Browsing by Author "Retamal, Marco"
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Item Analysis of some biological aspects on Euphausia superba population collected around the South Shetland Islands during the 1985 summer(1988) Retamal, MarcoIn order to analize some biological characteristics of Euphausia superba 18 samples using a I.K.M. T. were caught during the SIBEX. Samples were composed by 225 juveniles, 2.335 females and 2.357 males in a 1:1 proportion. The sexual proportion in each sampled station was different, mainly in St. C-1. The proportion of each sexual maturity stage, along the sampled area, was different making it possible to distinguish three different populations with the following characteristics: Around Piloto Pardo Islands and in the area opened to the Drake Passage, in Bransfield Strait and around the Palmer Archipelago the composition of the samples varied largely. We assumed that the area of the Piloto Pardo Island might be a spawning zone and the Bransfield a nursery zone. The minimum sexual maturity stage, in females, was 34 mm, total length. There is no relationship between size and sexual maturity stages. Adolescents in stage 2 A3 overlapped almost all the other stages, except some mature females in stage 3 D. Fecuendity showed a clear linear relation plotted vs. size. We believe that it is very important to mention that, in the samples studied, a large number of Thyssanoesa macrura was present, up to 60% and in some cases it was the only Euphausiid in the samples. Thus, it is highly recommended to study the fluctuation of this species in time and its importance in the antactic trophic web.Item Contribución al conocimiento de los Crustacea Decapoda Antarticos(1976) Retamal, MarcoDos especies de Crustáceas Decápoda Caridea fueron recolectadas durante la XXV, XXVII y XXIX Expedición Antártica Chilena, en estaciones bentonicas ubicadas en bahías de las Shetland del Sur. El material incluye las especies: Notocrangon antarcticus (Pfeffer, 1887) y Chorismus antarcticus (Pfeffer, 1887).