of neonatal reef sharks under stress.

摘要: Marine protected areas (MPAs) can protect shark populations from targeted fisheries, but resident may remain exposed to stressors like capture as bycatch and environmental change. Populations of young sharks that rely on shallow coastal habitats, e.g. nursery areas, be at risk experiencing these stressors. The purpose this study was characterize various components the physiological stress response neonatal reef following exposure an exhaustive challenge under relevant conditions. To accomplish this, we monitored markers secondary measured oxygen uptake rates (⁠MO2⁠) compare laboratory-derived baseline values in blacktip (Carcharhinus melanopterus) sicklefin lemon (Negaprion acutidens). Measurements occurred over three hours (gill-net with air exposure). Blood lactate concentrations pH deviated 3-h sample, indicating both species were still stressed 3 h after capture. Evidence a temperature effect status either equivocal 28–31°C. However, aspects species-specific; N. acutidens exhibited larger difference blood relative than C. melanopterus, possibly owing higher minimum MO2⁠. Neither experienced immediate mortality during challenge; although, single instances delayed documented for each species. Energetic costs recovery times could extrapolated melanopterus via respirometry; estimated expend 9.9 kJ kg−1 (15% energy expended daily swimming) require 8.4 recover. These data suggest are resilient brief gill-net durations, narrow range. Defining species' vulnerability is important understanding efficacy conservation tools, including MPAs.