IMIS - Marine Research Groups

This dataset contain the hyperbenthic data collected in the intertidal area. The hyperbenthos contain the biota collect in the first meter of the water column, and therefore living in close contact with the bottom and are collected by means of a hyperbenthic sledge. The sampling design for the monitoring is following the BACI-design (Before After Control Impact), with a control area with similar habitat characteristics outside the influence of the suppletion activity. There is sampled before the suppletion and in the following two years after suppletion. In this BACI-monitoring, the seasonal aspect is taken into account, by taking samples in spring (March) and autumn (September). The amount of sampling locations was determined by the client and contains six tracks for each sampling moment. In the intertidal, the sampling start 2 hours before low water until 3 hours after low water, to have a representative sample of the migrating fauna. The samples were taken with a hyperbenthic sledge by dragging it over the bottom by two persons in the surfzone of the beach, parallel with the coastline and at a water depth of 1m. One track takes around 20-30 minutes to execute a fixed distance (400m). The distance (100m) of the track was set out on the beach and covered 4 times. The hyperbenthic sledge consist of a metal frame of 100*40cm, with two nets above each other (0.5m in height each). The content of both nets were kept separately. The samples were fixed by an 8% formaldehyde-seawater solution. All biota were determined and counted to species level were possible and biomass is determined by wet weight. The biomass values from the fish species present was not determined. The density and biomass values were standardized to 1000m².