Last year, a research team looked into 31 different ray and shark species and found that their worldwide abundance plummeted by 71% since 1970. Forbes notes that this period's pressures in fishing and catching sharks and rays doubled and tripled, respectively.
Some fish species, such as rays and sharks, have their young at a rate significantly slower than others. This increases their vulnerability to mounting pressures in fishing.
While sharks are typically caught through targeted activities, they can also be captured accidentally, especially when fishermen aim at other fish, like swordfish and tuna. Sometimes, they still catch sharks even if they aim to capture different fishes.
When it comes to commercial fishing, there are five main ways to capture fish. One of these methods, longline hooks for fishing, uses hundreds or even thousands of hooks that fall below a main horizontal line. This specific method has been seen as a great shark killer, as noted by Forbes.
SharkGuard Device Emits Electric Pulses
A technology known as "SharkGuard" is a device that can save over 50 million rays and sharks from all over the world that unintentionally succumb to catching. According to Daily Mail, this device is a gadget with a cylinder shape and the estimated size of a double A battery.
Using the device has to get linked to longline fishing hooks. The gadget builds an electric field surrounding the hook, forcing creatures to avoid it.
The electric pulses lead to overstimulation and stop the rays and sharks from getting into contact with the fishing hook.
Both rays and sharks are armed with electrosensory capabilities within their skin that enable them to catch small changes in electric fields underwater. Hence, NewScientist notes that Phil Dohetry, a postdoctoral research associate from the University of Exeter, mentions that these devices are meant to overwhelm the senses. The case is similar to a human positioned very close to a speaker with blasting sounds.
SharkGuard Significantly Reduces Unintentional Catching of Sharks and Rays
Daily Mail notes that some research performed among French boats on the lookout for tuna revealed that lines linked to the device reduced accidental blue shark catching remarkably. More precisely, the device's presence decreased the unintentional catching of stingrays by 71% and blue sharks by 91%.
Dohetry also mentions an evident decline in ray and shark populations because of overfishing. He mentions a pressing need to decrease bycatches, which not only kill rays and sharks but also lead to higher monetary and time expenses.
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