FLEXIBLE REPRODUCTIVE STRATEGIES IN THE SQUID LOLIGO-FORBESI

Body size at sexual maturity, egg-size distributions, and potential re productive output have been estimated for female and male squid, Lolig o forbesi Steenstrup, off the west coast of Scotland. Two size modes a t maturity were found in both sexes, but separation into size cohorts was more pronounced in males (180 and 350 mm mantle length, ML). Preli minary ageing studies based on statolith ring-counts suggest that thes e size modes are not due to different age groups at breeding. Females have a single size mode of mature eggs in the proximal oviduct, but ma y have at least two size modes of eggs within the ovary. This finding is interpreted as evidence of batch-spawning in this squid. There was a weak relationship between total egg numbers (range 1000 to 16 000) a nd body size (range 196 to 318 mm ML) and between mature egg size and body size. Males showed a strong positive relationship between spermat ophore length and body length but a weak relationship between total nu mber of spermatophores and body size. The results are discussed in the context of flexibility of breeding strategies in the loliginids and v ariety of life-cycle patterns.