CONICET | Buscador de Institutos y Recursos Humanos

Allostichaster innaequalis has an extended distribution off the Patagonian Coast. It is a succesful predator of Chlamys patagonicus and C. tehuelcha and it is normally found on hard substractum (10 m depth) and recently associated with the invader algae Undaria pinnatifida in Golfo Nuevo ( Chubut, Argentina ). Monthly collection of 35 adults were taken since June 2000 . They were weighed and the radius ( center of disc to the ray tip ) measured. Gonads were dissected out and preserved for histological examination and calculation of the gonad index .Bodywalls , gonads and pyloric caeca were dissected out and dried at 60ºC to determine lipid ( by the gravimetric method of Bligh and Dyer ,1959 ) and protein ( by the colorimetric modified method of Lowry et.al.,1951 ).Reproduction in many populations of seastars occurs only during a relatively brief period of the year. The demand of this highest reproductive activity period is so great that animals spend most of the year preparing for it, nutritionally and physiologically (Ferguson 1975b). To understand the biology of a species it is important to konw the characteristics of reproduction. Production of biomass indicates the nutritional and energetic requirements . Measurement in terms of energy is more informative when based on proximate composition analysis, as mass includes water and ash ( Brody, 1945; Giese ,1966 ; Paine, 1971).Analyses of lipid and protein content has been performed for each organ. Data will be presented for an annual cycle.Analysis to this date indicate that sexual maturity is August ( winter ) and that spawning starts in September and ends in October ( spring ). A. innaequalis also has an annual cycle of fission, showing the highest percent of animals which had recently split in November ( spring ), just after the spawning.

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