Text: Julia van der Westhuyzen | Photo: Guy Ackermans Everyone on campus is indispensable, but not everyone is in the spotlight every day or gets much of the credit for the hard (team) work that goes on. Resource puts these colleagues in the limelight in the Key People series. This time, meet Pim van Dalen, a research assistant at Wageningen Marine Research in Yerseke.
‘I have been working at Wageningen Marine Research in Yerseke for six years now, as a research assistant on various projects. One of those projects is about the survival chances of rays that end up as bycatch in the nets of commercial fishermen.
A new EU policy requires fishermen to land all bycatch, but for rays an exception is made. Rays grow extremely slowly, so if they are all landed, it will have a negative effect on stocks. We use two species of ray in this study: the thornback ray and the spotted ray. These fish are native to the North Sea and I think it is very important that they remain there.
These fish are native to the North Sea and I think it’s important they remain there
We are now doing research to see if the rays can survive being caught and released again. I think a few rays end up in most fishing nets. We don’t have space for all of them, so we have collected about 50 from different fishing expeditions. We try to keep them in the most natural conditions possible – and those change, depending on the time of year. For example, the outdoor water temperature is currently around 10 degrees. We also monitor things like acidity, ammonium levels and oxygen in the water to ensure that our facilities have the right conditions for the fish. If the rays survive three weeks in our facility, we assume that they will survive when they are released too. Then they “pass” the test and we release them back into the Eastern Scheldt estuary.
I also enjoy working with microalgae. We are monitoring shellfish production sites for the presence of toxic micro-algae. This involves using a microscope to identify the various types of micro-algae and spot any toxic ones. I also cultivate algae for shellfish food because at the moment we have mussels from different countries that need to be fed live algae.
What I love about my job is that every day is different. One day I’m at my computer, the next in a boat, the day after that in a muddy meadow and the next day I’m working with the microscope. That variety is really nice!’
