Galloway Fisheries Trust


Galloway Fisheries Trust



 

Fishery Management Planning

After working across the region's waters for many years, GFT holds a large amount of data from each catchment. In order to collate this data and produce a meaningful future management strategy, Fishery Management Plans have been produced for each of the six major rivers GFT covers, covering all fish species.

Atlantic salmon
Several age classes of brown trout

The overall aim of a Fishery Management Plan is to produce a long term management strategy for a river catchment, incorporating all current fishery issues and management within the river, tributaries and still waters of that catchment. Plans include aims and objectives, a description of the fishery including an assessment of current stocks, apparent limiting factors within the fishery and a monitoring plan and review process.

A vital element within the plan is the collection of basic information about a river catchment including relevant historical and recent data relating to the catchment. In this way any gaps in knowledge of the system will be identified. It is essential to ensure that Fishery Management Plans are working documents that can be used by stakeholders, agencies and other interested parties.

Hatchery

The GFT salmonid hatchery programme stocks eyed ova and fry back into the Bladnoch and Fleet. Fish are always returned to their natal river. The hatchery programme was set up in 1992 to aid and promote the recovery of the acidified headwaters of certain rivers. Salmon eggs fail to hatch at a pH <5.5, therefore in order to counter this problem, salmon are stocked back into these waters as fry which are more able to cope with the low pH episodes. Further hatcheries are run by DSFBs on the Luce, Cree and Urr. The Dee hatchery is run by GFT and the Dee DSFB.

In 2005, GFT designed and oversaw the construction of the Dee hatchery, which was funded through Scottish Power Landfill Tax Credits. This hatchery can hold up to 300,000 eggs and is playing an important role in assisting the recovery of the Dee salmon population.

Are hatcheries the answer?
There is much controversy surrounding the use of hatcheries in fishery management, especially regarding bad practice. Examples of this include stocking fish into areas which already contain healthy populations of wild fish or stocking fish from one catchment or sub-catchment into another.

It is known that hatcheries can actually contribute to the decline in wild fish, particularly when fish have been introduced from different catchments. Hatchery fish have also been known to out-compete wild stock, lower the fitness of potential offspring when crossed with wild stock and the progeny have even failed to survive when stocked into the wrong places. Much of this has been highlighted through genetic studies, where fish of hatchery origin may fail to ascend obstacles such as waterfalls as a result of the wrong 'genetic make-up'.

Hatchery programmes do not directly increase rod catches as hatchery produced offspring will not produce significantly greater return rates than if the adult fish were allowed to spawn naturally, in fact, studies have shown that survival rates may be severely diminished, particularly smolt survival at sea. In 2011, RAFTS and the Spey District Salmon Fishery Board published some interesting results of a detailed genetic based study that showed that from annual stocking of well over 1,000,000 eyed ova and fry, this stocking only produced 50 salmon to the anglers out of a total of over 8000 caught each year. It also has to be assumed that all the broodstock collected out of the river would naturally have produced many fish if they had been allowed to spawn naturally.

Hatcheries can, however, be a useful tool in some types of fisheries management. In situations where the natural population has become critically low, man may step in to prevent in-breeding within the remaining population or re-establish viable populations in areas where populations have become extinct or very low. This is the basis of all of the stocking which GFT now undertakes. We stock key watercourses where acidification in the past has devastated the natural fish population through poor egg survival but where water quality has now improved to a level that introduced fish can survival.

GFT has developed a code of best practice to counteract problems associated with local hatchery programmes. This considers issues such as biosecurity, genetics, stocking with native stock and the stocking at different stages of development (e.g. eyed ova versus fry). Broodstock fish are collected each winter prior to spawning using a range of methods including electrofishing, rod and line, netting and fish traps. Broodstock are separated into catchment and sub-catchment categories so that their progeny retain their natal genetic integrity and they are stocked back into their natal sub-catchment.

North American Signal Crayfish Project on Loch Ken

It is well recognised that the presence of 'alien invasive non-native' species can have significant negative impacts on natural species. The local water environment has its fair share of alien species which are a concern to GFT, anglers and conservationists. North American signal crayfish is one of the nastiest alien species in the UK. Loch Ken and surrounding watercourses (mid Kirkcudbrightshire Dee catchment) contain a huge population of crayfish which are feared to be impacting on the aquatic biota, especially fish, through predation, competition for habitat / food and causing erosion by extensive burrowing into banks. In 2009 GFT managed a £100,000 Scottish Government funded project researching crayfish in Loch Ken.

The objectives of the project were to:

  • Find an effective method to undertake large scale trapping of crayfish in Loch Ken and measure the trapping efficiency.
  • Map the distribution of crayfish within Loch Ken.
  • Understand in more detail the crayfish population within Loch Ken.
  • Consider merit and cost of undertaking a longer term control programme of crayfish in Loch Ken.

The main findings from the project were:

  • An effective trap type for catching crayfish within the loch environment was the prawn creel trap. They were more effective at catching high numbers of crayfish compared to other trap types and were durable enough for use with a hydraulic creel hauler and self shooting system.
  • Trapped crayfish were effectively killed using an industrial boiler.
  • The whole length of Loch Ken was trapped to examine the distribution of crayfish. Crayfish were found to be present over an approximate length of 9500 m of the loch.
  • A 56 day heavy trapping programme caught an estimated 659,300 crayfish and found a reduction in the number of male crayfish caught over time.
  • Larger male crayfish were caught first by the traps.
  • Environmental changes such as water level and flow in the loch had a strong influence on daily crayfish catches.
  • Following the heavy trapping, anglers reported a noticeable reduction in bait interference from crayfish.
  • Mark and Recapture work showed a reduction of up to 60.2 % in the male crayfish population following the heavy trapping study. This work also suggested a possible crayfish density in the loch of between 1.06 – 9.05 crayfish per m2.
  • The marked crayfish were found to move up to 800 m in the loch in two weeks.

For more details on this work see:

Executive Summary of Loch Ken AS Crayfish StudyExecutive Summary of Loch Ken
AS Crayfish Study

Galloway Fisheries Trust