The discovery of a dead sunfish on a Norfolk beach is “extremely important” for scientists studying the world’s largest bony fish and potential links to climate change, an expert has said.
The juveniles, measuring around 1.5m, appeared on North Beach in Great Yarmouth last weekend.
Adults can grow up to 4 m (13 ft) and weigh up to two tons.
Dr Ben Garrod, from the University of East Anglia, said four had washed ashore in a year, but the cause was unknown.
“The sunfish is one of the strangest yet iconic fish in the sea,” said a professor of evolutionary biology and science presenter at the BBC.
The species – Mola mola – is the largest bony fish and generally lives in temperate and tropical waters.
Katherine Hawkes photographed the sunfish on a beach in Norfolk on New Year’s Day and said she didn’t know what she was looking at at first.
“Then I realized that I had seen a sunfish swimming once, but they are rare this time of year,” she said.
Sunfish (Mola mola)
The sunfish is the world’s largest bony fish
Fish descend to a depth of 50 to 200 m (164 to 656 ft)
They feed mainly on jellyfish
Their name refers to their habit of lying on their side on the surface of the sea as if sunbathing
(Source: Society for the Protection of the Sea)
At about 1.5m from top to bottom fin, Dr. Garrod said it was “the biggest we’ve seen … in the last few years.”
“But it’s still a baby compared to adult size,” he added.
This is the fourth he was told to wash up on Norfolk beaches in the last 12 months, three of which have been investigated by the UEA.
“We don’t know why they died, and this is an ongoing research project, but it’s extremely important because we know so little about them,” he said.
“I know they washed them up on the Norfolk coast – maybe once every 10 years – but four in the last 12 months is really interesting.
“We have no evidence that it is related to climate change, but no one denies that the oceans are changing.”
Prof. Heather Koldewey, Senior Marine Technical Adviser at the Zoological Society of London.
“A single sighting of one fish makes it difficult to draw far-reaching conclusions about climate change, especially as occasional dead sunfish have been recorded in previous winters off the UK,” she said.
“However, as sea temperatures change, we see changes in the distribution of many marine species.
“For example, more sunfish were seen in the south-west of Britain in the summer, which may be more indicative of climate-driven changes.”
“The Lost Migrant”
A spokesperson for the Norfolk Wildlife Trust said: “Sunfish are such a unique species to see here in Norfolk. It is unusual to find them on our coast as they tend to thrive in much warmer waters.
“Still, many sunfish have been found along the Norfolk coast [recently].
“The fish likely followed the jellyfish – their favorite food source – and found themselves in a difficult position in the much colder waters of the North Sea.
“Sightings of unusual species such as sunfish here in Norfolk appear to be increasingly common and may be related to climate change and warming seas.”
Joint marine recorder for Norfolk, Rob Spray, said: “We’re looking for trends and with climate change we’re looking for species to grow – and the North Sea is a pocket within reach, but a lost migrant like this has arrived at the end of what it can survive in “.
Dr Garrod added: “While it’s sad to see any animal die, the sunfish here is unusual, exciting and very interesting.”