Traditional Irish fish species are moving north due to warming sea temperatures, according to those working in the industry.
“Because the water is getting warmer, we are getting more fish stocks that you would have traditionally found down south,” says Sean O’Donoghue, chief executive of the Killybegs Fishermen’s Organisation.
“We are also seeing more anchovies and sardines coming into our waters, which you would normally see in the Bay of Biscay [off France].”
Warming sea temperatures means a concern is another important stock for Irish fishing: mackerel.
“That would be a huge blow,” says O’Donoghue. “We are worried that in 10, 15 years’ time, we will be fishing different stocks.”
This month’s findings from the United States National Oceanic and Atmospheric Administration (NOAA) – that the temperature of the water in some Irish seas was as much as four and five degrees Celsius higher last year than between 1991 to 2020 – have shone a fresh spotlight on warming seas.
Glenn Nolan, leader of the oceanographic and climate services group in the Marine Institute, Galway, believes, however, that the NOAA figures relate to “a relatively localised event, local weather conditions”.
Marine heatwaves, such as the one we are experiencing, “happen all the time”, he says.
“There have been eleven ocean heatwaves since 1982. This current heatwave will diminish over time. The heat is concentrated in the upper 10, 15 metres but the waves during the autumn and winter seasons will dissipate this heat,” he adds.
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Nolan is an author of Marine Institute’s Irish Ocean Climate and Ecosystem Status report, published in May, which, he says, looks at the “long-term weather, the climate of the ocean and seas off Ireland”.
This report finds that the sea surface temperature of the waters off Irish shores are 0.4 degrees Celsius warmer on average in the 21st century compared with the temperature between 1960 and 1990.
While this increase in temperature is significant in marine terms and may be causing species of fish to move to different areas, it is too early to be “definitive” about this, says Nolan.
The apparently new movement patterns of fish is an added pressure for the Irish fishing industry from the loss of fishing quotas as a result of Brexit.
“On the 11th hour on Christmas Eve, the EU transferred 15 per cent of the European quota to the UK in return for allowing EU fishermen access to the UK’s waters,” O’Donoghue says.
“Ireland took 40 per cent of the EU cut overall – our two main stocks, mackerel and nephrops [prawns], 25 per cent and 14 per cent respectively of our quota, gone overnight,” he says.
Furthermore, the war in Ukraine has also had “a devastating effect” on the shipping fleet, says O’Donoghue.
“We are very dependent on marine diesel, which, for six to eight months last year, was at the uneconomic price of €1.10 a litre, whereas the break even point is 60-70 cent a litre,” he says.
“Our French and Spanish colleagues were compensated by their governments for this difference. However, we received no such assistance from our Government,” he says.
“Overall, there are 16,000 people employed in the seafood sector,” he says, “but, significantly, in Donegal, it represents 15 per cent of all coastal employment.”
Ciarán Doherty (48), from Cruit Island in Co Donegal, has been a fisherman for the last 31 years. His father and his grandfather were also fishermen.
“It’s a family business. I have 11 Donegal men on our boat, the Áine,” he says. “We fish the pelagic shoaling fish like mackerel, blue whiting and boare fish.”
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Doherty is also more circumspect regarding the reported big increase in water temperatures.
“I haven’t seen anything like that. [The NOAA’s figures] could be a snapshot, localised weather,” he says.
“There has been a small change in the water temperature. We have seen more boare fish coming north. You would usually see them at the south end of Ireland and in the Bay of Biscay.
“Pilchards [a small, herring-like fish] are also becoming more prolific,” Doherty says. “But the amount that we are seeing of these new fish wouldn’t support a viable fishery.”
This may change in 10 or 15 years if stocks continue to increase, he says, adding that the weather at sea has gone in cycles over the years.
“The sea temperature hasn’t changed that much. The mackerel are still arriving off Ireland at the same time,” he adds.
Patrick Murphy of the Irish South and West Fish Producers’ Organisation says that the rise in temperatures will result in “huge repercussions” for marine life and will affect fish stocks coming into Irish seas.
“We are seeing different species of mussels appearing. The larvae of the mussels are changing year-on-year and it is causing growth in the algae. It is also causing other competitors to come into our waters – seals are increasing and blue fin tuna,” he says.
There will be positive and negative consequences, Murphy says. For him, however, the critical issue is that, due to rules under the EU Common Fishery Policy, Irish fisher people will not be able to take advantage of these consequences, such as catching species of fish that they normally would not have.
“[The Common Fishery Policy] should be reviewed. It is meant to be reviewed every seven or eight years but there was no review this time around. The Irish people, not just the fishing sector, are losing out,” he says.
“Twenty thousand tonnes of blue fin tuna can be caught in the EU. Ireland gets to share in 74 tonnes. Even though these fish are eating native Irish fish, changing the structure of the marine ecosystem, Irish fishermen get to catch none,” he says.
Jason Sheehan (35), a fisherman and managing director of Sheehan’s Fishing Company which is based at Dinish Island in Castletown-Bearhaven in West Co Cork, has four vessels catching pelagic fish, mackerel, tuna and prawns.
He has been fishing full-time since 2005 and, as a younger man, worked during the summers.
“A few years back, we noticed the temperature of the water going up but then it returned to normal,” he says. “This year, there seems to be a spiking.”
He, too, predicts fish moving due to the changing sea temperatures as the summers become warmer.
“The tuna is migrating north. They usually arrive in August but, this year, they are arriving in July,” he says.