Salmon Extinction Stories May Be Exaggerated

SALMON EXTINCTION STORIES MAY BE EXAGGERATED. IF YOU ARE THINKING ABOUT GOING SALMON FISHING IN THE BRITISH ISLES NEXT SEASON – READ ON!

INTRODUCTION

Fifty years ago, only a privileged few went salmon fishing. Cost was not the only barrier. Top beats across the British Isles accommodated few rods.  Plenty of fish, despite in-river netting and commercial fishing for wild salmon, meant tenancies were renewed each year.  You had to search for a ‘dead man’s shoes’.

Today, some salmon fishers still return year after year to a favoured river, but many wealthy anglers have found pastures new in Russia (currently out-of-bounds!), Iceland and Alaska. Newcomers are put off by reports of declines in catches in the UK and Ireland.  As a result, salmon fishing across the British Isles is available to all-comers. But are salmon numbers so low it is not worthwhile?

THE BIOLOGY LESSON

Our benchmark should probably not be the prolific the salmon populations of 50 years ago. Were they ‘normal’? The opposite may be true. Historical evidence suggests salmon numbers have always fluctuated wildly. Perhaps those numbers were an exceptional, and temporary, abundance.

A biology lesson helps to answer this question.

Salmon evolved from a freshwater ancestor. Their life cycle includes a marine migration to find more food, but they must return to freshwater to breed.

Salmon eggs and fry risk death from frost, drought, flood, and predation. Surviving juveniles must compete for a territory that provides food and refuge from predation. Then, they face a dangerous journey to the sea, make the difficult physiological transition into salt water and embark on a challenging marine journey, hopefully to rich feeding grounds.

When I was a young scientist, everyone believed that salmon smolts migrated to the sea from British rivers each spring, joined up with others, and set off towards the north Atlantic to unknown Arctic feeding grounds like a herd of wildebeest migrating across the Serengeti. It was assumed that the open ocean provided an endless abundance of food and that, when they reached maturity, a great ‘run’ of adult fish returned home and broke up to make their way to the river of their birth. Many of today’s salmon anglers still cling to this picture. It is not true. Here’s why.

Migration is a very high-risk gamble!

If you have survived to breed, it makes sense for your off-spring to inherit the same opportunity. Therefore, salmon have evolved to return to their natal river to breed. Tagging suggests there is a strong tendency to seek out the very same tributary. This increases the chance of mating with a fellow ‘winner’ and intense natural selection of genetic ‘instructions’ that reinforce their juvenile strength and successful marine migration route. This is how salmon ‘runs’ build over generations.

Atlantic salmon are a single species, but for millions of years their evolutionary pathway has been the natural selection of distinct ‘in-river tribes’. These tribes are like unique species. Their behaviour reduces inter-breeding. Each tribe is subject to different, changing pressures on their continuing survival.

This is a biological ‘bet’ that success must be built upon. Many migratory animals take the same gamble. Swallows return to the same barn each spring. Sea birds choose the same cliff-face.

There are two downsides to this evolutionary strategy.

Firstly, if a tribe’s migration route, or favoured feeding grounds, becomes short of food subsequent generations are genetically programmed to follow this doomed path. Extinction beckons unless conditions swing back in their favour. The second is that expanding distribution and re-population is very slow. If a ‘tribe’ dies out other salmon do not take their place, they follow their own genetic instructions. They do not seek out a fishless spawning stream or a better migration path, they positively avoid them! Therefore, salmon population cycles are long. It takes decades for runs that have been wiped out to rise again.

NATURE IS DYNAMIC

Only romantics believe there is a ‘balance of nature’. Nature is dynamic.

Populations of animals change, sometimes rapidly and ruthlessly, in response to food supply and habitat changes. Migration may be the key part of a successful life cycle, but it adds to the risk.

It is meaningless to simply describe Atlantic salmon as a declining species.

Here are some facts today, in November 2022. They are the current numbers of some salmon tribes. Every river provides other examples.

