Triploidy in Mytilus edulis allows better attachment which can result in higher production yields

2021 Physiomar & Australia New Zealand Marine Biotechnology Society (ANZMBS) Conference, 7-9 September
During the last decades, intensive work has been put into the production of triploid bivalves, as triploidy can lead to reduced investment in fertility and faster growth. In mussel farming, the seasonal weakening of their byssal attachment can cause fall-off from mussel socks. In this study, we investigated the production and mechanical properties of byssal threads of diploid and triploid mussels related to their physiological performance by measuring the scope for growth. Finally, the seasonal gametes’ production of juvenile and adult stage were estimated through histological observations. Production of byssal threads was induced with the use of a hydrodynamic flume to standardize the abiotic factors, including current and turbulence conditions. The triploid mussels produced 40% more threads than diploids characterized by different mechanical properties, particularly a higher Young’s modulus. Scope for growth was calculated through measurement of clearance rates, respiration rates and excretion rates and triploid mussels showed higher scope for growth, as well as higher clearance rates. Preliminary results of the histological measurement tend to show a reduced investment or a delay in triploid gametogenesis. Indeed, primary observations, performed mid-May 2021 just before the beginning of spawning events demonstrated more advanced development stage in diploid gametes. Overall, this study showed that triploid mussels can be of great interest in mussel farming as they seem to have better attachment, better growth potential, and reduced or delay gametogenesis investment