PDEPENDENCE OF EGG DIAMETER ON THE SIZE AND AGE OF CULTIVATED FEMALE LAKE TROUT (SALMO TRUTTA M. LACUSTRIS L.)
Ryszard Bartel*, Barbara Fałowska**, Krzysztof Bieniarz**, Piotr Epler**
*The Stanisław Sakowicz Inland Fisheries Institute in Olsztyn, Poland
*Department of Ichthyobiology and Fisheries, Agricultural University of Cracow, Poland
ABSTRACT. The aim of this study was to determine the impact of the size and age of cultivated female lake trout on the size of their eggs. The material was collected from 1995 to 1999 at the Olszówka Fish Farm in southern Poland. Eggs were obtained from 310 trout females with a total length range of 30-53 cm (fish aged three to seven years). Following the hardening phase, the maximum and minimum diameters of the eggs were measured and the water volume (calculated based on water displacement) of thirty eggs was determined. The mean egg diameter ranged from 4.08 to 5.85 mm. The variance of egg size within age groups was not large, and the coefficient of variation (V, %) ranged from 2.64 to 6.91. The results indicate that the egg size of lake trout cultivated in ponds was significantly dependent on the size of the females and to a lesser degree on their age.
Key words: LAKE TROUT (SALMO TRUTTA M. LACUSTRIS), EGG SIZE, AGE AND SIZE OF FEMALES
Prof. dr hab. Ryszard Bartel, Instytut Rybactwa Śródlądowego, ul. Reduta Żbik 5, 80-761 Gdańsk, Tel./Fax: +48 (58) 3057011;