Overfishing of Sharks

HUNTING THE HUNTER

Sharks and rays take a long time to reach sexual maturity, and when they finally can reproduce, they have very few offspring every 1-3 years. They do not produce millions of eggs as other fish species do, therefore they simply cannot replenish their numbers once they are hunted commercially. Generally speaking, all apex predators suffer from this biological limitation. They have evolved to hunt, not to be hunted.

Commercial fishing is devastating shark and ray populations all over the world, and still, some people doubt that the vast oceans can be depleted and that our practices are changing the natural systems. It is often argued that shark fisheries can be sustainable, but there are few to none that have proven to be that over time. Adding to the problem is illegal, unreported, and underreported fishing and the high death toll of accidental bycatch.

It is predictable that our actions will be destroying the remaining populations of sharks and rays in a matter of years, not decades. The result is not only a loss of Apex predators but dire consequences for fish populations and coral reef health. It’s a domino effect that is far-reaching and complex. Overfishing goes far beyond sharks and rays. 

One-third of the world’s Chondrichthyan fishes – sharks, rays, and chimaeras are threatened with extinction according to the International Union for Conservation of Nature (IUCN) Red List criteria.

• This determination has been made by the International Union for Conservation of Nature (IUCN)

• A group of experts have assessed over 1,000 species and have classified (study published 9/6/21 in Current Biology):

  • 90 as Critically Endangered

  • 121 as Endangered,

  • 180 as Vulnerable

  • Less than half of all species (44.1%) are of low conservation concern (Least Concern).

• Alarming Decline in Shark Populations Points to Need for Stricter Conservation Measures.

• Thresher & Silky sharks are 72-90% reduced, read more here.

• Dusky shark populations off the Atlantic coast are estimated to have plummeted by 85%, more on that here.

The widespread depletion of sharks and rays is endangering the health of ocean ecosystems around the world

This 2021 IUCN Red List update includes a comprehensive reassessment of the world’s shark and ray species, which reveals 37% are now threatened with extinction, demonstrating that effective management measures are lacking throughout much of the world's oceans. All of the threatened shark and ray species are overfished, with 31% further affected by loss and degradation of habitat and 10% affected by climate change.

BYCATCH & “UNINTENDED CATCH” OF SHARKS

As mentioned in the previous blog, bycatch is not always accidental. Mitigation methods exist, but they are not used because they may be more time-consuming, more expensive, or simply avoided because the bycatch is not quite as unintended as they would like us to believe. That is certainly the case with sharks. The excuse that all sharks are unintended catch really doesn’t hold up in many cases. But legally, as long as the sharks don’t seem to be targeted, and are on the list of permitted bycatch species, it’s essentially a no-limits shark fishery. 

Long line fishers know how to fish in order to avoid sharks. They have the option to select the area and the depth the lines are set that makes it less likely to catch sharks. They can use gear that lets sharks break loose. Switching back to nylon instead of steel leaders, and the use of weak or soft hooks would ensure that sharks could get away. They can make the effort to release sharks, like they used to. Many animals would survive and recover. Because of the value of fins, sharks are kept, if not targeted. And the argument that they were “unintended” catch is used as a convenient cover that makes it legal, even if the fishery does not have licenses as a shark fishery. Basically, it’s a free for all and no one being held accountable. While this seems like an insurmountable obstacle, what does work is to devalue the sharks by not allowing the sale of fins. If there is no money to be made, shark swill be avoided, as they are big animals that take up a lot of valuable storage space on a ship. As long as we allow shark fins to be traded because they are part of a sustainable fishery or because they were caught as so-called bycatch, we are keeping the doors wide open for sharks to be targeted. 

• Around 50% of the global taking of sharks from the ocean occurs from bycatch in high seas pelagic longline fisheries.

• Generally, most fisheries data obtained regarding elasmobranch bycatch don’t provide species-level data. Instead, mass/weight of elasmobranchs caught is obtained and estimated. 

• Global estimates are likely underestimates, as much bycatch data is not reported at all, data on bycatch can't really be taken from all countries/fisheries.