Abstract
On October 19, 2016, four adult female blacktip reef sharks (Carcharhinus melanopterus) were transported by road from Maryland to New York by experienced staff. The sharks weighed 13.3–15.4 kg. The sharks were transported in two 14-ft oval tanks, each with 2,500 gallons (9,500 L) of system water and life-support systems. Total transport time was five hours; observations and water quality (dissolved oxygen, ammonia, and pH) were within target ranges. Animals were swimming well upon introduction to the holding system. Within two hours, one shark showed muscle rigidity, reduced swimming, and reduced ventilation effort. Signs worsened despite treatment, and the shark was euthanized. Over the following five hours, two more sharks showed similar signs and were euthanized. The fourth shark showed muscle fasciculations that resolved.
Pre-shipment exams with complete blood count, biochemistry, and ultrasound three weeks prior to transport were normal (<10 min each). Post-transport findings in all three affected sharks showed severe lactemia (>20 mmol/L) with a subsequent mild to moderate respiratory acidosis. There were no significant gross findings. On histology, all animals showed multifocal myofiber degeneration and necrosis throughout the body, as well as renal tubular casts, degeneration, and necrosis suggestive of myoglobinuric nephropathy. These findings are consistent with acute rhabdomyolysis.1,2,3 No significant underlying pathology was seen. Nutritional analyses showed adequate levels of vitamin E in the serum and tissues. Exertional myopathy of ram-ventilating sharks is not uncommon but remains under-reported.2
This loss precipitated a thorough collaborative investigation of the pre-shipment, transport, and acclimation processes. A second planned shipment of blacktip reef sharks was put on hold pending the conclusions. The review did not indicate major deviations from common industry standards, but did show areas for improvement and variation in expectations. Potential contributing factors focused on physical exertion and water chemistry changes (Table 1). Most factors were adjusted for the second shipment. In October 2017, three adult female blacktip sharks from the same population were successfully transported with no morbidity or mortality.
Ram-ventilating sharks are high-risk species for capture, restraint, and transport. Even within ram-ventilating sharks, some species have shown far less resilience to capture stress than others, including blacktip reef sharks, blacktip sharks (Carcharhinus limbatus), bonnethead sharks (Sphyrna tiburo), and Atlantic sharpnose sharks (Rhizoprionodon terraenovae).4,5,6,7 A more detailed and nuanced approach to transport planning, including reviews of pre-shipment and acclimation processes, is indicated with these high-risk species to ensure the best outcomes and support animal welfare goals.
Table 1. Potential factors contributing to post-transport mortality
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Factors identified
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Changes for second transport
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Physical exertion
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- Pre-shipment exams 3 wk prior to transport
- Lack of conditioning of sharks for transport
- Transport time 5 h
- Two sharks per transport container
- Fish in receiving system
- Activity from resuscitation attempts post-transport
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- No pre-shipment exams
- Conditioned to slightly smaller swim area using gates
- Transported overnight to reduce time to 3 h
- One shark per transport container
- Some whitetip reef sharks removed from receiving system
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Water chemistry
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- No water exchange in transport container on arrival
- Differences in dissolved oxygen (160–260% during transport)
- Differences in alkalinity and cations
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- 50% water exchange over 30 min in transport container on arrival
- Supplemental oxygen added to receiving system (135%)
- Alkalinity and cations matched
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Feeding
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- 4 d pre-transport fasting
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- Additional thiamine supplementation prior to transport
- 8–32 h pre-transport fasting
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Acknowledgements
The authors would like to thank the staff who worked through the night to try to save the sharks and all the people at National Aquarium, Wildlife Conservation Society, and Dynasty Marine who helped with the evaluation and planning for the subsequent transport. This was a great example of how we can collaborate to improve animal welfare.
* Presenting author
Literature Cited
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