Effects of conspecifics on settling juveniles of the invasive golden mussel, Limnoperna fortunei

Abstract

We conducted a field experiment to assess the influence of conspecific adults on recruitment success of the golden mussel Limnoperna fortunei. Tiles of 225 cm2 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 (12 000 mussels m-2) density treatments. Results obtained indicate that recruitment is strongly affected by the presence and density of conspecifics: 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 relationship between the number of recruits and the number of adults in the three treatments assayed. Also, after three months of exposure recruits in all treatments with adults present were larger than recruits in the control treatment. Our results suggest that conspecific adults have a positive effect on recruitment success and growth of the newly settled juveniles through factors that enhance larval settling and/or that contribute to the survival of settlers in areas colonized by adult conspecifics.