ADAPTATIONS OF THE COMMON CUTTLEFISH SEPIA OFFICINALIS L. TO COLD WATER REPRODUCTION IN THE ENGLISH CHANNEL

摘要

The English Channel population of the common cuttlefish Sepia officinalis is the northernmost stock among the entire family Sepiidae. It is characterized by the largest eggs among the species (8.5-12.2 mm in length and 221-533 mg in weight). The potential fecundity is of 3,200-13,000 eggs and actual fecundity up to 3,000 eggs. Size of postovulatory follicles in June was similar to those in March, indicating similar spawning history of sampled animals. Females that lay eggs during the entire reproductive season from the beginning to the end probably are very rare. Despite cold climate and shorter "window" available for reproduction, the female cuttlefish still exhibits the same intermittent spawning as in more southern areas, although individuals release eggs in relatively short periods of time.