Conservation

Atlantic salmon and sea trout home thousands of miles back to thier natal rivers so that they can reproduce. It is vital that the rivers that they return to are in good condition and contain suitable habitat in which to spawn and for the resulting juveniles to develop in. In order to provide this and ensure high numbers of salmonids make it to smolt, the NDSFB strive to improve habitats throughout the Nith catchment.

Habitat requirements

Adults
Deep pools in which to rest
Obstacle free passage to their spawning grounds
Gravel beds in which to create redds (nests for the eggs)

Fry and parr
Fast moving, well oxygenated water
Pebbles and cobbles to hide behind
Good source of food (aquatic and terrestrial invertebrates)

Habitat Schemes

NDSFB has been involved in habitat enhancement initiatives for many years. Following on from an initial catchment wide juvenile salmonid survey conducted in 1991 by Dr Alistair Stephen, habitat degradation was identified as a problem in some areas of the Nith catchment. Schemes to upgrade the habitat for juvenile salmonids were developed. These included, fencing off and planting of riparian zones and the removal of obstructions to the free passage of spawner’s. It is worthwhile emphasising the benefits of each of these initiatives:

• Fencing off and planting of river banks promotes the growth of riparian vegetation and denies grazing by agricultural stock.
• River banks are subsequently stabilised and the vegetation provides draped cover for fish to hide under.
• Terrestrial invertebrates thrive on bankside vegetation and these invertebrates form part of the diet for juvenile salmonids and other species of fish.
• Vegetation falling into the river from riparian plants forms detritus which also encourages invertebrates.

Habitat improvement schemes in the Nith catchment

Afton Habitat Scheme

The Afton Water was identified in the early 90’s as producing limited numbers of juvenile salmonids. One of the contributing factors to decrease fish populations was the presence of sub-optimal riparian habitat in the upper Afton. In stream cover was both diverse and of a quality to sustain both fry and parr stages of salmonid development but the river banks were heavily grazed by agricultural stock. A habitat scheme was planned and implemented in 1996 and this involved the erection of riparian fencing and planting of suitable native riparian species of trees. The Board are encouraged by the success of this scheme with improved habitats being created by draped vegetation at the waters edge. Comparative electrofishing surveys have proven that the habitat enhancement scheme on the Afton has resulted in increased numbers of juvenile salmonids in this watercourse.

Wanlock Habitat Scheme

In 2008 the NDSFB completed a 2km habitat scheme on the Wanlock Water, one of the tributaries of the River Nith. Sea trout are a priority for NDSFB and the Wanlock Water is considered to be one of the most favoured spawning tributaries for sea trout in the River Nith catchment. Therefore investment has been made to protect this habitat. Works included riparian fencing and tree planting in a very challenging location within our catchment.