WFD in short
The aim of the WFD is: to establish a framework for the protection of surface water, transitional water, coastal water and groundwater (both fresh and salt, both surface and groundwater, both quality and quantity). The WFD focuses on water quality, protection and sustainable use of water, as well as drought and flood control. The measures to be implemented must result in surface water, including coastal water, and groundwater in the river basin districts being 'in good status', and maintaining this status. This applies to both chemical and ecological water quality.
Fish stock survey
Fish is one of the quality elements in assessing the status of waters. The status of waters is determined using yardsticks. The presence or absence of certain fish species provides insight into the quality of the entire aquatic ecosystem in both freshwater and saltwater systems. To be able to say something about the condition of the fish population, it will first have to be sampled.
What VisAdvies can do for you
Our staff carry out WFD surveys on both large, small, shallow and deep waters. Sampling is carried out using the fished surface method (BOM), as described in the STOWA handbook on fish stock sampling (Klinge et. al, 2003) and the Hydrobiology handbook (Bijkerk, 2019). In this method, a predetermined water surface is fished in a standardised way with a catching device of which the catching efficiency is known. Electrofishing is used to fish banks. Seine and codend fishing are used in open water. The electrofishing device, seine and codend are used to map fish species composition. From the catches and areas fished, the size and composition of the fish stock is calculated using the returns. Based on the results, we can advise you what stage your water is in according to the WFD criteria. We can also advise you on which measures can improve the fish stock