TEMPERATURE AND EMBRYONIC GROWTH IN BROWN TROUT (SALMO TRUTTA L.)
Emergence from the gravel nest represents an important ontogenetic niche switch for salmonid fishes (Elliott, 1989). During this phase, juveniles should compete for territories, which provide profitable feeding positions and protection against predators. Larger body size would be advantageous by inc...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.574.9673 http://www-heb.pac.dfo-mpo.gc.ca/congress/2000/Papers/variationpdf/ojanguren.pdf |
| Summary: | Emergence from the gravel nest represents an important ontogenetic niche switch for salmonid fishes (Elliott, 1989). During this phase, juveniles should compete for territories, which provide profitable feeding positions and protection against predators. Larger body size would be advantageous by increasing the ability for territorial competition, and by reducing the vulnerability to predation. A recent study on Atlantic salmon have demonstrated that selection may favour larger body size and early emergence (Einum & Fleming, 2000). According to Atkinson’s (1994) general rule for ectotherms, increased rearing temperature will increase both developmental and growth rates, but will reduce the size at a given ontogenetic stage. Thus, thermal environment during the embryonic development can be an influential factor affecting the whole life cycle of ectotherms. The aim of this study was to assess the effect of incubation temperature on embryo survival and growth during the endogenous feeding period in brown trout (Salmo t utta L.). We fertilised the eggs from 6 females with the milt of 10 males, this process was repeated three times and the whole eggs (18 females, 180 families) were pooled. We selected eight constant incubation temperatures, 4, 6, 8, 10, 12, 14, 16 and 18 ºC, covering a wide range and trying to approach to the thermal limits for egg development. D velopment was monitored by taking samples |
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