The physiological status and mortality associated with otter-trawl capture, transport, and captivity of an exploited elasmobranch, Squalus acanthias

Abstract

To assess the physiological responses and associated mortality in spiny dogfish (Squalus acanthias) following capture in an otter trawl and exposure to additional conditions, blood samples were obtained subsequent to three sampling intervals: capture (T1), transport (T2), and captivity (T3). The results indicate that marked differences existed in blood chemistry at each sampling interval. Acid-base parameters (vascular pH, pO2, pCO2), serum Ca2+ and Cl-, and haematocrit were maximally disrupted at T1, but progressively resolved to presumed basal values by T3. Concentrations of whole-blood lactate, plasma total protein, additional sera electrolytes (Na+, K+, Mg2+), and BUN (urea) were maximally compromised at T2, but also recovered by T3. In contrast, serum glucose levels were similar at T1 and T2 but rose to peak levels by T3. Although blood parameters were substantially altered, dogfish mortality was low (2 out of 34; 5.9%), suggesting a strong degree of resilience to compounded stressors associated with capture, transport, and captivity. © 2006 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.