Monitoring getijdenturbines Oosterscheldekering : Jaarrapportage 2017

Abstract

Dit project is mede mogelijk gemaakt door een bijdrage uit het Europees Fonds voor Regionale Ontwikkeling in het kader van OP-Zuid en het ministerie van Economische Zaken.

Monitoring getijdenturbines Oosterscheldekering : Jaarrapportage 2018

“…The numbers of animals counted per survey may have been influenced by many factors such as the weather conditions (especially in 2010), diving behavior of the porpoises, and training of observers. The numbers observed before and after turbine installation are similar (Leopold and Scholl, 2018). Both the number of live porpoises seen and the number of dead porpoises stranded in the Eastern Scheldt seem to be stable during the monitoring period (Leopold and Scholl, 2018).…”

“…Both the number of live porpoises seen and the number of dead porpoises stranded in the Eastern Scheldt seem to be stable during the monitoring period (Leopold and Scholl, 2018). Photo identification studies show that some individual porpoises have been observed often, which suggests that once they are in the Eastern Scheldt, they tend not to leave (Leopold and Scholl, 2018), this was also concluded from prey analysis (Jansen et al, 2013). However, it is not known whether or not harbor porpoises swim in and out of the Eastern Scheldt by crossing the barrier more than once.…”

“…The studies that were commissioned to assess the effects of the existing five turbines in Roompot 8, meanwhile provide useful location-specific knowledge on the strength and pattern of the currents and the tidal regime within the gates and in the surrounding area, and the consequences for natural movements of sand (de Fockert and Bijlsma, 2018), but only for this limited scenario. The same applies to the research on movements of harbor seals (Phoca vitulina) and harbor porpoises (Phocoena phocoena) between the North Sea and the Eastern Scheldt (crossing the barrier), and local population dynamics of harbor porpoises and harbor seals (Leopold and Scholl, 2018;Leopold and Scholl, 2019).…”

“…Harbor porpoises occur all year round in the Eastern Scheldt also in the years that porpoises in the North sea tended to migrate Northward and left the coastal waters of the Netherlands. Approximately 16 dead porpoises are found annually in the Eastern Scheldt (Leopold and Scholl, 2018); most of them are young animals, like those found on beaches elsewhere in the Netherlands. It is not known if any of the dead porpoises found in the Eastern Scheldt were sick or dead animals moved there by the currents from the adjacent North Sea.…”

“…Since the installation of the array of five tidal energy turbines in the Eastern Scheldt Storm Surge Barrier in 2015, 34 dead porpoises found in the Eastern Scheldt were investigated, only two of which had blunt trauma consistent with collision (IJsseldijk, in Leopold and Scholl, 2018). However, collisions may have occurred in the North Sea, and the dead bodies may have entered the Eastern Scheldt with the currents, or the collisions may have been with boats, rather than with the tidal energy turbines.…”