A record amount of salmon were caught in Scotland last year… but the fish are getting smaller.
A major study of the species in Scotland has revealed 100,000 fish were landed – the most since records began in 1952.
The average grilse, young salmon which have been at sea for just one year before swimming back to their home rivers to spawn, are a third less heavy and have shrunk by nearly a tenth.
Scientists also say that there are a third less salmon in the Atlantic than 40 years ago and twice as many as previously are dying at sea before reaching their rivers, perhaps because of the reduced size.
The Scottish research, part of the most comprehensive international study of Atlantic salmon ever undertaken, will come as a disappointment to fishermen and conservationists.
Commercial fisheries in the salmon's feeding grounds off West Greenland and the Faroes has been stopped and anglers return their catch rather than taking it home to eat.
At first it appeared the measures were working with 100,000 salmon landed in Scotland last year, the most since records began in 1952.
But Professor Chris Todd, professor of marine ecology at St Andrews University, said it was not just the numbers of salmon that was a concern but their quality.
He said that by monitoring an unnamed major Scottish river for the past 17 years he had found that the weight of the average grilse had fallen from 5.3lbs (2.4kg) to 3.74lbs (1.7kg), and that its length had shortened from 23 to 21 inches (59 to 54cm).
"It is pretty dramatic and very worrying," he said. "The fat content in the fish has also declined by about 80 per cent. People may be catching lots of fish but the quality is comparatively poor compared to the historical record. Also larger fish tend to produce more eggs. We don't yet know about the effect on egg quality – skinny fish may produce poor quality fish. It could be a vicious circle with big impacts for the future of the species."