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Microscopic Evidence of the Opportunistic Reproductive Strategy and Early Sexual Maturation of the Small‐Sized Characin Knodus moenkhausii (Characidae, Pisces)
Author(s) -
CenevivaBastos M.,
Taboga S. R.,
Casatti L.
Publication year - 2015
Publication title -
anatomia, histologia, embryologia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.34
H-Index - 35
eISSN - 1439-0264
pISSN - 0340-2096
DOI - 10.1111/ahe.12112
Subject(s) - characidae , biology , fecundity , reproduction , sexual maturity , reproductive biology , zoology , fish <actinopterygii> , ecology , demography , population , fishery , embryo , sociology , embryogenesis
Summary We investigated the reproductive biology of K nodus moenkhausii , an abundant small‐sized characin fish with broad occurrence in the P araná R iver basin, Brazil. Specimens were collected monthly to determine fecundity, length at first maturity, reproductive period and spawning type. Gonads were macroscopically classified according to their form, size and texture in three different stages (immature, maturing or mature). Histological procedures were conducted to confirm gonadal developmental stages, and it was possible to notice that maturing females actually presented atretic oocytes, and all males that were macroscopically classified as immature, maturing and mature actually presented abundant spermatozoa in their gonads. Because of these discrepancies, a reclassification of gonadal maturations stages was needed after histological analysis, reinforcing its importance to studies on the reproduction of small characins. Reproduction occurred throughout the year though with two peaks. The length of the smallest mature individuals was 13 mm SL for males and 24 mm SL for females. Despite presenting relatively small batch fecundity, some life history traits such as early reproduction, multiple spawning throughout the year, in association with known opportunistic feeding habits, explain the high abundance of this species in locations where it occurs.