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ResumoObjetivando avaliar a ocorrência de invertebrados associados aos macroaglomerados de Limnoperna fortunei (Dunker, 1857) (Silva & Thomé, 1985); Chilina parva (Martens, 1868) e Corbicula fl uminea (Müller, 1774). As relações interespecífi cas destes táxons são até o momento pouco conhecidas. Unitermos: invertebrados, incrustrações, invasora, lago sub-tropical, mexilhão dourado AbstractOccurrence of limnic molluscs and crustaceous on clusters of the golden mussel Limnoperna fortunei (Dunker, 1857), formed on "sarandi" at Guaíba Lake (RS, Brazil). In order to verify the occurrence of invetebrates associated with macro clusters of Limnoperna fortunei (Dunker, 1857) formed on branches of "sarandi" (Chephalanthus glabratus (Spreng.) K. Schum), quantitative samplings (N=28) were conducted for two years (2002 to 2004) at Veludo Beach on Guaíba Lake (municipality of Porto Alegre, RS, Brazil). From Comunicação Breve Biotemas, 21 (4): 179-182, dezembro de 2008

Understanding species linkages and energy transfer is a basic goal underlying any attempt at ecosystem analysis. Although the first food-web studies were based on gut contents of captured specimens, the assessment of stable isotopes, mainly δ13C and δ15N, has become a standard methodology for wide-range analyses in the last 30 years. Stable isotopes provide information on the trophic level of species, food-web length, and origin of organic matter ingested by consumers. In this study, we analyzed the ontogenetic variability of δ13C and δ15N obtained from samples of three Neotropical fish species: silver sardine (Lycengraulis grossidens, n=46), white lambari (Cyanocharax alburnus, n= 26), and the red-tail lambari (Astyanax fasciatus, n=23) in Pinguela Lagoon, southern Brazil. We developed a new metric, called the Weighted Isotopic Signature (φ 15N or φ 13C, ‰), that incorporates ontogenetic variability, body growth, and natural mortality into a single number.