ESTUDO DO DESENVOLVIMENTO ABSOLUTO DOS JUVENIS DO CARANGUEJO VIOLINISTA MINUCA RAPAX (SMITH, 1870) (DECAPODA: OCYPODIDAE), CULTIVADO EM CONDIÇÕES LABORATORIAIS

ABSTRACT This study observed the growth of juvenile Minuca rapax crabs reared in the laboratory up to the 10th juvenile instar. Juveniles were obtained after larval rearing and a total of 50 specimens were used for growth analysis, by measuring the width (L.C.) and length of the cephalothorax (C.C.). The crabs were kept individually in plastic containers containing sandy substrate and filtered seawater, without aeration and under constant conditions of salinity 30, temperature 26°C, pH 8.0 and photoperiod (12:12 h/light:dark). Newly hatched Artemia nauplii were used exclusively as food. The crabs reached the 10th juvenile instar after 184 days of cultivation, showing a reduction in survival rate over successive molts. The growth of M. rapax was continuous, with a strong positive correlation between C.C. and L.C., indicating a linear increase in these variables. A variation was also observed in the duration of the inter-moulting period of the respective instars. The average duration was shorter for the initial instars (4.9 ± 2.8) and extended throughout development, with the highest values in the most advanced instars (16.2 ± 7) days. The ratio between C.C. and L.C. showed a reduction as the juveniles grew, indicating that there was a change in the morphology of the cephalothorax during growth. The availability and type of food, as well as rearing conditions, can be determining factors in the growth of estuarine crab species in the laboratory. Keywords: Fiddler crab, development, juvenile, neotropical species.