New net fishing controls on the River Dee (Wales)

17. What is the life cycle of the salmon and sea trout?

Salmon: Salmon (Salmo salar) begin their life in many of the rivers of Wales. Eggs are laid and fertilised (spawning) in autumn and winter.  A female salmon can lay around 1,000 to 2,000 fertilised eggs (ova) per kilogram of her body weight.  Eggs are deposited into a nest (redd) in the gravel bed of rivers.

The following spring these eggs will hatch.  The young salmon emerge from the gravel as fry, when they begin feeding.  These young salmon (called parr after 1 year of age) stay in the river for up to 3 years, when they change in colour, behaviour and physically to become smolts.  These changes allow them to adapt to their life in salt water.  Smolts migrate from the rivers to the sea and after two or three years at sea; they return, to the rivers they were born in, as adults ready to spawn .

Most salmon die after spawning, but a small amount can return to sea and spawn again.

Trout: Sea trout and brown trout are the same species (Salmo trutta).  Sea trout go to sea to feed and grow before returning to rivers to breed, in Wales sea trout are also known as sewin.  Trout that remain in the rivers for their whole lives are known as brown trout.  Both the environment and genes play a part in whether a trout becomes a sea trout or brown trout.

Similar to salmon, eggs are laid and fertilised in autumn and winter.  A female trout can lay around 800 and 1,600 eggs per kilogram of her body weight.  Eggs are laid in a nest in the gravel bed of streams and rivers.  Eggs will hatch in the spring and emerge from the gravel.  Young trout will grow for about 2 years before they either change into a sea trout by smolting (like salmon) and migrate to sea; or choose to stay in rivers where they feed and grow as brown trout.

Sea trout smolts, generally migrate to sea in the spring.  They may stay in the sea for a few months before some return to the rivers they were born in (these are called ‘whitling’), or they may remain at sea for a year.   Most sea trout do not die after spawning, about 75% return to the sea to feed and spawn again, sometimes over several years.

What is a stock of fish?

A stock of fish is a group of fish that are the same species, live in the same geographical area and interbreed, that can be harvested by a fishery.

Why are salmon and sea trout stocks important on the Dee?

Salmon and sea trout are widely distributed around Wales and the River Dee is a ‘principle salmon river’ and a ‘main sea trout river’.  Salmon are also a designated species for the Afon Dyfrydwy a Llyn Tegid/River Dee and Bala Lake Special Area of Conservation.

Both salmon and sea trout are listed as UK Biodiversity Action Plan (BAP) priority species and are currently regarded as most threatened and requiring conservation action.

When sustainable, salmon and sea trout stocks support important fisheries in Wales.

Why have salmon and sea trout numbers declined?

Fewer adult fish are returning to the River Dee to breed and spawn and a number of factors have contributed including:

• Climate change affects both their marine and freshwater habitats.  It can contribute to reduced survival at sea, through changes in food sources.  Increasing temperatures in fresh water can contribute to added stress on their internal systems and affect their efforts to breed.
• Human activities, such as agriculture, increased urbanisation and water extraction all alter the quality and quantity of water available and reduce the habitat available for adult and juvenile fish.
• Barriers within rivers like weirs and dams, prevent fish from accessing areas upstream where they can spawn and breed.
• Predation is a natural phenomenon but can be increased where there are barriers to migration or poor habitats.  When populations are low, this can become more of a concern.
• Over exploitation, when too many fish are removed from a population.

What is the 'Plan of Action for Salmon and Sea Trout?

This plan is NRWs commitment, to protect and restore salmon and sea trout populations in Welsh rivers.  It identifies issues and actions we can take.

Both species, need high quality freshwater habitat to live.  They also provide important opportunity for recreation and access to our ‘blue spaces’.

Read the 'Salmon and sea trout plan of action for Wales 2020'

North Atlantic and European populations of salmon and sea trout have declined over the past few decades.  The ‘Plan of Action’ is our collective (Welsh Government, NRW, partners and stakeholders)  understanding of the complex issues facing populations and the severity of the situation.  It is how, together we will take steps to change these.

Are there enough salmon and sea trout stocks in the River Dee to support the net fishery?

Salmon and sea trout stocks are currently both ‘At Risk’ and not meeting their conservation limits or management objectives on the River Dee.  There are fewer adult fish returning to spawn and this means that there will be fewer eggs laid.  Both salmon and sea trout stocks are projected to continue to be ‘At Risk’ until 2028.  This means that there are not enough fish to support the natural population in the river and still allow a harvest of fish to be taken.  If fish were harvested by the nets, there may not be a salmon or sea trout population in the River Dee in the future.

Why are you proposing to close the net fishery?

We are proposing to close the net fishery to protect salmon and sea trout stocks that are vulnerable.  The net fishery on the Dee, has effectively been closed for 15 years.  Over the last 10 years salmon and sea trout stocks have declined further. Salmon is now considered ‘endangered’ by the International Union for the Conservation of Nature (IUCN) red list.  There are increasing pressures on fish populations and salmon and sea trout are affected in both the marine and freshwater environments.  With the uncertainties faced by these stocks, including climate change, we need to provide long term protection for their conservation and our future generations.

How will this happen?

The net fishery will be closed using byelaws.  This is specific to the River Dee (Wales).  These  byelaws can be found via a link on the consultation pages.

These byelaws if confirmed, will come into place on the 1^st July 2025.