According to Packard (1971) and Owens & King (1975), ETS activities of eight decapod species were measured with an optimised method for pelagic decapods: Polyvinylpyrrolidone (PVP) in the homogenizing buffer was reduced to 0.5 mg ml-1 (pH 8.1). The substrate solution comprised 1.3 mM NADH, 0.05 mM NADPH (pH 8.1), while the INT solution contained 2.5 mMol 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT) (pH 7.7). Wet mass (WM) of the decapod specimens was determined, so that the crude homogenate contained 3 mg WM per ml homogenizing buffer. The homogenate was centrifuged for 10 min at 4700 g at 0-4°C. The final reaction mixture was reduced to 1 ml: 600 µl substrate solution and 200 µl INT solution were incubated with 200 µl supernatant (3:1:1) while stirred in a thermomixer (Eppendorf comfort) at a chosen standard temperature of 10°C. No quench solution was used. Absorption was read at 490 nm directly after a species-specific incubation time using a temperature-controlled photometer (Kontron Instruments, UVIKON 941) and distilled water as reference. Incubation times varied from 50 min for Plesionika carinata to 90 min for Sergia robusta, depending on the highest activity. Each sample was measured four times and corrected by a sample blank (600 µl phosphate buffer, 200 µl INT solution, 200 µl supernatant) and substrate blank (600 µl substrate solution, 200 µl INT solution, 200 µl homogenizing buffer).Respiration rates of three decapod species were measured at a chosen standard temperature of 10°C in closed-bottle experiments using Winkler titration to determine oxygen concentrations (Ikeda et al., 2000). A total of 12 experiments were conducted with one individual each. Specimens were transferred into glass bottles (2 L) with filtered and oxygen-saturated seawater. Experiments were conducted for 18-26 h. After termination of experiments, oxygen concentration in the bottles was determined by Winkler titration (precision: 0.05 ml O2 l-1, Ikeda 2000) and compared to the oxygen concentration of animal-free controls. After the experiments, decapods were deep-frozen (-80 °C) for later dry mass (DM) determination.