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Rev. biol. mar. oceanogr. 46(2): 219-230


Effects of confinement in limited spaces on the growth of juvenile spider crabs, Maja brachydactyla, and the effect on maturity

Javier Alaminos1

1Instituto de Investigación y Formación Agraria y Pesquera ( IFAPA), Centro Agua del Pino, Carretera Cartaya-Punta Umbría s/n, 21450 Cartaya, Huelva, España 




Juvenile spider crabs (Maja brachydactyla), 15 days old, were distributed individually among cells of three different size classes: small (P), medium (M) and large (G), in order to compare their growth. At the end of the experiment (135 days), there was major growth with a greater number of moultings, and higher growth rates in cells G than any other cell. At the time when statistically significant differences in growth were displayed, a constant relationship ‘animal size / size of the cell’ (TA / TC) was found for the P and M cells. This was equal to 0.521 ± 0.01 where TA = length of the carapace and TC = diagonal of the cell. Mortality was similar for all cell size classes and the number of moults per individual was significantly lower for the small cells. Moulting frequency in the period considered followed a normal distribution with a peak in May, which were 1.78 moults per individual. Subsequently, all animals were moved to the same type of cells (large cells), in order to verify whether their previous stay in confined spaces had any influence on the size at maturity. There were no statistically significant differences among the three original groups, confirming that the previous stay in small cells did not affect the size at maturity. The average age at which maturity was reached was 405 ± 38 days.


Key words: Culture, isolation, aquaculture, Crustacea, terminal moult 



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