Optimized Screening Methods for Investigation of the Larval Settlement of Lanice conchilega on Artificial Substrates

Abstract

The Belgium sandy coastline is very vulnerable to erosion; therefore, development of sustainable and nature-based coastal protection solutions is important. Enhancing the settlement of the ecosystem engineer Lanice conchilega (Pallas, 1766) which stabilises the sediment bed, is a possible solution. In order to enhance larval settlement by artificial substrates in the field, efficient methodologies are required to screen a wide range of artificial substrates and measure how they influence currents and larval settlement. Therefore, in this study, we describe the development of innovative artificial substrate screening methodologies using an optimised recirculating aquaculture system (RAS) by: (1) analysing the capture rate of passively floating plastic particles, (2) measuring current velocity by means of an acoustic doppler velocimeter and (3) monitoring settlement of living L. conchilega larvae. Of the eight substrates evaluated, one was proven to significantly enhance the settlement of L. conchilega, namely Geotextile 3D knitted fabric with PES knit, PA spacers and wood sticks mounted at a density of 680 sticks/m2. The results of this study show that controlled lab conditions, in conjunction with innovative methods, allowed for successful screening of a number of substrates in a short time in terms of their ability to enhance larvae settlement.