|Pond Dynamics/Aquaculture CRSP||Aquanews ~ Fall 2002|
Culture of Mollusks to Improve Human Protein Intake in the Amazon Region
by Fernando Alcantara and Salvador Tello, Instituto de Investigaciones de la Amazonia Peruana, and Christopher C. Kohler, Susan T. Kohler, and William Camargo N., Southern Illinois University, Carbondale Adult Pomacea bridgesi. By: Stiyn Ghesquiere
Mollusks Offer an Alternative to Fish-based Aquaculture
he Amazon River region contains a high biodiversity of aquatic organisms hence an excellent potential for commercial aquaculture. The sustainability and expansion of aquaculture in Amazonia will be fostered by establishing new species for cultivation. Invertebrates, in particular, have received minimal attention in this regard. Several species of mollusks (gastropods and bivalves) have been exploited irregularly by the ever-declining commercial fishing industry in the Amazonian region. Currently, research is underway by the Instituto de Investigaciones de la Amazonia Peruana (IIAP) in Iquitos and Pucallpa, Peru, to develop simple technologies to culture aquatic and giant terrestrial gastropods as an alternative form of polyculture or integrated aquaculture.
[Image courtesy of <www.applesnail.net>.]
Applesnails (Pomacea spp.)and among them P. maculata, or churo, as it is known in Peruare the largest known freshwater gastropods, reaching lengths of 155 mm and diameters of 135 mm (Pain, 1960). This aquatic organism lives in the floodplain of the Amazon region (Cobos, 1998), preferring the zone where water mixes in the major and minor rivers (hardness from 35 to 256 mg l-1) as well as in their tributaries (Villacorta, 1976). It is a species of periodic reproduction (Cobos, 1998), depositing its eggs in clusters outside the water on hard surfaces (e.g., trees, shrubs, wood debris), most frequently in the flooding months (rainy season). The number of eggs produced per female at each spawn varies according to body size, ranging from 233 to 1,425 eggs (Cobos, 1998; Rojas and Mori, 1976; Villacorta, 1976). Ontogenic development takes from twelve to sixteen days (Alcántara et al., 1996) and hatching rate is 87% (Cobos, 1998). Churo is omnivorous, feeding either on fresh or partially decomposed organic matter, including floating macrophytes (e.g., water lettuce or huamaPistia stratiotes, duckweedLemna minor), rooted plants (e.g., gramalotePaspalum spp.), tree leaves (e.g., renacoFicus guianensis, ceticoCecropia spp., tangaranaPaniculata tachigalia, catahuaHura crepitans and quinillaVochysia lomatophylla) and shrubs (e.g., ñejillaBactris sp. and water chestnut or rayabalsaMontrichardia spp.) in the natural environment (Cobos, 1998).
Churo is a hardy species that readily adapts to controlled environments and reproduces in captivity. The egg-laying characteristics facilitate egg collection under culture conditions. In Iquitos, churo culture is conducted by IIAP in aquaria or in cement tanks slightly filled with water (15 cm depth). These are covered with a lid made of a wooden frame layered with a fine metallic mesh to provide a suitable surface for oviposition. Two weeks later, the eggs hatch and the juveniles fall into the water. At this time they are fed lettuce (Lactuca sativa, Villacorta, 1976; Sáenz, 2001), eggplants
Adult Pomacea bridgesi.
By: Stiyn Ghesquiere
Pomacea eggs on tree trunk near Iquitos, Peru. [Image courtesy <www.junglephotos.com>.]
Photo By: Roger Harris
Half-grown bivalve locally named "tumba-cuchara," Anodontites sp. (13.4 mm length, and 8 months old), found in a recently drained fish culture pond at IIAP Pucallpa.
|The Aquaculture CRSP is funded under USAID Grant No. LAG-G-00-96-90015-00
the participating US and Host Country institutions.
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