Abstract: The carbon and nitrogen budgets are estmi ated on the adult females,juveniles and post-furcilia larvae of Pseudeuphausia sinica in the laboratory with newly hatching nauplii of Artemia salina as food.It is found that the ingestion rate is linearly related to the food concentration,suggesting high feeding potential.The linear correlation can be established bewteen the resp iration rate (carbon consumption rate) and carbon ingestion rate,as well as carbon assmi ilation rate.The regression coefficients (i.e.specific dynamic action coefficients) are 9%~16% (ingest C) and 10%~17% (assmi ilated C) respectively,with lower in the post-furcilia larvae.There also existed a linear correlation equation bewteen estmi ated total nitrogen excretion rate and the rates of nitrogen ingestion and assimilation separately,except for the juveniles.The defecation rates increas with increasing the ingestion rate,as a result,assmiilation efficiency is not related to the ingestion rate,ranged from 0.84~0.95.The results indicated that the nitrogen content in food particles is a key factor lmiiting the growth of P.sinica.The critical ingestion rate is 10 μg/mg body dry weight perday.A ssimilated N is lostmostly by excretion,following a llocated to somatic growth.The nitrogen loss by moult only account for a minor part.As for carbon budget,resp iration and som atic growth also account for most of assimilation,but varie with ingestion rates.Moult loss isminor.Estimated reproductive growth (C&N) in the adult fem ales accounted for somewhat higher percent of assmi ilation than the moult growth.The net growth efficiency (K₂) increasw ith increasing ingestion rates,but decreas slightly for juvenile and post-furcilia larvae after the rates up to a certain value.