Development and hatching in cephalopod eggs : a model system for partitioning environmental and genetic effects on development.

The success of the egg, developmental and larval stages of marine animals is critical to completion of the life cycle and maintenance of their populations. Much of the variability in the density and distribution of marine invertebrates and fish, particularly those with strongly seasonal reproductive activity, can be understood in terms of the viability and fitness of the egg and larval stages in determining the strength of recruitment to growth and adult stages. Marine organisms commonly develop through several delicate larval phases, vulnerable to physical and biological conditions in the environment. Variability in the duration and success of these phases contributes in large measure to the ‘match or mis-match’ (Cushing, 1982) coincidence of the demands of the hatchling cohort with optimum conditions for growth and survival.