Can understanding squid life-history strategies and recruitment improve management?

Current views of the links between life-history strategies and recruitment processes in fish are contrasted with the pattern emerging for squid. A general perspective is that the roles of space and time are reversed in the two groups, suggesting that management strategies also should differ. The space/time reversal appears to be more marked in the wide-ranging commercial ommastrephids than in the loliginids, which are more localized and have less extreme strategies. Fish have large energy reserves and efficient lifestyles, allowing stocks to produce numerous co-existing year-classes; as larvae surviving a wide range of potentially limiting conditions in different years, they store genetic diversity and stabilize recruitment in time. Squid are primarily annual species, so stocks can only achieve such diversity and stabilization by spawning microcohorts throughout the year to disperse widely in space into equally variable microhabitats. This behaviour would link recruitment more tightly to environmental variability. The population dynamics and the tactics used appear quite complex, possibly including kinship, school cohesion and cannibalism.