After marine biologist Stuart Sandin talks about critters, it seems like he is describing Jedis of this sea. “They’re fantastic predators, fast swimmers and they have excellent perceptions — they could detect some disturbance in the sea from great space,” such as scents or small fluctuations in water currents.
Their capacity to rapidly feel anything beyond the standard in their surroundings helps them locate prey at the vastness of the ocean. But in addition, it makes them particularly vulnerable in the face of increased global fishing pressure, as international fishing fleets have dropped since 1950.
“You drop a fishing line from the open sea, and frequently it is sharks which are there — whether they’re the principal goal,” explained Sandin, that works in the Scripps Institution of Oceanography.
Researchers have known for decades that human shark species are falling, but a new study drawing 57 worldwide datasets underscores how radically worldwide populations have dropped in the last half century.
“The past 50 years have been fairly devastating for international shark populations,” explained Nathan Pacoureau, a biologist at Simon Fraser University in Canada and a co-author of this analysis.
Occasionally sharks are intentionally captured by fishing fleets, but often they’re reeled in as” bycatch,” in the course of fishing for other species like salmon and swordfish.
Sharks and rays are equally fish using skeletons made from cartilage, not bone. Compared to most other sorts of fish, they usually take a long time to attain sexual maturity, and they produce fewer offspring.
“In relation to time, they replicate more like mammals — which makes them particularly vulnerable,” explained Pacoureau. “Their inhabitants can’t replenish as fast as several different sorts of fish.”
The amount of fishing vessels trolling the open sea has increased steeply since the 1950s, as motor power enlarged ships’ range. And while climate change and pollution also imperil shark survival, higher fishing pressure is the best threat for every single whale shark species.
“When you eliminate top predators of the sea, it affects every component of the marine food web,” stated Stuart Pimm, an ecologist at Duke University, who wasn’t involved in the analysis. “Sharks are like the lions, lions and bears of this sea planet, and they keep the remainder of the ecosystem in equilibrium.”
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