Are Atlantic Salmon Endangered?

Are Atlantic Salmon endangered

Are Atlantic salmon endangered?

Britain’s wild Atlantic salmon populations have been declining steadily for decades. This magnificent fish, once abundant in Britain’s rivers, was officially classified as “endangered” on the International Union for the Conservation of Nature (IUCN) Red List in 2023. Chalk stream salmon, a subspecies of Atlantic salmon, are uniquely found in rare chalk stream habitats such as the Rivers Test and Itchen. The numbers of chalk stream salmon in our rivers have been decimated in recent years. In 2022 there were the lowest numbers of salmon in the Itchen since 1990 – just 20% of the conservation limit (the target for species stock survival.) The same year the Test had the 4th lowest numbers since 1990 at just under 50% of the conservation limit.

Why are salmon important to the ecosystem?

As the salmon population shrinks, the ecological balance of the rivers they inhabit is also disrupted. Atlantic salmon are an “indicator species”. This means that their health is directly affected by the health of the ecosystem of which it is a part. The decline of the salmon in the Test and Itchen should be seen as a warning about the overall health of our rivers. 

Is it too late to save the Atlantic Salmon?

Salmon already face many challenges at sea. But when they reach the rivers they face additional ones which are contributing to their decline. These include physical barriers to migration, climate change, pollution, over-abstraction and habitat destruction. It is not too late to save Britain’s salmon population but it will take urgent action on the part of the Government, regulators, river owners and conservationists to do so.

Why Are Atlantic Salmon Endangered?

Challenges Faced by Salmon at Sea

When wild Atlantic salmon are at sea, they face numerous challenges. One of the primary threats is overfishing. Commercial fishing operations often capture these salmon before they have a chance to return to their natal rivers to spawn. Bycatch, where non-target species are caught in fishing gear, also poses a significant threat.

Another major challenge is climate change. Rising sea temperatures and shifting ocean currents can disrupt the salmon’s migration patterns and food supply. Additionally, increased levels of pollutants and microplastics in the ocean can affect the health and survival rates of wild Atlantic salmon.

What Freshwater Conditions do Salmon need?

Salmon have a complex life cycle. They are highly vulnerable to stressors or anything that blocks their migration, up or downstream, or undermines the conditions they need for breeding and rearing juveniles.

A good way to think of Salmon is that they are oxygen junkies; they are muscular fish swimming upstream against good flow and overcoming barriers (both natural and man made). Following this the females need to build nests in the river and the males need to stand guard to fertilise the eggs. Many of them die simply from exhaustion. It is a series of sprint events, one after another, most probably akin to a continuous series of 400m olympic races for a human. 

Save endangered chalk stream salmon River Itchen

As such they need clean, cool, and well-oxygenated water. They need places to rest whilst they travel up stream with sufficient shade. The riverbed must consist of gravelly substrates, where females can dig nests, known as redds, to lay their eggs. Vegetation along riverbanks is crucial as it helps stabilise the banks, preventing erosion and providing cover for juvenile salmon.

For these reason, chalk stream salmon thrive in the unique environment provided by the chalk streams of southern England. Chalk streams are fed by groundwater from chalk aquifers, which results in consistent temperatures and high levels of dissolved oxygen. These rivers have traditionally been characterised by their clear, alkaline water and stable flow rates, which create ideal conditions for salmon spawning and rearing. Yet these conditions are now under threat from migration obstacles, pollution, over-abstraction of water and habit degradation. 

Challenges in the Rivers

Atlantic salmon require specific conditions to thrive. However, the decline in the condition of our rivers means that when wild Atlantic salmon  return to the chalk streams to breed they now face numerous challenges.

One of the first challenges that salmon encounter when returning to spawn is migration obstacles. Dams, weirs, and other barriers can block their passage upstream. While fish ladders and bypass channels exist, they are often inadequate or poorly maintained. These obstacles delay the salmon’s journey, exhaust their energy reserves, and sometimes prevent them from reaching their spawning grounds altogether.

Another obstacle to successful migration is pollution. The salmon are trying to return to their natal river, but in the time that they have been away, the smell of the river may have changed due to the pollution in its waters.

