Life history traits influence in gonad composition of two sympatric species of flatfish

AbstractParalichthys orbignyanus and Paralichthys patagonicus are flatfish with different life history traits, having in common the condition of breeding in seawater. Paralichthys patagonicus remain their whole life in open seawater and Paralichthys orbignyanus are sometimes found in brackish water bodies. As marine and estuarine food webs have different fatty acid (FA) compositions, the aim of this study was to characterize the gonadal maturation of P. orbignyanus and P. patagonicus females through the analysis of lipid content and FA profile in order to understand to what extent life history traits are reflected in the ovarian composition. During gonadal maturation lipid content increased and FA profiles changed in both species, but the lipid increase was greater in P. orbignyanus. The N-3FA and n-3HUFA proportions increased in both species but were higher in P. orbignyanus. The differences between the lifestyles of these species were reflected in the ovarian FA profile mainly as a result of differences in their FA metabolism, causing a greater accumulation of n-3FA and n-3HUFA in P. orbignyanus than in P. patagonicus. The higher lipid accumulation in P. orbignyanus’ ovaries could indicate that this species, feeding in brackish water bodies, has the possibility of storing more energy than P. patagonicus

Larval culture technique and quality control in juveniles of flounder Paralichthys orbignyanus (Valenciennes, 1839) in Argentina

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 i orbignyanus follow those described for olivaceus. At 40 days post-hatching (dph) and 798 degrees-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 pig orbignyanus juvenile mass production

Improvement in flounder Paralichthys orbignyanus controlled spawning in Argentina

Se evaluó el efecto de la temperatura sobre la maduración gonadal, la liberación de huevos y el comportamiento reproductivo del lenguado Paralichthys orbignyanus (Valenciennes 1839) en cautiverio. La relación de sexos fue de 1:2.2 y 1:2.5 (hembra:macho) en los grupos de reproductores B1 y B2, respectivamente. La talla promedio de las hembras en B1 fue de 3461 ± 861 g y en B2 fue de 1416 ± 435 g. La maduración gonadal se logró con la aplicación de un esquema de fotoperiodo y temperatura simulando las condiciones del medio natural en un periodo de 10 meses, alcanzando en febrero y marzo 19|00E2|??20ºC y 16 h L:08 h O. Las condiciones fototermales usadas en este estudio indujeron la liberación de huevos en P. orbignyanus. La producción de huevos se extendió por un periodo mayor a 4 meses con una frecuencia de 1 a 3 días. El grupo B1 desovó durante 133 días, produciendo 31.9% de huevos viables con diámetro de 882.5 ± 76.4 ?m, una tasa de eclosión de 76.9 ± 17.0%, una supervivencia al tercer día posterior a la eclosión (S-3dpe) de 38.3 ± 25.7%, y un índice de actividad larval (IAE) de 6.1 ± 6.6. El grupo B2 desovó durante 90 días con una producción de huevos viables de 67.1%, diámetro de 866.4 ± 37.9 ?m, tasa de eclosión de 66.4 ± 30%, una S-3dpe de 67.8 ± 26.9% y un IAE de 10.5 ± 7.5. No se hallaron diferencias significativas en la producción total de huevos, tasa de fecundación, fecundidad, diámetro del huevo, tasa de eclosión, S-3dpe y IAE (test no paramétrico de Kruskal-Wallis, P > 0.05) entre B1 y B2, sin embargo, el porcentaje de huevos viables fue significativamente diferente (P < 0.01) siendo mayor para B2. Los parámetros diámetro del huevo, tasa de eclosión y longitud larval serían criterios apropiados para determinar la calidad de huevos y larvas en P. orbignyanus. This study evaluates the effect of temperature on gonadal maturation, egg release and broodstock performance of the flounder Paralichthys orbignyanus (Valenciennes 1839) in captivity. The sex ratio (female:male) was kept at 1:2.2 in broodstock 1 (B1) and 1:2.5 in broodstock 2 (B2). Mean female body weight was 3461 ± 861 g in B1 and 1416 ± 435 g in B2. Final maturation of broodfish was achieved through the use of a photoperiod and water temperature regimen simulating natural seasonal changes over a 10-month period, reaching 19|00E2|??20ºC and 16 h L:08 h D by February and March. The photothermal conditions used in this study successfully induced egg release in P. orbignyanus. The spawning period was extended for more than four months, egg release occurring at a frequency of 1|00E2|??3 days: B1 spawned for 133 days, yielding 31.9% buoyant eggs, a mean egg diameter of 882.5 ± 76.4 ?m, a hatching rate of 76.9 ± 17.0%, a 3-day post-hatching (3dph) survival rate of 38.3 ± 25.7%, and a specific activity index (SAI) of 6.1 ± 6.6; B2 spawned for 90 days, yielding 67.1% buoyant eggs, a mean egg diameter of 866.4 ± 37.9 ?m, a hatching rate of 66.4 ± 30%, a 3dph survival rate of 67.8 ± 26.9% and SAI of 10.5 ± 7.5. No significant differences (Kruskal-Wallis nonparametric test, P > 0.05) in total egg production, fertilization rate, fecundity, egg diameter, hatching rate, survival at 3dph and SAI were found between B1 and B2; however, there were significant differences (P < 0.01) in the percentage of buoyant eggs, which was higher for B2. Egg diameter, hatching rate and larval length are good criteria for determining the egg and larval quality of P. orbignyanus