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Thermotolerance of brown trout, Salmo trutta , gametes and embryos to increased water temperatures
Author(s) -
Lahnsteiner F.
Publication year - 2012
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/j.1439-0426.2012.01934.x
Subject(s) - brown trout , biology , salmo , human fertilization , sperm , trout , embryo , sperm motility , larva , zoology , motility , ontogeny , embryogenesis , andrology , anatomy , fishery , ecology , botany , fish <actinopterygii> , endocrinology , microbiology and biotechnology , medicine
Summary The present study investigated the effect of increased water temperature on sperm motility when activated in water, on egg water hardening, on the fertilization process and on embryonic development in brown trout, Salmo trutta . Brown trout gametes had a broad temperature optimum ranging from 3 to 15°C. In this temperature range the processes of egg water hardening and fertilization were unaffected. Motility duration was also not affected. The percentages of initial sperm motility and swimming velocity were lower at 9–15°C than at 3–7°C, while the percentage of locally motile spermatozoa was higher. Exposure of brown trout embryos to ≥11°C resulted in reduced percentages of hatched larvae and in increased percentages of malformed larvae. More advanced ontogenetic stages (stages ≥9 according to Ballard [1973]) showed higher tolerance to increased temperature than did less advanced stages (stages <9) when the percentage of eyed stage embryos was used as the evaluation end point. However, when the percentages of hatched larvae and normal shaped larvae were used as evaluation end points, no differences in thermotolerance could be found between the different otogenetic stages.