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We describe size at age, growth, and population structure of short-finned squid (Illex illecebrosus) from Newfoundland waters during 1990. Ages were estimated from statolith increment counts and used to back-calculate hatching dates. Hatching ranged between December and June with the hatching months of March to May predominating. Constant interchange of individuals in the inshore population was evident in that the modal month of hatching progressed from March within the earliest (July) sample to May within the latest (November) sample. Within the mantle length range available, growth was adequately expressed by a linear model. Females grew faster than males, and during the March to May months of hatching, length at age and growth rate increased with hatching month. This positive effect of late time of hatching was also seen in growth in mass and in gonad development and sexual maturation.

SUMMARY: Two ongrowing experiments were conducted using a raft deployed for rearing mussels during summer and winter in the Ria of Vigo, Galicia, NW Spain. Two 3 m x 1.5 m x 6 m galvanized iron ongrowing cages were suspended from this platform, each equipped with dens constructed from PVC pipe. Small common octopus (Octopus vulgaris) were captured by the small-scale creel fishery in the ria and placed in one of two sex-specific experimental cages. Specimens were fed a standard diet (fish, decapod crustacean and mussels) at a daily feeding rate of 5% of the total weight of the animals in each cage. Due to the very high mortality as a result of decreased salinity in the winter experiment and spawning during the summer experiment, only data from the first 75 days of each experiment were compared. Growth rates were significantly higher in summer than in winter for both sexes, which was probably due to higher ambient culture temperatures during summer. Mortality was also higher during summer than winter. It was concluded that culture of common octopus on mussel rafts may be viable, especially if problems related to salinity, the acquisition of specimens from the wild and losses due to spawning can be reduced.Keywords: Octopus vulgaris, growth, ongrowing, NW Spain. RESUMEN: CRECIMIENTO DE PULPO COMÚN (OCTOPUS VULGARIS) EN JAULAS FLOTANTES. -En este estudio se realizaron dos experimentos de engorde de pulpo común (Octopus vulgaris) en jaulas suspendidas desde una plataforma de cultivo de mejillón en la Ría de Vigo (Galicia, noroeste de España). Las dimensiones de cada jaula de hierro galvanizado fueron 3 x 1,5 x 6 m, y cada una de ellas estaba equipada con cobijos de PVC. Los pulpos de pequeño tamaño se obtuvieron en la pesquería de la Ría de Vigo y se introdujeron por separado, machos y hembras, en cada una de ellas. Los ejemplares fueron alimentados con una tasa de alimento del 5% del peso medio de los animales de cada jaula con una dieta estándar compuesta por peces, crustáceos decá-podos y mejillón. Únicamente se utilizaron los datos de los 75 primeros días de cada experimento debido a la elevada mortalidad de los animales al final del experimento de inverno por descenso brusco de la salinidad y al desove de los animales de verano. Las tasas de crecimiento de ambos sexos fueron significativamente más altas en verano que en invierno posiblemente debido a las mayores temperaturas ambientales durante el estío. La mortalidad fue más elevada en verano que en invierno. Esta experiencia indicó que el engorde de pulpo en jaulas sería viable, especialmente si los problemas debidos al descenso de la salinidad, la obtención de ejemplares de la naturaleza y al desove de las hembras pueden reducirse.

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