In the fight against alien animals that invade and overrun native species, the weird and the wired sometime win.
Invasive species are plants and animals that thrive in areas where they don’t naturally live, usually brought there by humans, either accidentally or intentionally. Sometimes, with no natural predators, they multiply and take over, crowding out and at times killing native species.
A new underwater robot is targeting the stunning but dangerous lionfish. The robot, called Guardian LF1, uses a gentle shock to immobilize the lionfish before they are sucked alive into a tube. In its first public outing this month, the robot caught 15 lionfish during two days of testing in Bermuda. Top chefs competed in a cook-off of the captured lionfish which sells for nearly $10 a pound.
U.S. Fish and Wildlife officials are using souped-up old technology to catch Asian carp, a fish that’s taken over rivers and lakes in the Midwest. They use a specialized boat – the Magna Carpa – with giant winglike nets that essentially uses electric current as an underwater taser to stun the fish, said biologist Emily Pherigo. At higher doses, the fish are killed and float to the surface. In just five minutes, they can collect 500 fish, and later turn them into fertilizer.
Florida’s tropical waters are home to a great diversity of life, but perhaps the most endearing is the Manatee. The manatee is a grazing animal and spends between six and eight hours a day feeding on seagrasses and other freshwater vegetation. The manatee actually plays an important role in controlling the aquatic plant growth in Florida’s shallow rivers, bays, estuaries, canals and coastal waterways.
As the human population increases and waterfront development continues, manatees are losing habitat. The development also damages seagrasses, degrades water quality and reduces the availability of the warm waters that manatees rely upon to survive. Waters below 68° can prove fatal to manatees.
2013 was the deadliest year on record for the endangered manatee. With populations of less than 5,000 they have suffered due to boats strikes and algae blooms that not only left many manatees dead, but also destroyed their food supply resulting in even more deaths.
In order to protect the manatees, the U.S. Fish and Wildlife Service will establish a year-round manatee refugee in Kings Bay, its tributaries and adjoining water bodies. Kings Bay, located at the headwaters of Crystal River and consists of 30 known springs that used to be clear and beautiful.
The once crystal clear water with clean white sand bottoms is now in distress. Excess nutrients from wastewater, septic tanks and stormwater runoff resulted in declines in water clarity and growth of nuisance aquatic plants. One such aquatic plant, water hyacinth is now part of an experiment to help restore the Bay and save the manatees.
Water hyacinth once choked the waterways and extensive control measures began in the early 1900’s. With the water hyacinth under control, filamentous blue-green algae arrived. A controversial experiment is now under way in Kings Bay to reduce algae populations and remove nutrients by using the ever efficient filtering of the water hyacinth.
Water hyacinth will be placed in containment cages to prevent their spread. It is believed that the shade from the floating aquatic plants and the nutrients they will remove from the water will make a substantial difference in water clarity in the area.
Asian carp were imported from China to the U.S. in the 1970s to remove algae from catfish farms and wastewater treatment ponds. Somehow they escaped and migrated north through the Mississippi and Illinois rivers.
The species spawn in rivers and feed on phytoplankton, disrupting the food chain for younger fish. The voracious eaters can weigh as much as 100 pounds and grow to four feet. The longer the carp remain in large numbers, the greater the chance that they could devastate the aquatic environment.
Asian carp made national headlines in 2010, when federal and state officials worked to track the fish in Illinois and the carp threatened to reach the Great Lakes via the Chicago River. It was predicted that the carp would crush the Great Lake fishing industry and destroy the already fragile ecosystem if infiltrated.
In 2013, Asian carp DNA was discovered in the Wisconsin waters of Lake Michigan. It can’t be determined how the DNA got into the water whether by a live fish, dead or from a bird, but the threat is real. Last month, a joint Army Corps and U.S. Fish and Wildlife Service report showed fish were moving through the electronic barrier in the Chicago Waterway meant to serve as Lake Michigan’s last line of defense against the carp.
With the Asian carp within 55 miles of Lake Michigan, the Army Corps of Engineers were assigned the task of determining how to keep the carp from reaching Lake Michigan. After seven years, the report outlines eight different options, but didn’t recommend one.
The options provided include physical separation, special locks and gates and chemical agents. In a situation where time is of the essence, one option which relies largely on a new kind of lock, chemical treatments and more, but with limited physical barriers would take about 10 years and $8 billion to implement.
Another option would take 25 years and $15 billion to $18 billion and while may be the most effective option has now only time and cost hindering it, but would have a cost impact on commercial cargo. This option faces much criticism from business interests.
That option would be to put a physical separation at the edge of Lake Michigan. Not only would this keep the Asian carp out of Lake Michigan, but also prevent the invaders found in Lake Michigan from making their way into the Mississippi watershed.
While the separation is going to have a lot of opponents, it seems to be the only real solution that will truly protect the Great Lakes. It will not only stop the Asian carp from coming into the Great Lakes, it will stop any further diversion of the Great Lakes water.
According to a 2012 study by Canada’s Department of Fisheries and Oceans, it would take as few as 10 male and 10 female Asian carp to establish a reproducing population in the Great Lakes.
Penn State | News
April 18, 2013
When you look at lovely water gardens in backyards and at businesses — and feel soothed by the serenity they convey — you would not guess that they represent troubled waters for ecosystems in the mid-Atlantic region.
The explosion in popularity of water gardening has resulted in the proliferation of aquatic invasive species, according to Diane Oleson, a Penn State Extension educator based in York County, who created an educational program that shows water gardeners how to avoid giving aquatic invaders a free ride.
Invasive plants tend to displace native plants over time and create an unhealthy ecosystem because a lot of them form huge, dense, one-species stands in which other plants can’t grow. “Animals don’t eat them because the species that would control them are back in Asia or Europe or wherever they came from,” Oleson explained.
We focus a lot on aquatic invasive plants, just because that is our business – but there is another invasive species that certainly deserves some print on our blog. It is partically because of them that weed harvesters are needed.
Zebra mussels, a freshwater aquatic nuisance, which grow to about the size of a dime and live up to eight years, are rapidly invading North American lakes.
Zebra mussels have three main effects on the water bodies they invade.
Zebra mussels siphon a liter of water per day to live. They act as filters and clear the water of food necessary for small larval fish to survive – ultimately starving the top of the food chain – the walleye, catfish, and Northern Pike. The clear water is certainly desirable, but water that is too clear allows sunlight to reach the bottom creating ideal growing conditions for invasive aquatic plants like watermilfoil and flowering rush.
Clear waters as mentioned above not only kill off fish leaving anglers to find new fishing spots, but the number of invasive aquatic plants make water transportation difficult often getting tangled in engine propellers. The additional plant growth hinders swimming, boating, and paddling/canoeing. The zebra mussels can cause bodily harm with their razor-sharp shells and because they attach themselves to hard surfaces such as docks and boats, they are easily spread from lake to lake.
The U.S. Fish and Wildlife Service estimated zebra mussels have cost Great Lakes region’s water and power plants close to $5 billion in the past decade to clear clogged intake pipes. Annually zebra mussel-related maintenance was estimated to be around $100 – $200 million.