Curious about how offshore windfarms affect fish like herring? Join our research team!
The
Aquaculture and Fisheries group (AFI) and
Wageningen Marine Research (WMR) at Wageningen University and Research are looking for a PhD student to join them in the NO-REGRETS project that aims to study the ecological effects of offshore windfarms (OWFs) in the North Sea. The project is a collaboration among several research institutes and universities, including the Royal Netherlands Institute for Sea Research, Naturalis, the University of Amsterdam, and Wageningen University and Research. Other collaborations will involve a broad range of stakeholders in the North Sea area, including NGO’s and fisheries organisations.
You will focus on small pelagic fish (SPF) such as herring, sprat and anchovy in and around offshore windfarms in the North Sea. These offshore wind farms introduce artificial hard substrates to a mainly soft-sediment environment, leading to hard substrate benthic communities growing on the monopiles and scour protection. These communities consume organic and inorganic matter from the water, including the eggs and juvenile stages of small pelagic fish, potentially reducing their productivity. Moreover, competition for food caused by overlaps in diets between the grazing benthic community and the juveniles and adults of SPF may further affect productivity.
Vice versa, the pelagic eggs and larvae of benthic communities on hard substrates may serve as food for the small pelagic fish community for juvenile and adult life stages, resulting in increased growth of small pelagic fish and thus increased production. These opposing forces in the changes of food availability, competition though food overlap and predation for SPF around OWFs lead to potential changes in habitat use of small pelagic fish. Meanwhile, there is no knowledge on small pelagic fish diet around OWFs, food overlap, and potential competition. In addition, the monopiles and scour protection on the seafloor also attract larger pelagic predatory fish such as mackerel and cod.
Looking into the role of small pelagic fish in this complex foodweb around offshore wind farms will reveal to what extend effects of windfarms on small pelagic fish populations are to be expected, especially given the large quantity of future planned OWFs. Also we would like to test the attraction versus production hypothesis: are fish simply attracted to the monopiles for shelter or do the feeding opportunities provided by the new hard substrate, potentially lead to increased ecological fish production? This is important for fisheries, but also for predators, because small pelagic fish have a central role in the foodweb, serving as food for predatory fish, seabirds and marine mammals.
You will study the spatial distribution of different life stages of small pelagic fish, and relate this to the diet, food availability, and food overlap of species around OWFs in close collaboration with other PhD students of the project. You will monitor the spatial distribution of fish inside and outside of selected OWFs in the project using ship-based echosounders and wideband autonomous transceiver (WBAT) echosounders in combination with an Acoustic Doppler Current Profiler (ADCP). WBAT observations offer a variety of potential analyses on fish densities, distribution over the water column and behaviour such as schooling and swimming directions. You will test the effect of OWFs on SPF by contrasting densities of fish, vertical distribution and behaviour inside and outside OWFs. Potential differences in stomach content of SPF in and outside OWFs will be estimated using macroscopic observations and DNA metabarcoding of stomach contents.