Bluefin tuna and common dolphins could be threatening the local porpoise population, according to the founder of a Pembrokeshire environmental charity.

Sea Trust’s staff and volunteers were amazed to see a large tuna leap from the water close to the cliff during their most recent Strumble Head survey.

“In the last 15 minutes of the survey, we were watching some odd splashing very close to the cliff and were shocked to see a large tuna leap from the water,” said Sea Trust’s Nadia.

Her observations set Sea Trust Wales founder Cliff Benson, to thinking that the increased number of tuna and dolphins in the area could be leading to a decline in porpoises in the area.

“We only started recording bluefins about seven or eight years ago out in the Celtic Deep,” said Cliff, “And we only started seeing common dolphins inshore since 2000-2001, and then only once or twice in the summer.”

Cliff said that it was now normal to see common dolphins year-round at Strumble and often in large numbers of more than sixty.

At the same time the amount of porpoises spotted at Strumble seems to be going down.

“Porpoise numbers at Strumble seem to be declining since the days when we regularly experienced what was termed ‘porpoise soup’,” said Cliff.

“On a slow count, I might often register 40 or more individual surfacing porpoises, as I scanned across from the lighthouse to Mackerel Rock, about 150 degrees.”

Cliff said that seeing porpoises in these numbers would hardly ever happen these days.

“In fact I can remember when I last saw anything resembling ‘Porpoise Soup’,” he said.

Looking at what has changed at Strumble, Cliff believes that there is less human influence at the headland.

There are fewer commercial potting fishermen, and less large boat traffic, as the high-speed catamarans between Fishguard and Rosslare no longer run.

In terms of changes that might impact on the porpoise numbers at Strumble, Cliff thinks that other sea life could be the answer.

“Competition from other species such as common dolphins and in the past year or so, bluefin tuna that have infiltrated what used to be our porpoises happy hunting grounds,” he said.

Sea Trust runs regular surveys at Strumble Head and in the Celtic Deep.

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