Life history of a short-lived squid (Sepioteuthis australis): resource allocation as a function of size, growth, maturation, and hatching season

Many cephalopods continue growing while laying multiple egg batches over the adult life,\udwith repro-somatic allocation continuing beyond attainment of reproductive maturity. Many\udspecies show extreme individual variation in reproductive investment. Factors driving this\udvariation in adult Sepioteuthis australis were evaluated by examining allocation of energy\udto somatic and reproductive growth as a function of body shape, growth rate, maturation,\udand hatching season. Hatching season influence was sex-specific; males hatched in warmer\udmonths had greater reproductive investment, faster growth, and better somatic and reproductive\udcondition, whereas females hatched in spring and summer had less reproductive\udinvestment. Seasonal impacts on life history resulted in an ‘‘alternation of generations’’,\udwith slow-growing squid in poor condition and with high levels of reproductive investment\udproducing a generation with completely different life-history characteristics. This suggests\udthat abiotic and biotic conditions that change seasonally could play a large role in determining\udenergy allocated to reproduction. However, this was not driving trade-offs between size\udand number of offspring. Life-history trade-offs should be detectable as negative correlations\udbetween relevant traits. However, in Sepioteuthis australis there was little evidence\udof trade-offs between reproduction and growth or condition of individuals, suggesting\uda ‘‘live for today’’ lifestyle