ИСТИНА

The aim of the study was to determine if and how temperature conditions during incubation and biological characteristics of parent fish had any influence on incubation period and ratios of malformations and mortality during that period. Incubation was carried out on 3850 artificially fertilized eggs from 77 pairs of capelin (25 eggs from each pair). The eggs were incubated at two different temperatures: 5° and 8°C. Length, maturity stage, occurrence of food in the stomach, and age of each parent fish were recorded. The eggs were inspected at regular intervals (6-8 times during the experiment) and development stage, possible malformations, and mortality were recorded. After hatching, these observations continued for the larvae until they eventually died. While there was a clear difference in incubation period among the groups of egg kept at 5°C (normal temperature at the spawning beds in Finnmark) and 8°C (an extremely high temperature), it was difficult to detect any clear differences in mortality or malformation of eggs or larvae either based on temperature or on biological characteristics of the parents. Various graphical methods were applied to study the prevalence of malformations and the rates of mortality, in addition to standard statistical methods.