Biologie d'un copépode des mares temporaires du littoral méditerranéen français: Eurytemora velox

The respiration and excretion (ammonia and phosphate) of Eurytemora velox, a brackish copepod from temporary lakes of the south of France, were studied in 1978–1979 in relation to food ingestion, temperature and salinity. Suspensions of Tetraselmis maculata were used as food. Respiration was closely dependent on the quantity of the ingested food, displaying a linear relationship with a strong positive-slope coefficient. In most cases, the temperature effect on respiration and excretion was well described by a power-type equation (M=a b ^T , where M=metabolism and T=temperature) over a rather large temperature range. In some experiments, metabolism curves displayed a maximum at 20°C. The metabolismtem-temperature curves differed between successive experiments, depending on season and/or sampling area, perhaps as a result of different acclimatization processes developing in individuals from different generations and/or among geographically isolated populations. Salinity variations significantly affected respiration, but not excretion. Respiration increased in individuals placed in hypo- or hyper-salinity conditions for a period of 24 h. This inability for complete metabolic regulation is unexpected in a species from a habitat subjected to variable salinity, and may have resulted from a too short acclimatization time in the experiments.