Jaw-dropping fears for sharks

Sharks and rays are in the news, writes Richard Collins
Jaw-dropping fears for sharks

They have been found in an active underwater volcano, have attacked more people during 2015 than in any previous year, and a new global initiative has been launched to protect them. Although these magnificent creatures have survived for 400 million years, they are threatened as never before.

Kavachi, in the Solomon Islands, is one of the world’s most unstable marine volcanoes. There were major eruptions there in 2003 and 2007 and a minor one in 2014. Discharging hot acid into the ocean, the underwater cone is far too dangerous for divers to enter. Using robots to explore it, scientists found crabs and jellyfish living 50m below the surface. Most surprisingly, two species of shark and a stingray were filmed swimming inside the crater. One was the elusive Pacific sleeper shark, which had only been filmed on two previous occasions.

The other, the scalloped hammerhead, is a globally threatened species. Climate change is increasing the acidity of the world’s oceans. The discovery of sharks in such extreme conditions suggests that fish may cope better with rising acidity than was previously thought.

There were 98 unprovoked shark attacks on people during 2015, resulting in six fatalities. In 2000, the worst previous year on record, there were 88 such incidents. The statistics exclude cases where fishermen were bitten when handling captured sharks. The figures might suggest that sharks are becoming more aggressive but, according to the experts, there is no evidence of this; the increase in incidents is statistically insignificant.

As the human population increases worldwide, more and more people are swimming and surfing, so a rise in encounters with sharks is only to be expected. Also, with the increased use social media, confrontations are more likely to be reported.

Should we be afraid of sharks? According to the statisticians, you are more likely to be struck by lightning, or electrocuted by your toaster, than attacked by a shark. Jellyfish and bees present far greater threats to us. Nonetheless George Burgess, who prepares the Global Shark Attack File, recommends that swimmers avoid locations where fish congregate, as a hunting shark may bite a swimmer accidentally. Nor is wearing shiny jewellery advisable; it can gleam like fish scales. Sharks tend to attack solitary swimmers or surfers, so avoid entering the water alone.

Humans present a far greater threat to sharks than they do to us; about 100 million of them are slaughtered each year. Shark fin soup is a snob delicacy in Asian countries. More and more sharks are being caught to meet the increasing demand for it.

The unfortunate fish have their fins cut off and are thrown back into the sea to die a lingering death. Sharks and rays grow slowly, taking many years to mature. Each female produces relatively few young during her lifetime. With such a low reproductive rate, the current losses from fishing can’t be replenished.

Sharks and rays are vertebrates like ourselves but we don’t even know how many species there are; new ones are being discovered almost on a monthly basis. The International Union for the Conservation of Nature lists 1,038 species. An analysis presented to the Convention on Migratory Species meeting in Costa Rica in February, suggested that 24% of these are threatened with extinction. The common skate, found in Irish waters, is listed as ‘critically endangered‘, while the porbeagle is deemed to be ‘threatened’.

A new ‘Global Sharks and Rays Initiative’, launched at the meeting, recommends the introduction of science-based fishery management schemes to protect sharks. Fishing gear, it suggests, should be modified to reduce by-catch mortality. ‘Hotspot’ locations have been identified where ‘active intervention’ is required. Only a global effort will prevent the extinction of the most threatened species.

  • Global Priorities for Conserving Sharks and Rays: a 2015-2025 Strategy. Convention on Migratory Species. Costa Rica. 2016.

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