Report finds whales and dolphins unable to breed due to pollutants

Shannon dolphins and Cork killer whale biopsies contributed to international study

Man-made pollution is affecting the ability of marine mammals such as killer whales and dolphins to breed and may lead to the extinction of some species, according to new international research.

Bottlenose dolphins, striped dolphins and killer whales or orcas are under enormous threat from persistent pollutants such as toxic chemicals, the study involving 31 partners, including in Ireland, found. Some of these pollutants are no longer produced, but are still making their way into the marine environment from landfill leachate, the research published inScientific Reports says.

The Irish Whale and Dolphin Group’s chief science officer, Dr Simon Berrow, described the findings as “quite shocking”, adding that he had not seen the calf of a killer whale in Irish waters since former taoiseach Charles Haughey declared a sanctuary for whales and dolphins 25 years ago.

He said the focus of environmentalists had switched from pollution to climate change, fishing and seismic surveys. “This study shows the threat pollution poses to our coastal species has not gone away and indeed is far greater than we expected.”

Data collected by the Irish Whale and Dolphin Group in Irish waters fed into the research led by Dr Paul Jepson, of the Zoological Society of London.

Biopsy samples taken from the Shannon estuary dolphins showed the lowest levels of contamination in Europe but they were still “well above the toxicity threshold”, Dr Berrow said. Samples from a killer whale stranded in Cork showed some of the highest concentrations recorded for this species in the study, he added.