A Preliminary Report on a Pilot Investigation to Maximise Tasmania's Sea Urchin (Heliocidaris erythrogramma) Resource.

A commercial fishery for Heliocidaris erythrogramma has been in progress in Tasmania since 1983. At present (1993) there are two processors and 30 commercial divers of which 15 work at least 8 months of the year. For 1992, divers estimated total annual landings at about 520 tonnes with a value of approximately $2m. This study is aimed at maximizing the value of this resource through controlled fishing. This report details preliminary findings. A quadrat size of 5 x lm is determined as the optimal size for density determinations at the two research sites, Hope Is in the south of Tasmania and at Meredith Point in the east. Measured densities of urchins at these two sites are 2.8 +/- 11 % and 4.1 +/-15% per m^2 respectively (25 x lm quadrats used). Urchin sizes are greatest in vegetated areas with smaller urchins in shallower waters in those areas. Roe recovery as a proportion of urchin weight is least in barren areas. Roe condition (colour and coarseness) deteriorates with increasing size (age) of the urchin. The size at which deterioration occurs is site dependant. Roe of urchins from barren areas is in poorer condition at smaller sizes