to settled juvenile may exceed 99%. In 2019, the genome of a quagga mussel from the Danube River in Austria was sequenced, revealing how larvae use a system of intercellular 'cleavage cavities' and an expanded set of aquaporin transmembrane water channels for osmoregulation in low-salinity freshwater environments during the early stages of their development. Invasive species Europe Quagga mussels are presumed to have originated in the Ukrainian section of the Black Sea and probably began to spread further into eastern Europe in the 1940s. Today, they are an invasive species found throughout western Europe. In Romania, quagga mussels were first found in 2004 in the Danube River. In Germany, quagga mussels were first identified in 2005, and now populate many inland waters, such as the Rhine–Main–Danube Canal, the Main, and the Rhine. They were first identified in Switzerland in 2015, and in Lake Constance in 2016, where they have since spread massively and caused considerable problems, in particular to the machinery in waterworks. In 2014, the species was reported at Wraysbury Reservoir, not far from London's Heathrow Airport in the valley of the River Thames. In Ireland, the mussels were first discovered in 2021 in two lakes on the River Shannon: Lough Derg and Lough Ree. The mussel is expected to compete with existing zebra mussels and native species, becoming widespread due to its ecological tolerance and suitability to Irish climatic conditions. North America Zebra mussels, the first dreissenid mussel introduced in North America, rapidly spread throughout many major river systems and the Great Lakes, causing substantial ecological and environmental impacts. The quagga mussel was first observed in North America in September 1989, when it was discovered in Lake Erie near Port Colborne, Ontario. It was not identified as a distinct species until 1991. By 2021 the biomass of quaggas in the lower 4 Great Lakes was estimated to be so great as to become the primary regulator of phosphorus, remetabolizing and recirculating it instead of allowing it to sedimentize as normal. The introduction of both dreissenid species into the Great Lakes appears to be the result of ballast water discharge from transoceanic ships that were carrying veligers, juveniles, or adult mussels. The genus Dreissena is highly polymorphic and prolific with high potential for rapid adaptation attributing to its rapid expansion and colonization. Still, other factors can aid in the spread of these species across North American waters, such as