World’s biggest Whales off Mayo

Less than 80 kilometres (50 miles) off Mayo’s coast is the continental shelf edge where water depth goes from 200m to 2000m. This is a migratory highway for the world’s largest whales, including Blue and Fin whales. We must look to Mayo’s whaling legacy to learn about these magnificent animals.

The Norwegians operated two whaling stations in County Mayo between 1908 and 1923. The  Arranmore Whaling Company was on the South Inishskea Island of Rusheen and the second called the Blacksod Whaling Company (1910) at Mullaghroe on the Mullet peninsula. Between 1908-1914 and 1920-1922 around 895 whales were captured including blue whale (14%), fin whale (66%), humpback whale (1%), sei whale (10%), northern right whale (21%) and sperm whale (7%) all within 50-200km of the coast (Fairley, 1981).

The marine environment faces huge pressures from the impact of human activities around Ireland’s coast. Recent academic studies suggest that Europe’s fish stocks are less than 10% of their post-war levels, because of overfishing.

Noise pollution from shipping, and oil and gas exploration activities have increased the background levels of noise in the sea so much that scientists are concerned that it is effecting marine life. Whales and dolphins rely on sound “to see” in the sea, to navigate, to communicate with each other and to find food, much as humans use light to see on land. Increased noise in the marine environment can potentially kill or deafen whales and dolphins and interfere with finding food and communication.

In the last decade noise pollution has increased several-fold in Irish waters. This is mostly due to acoustic surveys for seabed survey mapping, mid frequency sonar used by Navies and oil and gas exploration. However, there has been very little monitoring of the effect of this increased noise pollution on marine life.

Seismic surveys are performed to find and investigate geological structures associated with petroleum deposits in the seabed. Air, under high pressure, is fired into the water from airguns towed behind the seismic survey vessel and the very loud sounds produced are reflected by the seabed and subsequently detected by hydrophones that are streamed in towed cables from the vessel.

Off Scotland, several whale and dolphin species were found to change their distributions and behaviour in the presence of seismic surveys conducted by oil and gas exploration companies. Sperm whales were noted changing their behaviour in response to seismic activity at ranges of several hundred kilometres and leaving areas as seismic activity commenced.

In 2004, the International Whaling Commission (IWC) concluded that increased noise from geophysical exploration, among other activities, was “cause for serious concern” and outlined measures to reduce its impacts, particularly on large whales. Its conclusion was based both on theoretical concerns about masking and population-level impacts, and on a spate of observations and experiments confirming that seismic pulses can indeed kill, injure, and disturb a range of marine animals.

Increase in noise pollution off Ireland’s waters

A US scientist, Chris Clark from Cornell University, has monitored large whales off Ireland since 1996 using seabed hydrophones formerly used for tracking submarines. Clark, speaking at a World Ocean Summit in Belfast in 2010, said that when seismic surveys are being carried out in the North east Atlantic its not possible to hear whales singing off Ireland.

“The process of exploration for offshore oil and gas is by its very nature dirty work. It requires exploring for hydrocarbons. To discover where they are, very short bursts of very high-energy noise are exploded within the ocean and injected into the earth. Those acoustic explosions are repeated over and over again, 24 hours a day, for days on end. They are the modern form of exploratory dynamite, controlled explosions going off every 9 to 12 seconds. They represent the most severe acoustic insult to the marine environment I can imagine short of naval warfare.” CHRIS CLARK, DIRECTOR OF CORNELLUNIVERSITY’S, BIOACOUSTICS PROGRAM, IN A 2000 STATEMENT TO THE CANADIAN GOVERNMENT ON THE POTENTIAL IMPACTS OF SEISMIC EXPLORATION.

A 22ft Cuviers Beaked whale was reported (07032015) to the Irish Whale and Dolphin Group from Mulranny, County Mayo. This is the tenth Cuvier beaked whale stranding on Ireland’s west coast and is unprecedented. Only 54 have been stranded in Ireland since 1904. Previous mass strandings of beaked whales have been linked to naval antisubmarine exercises however as Ireland has only recently set up a post mortem scheme (2018) for whales the cause of these deaths are not known.

Although Irish waters were declared a whale and dolphin sanctuary in 1991, very little is know about the distribution and abundance of baleen whales, information essential to their conservation in Irish waters. Twenty-four species of whales and dolphins occur in Ireland and account for 48% of all the native species of all mammals recorded in Ireland.

In 2007 the Irish government was found by the European Court of Justice, not to have carried out sufficient monitoring of whales and dolphins and not to have put in place a system of strict protection, which Ireland is obliged to do under the Habitats Directive since 1997. Since 2007 the National Parks and Wildlife Service have commissioned some research to assess the distribution and abundance of whales and dolphins in Irelands EEZ.

However no monitoring to assess what effect seismic surveys have on marine life has been instigated by the Irish regulatory authorities. Oil exploration companies are not required to carry out surveys to establish the abundance of whales and dolphins in an area prior to seismic surveys commencing. If the abundance and distribution of whales and dolphins is unknown in an area, risk assessments are meaningless.

The government is obliged by law to implement a system of strict protection for whales and dolphins in Irish waters. Why are oil companies not funding baseline surveys and research on the effect of the noise pollution that there activities impose on whales and dolphins? After all, the Irish taxpayer is subsidising the oil companies’ exploration development costs and all these costs are tax deductible. A government committed to protecting the marine environment would implement such a protection system. It would create also jobs for scientists and would show Ireland to be meeting its national and international obligations to help protect our marine environment.

The eye of a young Minke whale stranded in Omey Island, County Galway 25112015. Photo © Shay Fennelly

The increase in oil and gas exploration since 1996 gives added urgency to obtaining the data to clarify baleen whales’ abundance, distribution and migration routes off Ireland’s coast in order to assist in conservation management. By knowing where the whales are, they can be monitored and conservation management plans to inform marine spatial planning can be drafted and agreed with stakeholders to avoid conflict and to minimise the impact of anthropogenic activity on these endangered species. In this way we can minimize any potential negative impact of oil and gas exploration in Irelands EEZ.