Burrow distribution of three sandeel species relates to beam trawl fishing, sediment composition and water velocity, in Dutch coastal waters

Abstract

Sandeel partly spend their life buried in the sediment, without a permanent burrow opening or an inhalant opening in the sediment. We linked the presence of three sandeel species (Ammodytes tobianus, A. marinus and Hyperoplus lanceolatus) off the southern Dutch coast of the North Sea to sediment related environmental variables; (1) sediment composition, with a hypothesized preference for low silt content and high medium-coarse sand content, (2) water velocity near the seabed, with a hypothesized preference for high water velocity and (3) fishing effort of the beam trawl fleet targeting flatfish and shrimp, with a hypothesized negative impact of fishing on sandeel presence. Data originated from an intensive benthic sampling scheme, VMS and logbook databases and a hydrodynamic model. Statistical models were run including these environmental variables plus year, depth, water temperature and salinity. Sandeel presence was negatively correlated with flatfish and shrimp fisheries – both Ammodytes species with flatfish fisheries and H. lanceolatus with shrimp fisheries. Water velocity and silt content were correlated as hypothesized with the presence of all species, and sand content was positively correlated with both Ammodytes species. The remaining environmental variables also showed a significant relation with at least two sandeel species. These findings agree with and greatly expand on previous studies on the relation between sandeel and its environment.