Fisheries Biology

What tasks do you work on?

Set gillnets are the most commonly used nets in fisheries worldwide. Compared to trawl nets, they protect the seabed, their mesh size can be selectively adjusted to different fish species, and they are easy to handle. Unfortunately, many seabirds and marine mammals get caught in them. Our goal is to significantly reduce this bycatch. In the STELLA2 project, our focus is on harbor porpoises, which do not recognize the thin nylon yarn of the nets and therefore get caught in them. I am working on modifying the nets technically so that they are acoustically perceptible for the animals' echolocation.

What does your workday look like?

My work consists of two areas: Office work and field trials. At the desk, I research technical literature, and in the team we develop the research question and plan field experiments. In our work group, we run simulations on the computer and develop optimal reflectors. Our acrylic glass spheres with a diameter of 8 mm best meet our criteria.

The next step is to test the modified fishing net in the sea: Is our bead net more difficult to handle than a conventional net? Does it get tangled? Do the pearls hold? Does the net yield the same amount and weight of fish? To do this, we went out with the fishermen and documented the catch in great detail - what species were caught, how heavy and large were the fish caught. We also recorded other environmental parameters such as the oxygen content of the water, the depth of the nets set, and the wind speed and direction.

Back at the desk, we are digitizing the observations, evaluating them and checking if there are statistically significant differences. The results so far are very promising. Subsequently, we are writing scientific papers to publish our data.

What do you enjoy most about your work?

I find the practical work particularly exciting. Going out to sea is what I enjoy the most. Even as a child, I found it totally fascinating to see how many sea creatures there are and how they adapt to their environment. But I also quickly realized that the oceans are not doing well with warming, species extinction, pollution and plastic waste. That's why I want to contribute to sustainable use of the oceans. And now I feel that with the alternative fishing techniques in fisheries, I am actually making a difference and helping to preserve biodiversity. That's where I see the meaning of my work.

How does your work contribute to sustainability?

Getting caught in fishing nets is one of the most common causes of death for marine mammals. But fishing is also one of the world's most important sources of food, and in the global south in particular, but also here in the German Baltic Sea, coastal fishing with its gillnets is very important. My project contributes to reconciling fishing and marine nature conservation. For sustainable fishing, the fishing technique must be changed so that only the fish that is subsequently utilized is caught, but not the animals that are not to be caught such as other fish species, mammals, birds and turtles. Many animals that are caught are already endangered and on the red list. My project focuses on harbor porpoises, but the results are transferable to other whale and dolphin species, so our method can be used worldwide.