Galloway Fisheries Trust


Galloway Fisheries Trust



 

River Cree Rare Fish Project

The River Cree supports an important range of rare native fish. These are of high conservation status and are protected under local and international legislation, as well as being listed as UK Biodiversity Action Plan species. These rare fish include sparling, allis shad, twaite shad, spring running Atlantic salmon and brook, river and sea lamprey. The River Cree rare fish project will be used to find out more about these fascinating species and undertake various works that will result in their protection and enhancement. Additionally an underwater ROV with camera will be used to view fish in their own environment.

Underwater Remote Operated Vehicle
Underwater Remote Operated Vehicle

Most of these fish are anadromous meaning they spawn in freshwater, but spend much of their adult lives at sea, thus good habitat in the river and access to it is vital for completion of their life-cycles. This three year project will run from 2009 to 2012 and is funded by GFT, SEPA, SNH, FCS, The Tubney Environmental Trust, The Esmée Fairbairn Foundation, Scottish Government, SWEAT and Crown Estates.

Esmée Fairbairn FoundationThe Tubney Charitable Trust

Sparling

Sometimes known as smelt, the sparling is a silver fish related to salmonids. Once numerous and supporting a thriving fishery, they have undergone severe decline and the River Cree is one of the few places they still spawn. Monitoring of sparling spawning in the River Cree will take place, as well as the translocation of sparling to Water of Fleet to establish a new population. The area where these fish currently spawn in the River Cree is currently infested with an alien plant species the Japanese knotweed, this also adversely effects the spawning runs of other anadromous species, thus a program of eradication will be carried out.

A Twait Shad
A Twait Shad

Allis and Twaite Shad

These fish are related to herring, although they can reach lengths of40 or 50cm. These extremely rare fish are thought to spawn in the lower Cree and the Cree estuary, however despite ripe and spent fish being found in the area, this has never been confirmed. A survey of possible shad spawning grounds will be undertaken to allow the confirmation of their presence and allow subsequent protection.

Spring-running Atlantic Salmon

This is an important sub-population of the Atlantic salmon in the River Cree. Restoration work of spawning habitat and juvenile habitat will be undertaken on the High Cree, as well as work aimed at removing man-made barriers to up-steam migration on the Clauchrie Burn. Using electrofishing, the density of salmon juveniles in the acidified upper Cree will be investigated alongside water quality improvements.

Brook, River and Sea Lamprey

At first glance, lamprey look a lot like eels, however, they are a very different animal altogether. They have no paired fins and rather than a gill cover they have a series of holes at the side of the head to allow water to pass over the gills. Since they also have no lower jaw, their mouth forms a hood which is usually pointed downwards when relaxed giving the lamprey what looks like a large drooping ‘nose’. However, this mouth is used as a sucker to attach to rocks in fast water (lamprey are sometimes called ‘stone-suckers’) or to move rocks when building a redd (or nest) and to attach to fish if feeding parasitically.

Lamprey Head
The head of a river lamprey showing the distinctive large eye, seven external gill holes, lack of pectoral fins and the relaxed downward pointing mouth.

Lamprey are among the oldest living vertebrates, they have remained relatively unchanged for millions of years, with fossil lamprey closely resembling their modern descendents. Lampreys play an important role in the trophic ecology of a healthy river system. The larvae of all species, called ammocoetes, live in silt beds and filter-feed, cleaning the river water for up to seven years before metamorphosis. They provide food for other aquatic species at all life stages, and anadromous species of lamprey (those that migrate between fresh and salt water) play a role in nutrient exchange between the river and the sea. However, lampreys are most famous for the parasitic adult stages of some species, which feed on fish causing round lamprey scars, although this is often for a relatively short period of their lives, usually one or two years.

Ammocoetes
Larval lamprey known as ammocoetes, filter feed from silt beds.
It is almost impossible to distinguish between species at this life stage.

In Scotland there are three species, brook, river and sea lamprey. All these lamprey spawn in freshwater, and all build redds in areas of gravel and pebbles, into which they deposit their eggs. After spawning the adults die. On hatching the larvae are swept downstream where they burrow into silt. After living as ammocoetes for several years they metamorphose into transformers and at this stage the life history of different species diverges.

Transformers
Lamprey transformers become adapted to migration to the spawning
grounds or to the sea to feed, depending on the species.

Brook lamprey are the smallest of the British lamprey, usually around 15cm. They do not feed as adults and transformers mature and migrate to spawning grounds upstream without ever leaving the river. These lamprey tend to spawn in groups between March and May.

A bucket of river lamprey
A bucket of river lamprey using their mouths as suckers to
hold on to the side of the bucket.

River lamprey are usually around 30 cm in length. The transformers migrate downstream into the sea where they feed on fish, usually in estuaries and coastal waters. These then migrate back into freshwater and tend to spawn in groups between March and May.

Sea lamprey are the largest of the British lampreys, and can grow up to 1m in length. The transformers migrate downstream into the sea where they feed on fish, in coastal and offshore waters. These then migrate back into freshwater and tend to spawn in pairs between May and July.

Sea Lamprey
The largest of the British lamprey become mottled in colour
when returning to freshwater to spawn.

GFT want to find out more about these lamprey as part of the River Cree rare fish project. Lamprey are mainly riverine fish so can be effected by any adverse impact on the river, in particular lamprey are effected by pollution and barriers to migration. Part of our work will be to map important lamprey habitats in the River Cree. We want to find out where the adult lamprey are spawning and are asking for the help of local river users (see GFT news). This work will also involve electrofishing silt beds to find out where the ammocoetes are located and trapping of adult lamprey in the lower Cree.

Galloway Fisheries Trust