Colonization of artificial substrate by golden mussel, Limnoperna fortunei (Dunker, 1857), in the Jacuí River Delta, Rio Grande do Sul State, Brazil.

Abstract

In order to test a colonization method for Limnoperna fortunei, experiments were carried out in the Jacuí River Delta (Rio Grande do Sul State), using wood substrate (X form). The sampling localities are in the Jacuí River Delta: Jacuí Canal (CJ) and Port Docks (PO). In December (2005), three replicas of substrate were exposed at different depth levels (1; 1.5 and 2m) in each sampling locality (total of 18 replicas). In March, all substrates were collected from the water and transported to the laboratory. The substrates were dehumidified in a Pasteur oven (60°C). The individual adults (> 0.5mm) incrusted on different sides of the substrate (upperside, underside, lateral sides 1 and 2) were removed and quantified under a stereoscopic microscope. The average densities (ind.m-2) and standard errors of golden mussel adults were: CJ, 309.19 ± 30.70 and PO, 39.40 ± 6.00. The Kruskal-Wallis test (α = 0.05) did not present any significant differences between the depth levels (p = 0.715) or substrate sides (p = 0.617). However, the U Test presented differences (p < 0.0001) between sampling localities. The average densities of adult individuals verified in this study were situated between extreme values recorded earlier for wood substrate colonization, i. e. they were higher than those obtained for the Paraguay River and lower than those obtained for the Paraná River.

Keywords

• artificial substrate
• colonization
• invasors
• subtropical inner delta