In both the Northern Areas and AJK, government hatcheries attempt to hold rainbow and brown trout broodstock for egg production. However, currently the small numbers and generally poor condition of these fish (due to irregular supply and dubious quality of food) makes their value as egg producers very limited. Further, these fish occupy large volumes of raceway space which could be used more productively for market fish. It is therefore recommended that existing brooders be sold as food, and new, adequate stocks of known genetic background are developed as an output of the projects. Until the first batches of new brooders become sexually mature, eggs should be imported. It is also recommended that in future broodstock are held only in the larger fish farms in each area, and these distribute eggs or fry/fingerlings to the smaller units. These small farms should specialize more in market fish production, rather than attempting to do everything themselves.
Though more detailed studies on wild fish populations are required, and will be done during the projects, it appears that brown trout have already established thriving self-sustaining populations in most of the suitable waters available. Especially in the Northern Areas, rivers and streams contain large numbers of browns of all sizes. It is therefore probable that restocking with this species is unnecessary and of no value, except perhaps in lakes which have no suitable spawning streams. Brown trout are also generally not suitable for commercial trout farming, in which fish are held in captivity up to market size, because their growth is relatively slow compared with rainbows. For project purposes therefore, unless further evidence is found to the contrary, it is recommended that the fish farms' activities be restricted to rainbow trout only.
Several strains of rainbow trout can be tried and their performance compared. For Northern Areas, where waters are often cold, it is recommended that Norwegian domesticated strains (e.g. from Sunndalsøra hatchery) be tried. The growth rates of these strains have been improved by generations of scientifically-controlled selective breeding, and in suitable environments their performance is outstanding. They are spring spawners (Jan – March). To spread the time of hatch, leading to optimal sequential use of hatching facilities, these strains may be complemented by autumn (Oct – Dec) spawning stocks. The best known of these is perhaps the Kamloop strain from N. America, but others are also available in Europe. For AJK in particular, where high summer water temperatures may be a problem, strains tolerant to warmer waters should be tried. The consultant has heard of S. American strains said to survive and feed up to 24–25°C, but further enquiries are needed to identify suppliers for these. In all cases eggs must be purchased from reputable suppliers and accompanied by certification of disease-free status.
