Effects of the presence and density of conspecifics on settling juveniles of the invasive bivalve Limnoperna fortunei

SARDIÑA PAULA; CATALDO DANIEL; BOLTOVSKOY DEMETRIO

Montreal, Quebec, Canada

Congreso; ICAIS 2009 (16th International Conference on Aquatic Invasive Species); 2009

ICAIS

Effects of the presence and density of conspecifics on settling juveniles of the invasive bivalve Limnoperna fortunei The golden mussel Limnoperna fortunei was introduced in the Río de la Plata watershed in the 1990s swiftly becoming the sole dominant macrobenthic component on hard substrates, reaching densities of up to 200,000 ind. m-2. We conducted a field experiment to assess the influence of conspecific adults on recruitment success of Limnoperna fortunei. Tiles of ca. 0,025 m2 in surface were used as artificial substrates in four treatments: control (blank tiles), low (800 mussels m-2), medium (4000 mussels m-2) and high (12000 mussels m-2) density treatments. Results obtained indicate that recruitment is strongly affected by the presence and density of conspecifics on the substrate: after one and three months of exposure numbers of recruits were significantly higher on tiles with conspecific adults than on blank tiles, and there was a positive and significant correlation between the number of recruits and the number of adults in the three treatments assayed. On the other hand, after three months of exposure recruits in the medium and high density treatments were smaller than recruits in the low density treatment. This results suggest that while conspecific adults have a positive effect on recruitment success (through chemical cues released by the adults, enhanced food supply, protection from predators, etc.), they also hinder growth of the newly settled juveniles.