Blue and Mediterranean mussels, though closely related, possess distinct characteristics shaped by their unique habitats and genetic makeup. Blue mussels, scientifically classified as Mytilus edulis, are indigenous to the cooler waters of the North Atlantic. They are typically smaller in size and possess a more delicate flavour profile. Their shells exhibit a diverse color palette, ranging from deep blue to various shades of brown. These mussels thrive in the cold, nutrient-rich waters of the North Sea, the Baltic Sea, and the Atlantic coast of North America.
Mediterranean mussels, or Mytilus galloprovincialis, are native to the warmer waters of the Mediterranean Sea. They tend to grow larger than their North Atlantic counterparts and boast a more robust, slightly stronger flavor. Their shells are often darker, ranging from deep blue to almost black. These mussels are well-adapted to the warmer, saltier waters of the Mediterranean and Black Seas. However, sometimes the lines between these two species can blur.
A unique type of mussel termed “dock mussels”, has been found at multiple ports along the coast of France, and according to a recent study they exhibit a distinctive genetic makeup resulting from a recent admixture of both linages. In this article, researchers explore the potential origins and impacts of dock mussels, comparing them to naturally occurring admixed populations and laboratory crosses to ascertain the extent of repeatability in these hybridisation events. The study concludes that dock mussels are likely the result of anthropogenic introductions, confined to port environments due to a combination of factors including limited dispersal, habitat choice, and early-stage adaptation. Further studies are needed to understand how selection, hybridisation, environmental conditions and dispersal are shaping the distribution and genomic architecture of these dock mussels and similar introductions.
While both species are prized delicacies, their differing habitats and genetic makeup influence their growth rates, tolerance to environmental conditions, and ultimately, their taste and texture. The cold, nutrient-rich waters of the North Atlantic contribute to the delicate flavours of blue mussels, while the warmer, saltier waters of the Mediterranean shape the more robust flavour of Mediterranean mussels.
Beyond their culinary appeal, these two mussel species play vital roles in their respective marine ecosystems. As filter feeders, they contribute to water clarity and nutrient cycling. Additionally, they provide habitat and food for a variety of marine organisms, including fish, crabs, and seabirds.