Winter temperature and food quality affect age and size at maturity in ectotherms: an experimentaltest with Atlantic salmon

• Field studies have revealed that many ectotherms mature younger and smaller in warmer environments although they grow faster. This has puzzled ecologists because the direct effect of factors that accelerate growth is expected to be larger, not smaller size. We tested this experimentally for Atlantic salmon (Salmo salar) at two winter temperatures and diets. Logistic regression revealed that the probability of maturation during the second year in sea water, relative to the probability of older maturation, increased with temperature and growth rate during the first winter. Also, large size and high condition factor 1 year prior to maturation stimulated maturation. In females, a high lipid diet increased the probability of maturation as one-sea-winter fish, and there were significant interactions between winter temperature and food quality and between body size and condition factor the first autumn in sea water. Thus, if the direct effect of temperature on growth rate is the main effect of warming, salmon are likely to attain maturity younger and smaller. Also, richer food decreased age at maturation in females. This finding has consequences for interpretations of climate change impacts on age at maturity in Atlantic salmon and may also hold for many other ectotherm species.Salmo salar) at two winter temperatures anddiets. Logistic regression revealed that the probability of maturation during the second year in sea water, relative to theprobability of older maturation, increased with temperature and growth rate during the first winter. Also, large size andhigh condition factor 1 year prior to maturation stimulated maturation. In females, a high lipid diet increased the probability ofmaturation as one-sea-winter fish, and there were significant interactions between winter temperature and food quality andbetween body size and condition factor the first autumn in sea water. Thus, if the direct effect of temperature on growth rate isthe main effect of warming, salmon are likely to attain maturity younger and smaller. Also, richer food decreased age atmaturation in females. This finding has consequences for interpretations of climate change impacts on age at maturity in Atlantic salmon and may also hold for many other ectotherm species.

Ämnesord

NATURVETENSKAP  -- Biologi -- Zoologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Zoology (hsv//eng)

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Fisk- och akvakulturforskning (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Fish and Aquacultural Science (hsv//eng)

Nyckelord

Biology

Biologi

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