• A stable, healthy population of two-sea winter (2SW) salmon (they have spent two winters at sea after leaving freshwater as smolts) run the Owenmore River (they go through a counter) into Carrowmore Lake in Co. Mayo between February and May each year. There, they offer the best chance, anywhere in the British Isles, of catching an early ‘springer’ by traditional, loch-style fly fishing.
• In Scotland, the River Findhorn has a run (stable but not plentiful) of early spring 2SW salmon between March and May. Unfortunately, this run is subject to an outbreak of an endemic disease (Saprolignia), usually in late-May and June, in well-stocked pools. This disease is appearing in other Scottish rivers such as the Helmsdale and may be reducing the spawning stock.
• Fifty years ago, Aberdeenshire’s River Dee had a plentiful run of early 2SW spring salmon. Many were in the lower reaches by February and provided prime time fly fishing throughout the river by May. This tribe is much reduced. However, there is now a good run of 2SW summer salmon in July and August This increasing tribe provides the biggest rod catches of the year in August and September if the weather is kind (cold and wet!). Other Scottish east coast rivers are also experiencing increasing summer salmon runs.
• On Scotland’s west coast and islands increasing numbers of salmon farms using open sea cages cause severe biological pollution from parasitic sea lice. Some sheltered sea lochs are probably the most polluted marine environments in Western Europe. This pollution has caused the extinction of many tribes/populations of salmon and sea trout.
• Only ten years ago the river Tweed enjoyed an annual large run of autumn grilse (fish that have spent only one winter at sea) in September and October. This ‘tribe’ was probably the biggest salmon run in the British Isles and made the Tweed a world-famous autumn angling destination. The run declined catastrophically in 2013 and ’14 and is now functionally extinct. The river still enjoys a healthy run of late ‘spring’ salmon in May and June and an increasing run of summer (2SW) salmon.

The most important fact is that none of the tribes above have any direct relationship with each other. They might as well be different species.

It is possible (but risky!) to make some more generalised observations on salmon numbers.

• Over the past ten years populations of grilse (1SW salmon) have plummeted in most rivers. Runs that used to start in late June or early July and carry onto September now peter out by mid-July. (There are exceptions, the famous Grimersta fishery on the Isle of Lewis in the Outer Hebrides recorded its best-ever catches of grilse and summer salmon in 2022). Inevitably, this change is felt most severely in smaller rivers in Scotland and Ireland where grilse have always been the dominant salmon tribe.
• Summer salmon runs into bigger rivers seem to enter the lower reaches when they arrive rather than remaining at sea or in the estuary even when drought has reduced river flows. Often these fish seem reluctant to run upstream even when the rain comes.
• The speed at which populations can change is astounding.

Perhaps this is not surprising, if a tribe is ‘programmed’ to follow a doomed migration route that wipes out a whole year-class they will become extinct in 3 or 4 years. This what seems to have happened to the Tweed’s autumn grilse run. Conversely, if the gods are with a tribe’s year-class (successful spawning, good juvenile survival and successful marine migration) numbers of fish returning can sky-rocket. No wonder salmon numbers fluctuate so much.

AN EXAMPLE

Today, more salmon are caught in the Tyne than from any other English river.

It’s a remarkable recovery. Fifty years ago, like almost every river in northern England, it was an industrial sewer. A few salmon hung on, but every summer drought caused fish kills in the estuary. Then, the river got cleaner, but the construction of Kielder Water wiped out miles of spawning grounds on the North Tyne, its major tributary.

Uniquely, the lower Tyne boasts a fish pass at Riding Mill which has accurately counted the migratory fish that enter the river system since 1996.

Over these twenty-six years the annual run of fish has varied between a high of 48,000 in 2005 to a low of 15,000 in 2001. Over the last 6 years it has varied from a high of 43,000 in 2016 to only 17,000 in 2019. In the hot, drought year of 2018, when anglers all over Britain were complaining about catching no fish, the total was a respectable 34,000.

Statistically, these numbers are within a normal distribution with lots of annual variation. They indicate no real change over quarter of a century. Total salmon numbers go up and down considerably depending upon breeding success and mortality. Angler’s catches depend mostly on the weather!

However, the timing and make-up of these runs has changed.

Like the Tweed, its Scottish neighbour, the Tyne used to see a big run of a ‘tribe’ of autumn grilse, peaking in October. From 1996 to 2011, October was the peak month for running fish recorded at the Riding Mill counter. Since 2012 (when the recorded annual run was 50% below average) the peak month has been July or August. From 2013, annual numbers have been close to average and, while most fish still run the Tyne in the second half of the season, regular fishers know these are mostly 2SW salmon, not grilse. This is a continuing trend. In 2019 until July, which was again the peak month, numbers were normal. Then, from August to November only 3,685 ran through the counter, a reduction of 83% on 2018. The 2019 total was just over 17,000 fish, only the fifth time since 1996 when the total has been below 20,000. The autumn grilse ‘tribe’ had perished.

 

WHAT HAPPENS NEXT?

There is evidence that grilse, genetically ‘instructed’ to undertake a one-year migration, are starving at sea. No one knows if the juveniles die soon after going to sea or during the winter when the plankton blooms disappear. Research is underway to find an answer.

In the N. Atlantic rising sea temperatures have pushed pelagic fish stocks, mostly herring and mackerel, further north. Commercial fishing for these fish is now at a sustainable level unlike the 70’s and 80’s when they were heavily over-fished. Perhaps big increases in the populations of north Atlantic herring and mackerel, including their billions of juveniles, have impacted upon the food supply available to migrating grilse?

