Growth and reproduction in captivity unveils remarkable life-history plasticity in the smallnose fanskate, Sympterygia bonapartii (Chondrichthyes: Rajiformes)

F. J. MEIJIDE; F. ARGEMI; L. O. LUCIFORA; J. A. JAÑEZ; C. ABRAHAM

NEOTROPICAL ICHTHYOLOGY

SOC BRASILEIRA ICTIOLOGIA

Lugar: Porto Alegre; Año: 2018 vol. 16

1679-6225

We analyzed growth and reproduction of captive-born smallnose fanskates Sympterygia bonapartii. Egg-cases wereobtained from oviposition of two females caught in the wild and held atTemaikèn Aquarium. Following hatching, growth was analyzed in 13 females and 21males until sexual maturity. Pattern of oviposition activity and reproductive performancewere evaluated in six of the captive-reared females. Four models were fitted togrowth data, among which the logistic function was the one attaining the bestfit. The highest growth rate for both sexes was recorded during the first yearof life, whereas growth was significantly higher in females than in malesduring the second year. Size at first oviposition was 61.67 ± 3.49 cm TL,similar to wild specimens. However, captive-reared females reached maturitybefore two years of age, i.e. much earlier than wild skates, implying a significantphenotypic plasticity in thisspecies. The similarity in size atmaturity and the difference in age at maturity between captive and wildspecimens indicate that there is a decoupling of both parameters mediatedthrough growth rates. Captive-born skates reproduced successfully andyielded viable offspring, indicating that the environment at Temaikèn Aquariumis suitable for S. bonapartii toattain its full life cycle.