They might be among the fastest and strongest predators under water, but one-third of the population of sharks, are threatened with extinction globally, shows a recent study by the Zoological Survey of India. Even rays and chimeras face a similar threat.
The study stated that the alarming decline in the population of sharks will create an ecological imbalance in the marine ecosystem. Researcher K K Bineesh, who was part of the team, told TOI that in the Indian marine waters there are 170 species of sharks. Of this, 19 species are critically endangered, and another 30 are categorised as endangered. Along the east coast, 16 species are critically endangered and 24 are endangered species, he said.
In the ocean, the risk of extinction has increased with the growth of human population, associated intensification of industrial fishing, and the rapid development of coastlines.
While these pressures have been well documented for coral reefs, much of the understanding of fishery impact is heavily biased toward the most data-rich target species. However, statistical predictions, based on life histories, catch, and fisheries development, warn that the unassessed datapoor fisheries, particularly for sharks, may be highly unsustainable, he said.
The study shows that two types of fishing threatened sharks, rays and chimeras. Target fishing and bycatch. Bineesh said fishermen now go for longline tuna fishing to catch sharks, as this fish species has great demand in the export market. In the second case, sharks are trapped in the nets of fishermen as bycatch. When sharks are trapped in a net, fishermen ignore them. By the time they reach the fish landing centre, the sharks die.
Lack of awareness among fishermen about the need to conserve sharks is the main reason for the decline in their population. More than two decades ago there were no takers for juvenile sharks, they were considered waste. But, now bycatch is also in demand among fish meal making units. This has given an incentive for fishermen with small boats to catch juvenile sharks and sell them, said Bineesh.
In his opinion, demarcating and declaring the shark moving areas as sanctuaries will help protect the species. Already 17 countries in the world have declared shark sanctuaries. This included Maldives and Indonesia.
Similarly, better enforcement of laws with the help of fishermen will be another way to reduce the killing of sharks, he said.
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