Egg size plasticity corresponding to maternal food conditions in an annual fish,Ayu <Emphasis Type="Italic">Plecoglossus altivelis</Emphasis> |
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Authors: | Email author" target="_blank">Kei’ichiro?IguchiEmail author |
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Institution: | (1) Ueda Station, National Research Institute of Aquaculture, Ueda Nagano, 386-0031, Japan |
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Abstract: | The classic model of Smith and Fretwell predicts that the optimal egg size will vary according to the shape of the relationship
between offspring size and offspring fitness, which may vary among environments. Adaptive significance of intrapopulation
egg size variation was examined using Ayu (Plecoglossus altivelis). The species has an annual and migratory life history. Fish under controlled rearing conditions become sexually mature with
a trend that smaller females produced larger eggs later in the season. Observed egg size variation was explained by the maternal
specific growth rate, which was composed of maternal body size and growing period. Hatchlings from larger eggs had a larger
notochord length, larger yolk-sac and grew faster. Such offspring traits provide general advantages of increased larval size,
which confer competitive ability for assuring early survivorship. In conclusion, egg size plasticity in Ayu suggests higher
offspring fitness through enhancement of their accessibility to food. |
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Keywords: | |
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