Reproductive biology of the freshwater crab Goyazana castelnaui (Brachyura: Trichodactylidae) in a semiarid region of Brazil

ABSTRACT The reproductive pattern of Goyazana castelnaui is described based on the variation of gonadal maturation stages and secondary sexual characteristics. We analyzed 89 specimens from the Pajeú River in the semiarid region of Brazil from September 2014 to August 2015. The average sex ratio was 1F: 0.5M. The carapace width (CW) and weight of females ranged from 1.18 to 4.97 cm and 1.76 to 37.46 g. Male carapace width and weight were between 1.05 and 4.34 cm and 1.11 to 39.71 g. Goyazana castelnaui had a seasonal reproductive cycle that was more active between September and December. Gonad maturation was before the pubertal moult. The spawning season began in August when temperature increased, and ended in February. The onset of the rainy season (November) is thought to be the trigger for a decline in spawning. The gonads of females and males became mature at the same CW50 (2.84 cm). This size is smaller than the morphometric maturation size: 3.85 cm CW in females and 3.65 cm CW in males. This first contribution to the reproductive biology of G. castelnaui should be a basis for further research on its reproduction, especially in other areas of its distribution. Abbreviations: AM: adult male; AF: adult female; °C: Celsius degree; cm: centimeters; Cw: carapace width; CNPq: Brazilian National Council for Scientific and Technological Development; F: female; FC: folicular cells; g: grams; h: hour; INPE: National Institute of Space Research; JF: juvenile female; JM: juvenile male; M: male; MO: mature oocytes; mm: millimeters; µm: micrometer; OO: oogonia; PCA: Principal Component Analysis; PE: Pernambuco; PRPPG: Pro-Rectory of Research and Post-Graduate; PSW: pleon segment width; PVO: pre-vitellogenic oocytes; PVD: posterior vas deferens; RCL: right chela length; RC: ruptured cells; SM: spermatophoric matrix; SP: Spermatophores S: south; Tw: Total weight; UFRPE: Federal Rural University of Pernambuco; VO: vitelogenic oocytes; W: west;