Final answer:
The distribution of a mussel species one year after initial sighting would likely include expansion to nearby suitable habitats such as mussel beds and mudflats, potentially influenced by human activities like aquaculture. Their densities could vary, and they may affect biomasses of other species like phytoplankton. Management actions are crucial for the control of their spread.
Step-by-step explanation:
To describe the distribution of a mussel one year after it was first sighted, it is important to consider the growth and expansion patterns typically observed in invasive mollusk species. For example, if we look at cases like the marine mussel Musculista senhousia or the history of the marine snail Littorina littorea in northeast North America, we usually see rapid expansion in favorable conditions. These expansions are facilitated by factors such as high reproductive rates, adaptability to local environments, and human activities like aquaculture and shipping, which can spread the species, either intentionally or accidentally.
Instances mentioned in literature, like the unintended spread of oysters in Denmark or the distribution patterns of Aphanomyces astaci in Slovenia, showcase how quickly and widely aquatic organisms can disperse. Similarly, mussel populations can colonize new habitats, often joining or replacing existing ones. In the New Zealand case, mussel farming became a vector for the spread of invasive species, highlighting the role of aquaculture in such distributions.
Within a year, the observed mussel could have expanded to nearby blue mussel beds, mudflats, or other suitable environments, with densities potentially varying from location to location. Continuous monitoring and management actions, such as boat and ship hull inspections, are necessary for prevention and control of further spread. If these mussels proliferate, they may impact biomasses of natural populations like phytoplankton, which are crucial to the ecosystem balance.