Reproductive aspects of Notothenia rossii and N. coriiceps (Perciformes, Nototheniidae) at Potter Cove, 25 de Mayo (King George) Island during austral summer

FERREIRA, M.F.; VARELA, M.L.; LO NOSTRO, F.; ANSALDO, M.; GENOVESE, G.

POLAR BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2017 vol. 40 p. 1 - 11

0722-4060

Several fish species of the suborder Notothenioidei(Perciformes) predominate in the Antarctic ConvergenceZone; nevertheless, reproductive studies arescarce due to difficulties on regular sampling. This studytakes the research area of reproductive biology ofnotothenioids to a new level by providing, for the first time,data on sex hormone and vitellogenin detection in theblood of females of Notothenia rossii and N. coriiceps andcorrelates this data with morphological maturity indices aswell as ovarian histology. Fish were captured during theAntarctic summer at Potter Cove, 25 de Mayo (KingGeorge) Island, and blood and ovary were collected. Histologicalanalysis revealed that females of both fish possessgroup synchronous ovarian development with two distinctclutches of oocytes: a more advanced batch of vitellogenicoocytes ready for spawning and a second batch of previtellogenicoocytes for the next spawning event. Sinceliver vitellogenin synthesis is stimulated by estradiol producedby the ovaries, gonadal development, estradiollevels, and vitellogenin showed that both species were at amore advanced stage of maturation in March than in January.On the other hand and irrespectively of the month,gonadosomatic index and plasma estradiol levels of N.coriiceps were higher than those of N. rossii. Furthermore,females of N. coriiceps showed an advanced stage ofvitellogenesis or were ready for spawn, contrary to resultsof previous studies. Our results indicate the successful useof gonadal morphology, estradiol, and vitellogenin detectionfor the estimation of sexual maturity stage of femaleadults.