Assessment of acid–base derangements among bonnethead (Sphyrna tiburo), bull (Carcharhinus leucas), and lemon (Negaprion brevirostris) sharks from gillnet and longline capture and handling methods ☆ Michael W. Hyatt a, ⁎, Paul A. Anderson b , Patrick M. O'Donnell c , Ilze K. Berzins d a Georgia Aquarium, 225 Baker St. NW, Atlanta, GA 30313, USA b The Florida Aquarium Center for Conservation, 701 Channelside Dr., Tampa, FL 33602, USA c Rookery Bay National Estuarine Research Reserve, 300 Tower Rd., Naples, FL 34113, USA d John G. Shedd Aquarium, 1200 South Lake Shore Dr., Chicago, IL 60605, USA abstract article info Article history: Received 17 February 2011 Received in revised form 4 May 2011 Accepted 4 May 2011 Available online xxxx Keywords: Acidosis Capture and handling Gillnet i-STAT Longline Blood gasses of wild bonnethead, bull, and lemon sharks were measured with the i-STAT clinical analyzer with the CG4+ cartridge immediately after capture; and again immediately prior to release after tagging, handling and morphometric measurements were taken. Relative reference ranges of post-capture status were established. Among species, stress response to capture was similar for all parameters; however, pH declined and lactate concentrations rose over time, indicating continued insult from capture and/or response to additional handling stress. pCO 2 rose faster for S. tiburo than for C. leucas, and lactate concentrations rose faster for S. tiburo than for N. brevirostris. All species caught in gillnets experienced lower pH and higher lactate concentrations than on longlines. Discriminant analysis justified the use of blood gas analysis to assess physiological stress induced by different capture methods. From these results, we recommend 1) that gear be monitored closely and sharks be removed immediately, or suboptimally, that gear is deployed for the shortest soak time possible; 2) longline over gillnet gear; and 3) extra caution with sensitive species (e.g., S. tiburo), which may include the administration of blood buffers and other therapeutics if a shark is beyond the limits of relative reference ranges reported here. © 2011 Elsevier Inc. All rights reserved. 1. Introduction Carcharhinid sharks have become important ambassadors for threatened species in conservation research, sport and commercial fisheries, and public display in aquaria. Working with carcharhinid sharks, however, presents challenges due to their extreme sensitivity to capture and handling stresses, especially affecting acid–base physiology. In general, sharks have a low capacity for aerobic metabolism and quickly shift to anaerobic metabolism when caught or handled (Cliff and Thurman, 1984; Hoffmayer and Parsons, 2001; Manire et al., 2001; Brill et al., 2008; Mandelman and Skomal, 2008). Sharks will use anaerobic muscle activity for short bursts of speed, but response to prolonged capture and handling stress can exacerbate anaerobic metabolism, often to exhaustion. This leads to a metabolic acidosis as lactate and hydrogen ions (H + ) move from muscle cells to the extracellular space and bloodstream. The resultant acidemia lowers blood pH and increases blood lactate concentrations (Holeton and Heisler, 1983; Cliff and Thurman, 1984; Hoffmayer and Parsons, 2001; Manire et al., 2001; Mandelman and Skomal, 2008). In addition, many sharks are obligate ram ventilators; they need to continually swim to provide oxygenated water to their gills for respiration. In times of capture stress, their ventilation is depressed or even stopped, leading to an increase in carbon dioxide in the blood (pCO 2 ), which can deleteriously lower the blood pH further due to conversion of CO 2 to carbonic acid, thus producing a respiratory acidosis (Mandelman and Skomal, 2008). Sharks that struggle and are unable to swim are more severely affected with a mixed metabolic and respiratory acidosis (Manire et al., 2001; Mandelman and Farrington, 2007a,b; Mandelman and Skomal, 2008). This is a major reason that sharks experience a high rate of morbidity and mortality associated with capture and handling. Sharks are more often exploited as by-catch in commercial fisheries than they are the primary target, but even as by-catch, sharks suffer high mortality rates (Hueter and Manire, 1994; Skomal, 2007; Mandelman et al., 2008; Frick et al., 2009, 2010; Walsh et al., 2009). These rates vary greatly among shark species in commercial and recreational fisheries. In the U.S. Atlantic pelagic longline fishery, mortality rates ranged from 12% in blue sharks (Prionace glauca), 35% in shortfin mako (Isurus oxyrinchus), to 80% in night sharks Comparative Biochemistry and Physiology, Part A xxx (2011) xxx–xxx ☆ This paper stems from a presentation in the Symposium “The Physiological Stress Response in Elasmobranch Fishes”, at the 26th annual meeting of the American Elasmobranch Society, held on July 11, 2010, in Providence, Rhode Island (USA). ⁎ Corresponding author. Tel.: +1 404 581 4158; fax: +1 404 581 4379. E-mail addresses: mhyatt@georgiaaquarium.org (M.W. Hyatt), panderson@flaquarium.org (P.A. Anderson), patrick.odonnell@dep.state.fl.us (P.M. O'Donnell), iberzins@sheddaquarium.org (I.K. Berzins). CBA-09168; No of Pages 8 1095-6433/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.cbpa.2011.05.004 Contents lists available at ScienceDirect Comparative Biochemistry and Physiology, Part A journal homepage: www.elsevier.com/locate/cbpa Please cite this article as: Hyatt, M.W., et al., Assessment of acid–base derangements among bonnethead (Sphyrna tiburo), bull (Carcharhinus leucas), and lemon (Negaprion brevirostris)..., Comp. Biochem. Physiol., A (2011), doi:10.1016/j.cbpa.2011.05.004