DWARF CRUCIAN CARP (Carassius carassius L.) POPULATION IN A FOREST POND

Abstract

Studies were carried out on a dwarf crucian carp, Carassius carassius (L.) population in a small forest pond near Olsztyn. Sex, age, and body weight composition of the population were assessed, as well as mortality, biological production, and standing crop. The population consisted of 267 females, 81 males, and 205 juveniles. Fish age varied from 0+ to 8+, and their body length from 2.0 to 10.8 cm. Total number of harvestable fish in the pond, estimated by fish tagging, was 3513, and standing crop was 24 kg. Mortality coefficient (Z) in the third and fourth year of fish life was equal to 0.35 and 0.24, respectively, and was highest in the sixth year - Z=1.10. Production of age groups from III to IX was equal to 40% of the standing crop.