Only the brave: Scientists to ask if some salmon are too timid to survive?
Researchers to explore if personality of fish seals their fate
Salmon born with an adventurous streak might be more likely to perish because they swim into harm’s way, scientists suspect.
Fish are known to have traits such as boldness or caution and their personalities could contribute to their chances of survival.
Now experts are to study the DNA of salmon smolts from the Moray Firth to see whether some have inherited a genetic advantage.
Fa c t o r s being considered will include their temperaments, metabolism and resistance to water- borne parasites or disease. Tissue samples were taken from the fins of smolts being tagged for a project examining the reasons behind the collapse in Scotland’s wild Atlantic salmon population. Early findings from the
Missing Salmon Project have shown that half of the 850 tagged smolts did not make it out of their home rivers after embarking on their migration. Only around 35% got as far as the sea, as another 10 to 15% vanished in the estuary.
Experts at the University of Hull will now analyse some of the smolts’ DNA to look for clues, such as whether a tendency to gain weight quickly boosts their prospects. Dr Domino Joyce, senior lecturer in evolutionary biology at Hull, said: “We’ll know which of the fish have made it to the end of the river, which ones made it all the way out to sea, and another group which haven’t made it anywhere.
“We’re going to see if we can find any genetic differences between the groups.
“It depends on the reason the fish are being lost. If it’s completely predation then it might be that there’s no genetic differences and it’s purely random.
“But there could be things like differences in when they move. So if some of them are much more cautious and only move at night then they might be less likely to be predated.
“In fish and lots of animals, you do often see personalities. Boldness is quite a common personality trait in animals where they’re more likely to explore or come out of hiding.
“The genetic basis for things like that are difficult to find and it might be that we don’t find it.
“But it might be that there’s something there.
“It might also be that there are fish with a more efficient metabolism and are better at putting on weight so they might be more likely to make it down the river.”
The research – scheduled to take place over the next year – is part of a wider Cluedo- style investigation being led by the Atlantic Salmon Trust (AST). Young salmon – or smolts – migrate to sea from the river of their birth before eventually returning to spawn.
But in the past 25 years, the numbers coming back have dropped by 70%, and fewer than 5% make a successful return journey. Last year was the worst on record.