How did Zebra Mussels, the annoying invasive species we have in Mississippi Lake, get into our lake?
Zebra mussels can spread from one lake to another by attaching themselves to various parts of a boat. The specific part of the zebra mussel that attaches to boats is their byssal threads.Â
These byssal threads are strong, hair-like filaments that zebra mussels secrete from a specialized gland in their foot. The threads are made of proteins and function like an adhesive, allowing the mussels to anchor themselves firmly to surfaces such as boat hulls, motors, and other underwater equipment.Â
When a boat moves from an infested lake to a new body of water, the attached zebra mussels can easily hitch a ride, thus spreading the invasive species to a new environment.
Does the mussel move through the water to attach itself and how far can it travel?
Zebra mussels have a unique way of moving through the water to attach themselves to surfaces. In their larval stage, called the "veliger" stage, they can swim and move freely in the water. During this stage, they use small hair-like structures called cilia to propel themselves through the water. Zebra mussel larvae can travel significant distances in water bodies due to their swimming ability and being carried by currents.
However, once zebra mussels transition to the adult stage, they lose their ability to swim and become sessile, meaning they remain fixed in one place. Adult zebra mussels rely on their byssal threads to anchor themselves to surfaces. They can't actively move through the water like their larvae, but they can still be transported by attaching to boats or other floating objects.
As for the distance they can travel, it depends on environmental conditions, water currents, and the availability of suitable attachment surfaces. In their larval stage, they can travel several kilometers from their original location. When they attach to boats or other equipment, they can potentially be transported across great distances, even between different bodies of water. This is one of the reasons why zebra mussels have become an invasive species in many regions around the world.
Is the larval stage seasonal?
Yes, the larval stage of zebra mussels is indeed seasonal. Zebra mussels typically spawn during the warmer months of the year, generally from late spring to early autumn, when water temperatures are above 12°C (53.6°F). The exact timing of spawning can vary depending on regional climatic conditions and local environmental factors.
During the spawning season, female zebra mussels release millions of eggs into the water, which are then fertilized externally by sperm released by male mussels. The fertilized eggs develop into free-swimming larvae, called veligers, within a few days.
The veligers remain in the water column for several weeks, feeding on phytoplankton and gradually growing larger. As they mature, they eventually settle down and attach to hard surfaces, metamorphosing into adult zebra mussels.
Since the larval stage of zebra mussels is seasonal and coincides with warmer water temperatures, the risk of their spread through aquatic systems is generally higher during the summer months.