Great :/ Now seals are killing porpoises

[nomad100]

First the otters are killing the seals, now the seals are killing the porpoises.  When will the cycle of violence end?  Must the porpoises kill the otters?

news.yahoo.com/cuddly-critter-killing-europe-harbor-porpoises-184238683.html

When dead and mutilated harbor porpoises began washing ashore on the coast of the Netherlands in 2006, marine biologists thought North Sea fishers had killed the animals. But now they have identified the true culprits: gray seals.

“There were five badly cut up animals, that at the time, were considered bycatch victims that had been cut loose and mutilated, either out of spite—competition for fish—or to make them sink and go away,” Mardik Leopold, a marine biologist at the Netherlands’ Wageningen University Research Center, said in an email.

“From then on, we saw these mutilated porpoises every year, and in ever-increasing numbers,” Leopold said.

As researchers began conducting autopsies on the porpoises, they noticed bite marks consistent with harbor seal teeth. Now their evidence has been published in a new study, co-authored by Leopold, in the journal Proceedings of the Royal Society B.

“The recent detection of gray seal DNA in bite marks on three mutilated harbor porpoises, as well as direct observations of gray seal attacks on porpoises, have identified this seal species as a probable cause,” the authors wrote.

More than 270 porpoises that stranded between 2003 and 2013 on the Dutch coastline were sufficiently fresh to provide evidence of gray seal-inflicted wounds. “In 25 percent of these, bite and claw marks were identified that were consistent with the marks found on animals that had tested positive for gray seal DNA,” according to the study.

Most of the mutilated porpoises were young and healthy, with thick layers of blubber. The authors hypothesized that seals killed the porpoises to feed on the high-calorie fat.

The killings appeared to be a relatively new phenomenon, the scientists said.

“The gray seal is an opportunistic predator,” they wrote, “but predation on harbor porpoises, or any other marine mammal, had to our knowledge never been described.”

So why the change in feeding habits?

The researchers speculated that the animals began eating porpoises trapped in fishing nets, and then decided to hunt porpoises swimming in the open ocean.

The predominant fishing technique in Dutch coastal waters, has long been trawling the sea floor with nets. But that has changed in recent years.

“With rising fuel prices, and with mounting opposition against this sea-floor unfriendly fishing, more and more fishermen opted out and started with set nets,” closer to the surface, Leopold explained. “In our waters, this type of fishing is fairly recent.”

Meanwhile, the seal population in the southern part of the North Sea has increased dramatically in recent years, at about 15 percent annually.

“Changes in food availability further north might be climate driven or stem from overfishing, but this is not yet understood,” Leopold said.

For now, the change in predation patterns appears to be limited to the southern part of the North Sea. “The phenomenon is very rare in England and non-existent in Scotland,” Leopold said. “This might be just a matter of time, as gray seals often swim across the North Sea, so they might export this behavior.”

So far, there is no evidence that seals are putting the North Sea porpoise population at risk of decline, though that, too, could change.

“There are some 250,000 [porpoises] in the whole North Sea,” Leopold said. “Local predation probably won’t hurt the population as a whole. However, if this behavior becomes commonplace, things might get worse quickly.”

The researcher said the new study carries at least two warnings.

“People should be aware that we swim with predators and that we should not approach them, for our own safety,” said Leopold, noting that a male gray seal can weigh more than 660 pounds. “This is no laughing matter. A person would not stand a chance if a gray seal meant business.”

The other implication of the study: Humans may be saving gray seals at the cost of the local marine ecosystem.

“We save a lot of seals from mishap, in seal rehab centers,” Leopold said. “Unknowingly, we are nursing super-predators that, after having been released back into the wild, may take on another protected species. We may have to rethink this.”

[pixy0stix]

Seals also kill penguins.

So really, we should be thanking the otters for raping and killing the monster seals first.

[aurora]

I think it's pretty safe to blame humans as the root cause of all of it. Stealing all of the seals' and porpoises' food isn't going to help them get along better.

[gpw]

ASSHOLES!

[josieposy]

Man, the aquatic world is tough!


Baby Beluga in the deep blue sea
Better watch your back!!