Anglers are known to catch and release sharks in order to protect species that are endangered but success depends on the species caught.
A new landmark study of over 300 sharks found that some species are extremely resilient to the stress of being caught and released in commercial longline fisheries while other species are much more likely to die.
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Blacktip and spinner sharks are least likely to survive. From 42% to 71% of these sharks will die even after being released alive. Sandbar and tiger sharks were much more resilient, with only 3% or less dying after release.
Two former Mote Marine Laboratory biologists researched sharks around Florida near Naples, Madeira Beach and Key West, using accelerometers that sense how sharks swim, tilt, roll and dive.
The data graphs reveal healthy movement in a sandbar shark and a flat black line where an unfortunate blacktip shark sank to the seafloor and died.
The high-intensity, exhaustive swimming exhibited by hooked sharks producing cell damage that can impact behavior and cause death.
This was the first large study to connect the lines between stress changes in blood with the actual death rates from commercial bottom longline fishing using the sensors mounted on the shark’s dorsal fin.
Blacktip sharks are the second most commonly caught species in the fishery behind sandbar sharks, and longlines are very hard on them. By the time they’re caught, 35% of blacktip are dead and many more will die after release, producing total mortality of around 62%.