Distinctive reproductive tactics between sympatric specimens of Astyanax aff. fasciatus in the wild and in captivity

Autor(es)

Brambila-Souza, Gabriela ^[1] ; Gomes, Aline Dal'Olio ^[1] ; Honji, Renato Massaaki ^[1] ; Silva Hilsdorf, Alexandre Wagner ^[2] ; Moreira, Renata Guimaraes ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Biociencias, R Matao, Trav 14, 321, BR-05508090 Sao Paulo - Brazil

^[2] Univ Mogi das Cruzes, Mogi Das Cruzes, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ENVIRONMENTAL BIOLOGY OF FISHES; v. 102, n. 9, p. 1179-1191, SEP 2019.
• Citações Web of Science: 0

Resumo

Astyanax fasciatus is a group of neotropical fish with two different diploid chromosome numbers, and in the wild, these individuals are found in sympatry. The annual reproductive cycles of adult females of species with different numbers of chromosomes (G1: 46 chromosomes, low responsiveness to induced spawning; G2: 48 chromosomes, responsive to induced spawning) were investigated in the wild and in captivity. Plasma estradiol (E2) levels, relative fecundity (RF), oocyte diameter, gonadosomatic index, and ovarian morpho-histology were evaluated to identify the ovarian maturation stage. The G1 females in both environments began the vitellogenic phase during winter, concurrent with increased plasma E2 levels. In wild G1 females, large numbers of vitellogenic oocytes were observed during spring and summer, when plasma E2 levels remained high. In contrast, captive G1 females showed higher E2 levels during the winter. They also retained significantly higher RF and vitellogenic oocyte numbers than wild females, but showed no spawning and slow yolk reabsorption. Wild G2 females began the vitellogenic phase in autumn and had progressively increasing E2 levels that peaked in the spring, with spawning occurring during the summer. In captive G2 females, the E2 levels and RF remained high throughout the year. These data suggest that A. aff. fasciatus with different numbers of chromosomes differ in their reproductive performance in the wild and show altered sensitivity to environmental cues in captivity. Our results indicate that G1 females likely respond best to artificial spawning just after winter, whereas G2 females should respond year-round. (AU)

• Processo FAPESP: 08/57687-0 - Effects of global climate change of the Brazilian fauna: a conservation physiology approach
• Beneficiário: Carlos Arturo Navas Iannini
• Linha de fomento: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático