New Delhi (NVI): Overfishing has savaged populations of some sharks and rays by more than 70 per cent in the past 50 years, leaving a gaping, growing hole in ocean life, according to a new study.
Decades of data show an alarming decline in species ranging from hammerhead sharks to manta rays.
A huge increase in fishing since 1970 has ravaged the abundance of sharks and rays in our oceans, with previously widespread species such as hammerhead sharks now facing the threat of being wiped out.
Half of the world’s 31 oceanic shark species are now listed as either endangered or critically endangered by the International Union for Conservation of Nature.
“The decline isn’t stopping, which is a problem,” said Nathan Pacoureau, a researcher at Simon Fraser University in Canada who was lead author of the study, published in Nature.
“Everything in our oceans is so depleted now. We need proactive measures to prevent total collapse, this should be a wake up call for policy makers.”
The populations of these marine creatures have collectively tumbled by 71 per cent, as they are caught in huge numbers for their meat, fins, gill plates and liver oil – as well as accidentally by fishing boats seeking other species.
Pollution, climate change, overfishing of their prey and habitat destruction are also playing a part in their decline.
The losses could be even deeper in reality, with insufficient data to chart population trends back to the 1950s, when the explosion in mass industrialized fishing started.
It has been previously estimated that 100 million sharks are killed by humans every year, overwhelming their slow reproductive capacity to replenish numbers.
“Ongoing declines show that we are not protecting a vital part of our ocean ecosystems from overfishing, and this will lead to continued decline in the health of our oceans until we do something about it,” said Dr Cassandra Rigby, a biologist at James Cook University in Australia and study co-author.
Three sharks were found to be critically endangered, with their populations declining by more than 80 per cent — the oceanic whitetip shark, scalloped hammerhead and great hammerhead.
-CHK
