Qualitative Analysis Of The Macroalgal Diet Of The Snail Astraea Undosa Wood 1828, In Punta Banda, Baja California, México

Abstract

The feeding behaviour of the snail Astraea undosa Wood 1828 was studied through a qualitative analysis of the macroalgal diet of a sublittoral population. Observations and samplings were made between November 1987 and June 1988, in Punta Banda, Baja California, Mexico. A total of 17 genera and 10 species were identified, of which the following were consistently found to form part of the diet: Sphacelaria furcigem, Cladophom columbiana, Gelidium pusillum, and the coralline algae Jania sp., Corallina sp. and Lithothrix aspergillum. From the analysis of the macroalgal diet, A. undosa can be described as an oppartunistic herbivore with absence of differential feeding preferente by sexes. Punta Banda proved to be an area with limiting conditions of macroalgal food, where the interspecific competititon of the sea urchin Strongvfo- cenmtuspurpumtus was an important factor limiting the diet of the snail.