Astaxanthin is an impor tant pigment in fish and shellfish aquacultur e and incr eases the mar ket value of fish such as salmon and tr out. Commer cially synthesized astaxanthin costs about $1,000/kg. Car otenoids have been extr acted fr om cr ustacean wastes with or ganic solvents, but in many of the methods the pigments ar e degr aded.Astaxanthin extr action yield fr om cr awfish tail shells by supercr itical CO 2 was optimized for temper atur e, pr essur e, and moistur e. The cosolvent ethanol (10% w) incr eased yield significantly. Temper atur e, pr essur e, and moistur e content wer e other impor tant independent var iables. These wer e studied using an incomplete 3 3 factor ial (Box-Behnken) design. The equation of the model fitted to the data was extr acted astaxanthin (mg/kg dr y shell) = Ϫ169.3 + 5.36 T + 0.061 P + 7.32 M Ϫ 0.0003 T P Ϫ 0.10 T M + 0.0003 M P Ϫ 0.02 T 2 Ϫ 0.000006 P 2 Ϫ 0.033M 2 , wher e T = temper atur e (EC); P = pressur e (psi); M = moistur e (% ). The maxima for moistur e, pr essur e, and temper atur e wer e 13% , 24 MPa, and 75EC, r espectively. [Article copies available for a fee from The Haworth Document Delivery Service: 1