A new study has found that the number of oceanic sharks and rays has plummeted by over 70% between 1970 and 2018.
Many of the shark species are threatened with extinction, whilst the oceanic whitetip sharks, scalloped hammerhead sharks and great hammerhead sharks are critically endangered.
Sharks are often caught by accident by boats fishing for other fish such as tuna and swordfish. The number of fishing boats has dramatically increased since the 1950s, whilst climate change and pollution are also having an affect on shark numbers.
Nathan Pacoureau is a co-author of the study. He said: “The last 50 years have been pretty devastating for global shark populations. In terms of timing, they reproduce more like mammals – and that makes them especially vulnerable. Their populations cannot replenish as quickly as many other kinds of fish.”
Study researcher, Dr Richard Sherley of the University of Exeter, blamed fishing for the drop in numbers. He said:
“That’s the driver for the 70% reduction in the last 50 years. For every 10 sharks you had in the open ocean in the 1970s, you would have three today, across these species, on average.”
Sharks are at the top of the food chain, and their decline in numbers will affect other marine animals and humans.