Impact of egg size and origin on the course and period of sea trout (Salmo trutta L.) hatching

Abstract

A comparison was made of the incubation period and the dynamics of the hatching of the offspring of three groups of fish (brown trout, sea trout that had smoltified, sea trout that had not smoltified) that were reared under the same conditions and spawned on the same day. The length of the incubation period differed ranging from 304 to 376°D among the offspring of individual fish as well as among the fish groups. The eggs of brown trout developed the most slowly (average 347°D), while those of the smoltified sea trout developed the quickest (average 336°D). No dependence was determined between incubation period and egg size. The longer the incubation period was, the shorter the entire hatching period was, but its peak was more extended lasting from 5 to 34°D. The duration of the hatching peak decreased as the average egg size increased.

CORRESPONDING AUTHOR:

Dr hab. Piotr Dębowski, Instytut Rybactwa Śródlądowego, Zakład Ryb Wędrownych, ul. Reduta Żbik 5, 80-761 Gdańsk, Tel./Fax: +48 (58) 3057011; e-mail: pdebow@infish.com.pl.