Weight-Length Relationships and Relative Growth of the Cuttlefish (Sepia officinalis): Causes and Effects of Hypoallometry

The present study reports the weight-length (W-L) relationships and assesses the relative growth of the common cuttlefish (Sepia officinalis) from the Algarve coast (southern Portugal). Overall, were sampled and analysed 5883 individuals with broad ranges in both mantle length and total weight, with females being significantly larger and heavier than males. In males, females and sexes combined, the W-L relationships were highly significant and the morphometric parameters were highly correlated. Regarding relative growth, males, females and sexes combined displayed negative allometries, reflecting a slower growth rate in total weight than in mantle length during the species ontogeny, being the hypoallometric growth less intense in females than in males. An extensive compilation of analogous data reported throughout the distributional range of S. officinalis (Atlantic Ocean and Mediterranean Sea) further confirmed that negative allometries (weaker in females than in males) between specimen size and total weight are a typical feature in this species. The main factors responsible for this hypoallometric growth are analysed and their implications are discussed in terms of the species functional morphology and behavioural ecology.