Catch and Release - Sharks
Grey nurse shark at South West Rocks
|
Dr. Kelli Anderson This article originally appeared on SCUBAVERSE Catching fish with the sole purpose of release is seen by some as an alternative to catch-and-kill fishing, and has become a popular recreational activity in itself. Sharks are often the target, and given their ecological importance, it’s important to consider any potential impacts that this style of fishing may have. |
Data regarding mortality rates of catch and release on sharks are scant, however it’s estimated that mortality from capture from scientific research is ~10 % for sharks in general, and may be higher for sport fishing due to longer ‘fight’ times and extended time out of the water. Indeed, a study of juvenile lemon sharks in the Bahamas, found that ~12 % of released sharks died in the 15 minute monitoring period following release, and on the east coast of Australia 6 out of 8 necropsied grey nurse sharks were found to have internal hooks despite having no external signs of fishing gear. Severe injuries and infections have been documented in grey nurse sharks as a result of catch and release, although the long term sub lethal impacts of such maladies are unclear.
Sharks are keystone predators that have a disproportionate influence on the health and stability of their environments, and globally their numbers are in decline. While it’s not clear whether injuries or the relatively low mortality rates from recreational fishing can affect marine ecosystems as whole, current data suggests that outcomes for sharks can be improved with shortened fight and handling times. As scuba-enthusiasts and stewards of the ocean, it’s up to us to make a conscious effort to interact with the ocean and its inhabitants in a way that’s not destructive, and that may mean modifying the way we approach even catch and release fishing.
fURTHER rEADING
Bansemer, C. S., & Bennett, M. B. (2010). Retained fishing gear and associated injuries in the east Australian grey nurse sharks (Carcharias taurus): implications for population recovery. Marine and Freshwater Research, 61, 97-103.
Danylchuk, A. J., Suski, C. D., Mandelman, J. W., Murchie, K. J., Haak, C. R., Brooks, A. M. L., & Cooke, S. J. (2014). Hooking injury, physiological status and short-term mortality of juvenile lemon sharks (Negaprion bevirostris) following catch-and-release recreational angling. Conservation Physiology, 2(1).
Otway, N. M., Bradshaw, C. J. A., & Harcourt, R. G. (2004). Estimating the rate of quasi-extinction of the Australian grey nurse shark (Carcharias taurus) population using deterministic age- and stage-classified models. Biological Conservation, 119, 341-350.
Danylchuk, A. J., Suski, C. D., Mandelman, J. W., Murchie, K. J., Haak, C. R., Brooks, A. M. L., & Cooke, S. J. (2014). Hooking injury, physiological status and short-term mortality of juvenile lemon sharks (Negaprion bevirostris) following catch-and-release recreational angling. Conservation Physiology, 2(1).
Otway, N. M., Bradshaw, C. J. A., & Harcourt, R. G. (2004). Estimating the rate of quasi-extinction of the Australian grey nurse shark (Carcharias taurus) population using deterministic age- and stage-classified models. Biological Conservation, 119, 341-350.