Growth in the brown shrimp Crangon crangon. I. Effects of food, temperature, size, gender, moulting, and cohort

Laboratory experiments were performed to determine the growth rates of Crangon crangon as a function of total length (L = 20 to 60 mm) and temperature (T = 5, 10, 15, 20 and 25 degrees C) under ad libitum feeding conditions. Mean (+/- SD) growth rates ranged from 0.04 +/- 0.03 to 0.56 +/- 0.1 mm d(-1) at 5 and 25 degrees C, respectively. Unexpectedly, the catch date also influenced growth rates, indicating that recently recruited animals grew faster than overwintering shrimps of the same size. Female shrimps of the recent recruitment wave showed significantly higher growth rates than male shrimps. Individual moult intervals were determined using a marking method. Mean intervals (+/- SD) varied between 8 +/- 3.6 and 45 +/- 7.6 d for 30 mm shrimps at 25 and 5 degrees C, respectively. Temperature and length affected the moult interval but not the moult increment. Variability in the observed growth rates at a given length and temperature was mainly an effect of variable moult increments. Results from 2 pre-experiments also indicate an effect of food quality on growth, with shrimps growing faster when feeding on live copepods in comparison to several other food sources.