The marine worm Paraprionospio pinnata population of a mud-bottom station at a depth of 65 m off Conception Bay, Chile, has been studied over the period October 1976 to October 1977. The epscies were counted, divided into year groups and the biomass of each group estimated as ash-free dry weight. Production estimate has been made by compunting mortality and residual biomass. Two year-class were present. The biomass, averaged over the year, was 1886 mg/m² and the production 4529 mg/m²/year, giving a P: B ratio of 2,4:1.
