Triploidy in Mytilus edulis impacts the mechanical properties of byssal threads

A major problem in mussel farming is mussel fall-off from mussel socks due to weakened byssal threads. This weakening is particularly prevalent following spawning events. During the last decades, significant work has been devoted to the production of triploid bivalves, which have a lower reproductive investment. In this study, we compared the byssal properties and energetic rates of triploid and diploid 1-year-old mussels (<30-mm). To determine the effect of triploidy on byssal threads, diploid and triploid mussels were placed in a recirculating flume to induce the production of byssal filaments. Our results showed that triploid mussels produced up to 65% more threads than the diploids. Furthermore, tensile measurements showed that byssal threads from triploid mussels had higher Young's modulus values (45% increase) and had multiple yield points. Energetic rates and metabolic investments were measured through food assimilation and oxygen consumption. The results showed that triploid mussels had a higher clearance rate (40% increase) and scope for growth (260% increase) when compared to diploids. Morphological comparisons showed variations between the two groups, with triploid mussels having a larger shell height than diploids of the same length.

Automated summary

A major problem in mussel farming is the fall-off of mussels from mussel socks due to weakened byssal threads, especially after spawning events. In recent decades, efforts have been put into producing triploid bivalves, which have lower reproductive investment. This study compared the byssal properties and energetic rates of triploid and diploid 1-year-old mussels (<30-mm). The results showed that triploid mussels produced more threads, had stronger byssal threads, and had higher clearance rates and scope for growth compared to diploids.