Salmon and Trout Hatcheries

(Artificial Stocking)

Stripping eggs from a hatchery salmonIncubating eggsAlevins

Wouldn't life be easy if we could correct all the problems and damage done to our rivers by releasing artificially reared fish? There is seldom a more controversial topic in fishery management than that of artificial stocking but is this a solution for the Wye and Usk and what drives the polarisation of views?

Stocking can work: one only has to look at any of our reservoirs which can be made to hold considerable numbers of rainbow trout, stocked to order and secure in the confines of their environment, ready to deliver instant sport and bred large enough to evade most of the likely (but not all!) predators. But can it work for salmon, which have to travel 2,000 + miles to feed and then negotiate their way back to their natal rivers to spawn?

There are several techniques in the artificial stocking toolbox:

Click here to read about the history of hatcheries in the Wye and Usk.

Our Policy

Declining numbers of rod caught fish are symptomatic of problems in the rivers and/or at sea. The Foundation's policy is to deploy methods that deal with the causes rather than the symptoms. An example of the effectiveness of such a policy is the Wye in Victorian times. By 1900 the river was so over-netted that the yearly rod catch had plummeted to below 450. However, it had a pristine and barrier free tributary system. The reduction in netting (cause) in 1901 resulted in a spectacular turn around in salmon numbers, as shown in the graph below.

This is an example where a hatchery would not have resolved the issue as the cause of the decline (extensive river netting) would not have been corrected.

Salmon Fry Stocking salmon fry into a Wye tributary

Another example is the Tyne where the toxic state of the estuary prevented fish entering and leaving the river except in very high flows. In the mid-1960s when the water quality improved sufficiently to allow fish passage, the river became a salmon fishery again (it was a very good one before industrial pollution curtailed the runs, incidentally). The improvement was spectacular and helped further by the removal of the northeast drift nets 2003. Complicating the understanding of the issues behind the recovery, however, was a hatchery that was built to mitigate the effect of Kielder Water. This reservoir blocked off 7% of the catchment, which at the time already supported a good and improving population of salmon. The success of the Tyne recovery has often been incorrectly attributed to this hatchery. However, a long term assessment by the Environment Agency shows that it only accounts for 2% - 7% of the fish returning to the river. Please click here for the Tyne report.

Today, both the Wye and Usk face a range of problems rather than a single issue. Not least is a seemingly inexorable decline in the % survival of smolts at sea as shown by the graph below. This long term sea survival decline has been met with reductions in the exploitation of salmon: the WUF buy-off of the estuary putchers and nets in 2000; the legal Irish drift net cessation in 2007 and the 2010 buy-off of the Lydney Park putchers and subsequent limit on their catches. Voluntary catch and release by the Wye rod fishery was superseded by a 100% release byelaw in 2012. On the Usk, catch & release is mandatory until 15th June and voluntary after that.

Marine survival (from smolt release to return to the coast) for wild and hatchery salmon in Ireland. In his book, "Swimming Against The Tide" (2010), Peter Gray, Keilder (Tyne) Hatchery Manager, omits the section post 2002 (or to the right of the green line) on this graph, yet includes the rod catch statistics from the Wye in 2010!

Our strategy therefore is to deliver permanent in-river works, including barrier removal, water quality improvements, habitat restoration and reduced estuarial salmon exploitation. This has several advantages:

What we have noted as the arguments for artificial stocking for Wye and Usk:

Dead salmon in a West County hatchery (2010), caused by a faulty aeration pump.And the arguments against stocking for Wye and Usk:

DIVIDED MIGRATION. The table above, based on over 50,000 salmon scale samples, shows the sophisticated way salmon have evolved to survive catastrophic events. Wye salmon will be returning in each of seven years after one spawning year, and that is repeated in each subsequent year. This ability to adapt and compensate would be lost in artificially reared fish.

Additionally, there are a number of regulatory and legal considerations. The Wye and Usk site plans, drafted pre Natural Resources Wales (NRW) by the Countryside Council for Wales, regulator of both the Special Areas of Conservation (SACs), state that a hatchery should not be a method used in the management of the two rivers. The Agency has a set of practical constraints about sites that may be stocked and the numbers of fish that may be caught up. This is rigidly limited to 30 cocks and 30 hens on the Wye.

In conclusion:

The achievable levels of stocking will never restore the Wye, nor will a hatchery sort out the causes of the Wye's decline. We must therefore pursue other methods of restoration that are permanent and sustainable. The Usk also requires work to optimise salmon productivity and these other methods are the best use of available funds for both rivers.

The current situation:

Following a consultation Natural Resources Wales decided to close their operating hatcheries in Wales and to proscribe stocking salmon in all Welsh rivers. The consultation found no further evidence to support the use of hatcheries and so the last stocking has taken place using fish caught up in 2013. The money used to manage the Wye hatchery has been allocated for works on the river that go above and beyond existing and planned projects. The Cynrig site is now being used for educational and research purposes.

Against strong and, at times, over emotional opposition, NRW are to be congratulated for staying with the best available scientific evidence and pushing through the controversial but necessary measure.

Further reading:

Click here for the Wild Trout Trust's advice.

Mcginnity et al

Tweed Stocking Results

SFB Briefing July 2011

Dess hatchery 2011 survery bulletin

K.A. Young, 2013

Journal of Fish Biology Review Paper - "Maladaptation and phenotypic mismatch in hatchery-reared Atlantic salmon Salmo salar released in the wild."

A Review of the Welsh Region Microtagging Programme 1984 - 1993 (G Jones)