Fighting Back: Zebra Mussel Invasion
Zebra Mussels have been found in multiple locations throughout Wellington Lake in Kansas (KMUW 2015). This is yet another lake to become exposed to the invasive species. You may or may not have heard about the freshwater species that originated in Russian area lakes and rivers, or how they arrived in the Great Lakes and the Mississippi River (Hoddle 2010). Most importantly, what are the issues they cause us and how do we solve them?
Let’s begin with the species themselves. Zebra mussels are a small, brown and cream coloured freshwater clam (pictured above) that feed on phytoplankton in water by filtering up to one litre of water per day (Invading Species 2006). Female zebras are able to produce up to one million eggs. These hatch into larvae during warmer seasons and eventually develop a shell and settle onto hard surfaces where they secrete a sticky fibre and live for two to five years (Invading Species 2006).
This rapid reproduction leads to environmental and structural issues when they face no predators. Most fish cannot crush their shells, so only specialized fish with strong jaws or teeth such as the Roach native to Europe. These predators live in a natural balance in the Eurasian regions of the world. It is believed though that in the 1980s some zebra mussels were attached in the ballast tanks of cargo ships from these Eurasian regions and when the water was drained near the Great Lakes, the zebra mussels flowed with it (Invading Species 2006).
These mussels, facing no predators, were able to feast on the once plankton filled waters of the Great Lakes and other freshwater regions and reproduce at an alarming rate. The main issues that arose from this mass invasion are:
- Altered Food Webs
The mussels grew into such mass populations that their filtering process actually removed plankton from the food web, causing many fish species to starve out of the ecosystem (Invading Species 2006).
- Clearer Water – Algal Blooms
This may seem like a good problem to have, however this allows sunlight to penetrate deeper and develop deeper water vegetation, which also affects the food web. Algal blooms thrive in sunny conditions.These blooms grow as a result of their predator, phytoplankton, being wiped out by the mussels. Fish and wildlife struggle to survive in toxic waters created from algal blooms (EPA 2015).
- Occupying Hard Surfaces – Lose Fish Spawning Grounds
The large area the mussels occupy leaves no room for fish to spawn their eggs. This hurts the survival of the fish eggs long term (Invading Species 2006).
- Cutting Feet
Swimmers and Divers can be cut by the extremely sharp shells of the mussels. This makes any construction or recreation in these lakes dangerous (Invading Species 2006).
- Clogging of Intake Structures
Hydroelectric dams and water treatment facilities intakes are prime zebra mussel colonization grounds because they are generally metal or cement (hard surfaces). They gather in these structures until a point where filters or the intakes themselves struggle to keep the necessary flow through them (Invading Species 2006).
The economic impact of the species is expected to be in the BILLIONS of dollars (Missouri Department of Conservation 2015). So how do we get rid of them? The number one method being presented by the majority of authorities is inspection by boat owners. Ship hulls and engines make prime real estate for the mussels and if they are transported to a region that has yet to be affected, it will quickly become victimized.
Various chemicals, mechanical scrapings and filters are being used as well, but are expensive and time consuming. It is important that these methods are used only when the infestation has taken over an area completely. Keeping eyes underwater and inspecting regularly is the best way to keep the zebra mussels under control and recognize when they are becoming an issue.
The DTG2 Worker makes the perfect tool for inspections and can even be used to sample and remove mussels. Watch the DTG2 in action against the mussels:
Learn more about the DTG2 Worker here.