Sexual development and reproductive cycle of the Eyespot skate Atlantoraja cyclophora (Regan, 1903) (Chondrichthyes: Rajidae: Arhynchobatinae), in southeastern Brazil

Oddone, Maria Cristina; Norbis, Walter; Mancini, Patrícia Luciano; Amorim, Alberto Ferreira de

Abstract:

 
Specimens of Atlantoraja cyclophora were collected monthly from commercial fishing landings at Guarujá, São Paulo State, Brazil, from March 2005 to April 2006 at depths between 10 and 146 m. Males ranged from 13.3 to 58.5 cm TL (n = 396). Both the smallest mature male and the largest immature male were 47.0 cm long. Males’ size-at-50% maturity was calculated to be 46.3 cm. Females ranged from 11.5 to 68.0 cm (n = 401). The smallest mature and the largest immature female were 51.6 and 53.0 cm long respectively. For the females, size-at-50% maturity was calculated to be 53.2 cm. In the males the hepatosomatic and gonadosomatic indices varied between 0.48 (August) and 3.54 (November) and between 0.15 (November) and 1.45 (June) respectively, with no significant variation for the fourteen-month period. In the females the hepatosomatic and gonadosomatic indices varied from 1.55 and 6.30 3.54 (both for April 2006) and from 0.08 (December) to 4.41 (October) respectively, with no significant difference among months. Egg-bearing females were found in all months with proportions varying from 0.03 (March) to 0.67 (April). Both males and females undergo an annual cycle, with slight seasonal variations in reproductive activity and a peak in the proportion of egg bearing females between April and July.
 
Jedinke raže okatice, Atlantoraja cyclophora prikupljene su mjesečno iz gospodarskih lovina u Guarujá u, država São Paulo, Brazil, od ožujka 2005. do travnja 2006. na dubinama od 10 do 146 metara. Duljina mužjaka kolebala je od 13.3 do 58.5 cm TL (n=396). Najmanji spolno zreli mužjak i najveća spolno nezrela ženka bili su dugi 47.0 centimetara. Izračunata dužina mužjaka pri stadiju 50% zrelosti populacije je iznosila 46.3 cm. Dužina ženki se kretala u rasponu od 11.5 do 68.0 cm (n=401). Najmanja spolno zrela i najveća nezrela ženka su bile dugačke 51.6 cm, odnosno 53.0 cm. Izračunata dužina ženki pri stadiju 50% zrelosti populacije je iznosila 53.2 cm.Kod mužjaka su hepatosomatski i gonadosomatski indeks kolebali od 0.48 (kolovoz) i 3.54 (studeni) i između 0.15 (studeni) i 1.45 (lipanj) bez značajnih kolebanja tijekom razdoblja od četrnaest mjeseci. Kod ženki su hepatosomatski i gonadosomatski indeks kolebali od 1.55 do 3.54 (oba u travnju 2006.) i između 0.08 (prosinac) i 4.41 (listopad), bez značajnijih mjesečnih kolebanja. Ženke s jajima su bile nazočne tijekom svih mjeseci u razmjerima koji su kolebali od 0.03 (ožujak) do 0.67 (travanj). I mužjaci i ženke prolaze kroz svoj godišnji ciklus, sa neznatnim sezonskim kolebanjima u reproduktivnoj aktivnosti i maksimumom u proporciji ženki s jajima između travnja i srpnja.
 

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