Sobre la bilogía de las Sagitta del plancton del Levante español

Abstract

[EN] In a collection of plankton samples, obtained near Castellón (West Mediterranean, Table I) from January to July 1950, Sagitta bipimdata, S. inflata, and some undetermined specimens of chaetognata were found. It seems to exist an alternating dominance of both species (fig. 2) ; S. bipunctata is dominant during the spring, and the relative proportions of both species tend to converge in midsummer. S. inflata has, in average, a greater lenght; the máximum dimensions in both species are found in February (table IV). The sexual stages are determined according to Russell ; Tables V and VI show the percentages of different stages in the collections of every month; fig. 3 has been drawn following the graphs of Pierce (1941) and gives the distribution of Sagitta bipunctata in lenghts and in sexual stages. In the gut of Sagitta, copepoda, larvae of fishes, crustacean larvae and salpae have been identified. [...] Sagitta bipunctata Quoy et Gaimard, Sagitta inflata Grassi [...]

[ES] Trabajos de diversos autores, han mostrado que la presencia de determinadas especies de Sagitta es característica de masas de agua de propiedades especiales y que se extinguen en cuanto van a parar a otras masas de características hidrográficas diferentes, de manera que se comportan como organismos indicadores, de uso práctico por ser grandes y fácilmente reconocibles. Por lo dicho, y por la importancia de los quetognatos como alimento de peces de interés comercial, hemos creído oportuno hacer el estudio de la biología local de las Sagitta