Biological characteristics of juvenile atlantic salmon and trout from west pomeranian rivers

Podstawową formą zarybiania polskich obszarów morskich są smolty [1]. Jednakże część smoltów łososi i troci pochodzi z zarybień rzek polskich i ich dopływów, wylęgiem żerującym i narybkiem letnim i jesiennym. Interesującym było sprawdzenie rozmiarów uzyskiwanych przez te ryby w pierwszym i drugim sezonie wzrostu w warunkach naturalnych. Badania przeprowadzono w zlewniach trzech rzek zachodnio-pomorskich - Regi, Parsęty i Iny, których dopływy zarybiano łososiem i trocią.The basic form of restocking Polish marine areas are smolts. However, some salmon smolts and trout smolts come from stocking of Polish rivers and their inflows by summer and autumn fry. It was interesting to check the sizes obtained by those fish in the first and second season of growth under natural conditions. The study was carried out in three rivers' basins of the West Pomer-ania - Rega (fish from 8 tributaries), Parsęta (from 3 tributaries) and Ina (from 2 tributaries), which were stocked by salmon and trout. We caught totally 407 salmon and 411 trout aged 0+ and 158 salmon and 273 sea trout aged 1+. Salm-on aged 0+ had an average length from 7.46 to 12.12 cm, average weight 11 g and had condition factor KF 1.1. There were more trout in the same rivers and they were larger than salmon, although they developed from the hatching fry. At the age of 0+ trout measured (average) from 8.13 to 12.14 cm, weighed 14 g and had condition factor KF 1.06. Studies have shown that trout fry grow faster in our stream than salmon fry in similar age