Original paper

Recruitment and small-scale spatial distribution of Dreissena polymorpha (Bivalvia) on artificial materials

Kobak, Jarosław

Abstract

Recruitment of the freshwater mussel Dreissena polymorpha Pallas 1771 on artificial substrates of different material was studied in the Włocławek Dam Reservoir (the Vistula River, Poland). Juvenile densities after 3 months were high on phenoplast plastic (resocart), glass, aluminium, methyl polyacrylate (acrylic), PVC and silicone aquarium glue-coated resocart plates. Significantly lower densities were found on Penaten® cream-coated resocart, rubber, zinc and brass. Al, PVC and silicone aquarium glue coating were colonised relatively less frequently by the younger plantigrade stage. Additional experiments with suitable materials placed next to unsuitable ones, and surfaces composed of substrate patches, revealed that post-settlement events (mortality, emigration) and/or impaired attachment on some substrates were the main factors responsible for the observed differences. Active substrate selection by settling larvae was not found. Mussels were influenced by surface properties of the substrates, and no impact of substances released to water was demonstrated. Mussel distribution was contiguous (Lloyd index >1), with the highest level of aggregation found on the Penaten® substrate. Juveniles were more abundant on the upper edge of vertically oriented plates, probably due to negative geotaxis, and both stages were more abundant on the surfaces directed downstream.

Keywords

larval settlementsubstratepost-settlement behaviorsubstrate surfaceproperties.