POPULATION DIFFERENCES IN THE REPRODUCTIVE-BIOLOGY OF EVECHINUS-CHLOROTICUS (ECHINOIDEA, ECHINOMETRIDAE)

We describe the reproductive biology of E. chloroticus from four local ities in New Zealand waters. Most of the work was done at Dusky Sound where we found an asynchrony in gonad development among sites separate d by hundreds of metres. Spawning occurred in summer in Dusky Sound, b ut there was little reproductive seasonality evident in individuals fr om a northern locality, Reef Bay. In Dusky Sound, the relative size of gonads of very large individuals (> 130 mm diameter) was small, but f ertilisation trials showed that the gametes were viable. The size at f irst maturity differed between males and females with males maturing a t a smaller size (about 50 mm diameter) than females (about 65 mm diam eter). The size at first maturity varied among localities, with indivi duals from the other localities (D'Urville Island, Arapawa Island, Ree f Bay) maturing at a smaller size (sexes combined) than those from Dus ky Sound.