Water quality is a significant concern. Pollution from agricultural runoff, sewage discharge, and industrial waste has degraded the water quality in chalk streams. High levels of nitrates and phosphates can lead to algal blooms, which deplete oxygen levels in the water, making it difficult for salmon to survive. Moreover, pollutants can accumulate in the tissues of salmon, affecting their health and reproductive success.

A good rate of flow is essential to create the conditions that salmon need. When too much water is extracted from the rivers this affects flow rates to a level that endangers the salmon. The Test & Itchen are the only source of water supply to hundreds of thousands of homes and businesses in Hampshire and the Isle of Wight. Despite their SSSI and SAC statuses, Southern Water is legally allowed to take water from the rivers to supply customers even when it means flow rates are affected. Under drought conditions, the legal limitations on the amount of water that can be taken out of the rivers can be lifted further, thereby exacerbating the problem for the fish.

Read more about the impact of over-abstraction of water on the environment

Habitat degradation in chalk streams is a critical issue. Urban development and agricultural activities can lead to the loss of riparian vegetation, which is essential for maintaining water quality and providing shelter for juvenile salmon. Without adequate vegetation, riverbanks become unstable, leading to increased sedimentation in the water. This sediment can smother salmon eggs and reduce the availability of suitable spawning sites.

Are Atlantic Salmon endangered

What We Are Doing to Save the Salmon

First and foremost, we must ensure that the rivers are in good health. This means water in plentiful supply, pollution free and with a thriving ecosystem. A good habitat, free of obstructions to up and downstream migration, will lead to improved chances for successful salmon survival. The Test and Itchen Association are working with other environmental NGOs are working hard for:

An End To Over-abstraction

Good river flows and pressing for the EA and SW to stop over abstraction. We are supporters of the Hampshire Water Transfer and Water Recycling Project, a scheme to build Havant Thicket Reservoir and to use advanced techniques to recycle waste water that would otherwise be lost to the sea. This is one of the strategic national infrastructure projects SW are due to deliver to reduce the need to abstract from our chalk stream rivers. 

Improved Water Quality

We have set up a Water Quality Monitoring Network and also help coordinate training and volunteers for river fly monitoring to help identify incidents of pollution. Since 2015 we have been funding a Smart Rivers survey twice a year to provide baseline data on invertebrate life in the rivers.

We have coordinated some peaceful public protests to raise awareness of the sewage scandal in our rivers. This has also led to an opening of a new dialogue, alongside others, with SW  in order to  help them understand the priorities of the riparian owners, keepers and anglers as well as our communities along the river.  

Habitat Improvement

We are working with riparian owners to identify opportunities for improved general river habitat and in particular habitat for salmon sanctuaries for both juvenile and adult salmon, improved spawning grounds through weed and gravel management, including cleaning, and appropriate planting of trees to provide shading.  

Removal of Migration Barriers

We are promoting the need to remove barriers to fish passage, such as  weirs and locks and other obstructions to fish migration.  Progress is slow and really needs to speed up.  

Angler Behaviour

The other key to this is the behaviour of anglers and the fishing methods employed. We have helped instigate a policy of catch and return, of keeping caught salmon in the water to reduce the post catch mortality. We also now do not fish for salmon once the water temperature exceeds 19C at 0900 in the morning or 20C at any time of the day. If you are an angler, consider whether you need to fish for Salmon on the Test or Itchen.  If you chose to do so, then please ensure you are conforming to the best welfare practice. 

catch-release-chalk-stream-salmon

How to Help Save the Salmon

Get Involved

If you are concerned that Atlantic Salmon are endangered there are lots of things that you can do to help. You can volunteer to help with monitoring the health of the rivers.

You can support a campaign run by us or one of our partner organisations, lobby your MP, the Government or Southern Water. Look out for any organised protests around sewage, pollution or over-abstraction and come and add your voice.We will share details of upcoming campaigns in the coming months.

Changes You Can Make Yourself

If you don’t want to get so involved simply changing the way you use water at home. It might not seem like much but if everyone made small changes at home then it would have a big impact on the health of our rivers.

On the river, follow our good practice guidelines so that you don’t unwittingly harm the fishes’ habitat.

It will only be through behaviour change and public pressure that we will be able to bring the Hampshire chalk streams back to health and save the salmon.