Biologia reprodutiva de fêmeas de camarão Macrobrachium amazonicum (Heller, 1862) em um ambiente de semiárido nordestino

Abstract

We aim with this study to analyze the reproductive aspects of females of Macrobrachium amazonicum (Heller, 1862), including morphometry, with individuals from a reservoir in the semi-arid of Northeast Brazil. Considering all individuals sampled in the present work (n = 533), the carapace length of the individuals ranged from 5.00 to 17.80 mm, with mean and standard deviation (SD) of 11.10 ± 2.10 mm. The total length of the individuals ranged from 14.50 to 80.63 mm (52.42 ± 9.61 mm). We observed that the total length increased in a highest proportion than the carapace region (positive allometry), as well as this region increased in a highest proportion in relation to the weight (negative allometry). Ovaries were observed presenting the following reproductive cells in developmental sequence: oogonia (OO) with mean diameter and SD of 25.4 ± 6.5 μm, previtellogenic oocyte (PVO) with 61.7 ± 10.7 μm, vitellogenic oocyte (VO) with 113.9 ± 24.5 μm, and mature oocyte (MO) with 308.7 ± 56.3 μm, showing an increase in volume due to vitellogenesis process. The ovaries of M. amazonicum were classified into six stages: Immature, In maturation, Mature, Spawned in maturation, Spawned and Resting. Using the carapace length (CL), the size at first gonadal maturation (CL50) found was 9.48 mm. The estimated fecundity ranged from 78 to 2805 eggs per female (690.91 ± 508.32 eggs). The specie presented a continuous reproduction, with parceled spawning and a seasonal variation in which higher water temperatures and lower rainfall period favored the occurrence. Due to the economic value of the M. amazonicum, the observations exposed here contribute to the knowledge of its biology, being able these information be applied for commercialization and conservation purposes.