autumn spawning and the transition to full winter spawning; (b) to examine the effects
upon spawning of lowered temperature, varied photoperiod and the provision of simdated
tidal cover; (c) to establish if seasonal breeding in R. obtusa is timed by environmental
signals or might be the passive consequence of the time needed for growth
of the animal and its gonad following the sudden provision of young H. ulvae as prey
for sub-adults.