Life-history traits of an exploited skate: The short-tail yellownose skate Zearaja brevicaudata (Chondrichthyes: Rajiformes).

The short-tail yellownose skate, Zearaja brevicaudata, occurs off southern Brazil and along the Argentine continental shelf, including waters surrounding the Islas Malvinas and the upper slope, and is very frequently caught by trawl fisheries throughout its range. The age, growth, and maturity of Z. brevicaudata were investigated using 204 individuals collected by commercial fishing vessels from northern Argentina, between March 2016 and September 2019. Age was determined on a sample comprising vertebrae from 151 individuals, 60 males, ranging in size from 391 to 956 mm total length (TL), and 91 females, ranging in size from 324 to 1060 mm TL. Maximum ages determined for males and females were 22 and 29 years, respectively. A Bayesian framework was employed with a set of three candidate models to estimate growth parameters (von Bertalanffy, Gompertz, and Logistic). The von Bertalanffy model had the best fit, and the sexes showed undistinguishable growth parameters. For sexes combined, derived growth mean parameters (± S.D.) were L∞ = 1081 mm ± 64.34 mm, k = 0.09 ± 0.01 years-1, and L0 = 248 mm ± 23.52 mm. The age at maturity was estimated at 13.15 and 14.66 years for males and females, respectively.

Reproductive biology of Parona signata (Actinopterygii: Carangidae), a valuable economic resource, in the coastal area of Mar del Plata, Buenos Aires, Argentina

The reproductive biology and life cycle of Parona leatherjacket, Parona signata, present in Mar del Plata (38º 00'S 57º 33'W) coast, was studied. Samples were obtained monthly since January 2018 to February 2019 from the artisanal fishermen and the commercial fleet of Mar del Plata. A histological analysis was carried out and the main biologic-reproductive parameters were estimated: fecundity, oocyte frequency distribution and gonadosomatic index (GSI). Both the macroscopic and microscopic analyses showed reproductive activity in March and November. Mature females were recorded, which showed hydrated oocytes, as was evidenced by the histological procedures. Both, the histological and the oocyte diameter distribution analyses showed the presence of all oocyte maturation stages in ovaries in active-spawning subphase, indicating that P. signata is a multiple spawner with indeterminate annual fecundity. Batch fecundity ranged between 36,426 and 126,035 hydrated oocytes/ female. Relative fecundity ranged between 42 and 150 oocytes/ g female ovary free.(AU)

Se estudió la biología reproductiva y el ciclo de vida de la palometa pintada, Parona signata en Mar del Plata (38°00'S 57°33'O). Las muestras fueron obtenidas mensualmente desde enero de 2018, hasta febrero de 2019, provenientes de la pesca artesanal y/o de la flota comercial de la localidad Mar del Plata. Además, se llevó a cabo un análisis histológico y se estimaron los principales parámetros reproductivos tales como: la fecundidad, análisis de la distribución de la frecuencia de diámetros ovocitarios e índice gonadosomático (GSI) mensual. Tanto el análisis macroscópico como el microscópico permitieron afirmar que en los meses de marzo y noviembre existe actividad reproductiva. Se encontraron hembras en puesta, las cuales presentaron ovocitos hidratados en los cortes histológicos. Ambos, los análisis histológicos y de distribución de la frecuencia de diámetros oocitarios mostraron la presencia de todas las fases de maduración oocitaria en ovarios correspondientes a la sub-fase de desove activo, indicando que P. signata es un desovante parcial con fecundidad anual indeterminada. La fecundidad parcial osciló entre 36.426 y 126.035 oocitos hidratados/hembra. La fecundidad relativa varió entre 42 y 150 ovocitos por gramo de hembra libre de ovario.(AU)

Reproductive biology of Parona signata (Actinopterygii: Carangidae), a valuable economic resource, in the coastal area of Mar del Plata, Buenos Aires, Argentina

The reproductive biology and life cycle of Parona leatherjacket, Parona signata, present in Mar del Plata (38º 00'S 57º 33'W) coast, was studied. Samples were obtained monthly since January 2018 to February 2019 from the artisanal fishermen and the commercial fleet of Mar del Plata. A histological analysis was carried out and the main biologic-reproductive parameters were estimated: fecundity, oocyte frequency distribution and gonadosomatic index (GSI). Both the macroscopic and microscopic analyses showed reproductive activity in March and November. Mature females were recorded, which showed hydrated oocytes, as was evidenced by the histological procedures. Both, the histological and the oocyte diameter distribution analyses showed the presence of all oocyte maturation stages in ovaries in active-spawning subphase, indicating that P. signata is a multiple spawner with indeterminate annual fecundity. Batch fecundity ranged between 36,426 and 126,035 hydrated oocytes/ female. Relative fecundity ranged between 42 and 150 oocytes/ g female ovary free.(AU)

Se estudió la biología reproductiva y el ciclo de vida de la palometa pintada, Parona signata en Mar del Plata (38°00'S 57°33'O). Las muestras fueron obtenidas mensualmente desde enero de 2018, hasta febrero de 2019, provenientes de la pesca artesanal y/o de la flota comercial de la localidad Mar del Plata. Además, se llevó a cabo un análisis histológico y se estimaron los principales parámetros reproductivos tales como: la fecundidad, análisis de la distribución de la frecuencia de diámetros ovocitarios e índice gonadosomático (GSI) mensual. Tanto el análisis macroscópico como el microscópico permitieron afirmar que en los meses de marzo y noviembre existe actividad reproductiva. Se encontraron hembras en puesta, las cuales presentaron ovocitos hidratados en los cortes histológicos. Ambos, los análisis histológicos y de distribución de la frecuencia de diámetros oocitarios mostraron la presencia de todas las fases de maduración oocitaria en ovarios correspondientes a la sub-fase de desove activo, indicando que P. signata es un desovante parcial con fecundidad anual indeterminada. La fecundidad parcial osciló entre 36.426 y 126.035 oocitos hidratados/hembra. La fecundidad relativa varió entre 42 y 150 ovocitos por gramo de hembra libre de ovario.(AU)