QualiZander

The reproduction of new aquaculture-relevant species often leads to morphological deformations of embryos and larvae due to insufficient knowledge about nutrient requirements and other parameters. Deformed fish cannot be sold and are therefore recorded at the larval stage at high personnel expense and subsequently sorted out by hand. Pikeperch is a relatively new fish species for farming and has a high potential for diversifying inland aquaculture in Europe. This is due to the increasing demand due to the decline in wild catches and also due to the quality of pikeperch meat (neutral taste and boneless fillets). One of the biggest bottlenecks for the further expansion of pikeperch farming in Europe is the low survival rate of the larvae. During larval development, deformities occur frequently and affect the quality of the stock.

The causes of deformities are not yet fully understood, but several factors seem to play a role. Whether bacteria are responsible for larval deformities is being investigated in this project by Astrid Gärdes (AWI). Screening at the molecular level (toxin genes) can quickly shed light on whether pathogens are responsible. As part of the work taking place in the marine bioeconomy section, an automated determination of the degree of deformation/percentage of deformed larvae is being developed in this project. This automated deformation detection will be used in conjunction with the work being carried out in the Polar Biological Oceanography Section. The development of a gene probe for rapid screeing of known pathogens will facilitate the work of breeders in the future.

By means of on-farm smartphone recording of the deformation frequency of a larval batch, an initial diagnosis can be achieved. This early detection enables the earliest possible countermeasures. In the second step, a more precise diagnosis of the bacterial contamination and the associated toxins takes place. Depending on the identification of the bacteria present and the corresponding toxins, suitable treatment methods can be recommended via Zander QualiScore. The results of these two focal points are weighted and finally summarised in a quality scale (comparable to the "Nutriscore" on food).

For further information and questions about the current status of the project, please get in touch with the contact persons listed.