Production of the euphausiid Nyctiphanes australis in Storm Bay,south-eastern Tasmania

The euphausiid Nyctiphanes australis Sars is an important food item for a wide range of seabirds and commercially exploited fish in coastal waters of south-eastern Tasmania. During most of the year, N. australis forms the major component of the zooplankton biomass in Storm Bay, particularly during the summer months when it swarms in dense aggregations. Production was calculated using methods devised for individuals with continuous recruitment. Estimates of production, integrated for the whole of Storm Bay (approx 18.5km³) were from 78.3 to 84.8 mg m^-3 yr¹. The P:B ratio obtained for the period December 1979 to March 1981 was about 14. The production of exuviae was also calculated based on certain assumptions about moulting rate and dry weight of the moult, supported by some experimental data. The production of exuviae was 41.03 mgm^-3yr^-1 or 7.6 times the mean biomass. This gives a total production of flesh and exuviae of 2 212 tonnes dry weight per year for Storm Bay.