A study published in the Biological Conservation journal highlights capture-induced abortions, a little-known, poorly understood fact that affects almost a quarter of pregnant sharks and rays when they are caught.
About 24 percent of 88 species of pregnant sharks and rays have been found to abort their young or induce a premature birth when they are captured, according to a new study. In some species like the pelagic stingray, the rate is as high as 85 percent.
“It’s quite prevalent across a lot of species and also seems to be not well known by both researchers and recreational fishers. They don’t realise these events are abortions, they think they are witnessing a natural birth,” said lead researcher Kye Adams, a PhD student from the University of Wollongong.
This phenomenon is not well known and poorly understood, so it is not considered as part of the by-catch.
Adams’ research was based on a study of recorded instances of such incidents, as well as 40 videos found on social media. He and his team concluded that many of the incidents were trauma-induced abortions, rather than actual births.
Although 80 percent of sharks and rays caught by recreational fishermen in Australia are released, the trauma of being captured is sufficient to cause the mothers to abort their young.
Adams said that recreational fishers and marine researchers should be educated about this phenomenon when catching pregnant sharks, rays or skates: “I don’t want to attack recreational fishers for this: it’s equally a problem for researchers like myself who catch sharks and rays to tag them.”
He added, “We would recommend that if you do catch a pregnant shark or ray—and you can usually tell because they are very fat—the best thing to do is release it without raising it from the water. Cut the line as close to the mouth as you can without harming yourself, and don’t take it from the water.”