Broodstock management and induced spawning of flounder Paralichthys orbignyanus (Valenciennes, 1839) under a closed recirculated system Manejo de reproductores e inducción de desoves del lenguado Paralichthys orbignyanus (Valenciennes, 1839) en sistema cerrado de recirculación

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ABSTRACT. The early life history, from egg to juvenile, of red porgy Pagrus pagrus, in captivity is described. Yolk larvae were hatched 50 hours after fertilization, at 18°C water temperature. The opening of the mouth took place between the third and fourth day after hatching, corresponding to 2.6-2.8 mm notochordal length. The transformation stage began at 9 mm standard length, approximately 40 days after hatching. The appearance of the fins favored the displacement of pelagic larvae towards the bottom, acquiring their demersal habit during the juvenile stage.

Paralichthyds are the most economically important fish in the Southern Atlantic due to their abundance, flesh quality, high market price and increasing fishery demand. In Argentina, the first juvenile mass production of flounder Paralichthys orbignyanus in captivity was done in 2002. Morphological description of the different stages of development (yolk sac, drifting, premetamorphic, metamorphic, postmetamorphic larvae and juvenile) are presented, including their duration (days post-hatching), degree-days and feeding schedule. Also, abnormalities in both pigmentation and eye-migration were characterized. Larval developmental stages described in this study for P. orbignyanus follow those described for P. olivaceus. At 40 days post-hatching (dph) and 798 ºC days, juveniles measured in average 11.6±0.5 mm. Mean survival rate after 142 dph was 49.7%. More than half of the total juveniles obtained (59.1%) were albino, whereas 15.5% were normally pigmented and 13.2% showed abnormal eye migration (dextral or reversed). Development of larval culture methods and quality control of batches will allow the optimization of P. orbignyanus juvenile mass production.Additional key words: eye-migration, flatfish, juvenile abnormalities, fish larval development, fish larval rearing. ResumenTécnica de cultivo larvario y control de calidad en juveniles del lenguado Paralichthys orbignyanus (Valenciennes, 1839) en ArgentinaLos lenguados de la Familia Paralichthydae constituyen un recurso muy importante en el Atlántico Sur debido a su abundancia, calidad de su carne, alto precio en el mercado e incremento del esfuerzo pesquero. En Argentina, la primera producción masiva de juveniles del lenguado Paralichthys orbignyanus en cautiverio se realizó con éxito en el año 2002. Se decribe la morfología de los diferentes estadios de desarrollo de esta especie (larvas vitelina, pelágica, premetamórfica, metamórfica, postmetamórfica, y juvenil), relacionándolos con la duración de los mismos (días posteriores a la eclosión), grados días y el esquema alimentario aplicado. Además se caracterizan las anormalidades pigmentarias y aquéllas relacionadas con la migración ocular. Los estadios del desarrollo larvario de P. orbignyanus son similares a los descriptos para P. olivaceus. A los 40 días posteriores a la eclosión y 798 grados días, se alcanzó el estadio de juvenil con una talla media de 11,6±0,5 mm. La supervivencia promedio obtenida al cabo de 142 días de cultivo fue de 49,7%. Más de la mitad de los juveniles obtenidos (59,1%) fueron albinos, mientras que el 15,5% presentó pigmentación normal. El 13,2% de la camada mostró migración del ojo al lado derecho del cuerpo (individuos dextro). El desarrollo de métodos de cultivo larvario y el control de calidad de las camadas obtenidas, permitirá la optimización de la producción masiva de juveniles de P. orbignyanus.Palabras clave adicionales: anormalidades larvales, cultivo de larvas, desarrollo larvario, migración ocular, pez plano.Abbreviations used: DHA (docosahexaenoic acid), dph (days po...

Patagonian octopus (Octopus tehuelchus) is a species that holds an artisanal fishery in the northern area of the Argentine Patagonian coast and has a potential for aquaculture development. This work aimed to characterize the mating behavior of four pairs of Patagonian octopuses under laboratory conditions. Results showed that this species has a complex reproductive behavior. Remarkably, female remained inside her shelter during pre-copula, copulation and intercourse events. Male and female faced by the oral face during sexual intercourse, which lasted 3 to 5 min. The observations will contribute to the better management of the reproductive specimens of the species in captivity.