Eider duck predation affected mussel growth at Musholm Bay
Baltic Blue Growth partners Orbicon and Musholm have published a summary report on the mussel growth in the Baltic Blue Growth project farm in the Danish Musholm Bay during 2016. “Predation by Eider ducks has considerably affected the mussel production at Musholm last year”, says Maren Lyngsgaard, biologist with Orbicon. The total estimated biomass at the Musholm site was only 0.2 – 3.7 tonnes per production unit, whereas up to 20–25 tonnes of mussels per production unit have been recorded at other Danish mussel farms using similar production systems.
Project activities in 2016 focused on comparing the growth and recruitment of mussels on different substrate types. In the Musholm farm, four different Trawl test nets with mesh sizes of 50 mm, 80 mm and 150 mm were tested. In addition, a standard Smartfarm unit was placed next to the test area. Results from 2016 indicate that nets with 80 mm could be more optimal for recruitment and initial production compared to those with mesh sizes of 50 mm and 150 mm.
Test of different substrates and production units will continue at the Musholm farm during 2017 and 2018 and compared with the other Baltic Blue Growth project farms. During fall 2017, special focus will be on preventing biomass loss from predators such as eider ducks using continuous laser systems to scare them away.