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Survival, growth and feeding of Atlantic salmon, Salmo salar L., smolts after transfer to sea water in relation to the failed smolt syndrome
Author(s) -
STRADMEYER L.
Publication year - 1994
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.1994.tb00670.x
Subject(s) - salmo , biology , cage , fish measurement , zoology , fishery , fish <actinopterygii> , population , smoltification , body weight , salmonidae , endocrinology , demography , mathematics , combinatorics , sociology
. An increase in mortalities, due to the failure of some smolts to feed after transfer to sea cages, has been observed in many fish farms during the last 2 years. In the present study mortalities were as high as 9–5% and the majority of these appeared 7–9 weeks post‐transfer. Comparisons of length‐weight relationships between the initial group of smolts released in the cage and at 3‐, 6‐ and 8‐wcek intervals after transfer showed that a proportion of the fish had lost weight. The condition factor of individually measured fish also confirmed that with increasing time after transfer some fish were in a much poorer condition. The feeding of smolts after transfer was not related to their size. The fork length distribution of feeding and non‐feeding fish showed that feeding fish were recruited from all size classes of the initial population. The lack of appetite in smolts after transfer was demonstrated by the reduced number of fish feeding and by the amount of food consumed. In the first week after transfer only 10% of the fish were feeding in the sea cage, increasing to 65% after 5 weeks. In the tanks (where there were no failed smolts) 95% of the smolts were feeding within 5 weeks after transfer, whereas in the sea cage it took 8 weeks before this figure was reached.