There are parallel collapses in the numbers of some Atlantic sea birds. Puffins and kittiwakes that feed close to the surface are struggling to find enough food while the numbers of gannets, which feed on adult mackerel and herring, are at record levels. This may change, they are suffering heavily in the current avian flu epidemic.

Interestingly, puffins are thriving on the north coast of Iceland. The changes affecting bird numbers in the N. Atlantic may not be as severe above the Arctic Circle. Perhaps UK salmon ‘tribes’ that race to arctic feeding grounds and spend two winters at sea are also benefitting?

No one knows what happens next, but positive trends are continuing on some rivers. Many ghillies and proprietors believe salmon runs in 2021 were the best in 30 years. The best lower Spey beats were catching 60 salmon a day when fishing resumed in August after covid restrictions. On one Findhorn beat, an estate worker given permission to fish when there were no tenants caught fourteen springers from one pool in a single, early summer day when conditions were perfect.

The downward trend in grilse numbers has not been reversed in 2021 and ‘22 but numbers have held up better than the pessimists feared in some rivers despite the recent drought.  No one doubts the numbers of summer-running 2SW salmon are increasing or holding up on all east coast rivers.

On the Tyne the run of migratory fish (11,845) through the counter in July ‘22 was the biggest recorded for that month since counting started in 1996. The August numbers were the third highest despite the river being chronically short of water in the worst drought since 1976. The number dropped to just over 3,000 in September.

WHAT SHOULD THE NEWCOMER (OR DESPERATE OLD HANDS!) DO IF THEY WANT TO FIND SUCCESS?

• Ask yourself, do I want to catch an elusive, chrome bright springer that might take weeks of effort? Or do I want to fish on a beat when salmon are in the greatest numbers and conditions are likely to be good? Do I want to fish a wide, lower river beat with deep wading/boats? Or a small spate river where conditions are often impossible? Can I go anytime or am I limited to a specific week? What is my budget?
• Most importantly, study the catch record. The great advantage for salmon fishers is that all catches are carefully recorded. Be ruthless in your decision making! Any beat you enquire about will tell you their record of monthly catches. Do not accept any excuses like ‘only lightly fished’ or ‘record not kept’. Last year’s catch for the month you are interested in may not tell you too much (perhaps there was a drought or fewer fish) but the returns for the last five years should tell you all you want to know. Do the numbers fall on either side of the mean or is there a definite upward or downward trend? How many rods fish? Work out the rod average. You are likely to catch the same, especially if you commit to the beat for a few years. Old records of more than five years back are meaningless. They have no relationship with current runs. Yet, many beats still advertise by referring to some bonanza year from the distant past!
• Research very, very carefully before renting salmon fishing anywhere in S.W. England, Wales, Ireland, or Western Scotland. Many, but not all, west flowing rivers are struggling. Most are predominately populated by grilse. These rivers are precarious habitats. They are food-poor and severe winter floods can wash-out redds and juveniles. It also appears that high marine mortality is reducing grilse runs in most rivers. Pollution from salmon farming has wiped out salmon and sea trout in many rivers in western Scotland and some in Ireland.
• Some rivers have a small run of ‘early’ spring salmon that run between February and May. These tribes do not seem to be increasing in numbers. On some rivers (often the same ones) there is a ‘late’ spring run between late April and June. Their numbers seem to be increasing.
• There is no doubt that many rivers are seeing better numbers of summer (2SW) salmon running in July and August. Low water and high temperatures in mid-summer mean catches often peak in September when rain and cold autumn nights lift the water and lower the temperature. By October these same fish are getting ready to spawn and are past their best. Although the Tweed is still open in October everyone accepts that few fresh fish enter the river after the end of August. Most Highland rivers close at the end of September.
• May is often a dry month in northern Britain. June is often wet and windy. If you have a choice June is a better bet for a ‘late’ spring salmon.
• Many beats now offer 3-day lets. If conditions are hopeless, three days is bearable, but a week is not. If conditions are perfect, three days may be just right.
• Never buy a salmon fishing time-share. It is an investment in an unknown future
• To guarantee salmon fishing success go to Iceland or Alaska. If the cost per fish calculation is important to you, and you can afford the outlay, this is the better option.

CONCLUSION

The summary is simple. Never ignore the facts. If catches on a river are going down, find another. Look for a beat trending upwards. Which is the peak month? Follow the numbers ruthlessly.  Make allowances for conditions. You might find a gem.

But, in truth, to catch lots of British salmon, you must pick your time on earth very carefully!

 

NEXT MONTH – ARE WE READY FOR A SALMON INVASION?