June 12, 2009

Researchers Observe Disabled Minke Whale Injured By Fishing Nets

Experts say a minke whale that was likely injured by floating rope has provided a unique insight into the dangers posed to marine animals by fishing gear, BBC News reported.

The large whale was spotted off the coast of Quebec, Canada, with a huge scar around its throat and feeding in a way never before recorded for minke whales, probably in response to its injury.

It is one of the first sightings to detail the handicaps that can be caused to animals that become entangled in fishing nets and BBC's Earth News is reporting the development as part of a series of articles highlighting the dangers such nets pose to marine animals.

The minke whale was first noted near the coast of Longue-Pointe-de-Mingan, Quebec, in the Gulf of St Lawrence, where marine biologist Brian Kot of the University of California and colleagues noticed it had a deep laceration running the circumference of its feeding pouch, from near its throat up both sides of its head close to each eye.

Kot said the width of the laceration, which ran through the whale's skin and into its blubber in parts exposing the muscle underneath, was very similar to the ropes from crab pots that are set by fishermen in his study area.

The injured minke was observed and videoed by Kot and his team as it fed on schools of capelin for over 80 minutes. Further analysis of the video showed that the whale had no problem accelerating into each lunge.

However, experts say it often breached in a way never before recorded among minkes.

The whale breached at an angle of 30 to 45 degrees to the surface on 18 of the 50 lunges, feeding on its right side only and rotating in the air to land upright on its chin, they said.

Kot said the injury seemed to affect the expansion of the ventral pouch.

"I noticed a unique lunge-feeding behavior that has not been previously described in the scientific literature," he said.

He said they had not seen the injured minke whale again, and the team is still unsure what long-term impact the wounds had.

He said perhaps the injured animal left the area and survived or perished some time in the future.

However, the sighting of the minke whale is valuable as it's "one of the first to show the effect of an entanglement-like injury in a live animal," Kot said.

By some estimates, fishing gear poses the greatest threat to whales; yet little is actually known about the impact fishing gear has on the survival of these ocean giants and almost nothing is known about the non-lethal impact caused by entanglement injuries.

Kot said that cetacean entanglements involving various kinds of fishing gear have been a global concern for many years, but with the steadily increasing demand for food, fishing pressure in the world's oceans has increased the amount of gear that whales can come in contact with.

"Some of the largest whales, such as blue or fin, can sometimes free themselves from entanglements due to their size and strength," Kot explained.

However, he said many whales like minke likely don't have that ability, as most small whales that do get trapped probably drown and sink, never to be found by anyone, including the fishermen who own the net, he said.

Kot and his crew, who were working for the Mingan Island Cetacean Study non-profit research organization, have published further details of the injured minke whale in Marine Mammal Science.


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