Seasonal variations in the total lipid content of Chorismus antarcticus (Pfeffer) (Crustacea: Decapoda) at South Georgia
The Antarctic benthic prawn Chorismus antarcticus (Pfeffer) was sampled regularly for a year and its total lipid content measured. Immature and transitional prawns had very variable lipid contents but similar mean values (2.92 and 2.91 % fresh wt, respectively); the variation was, in part, due to fluctuations in lipid reserves associated with ecdysis. Maturation of the testes involved the synthesis of ≈ 1.8 mg lipid, and female prawns synthesized an average of 50 % of their own lipid content for the gonad. Fecundity did not appear to be limited by the demand for egg lipid and synchrony in the breeding cycle was probably related to the planktonic feeding of the newly-hatched larvae. Eggs showed an unusual increase in total lipid content during the early stages of embryonic development, followed by the more normal decrease; larvae probably hatch with some reserve lipid.Available data on lipid contents of Antarctic crustaceans are briefly reviewed. The high lipid contents observed in herbivorous Antarctic planktonic crustaceans are due to the patterns of feeding imposed by the strongly seasonal nature of primary production in Antarctic waters, rather than low temperature per se. There is no evidence from the benthos of any systematic elevation of lipid content in polar species, although there is an indication of an increased lipid content in the muscle of polar crustaceans.