Salmon numbers declining despite best efforts

Salmon numbers declining despite best efforts
Salmon, file photo

Despite various conservation efforts and bans on fishing, we now have fewer wild salmon than even a decade ago and many reasons are being put forward for the continuing decline.

As scientists continue to probe reasons for the huge drop in salmon numbers, an expert says it’s an issue for everybody in our society; not just anglers and nature lovers.

Some of the reasons are man-made. In the River Nore, for example, a recent Eco Eye RTÉ programme reported over 500 obstacles in the paths of salmon returning there to spawn. It should also be said that Co Kilkenny angling clubs are involved in efforts to make the river more salmon-friendly.

Salmon numbers peaked in the mid-1970s when around 1.7m returned to Ireland. Today, returns are estimated at 250,000 to 300,000. These are figures from graphs quoted by Inland Fisheries Ireland chief executive Ciaran Byrne. He also looks at the number of juvenile salmon which survive at sea and make it back to their birth rivers and lakes to breed. Marine survival peaked around 1986, with about 31 of every 100 which set out on the perilous journey from an Irish river to the Atlantic returning compared to seven today.

Salmon produce thousands of eggs and there’s a biological reason for this. Nature decrees that only a small amount will survive. What’s different now, says Dr Byrne, is that the number which die is higher than what salmon have biologically planned for and this is leading to the fall in stocks.

Writing in the latest issue of Sherkin Comment, he says this is also happening in many other countries. The easy answer would be to blame sea lice and fish farming, which can be significant factors, but the reality is far more complex.

There are multiple factors in the decline of salmon stocks, each of which can have a different level of influence in different years,” he says.

Though illegal fishing has declined, according to Inland Fisheries Ireland, and all drift netting has been banned since 2006, salmon levels continue their decline.

Dr Byrne says it is likely that changes in ocean temperatures, food availability and predators are also having dramatic impacts on salmon abundance. However, he says, such factors are effectively uncontrollable.

“So, what we have to do is to focus our efforts on controlling the controllables to ensure our juvenile salmon are given the best chance possible to survive at sea,’’ he says.

Salmon is the freshwater equivalent of the canary in the coalmine — an early warning system for something being wrong, he says.

“Healthy salmon populations are possibly one of the best indicators of a healthy environment and every one of us will benefit from a healthy environment.”

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