Almost 30 whales died off the Irish coast in a two month period.
A recent UK study showed that half of the world's killer whale population is facing extinction because of toxic pollution in the oceans.
The news comes just after the revelation that an unprecedented number of beaked whales died off the Irish coast — 28 for August and September.
Investigations are underway to determine the causes of death, but in the interim, marine experts have called for more protection for whales off the Irish coast.
Simon Berrow, the chief science officer and acting chief executive of the Irish Whale and Dolphin Group (IWDG), told the Irish Examiner that key issues must be dealt with.
"Whales and dolphins are on top of the food chain, so healthy populations of the species are a barometer of the state of the marine ecosystem," he said.
“Unprecedented” #whale deaths spanning the west coast of Ireland. Cause of death is unclear, UK and Scottish governments are launching investigations: https://t.co/oaOWCwXjKp pic.twitter.com/QW5vIIijzi— MMCommission (@MarineMammalCom) October 21, 2018
The IWDG believes that the overfishing of sprat, a hugely important food for many marine mammals, needs to be monitored. Berrow stated that if Ireland is to become a true whale sanctuary, sprat resources must be managed better in the interests of coastal communities and the marine ecology.
He also addressed the issue of poisonous chemicals (PCBs) that despite being banned decades ago, are still seeping into the seas.
The chemicals get into the food chain and killer whales are seriously affected, as are their calves through drinking their mother’s contaminated milk, he said. These chemicals can also cause infertility in killer whales.
Another reason for the widespread deaths of the beaked whales may be the result of warships using active sonar to hunt for enemy submarines, or naval anti-submarine exercises.
Berrow told Live Science that, "beaked whales are sensitive to the very loud sounds caused by anti-submarine sonar sounds. The sounds cause intense pain to beaked whales diving at extreme depths so that they surface too quickly and die from decompression sickness."
Columnist Donal Hickey writes that former Irish leader Charlie Haughey agreed to a request from the IWDG to declare all Irish territorial waters to be a whale and dolphin sanctuary in the 1990s.
"Since then, there has been a big increase in whale-watching, which has real potential for tourism. West Cork and west Kerry are now probably the best places in Ireland to see these magnificent creatures," Hickey states.
The journalist also reports that, on the positive side, the number of humpback whales along the south and west coasts, from Co Wexford to Co Galway, is also growing.