Effect of food quality on the growth of the brackish water mysid <i>Neomysis integer</i> (Crustacea; Mysidacea)

The growth of the brackish water mysid Neomysis integer can be described in three alternative ways: (1) by the increase in standard length (SL), (2) by the intermoult period (IMP) and growth factor (GF), or (3) by the intermoult growth rate (GR). Individual variation of these growth parameters in growth experiments is small. These endpoints can thus be used to evaluate the effects of environmental variables, food quality and quantity, and toxic substances on the growth of the mysid species. The present study evaluates to what extent diets of Artemia salina (nauplii), Eurytemora affinis (copepodites and adults), laboratory-made estuarine flocs and macrophytal detritus (Scirpus maritimus and Spartina anglica), all administered ad libitum, influence the survival and somatic growth of subadult Neomysis integer.Detritus originating from non-leached Spartina anglica was toxic to Neomysis integer, leading to morphologic aberrations and a high mortality. The growth of N. integer individuals was slower on a diet of Scirpus maritimus detritus than on a diet of animal food items or laboratory-made flocs. Artemia nauplii were the highest quality food for N. integer: a relatively smaller IMP and higher GF and GR resulted in a significantly higher SL at the end of this experiment. When fed with laboratory-made flocs, N. integer moulted as frequently as when fed Artemia, but GR decreased over the course of the experiment. A Eurytemora affinis diet resulted in a significantly elongated IMP from the first moult onwards as compared to mysids fed Artemia or flocs. The mean associated growth rate however, was comparable with the flocs treatment and significantly lower than fed Artemia