During your ramblings around the internet and the “Up Next” column on YouTube, you might have come across some viral videoes of a shark or a ray giving birth to a litter on the beach in the hands of a person. Well, it turns out these videos are not as cool as they first appear.
There's a pretty high chance the animal is actually aborting its litter. A new study published in the journal Biological Conservation has found that rays and sharks frequently abort their young when they are captured due to stress. If late enough in the pregnancy, the litter might survive. However, in many cases, the young can die.
Around 60 percent of shark species and all rays bear live young. An average of 24 percent of pregnant females from the 88 different live-bearing species studied were found to give birth prematurely. In some species, it occurred more often; pelagic stingrays aborted their young upon capture up to 85 percent of the time.
This could potentially have a huge effect on the population health of these magnificent creatures, especially those that are endangered. Sharks and rays put huge amounts of energy into reproduction and have one of the longest gestation periods in the animal kingdom, as well as being among the slowest growing and oldest maturing vertebrate animals.
“Given that sharks are more than 300 million years old, it's probably evolved as a survival strategy,” lead researcher Kye Adams from the University of Wollongong Australia, said in a statement.
“Either the mother gives birth to help her escape predators – so the predator eats the pups instead of her and she can go on to have more pups in the future – or alternatively she self-sacrifices for her pups and gives birth so that they might survive.”
The scientists on the project hope their research will raise awareness among fishermen and marine biologists since there's been very little scientific research on this issue before.
Adams also had some advice for fishermen who accidentally capture a shark or ray: “If you do capture a shark or ray and suspect they might be pregnant – and a lot of time it’s obvious because they're so fat – the best thing to do is leave it in the water. Don't try and remove it, just cut the line as close to its mouth as you can and minimize handling time."
“Another option – not for all species, just for those that are most in danger – is seasonal or spatial closures of fishing around pupping or nursery areas.”