➢ An association of riparian owners, leasees, anglers and individuals interested in protecting and improving the River Lynher and its environment.
➢ Membership is open to anyone interested in helping to achieve these aims.
➢ The association does not control any waters or provide fishing.
➢ Website: https://lynherriverassociation.com/
THE FISH OF THE LYNHER
Due to the acidity of its water, the river supports a limited number of fish species.
These are primarily:
➢ Brown Trout – usually small, the occasional larger fish being cannibals.
➢ Sea Trout – a variant of the brown trout which migrates to sea. Up to 15lbs, normally 3-5lbs, with smaller school peal.
➢ Salmon – migratory species, normally grilse to 8lbs, but larger fish to 40lbs have been captured.
BROWN TROUT
SEA TROUT
FEMALE SALMON
MALE SALMON
LIFE CYCLE OF THE SALMON
➢ Adult salmon spawn November to March.
➢ Fry will normally spend 2 years in the river growing to about 6”, the parr stage.
➢ In April or May, the fish will turn silver and move down to the sea as smolts.
➢ A percentage will return after one year at sea and are known as grilse.
➢ Others will remain at sea for two or more years, returning as larger, multi sea winter salmon.
HISTORY OF THE LYNHER FISHERY
➢ In the 19th century, the Lynher, as with several other Cornish rivers, was virtually dead due to the impact of mining run-off.
➢ After mining ceased an improvement in water quality saw a restocking of the river with fish from Scotland and Norway. The true Lynher salmon no longer exists.
➢ Catches peaked between the 1960’s and 1980’s, averaging some 600 fish annually, the majority taken in the net fishery.
SALMON IN DECLINE
➢ During the early 1990’s there was a general downturn in salmon stocks arising from several factors.
➢ High seas netting, coastal drift net fishery, illegal netting, abstraction, hydro electric schemes, silting of spawning grounds and parasites all impacted adversely on stocks.
➢ In the early 2000’s net catches had fallen to minimal levels, and the rod catch had also fallen significantly.
RIVER LYNHER ASSOCIATION
SALMON HATCHERY PROJECT
SALMON – A SPECIES UNDER PRESSURE
➢ We are fortunate that Cornwall is still an area where wild salmon can be found, but stocks are under pressure from illegal and high seas netting.
➢ Anglers realise the problem and 100% of fish caught on the Lynher are normally returned alive, in addition to which fish are donated to our hatchery programme.
➢ These hatchery brood fish are held until ready to spawn, their eggs stripped and fertilised, giving a far higher egg viability than from natural spawning – up to 95%.
➢ Of the fertilized eggs up to 90% or more will hatch successfully, giving high numbers of fry for stocking to the river, substantially boosting those from natural spawning.
➢ At the outset it must be said that there is no guide book to running a salmon hatchery. Currently we are the only voluntary hatchery in the South West. There is a major hatchery at Keilder, and a small one on the Fowey, but both are operated with compensation monies provided by water companies following reservoir building.
➢ Although having obtained guidance from some Scottish hatcheries what we have achieved is from learning over many years – we still do not have all the answers!
BREEDING PROGRAMME
➢ October/November - Capture of brood stock – The hard part!
➢ October to December - Regular treatment of brood stock to prevent fungal infection.
➢ December – Stripping of eggs, fertilization and transfer to rearing trays (brood fish returned to river).
➢ December to March – Daily removal of dead eggs.
➢ March to September – Stocking of fry to river.
BROOD FISH HOLDING
CHECKING BROOD FISH FOR STRIPPING
Cold work at times.
On this occasion air
temperate -3oC.
Water temperature
+2oC.
EGG STRIPPING
EGG TRAYS
After stripping, eggs must be held in circulating river water chilled to below 10oC.
Above this temperature eggs develop abnormally with physical deformities to alevins and fry.
THE EGG CYCLE
➢ Stripped eggs are fertilized with milt from male fish (the eggs must be kept dry until fertilization occurs). After fertilization water is added.
➢ The eggs are counted and transferred to floating egg trays in tanks of flowing river water. Dead eggs removed daily.
➢ Eggs hatch after 450 degree/days, the hatched fry feeding on an egg sac for one month – the alevin stage.
➢ Once the egg sac is exhausted the fry will feed naturally, and can be reared on, or stocked to the river.
NEWLY HATCHED ALEVINS
THE DEVELOPING PLAN
➢ Water supply – The first year’s operation identified a problem with silt, arising from taking water from the river at times of flood. A full re-design of the supply system has been made to eliminate this problem
➢ Capacity – To be successful we needed to increase the number of eggs hatched, and fry reared. This has required investment in further tanks and equipment.
➢ Workforce – All hatchery work is undertaken by our members on a voluntary, unpaid basis, with a nucleus of some 6 members.
➢ The hatchery can now handle some 16 brood fish, with a capacity of up to 60,000 eggs. Assuming a 2% return rate of adult fish this could boost stocks by over 1000 fish annually.
INTAKE IN FLOOD CONDITIONS
BENEFITS OF HATCHERY PROJECT
➢ Improved egg fertilization rates.
➢ Improved egg to fry rates – over 90%.
➢ Elimination of loss of eggs and alevins due to washing out of spawning redds during major flood conditions.
➢ Fry release into non-spawning areas.
➢ However, we can only hope to augment the natural spawning on the river, and maintaining a healthy river environment remains a priority for the salmon’s future.
SWIM-UP FRY
GROWING ON FRY
AUTUMN FRY READY TO STOCK
OTHER ACTIVITIES
➢ The association carries out weed removal and gravel bed cleaning to maintain and expand suitable spawning areas for salmon and sea trout.
➢ A section of the river where salmon normally spawn is rented by the association as a sanctuary area for salmon, no angling being permitted.
➢ The association is a member of the South West Rivers Association which looks after the wider interests of rivers in the region, acting as a liaison body with the Environment Agency.
PROGRESS
➢ 16 Brood fish are obtained annually, held, stripped, eggs hatched and 50% stocked in Spring with the remainder reared through to Autumn.
➢ Subject to size of brood stock we are now able to hatch up to 60,000 eggs annually.
➢ Our main expenditure is on electricity, all volunteers giving their time freely and do not receive any payment for any personal costs such as travel.
TEMPERATURE CONTROL OF WATER
➢ In recent years water temperature in the river has at times been above 10oC causing abnormal egg to fry development.
➢ We now operate a closed re-circulation and chilling scheme which keeps water below this figure, resulting in a normal egg to fry released percentage in the mid90% range.
➢ This shows we are still learning.
FINANCE OF THE PROJECT
➢ Association Membership – Individual £10 per year Riparian owners £20 per year.
➢ Funding – It costs us approximately £370 annually in Environment Agency charges to remove and return the hatchery water to the river! In addition, we spend some £1200 on electricity for pumping water 24 hours daily Fungal treatment for fish and feeding costs are a further £300.
➢ We receive no funding other than membership fees and donations.
➢ Please contact our Secretary if you are interested:
➢ Arthur White, 14 Wadham Road, Liskeard, PL14 3BD
