Production of the Euphausiid Crustacean Thysanoëssa raschii in the Gulf of St. Lawrence

From field data on growth and population numbers, production of Thysanoëssa raschii, excluding molts, was calculated to be about 1.8 mg dry wt∙m−3∙yr−1 in the Gulf of St. Lawrence. The mean annual biomass of T. raschii was 0.47 mg dry wt∙m−3, comprising about 1% of the total zooplankton biomass in the Gulf, and giving a production to biomass (P:B) ratio of about 4. Production and biomass were probably underestimated due to some sampler avoidance, lack of egg to nauplius–metanauplius interval of population production and loss of weight due to leaching in preserved samples.