Effect of maternal growth history on egg number and size in wild white-spotted char (Salvelinus leucomaenis)

Differences in egg number and egg size within a wild population of white-spotted char (Salvelinus leucomaenis) were examined from the perspective of maternal growth history by using a back-calculation method. Relatively greater egg size variation occurred among females (61.6%) than within females (38.4%). Larger females produced a larger number of eggs, which were also larger in size. To understand the causes of variation in egg number and egg size, several contributory factors determining maternal size were considered (initial size, growth rate for each age, total age). Egg number was not associated with maternal growth history. Contrary to egg number, egg size was strongly associated with maternal growth history; high growth in the first year was negatively associated with egg size, but high growth in the second year was positively associated with egg size. The results indicated that white-spotted char potentially exhibit phenotypic plasticity in egg size according to their growth history.