Growth and Biomass Production of An Amphibious Snail, Pomacea Urceus (Müller), from the Venezuelan Savannah

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Journal of Molluscan Studies


It has been pointed out that there are relatively few adequate field studies on mollusc growth rates and life cycle (Russell-Hunter et al., 1968). For natural populations of freshwater snails, many of these studies are based on linear measurements of shell dimensions (Cleland, 1954; de Wit, 1955; De Witt, 1955; Geldiay, 1956; Duncan, 1959; Russell Hunter, 1953, 1961a, b; Berrie, 1965, 1966 and others). One advance is exemplified by Burky (1971) who evaluated total organic carbon and subsequently the rates of biomass turnover for natural populations of pulmonate snails. Prosobranch gastropods belonging to the family Ampullariidae are tropical to sub-tropical in distribution and have long been known (Troschel, 1845; Pelseneer, 1895; Prashad, 1925, 1932) for their 'amphibious' respiratory structures, one part of the mantle cavity containing a ctenidium and another part being modified as a gas-filled lung. There are extensive references to anatomy, functional morphology, behavior, respiratory physiology, metabolism, and excretion of ampullariid snails. However, apart from field notes and references to the natural history of various representatives (Prashad, 1925, 1932; Pain, 1950, 1960; Saxena, 1956; Radke, Ritchie and Ferguson, 1961; Meenakshi, 1964; Demian and Lufty, 1966; Coles, 1969; Snyder and Snyder, 1971; and others), there are neither extensive field studies nor extensive investigations on the growth or biomass production in natural populations of this group of gastropods.

This paper reports on the life history, growth, and biomass production in a natural population of Pomacea urceus (Miiller). These data are related to the annual dry and rainy seasons of the Venezuelan savannah and to the other existing data on Pomacea urceus (Burky, Pacheco and Pereyra, 1972; Burky and Burky, in preparation).


Online ISSN 1464-3766; Print ISSN 0260-1230


Oxford Academic



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