Effect of feed size on the growth of the flathead grey mullet Mugil cephalus
Supervisors: Urtzi Izagirre, Manu Soto (UPV/EHU)
The EU’s contribution to world aquaculture production represented less than 2% of global production in 2018 (FAO 2020). Aquaculture produces one out of every four seafood products consumed in Europe. However, imports account for the majority of seafood consumption, accounting for around 60% of total supply. EU aquaculture accounts for only 10% of total EU seafood consumption. This indicates a huge development potential. However, demand for fish is increasing, as is demand for aquaculture products that are more sustainable and have a reduced environmental effect.

In this framework, the objective of the AKURA, project funded by the European Commission through the Government of the Basque Country is to develop a sustainable culture process for the Flathead Grey Mullet (Mugil cephalus) in the way to sustainably culture without affecting the nutritional quality. As the part of the project, M. cephalus was cultured in open flow system fed with different sizes of feed to determine the suitable feed size for the maximum growth of the fish.

Fish were fed with 2-2.5% of their body weight with morphometry data collection after every 15 days of interval. Growth was determined by the morphometry, histological and histochemical methods. The growth pattern was determined using the Feed Conversion Ratio (FCR), Specific Growth Rate (SGR), Condition Index, and length-weight correlations.

After 79 days of experimental study, the experimental group fed with 1.0mm and 1.2mm had better SGR, FCR and condition index than the other feed size. The fish oesophagus diameter was also measured and showed low linear relationship with the fish fork length. In general, growth was better with the feed size of 1.0mm and 1.2mm.