Penchaszadeh, Pablo E.
Invasive freshwater mytilid Limnoperna fortunei in the Plata Basin - South America - / P. E. Penchaszadeh, G. Darrigran
En: Perspectivas da Limnología para o Século 21. T.1 / Congresso Brasileiro de Limnología. Perspectivas da limnología para o século 21. -- Florianópolis : Campus Universitario (UFSC), 1999
Disponible en estante de INICNE
The invasion of the Southeast Asian mussel Limnoperna fortunei was first reported in the Americas at Río de la Plata, Argentina, in 1991. In 1993 this bivalve, developed population densities of more than 100.000 individuals per sq.m, and entered the Paraná River. Since 1991, it has colonized 1,100 km through the Plata basin. Among the problems associated with the presence of this fouling animal, it has been demonstrated that the community is rapidly changing, i.e. the number of invertebrate species (mainly Olygochaeta and Hirudinea) is favored by the presence and abundance of the mussel while indigenous mollusks are generally constrained and displaced. Limnoperna fortunei is a dioecious species. Hystological analysis for Río de la Plata populations, proved that sexes differentiate at 5 to 10 mm in shell length and that mature oocytes measure 70-100 microns in diameter. During a two year study, three main spawning processes were recorded, in May-July 1993, April-May 1994 and October 1994. Nevertheless other minor spawning were recorded from October 1993 to February 1994 and from June to October 1994. Oocyte proliferation was continuous and immature oocytes were recorded throughout the year. Temperature must be regarded as the main factor responsible for the variations in the spawning intensity, which is related to the minimum and to the maximum temperatures recorded. Several fish were identified as predating on Limnoperna in the coast of Buenos Aires City. Among them, the Anostomidae Leporinus obtusidens, one of the most abundant in the sportive fishing yields, proved to be the most important predator on the mussel. 60% of Leporinus 20-30 mm in total length contained Limnoperna in their digestive tract; Limnoperna shells constituted the 33.4 % of the totaldry content. ; larger fish shows a 100% of presence of Limnoperna in their digestive tract. As much as 120 beacks containing the umbo region (60 mussels) were couned for an individual fish. Small mussels (1.5-5.7mm in shell length) are frequently found unbroken and appear as not bieng digested. The presence on Limnperna forturnei in the Paraná-Río de la Plata basin, with its extraordinary secondary production, occupying an empty ecological niche in this environment, has introduced a new item in the diet of some fish and constitute the principal food for Leporinus obtusidens. As this fish lives in all the basin, in current waters as in pounds, and it is a species wth high marketable value, that adapts extraordinarily to captivity conditions, it could be used as a control for the mussel Limnoperna fortunei in affected enclosed systems.
1. PECES DE AGUA DULCE; 2. LEPORINUS OBTUSIDENS; 3. BOGA; 4. ALIMENTOS; 5. MOLUSCOS; 6. LIMNOPERNA FORTUNEI; 7. RIO DE LA PLATA; 8. RIO PARANA; 9. ARGENTINA; 10. FRESHWATER FISH; 11. INLAND WATERS; 12. FEEDING I. Darrigran, Gustavo Alberto II. Congresso Brasileiro de Limnología. Perspectivas da limnología para o século 21 (1999-1999)
(61) Inv.: 01-003341 S.T.: 597 CON/1 ej.1
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