Reproductive versus somatic tissue allocation in the cuttlefish Sepia dollfusi Adam (1941)

The effect of sexual maturation on the relative growth of somatic tissues in Sepia dollfusi was examined through multivariate regression and multivariate analysis of covariance. Monthly changes in dry weight of somatic and reproductive organs were studied in relation to mantle length. In females, total mass, mantle, head and visceral masses declined significantly with maturation. In males, only the mass of the viscera declined significantly with maturation. The water content of the mantle and head of females increased significantly during the spawning period (i.e., the protein decreased) indicating that maturation took place in lieu of somatic growth, with death apparently following shortly after spawning. In both sexes, there was a marked decrease in stomach fullness from immature, through maturing and spawning animals, indicating that feeding decreased in the last maturity stages. The digestive gland mass remained relatively constant throughout the different maturity stages and months examined. These features are considered in relation to processes contributing to the irreversible maturation and short life cycle of S. dollfusi. Cephalopods are active organisms with high metabolic costs supported by high rates of food ingestion (O'Dor and Wells, 1987). The ingested food has to provide enough energy and nutrients for routine and active metabolism, rapid growth and reproduction.