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Suggestions for master’s thesis

Biological control of field slug

Field slugs (Deroceras reticulatum) are an increasing problem in Danish agriculture, with great economic consequences to Danish farmers. Research suggests that slugs will have improved living conditions in Denmark as a result of global climate change.

The only active ingredient currently permitted in molluscucides in Denmark is ferric phosphate. Unfortunately, ferric phosphate is far from always able to solving the slug problem. Therefore, an efficient means of biological control is needed. Currently, nematodes are used in gardens to control slugs. One of the products is the nematode P. hermaphrodita, which is sold commercially for slug control under the name Nemaslug®. Nemaslug® is effective in controlling field slugs, if it is applied under optimal conditions.

But what exactly are optimal conditions? At which temperature, light and humidity conditions should these nematodes be used and still be efficient for snail control

The aim of the master’s thesis could be examining under which abiotic conditions nematodes are best used as a biological control agent in Denmark and examining whether the recommended dosage of nematodes can be reduced, if they are used under optimal conditions.

The thesis would be part of a larger project, SmartSLUG, which aims at developing a databased smart-farming tool that can identify optimal control strategies on the field (mechanical, slug pellets, and nematodes). The tool will act as decision support for effective slug control that will ensure continued high yields. In addition, the biological product (Nemaslug®) will be adapted to application on the fields.

Contact: Stine Slotsbo (stsl@bios.au.dk)

Production of worms for sustainable fish feed

The growing world population requires increased and sustainable production of animal protein e.g. from fish in aquaculture. Fish feed is largely produced from fishmeal, but the demand is so great that this contributes to overfishing of many species in the sea. Thus, new and ecologically sustainable feed types need to be found that can support intensive aquaculture production without simultaneously destructively exploiting natural resources.

Invertebrates are a new source for fish that are evolutionarilyare adapted to a menu consisting of e.g. worms. The project aims to develop economically and environmentally sustainable fish feed (perhaps feed for poultry as well) based on mass production of the annelid Enchytraeus. This worm occurs naturally in (and feeds off) seaweed washed up on beaches, where it is found in great densities. Enchytraeus grown on seaweed is rich on nutrients (protein and fats) that are important for ensuring good health and growth of fish in aquaculture. Particularly as the worms have a very high content of polyunsaturated omega-3 fatty acids, which are important for both fish and humans.

Enchytraeus can be mass-produced by using seaweed collected from the beach as a food source, provided suitable environmental conditions are maintained. The project will examine how environmental conditions (e.g. temperature, salinity and the quality of seaweed and organic residues) can be adapted to optimize growth and reproduction of Enchytraeus.

During your thesis project, you will be part of a large group of researchers, fish feed and aquaculture companies that are working on expanding the project to an industrial scale.

 Contact: Professor Martin Holmstrup, mail: martin.holmstrup@bios.au.dk