The pattern of growth in the early lifecycle of individual Sepia pharaonis

Abstract

The pattern of growth in the early lifecycle of the pharaoh cuttlefish, Sepia pharaonis, was investigated by rearing hatchlings at 26°C in two separate trials. In each trial, the mean weight and mantle length (ML) was recorded in 5-day intervals. In addition, in each trial the growth of 20 group-reared cuttlefish was measured as a control to compare against the individual data. After 60 days of growth, the mean size for individuals in trial 1 was 2.75 g (maximum size 3.32 g) and in trial 2 was 12.76 g (maximum size 14.99 g) at 90 days. Each individual went through distinct growth phases during the first 90 days after hatching. The first growth phase matched exponential curves with an R-value of 0.98 or better, and the second growth phase corresponded with linear and power growth curves at an R-value of 0.98 or better. In trial 1, the mean growth rate for individuals during the first phase was 5.91% BW day–1 and the control group growth rate was 6.36% BW day–1. In trial 2, the mean growth rate for individuals during the first phase was 6.06% BW day–1 and the control group growth rate was 6.70% BW day–1.