By Jean-Francois Rubin
Fisheries Research, Volume 20, Issue 1, June 1994, Pages 1-12, ISSN 0165-7836, DOI: 10.1016/0165-7836(94)90002-7.

From November 1992 to April 1993, the influence of saltwater on the egg-to-fry survival of the sea trout, Salmo trutta (L.), of Gotland was investigated. Eggs were incubated at six different salinities (0.0, 2.8, 4.3, 5.1, 5.8, 6.2 [per mille sign]) from pure freshwater to almost pure Baltic Sea saltwater. Incubation in saltwater had no influence on the time of appearance of dead eggs, on the mean length of the fry at hatching, on the mean fry total-weight, body-weight, yolk sac-weight at hatching, or on the mean yolk sac/total weight ratio. Incubation in saltwater caused a delay in hatching and the duration of the hatching period was increased. For the salinity range found in the Baltic Sea, egg-to-fry survival decreased with increasing incubation salinity. The difference in survival from incubation in freshwater to saltwater was about 11%. Owing to the physico-chemical characteristics of the Baltic Sea, spawning in saltwater should be successful. The infrequent use of apparently good spawning areas in saltwater could be due to high vulnerability of these sites during winter storms.

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