Climate triggers shoreline changes

Donal Hickey says the tide is washing up rare fish

PEOPLE spending time in the water, or walking on beaches, are noticing the appearance of growing numbers of exotic fish along our shores.

Dead triggerfish are now turning up quite regularly on the west coast — yet another species from warmer southern climes being lured northwards by rising water temperatures, according to marine experts.

Recently, a UCC research group headed by Dr Tom Doyle tracked a sunfish, caught off the Kerry coast last summer, to the Bay of Biscay. It was the first time that a sunfish — a species about which little is known — was tagged with satellite equipment in Irish and British waters.

Triggerfish are distinguished by marked lines and spots and there are variations in the species, all quite colourful and looking out of place in Ireland.

They are normally found in the south Atlantic, the Mediterranean Sea and the Indo-Pacific Ocean. But, they are now being washed up on west Clare beaches, such as Seafield, White Strand and Doonbeg.

An interested observer is Dr Simon Berrow, of the Shannon Dolphin and Wildlife Foundation, in Kilrush. ‘Triggerfish have been turning up here for quite a long time, but I’ve never seen so many of them,’ he remarked.

No marks, yet again, for guessing the reason. In Dr Berrow’s view, it’s another example of the effects of climate change, just like the catching of the sunfish off Dingle last summer.

’What happens is that triggerfish can’t survive when the water temperature drops in the autumn. They don’t swim back to the warmer waters from which they came and they can’t tolerate the colder temperatures,’ he pointed out.

Triggerfish have a roundish, flat body and can use their dorsal spines to prevent predators from swallowing them or pulling them out of their holes in rocks. It is because of this locking and unlocking behaviour they are named triggerfish.

The spine of the triggerfish can be held in place by a second spine to make it more threatening to the predator. Their small eyes, situated on top of their large head, can be rotated independently.

Another feature is their tough skin, covered with rough scales that form an armour on its body.

A big, angular-shaped head extends into a snout with strong jaws and sharp teeth made for crushing shells. Each jaw contains a row of eight teeth, while the upper jaw has another set of six plate-like teeth.

They mainly feed on hard-shelled fish, with some of the triggerfish family feeding on large zooplankton or algae. Triggerfish can sometimes be a risk to divers because of the power and ferocity of their teeth.

Moving inland, a festival celebrating the rivers, lakes, streams and biodiversity of Co Kerry will take place at the Killarney National Park Education Centre, Knockreer House from 11am to 2pm, this Wednesday (May 21).

The festival marks the culmination of a Kerry County Council project running in the Flesk/Leane/Laune catchment in which schools and community groups assessed local rivers, learned of the rich biodiversity which healthy freshwater resource supports and how environmental best-practice in the home can reduce impacts upon water quality. The festival is linked to nationwide celebrations of International Biodiversity Week.

“Farms, forestry, and industry are cleaning up their act, but our own households have an enormous capacity to discharge nutrients and toxins which not only overwhelm sewage treatment, but cause harm to the natural environment,” said Micheál Ó Coileáin, environmental awareness officer, Kerry County Council.

Fourteen schools and several community organisations were engaged in aquatic studies under the council’s StreamScapes Aquatic Education Programme. The festival also will feature an exhibition of participants’ projects, to which the wider public is invited.

StreamScapes director Mark Boyden said students found the lessons, particularly the field trips, immensely stimulating and educational.

“We work on the basis that awareness of this rich biodiversity leads to pride in that resource and wanting to learn how to protect it. We have to seriously address habitat restoration and a huge start can be made in people’s own homes,” he said.

“The signs are that this next generation will get the balance right between prosperity and ecology. The public are invited to this impressive exhibition to see what the participants have learned.”

Household Best Practice leaflets will be distributed on the day. Along with the national roll-out of a Carbon Footprint Calculator to enable citizens to reduce their contribution to global warming, Kerry County Council is developing a Phosphate Footprint Profile to make people aware of how they contribute of phosphates to the natural environment.

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