Aquarium dumps harm Griffy habitat

Aquariums dumped into Griffy Lake introduced an invasive plant species to the lake in recent years. The plant’s gone now, but wildlife managers at Griffy want to prevent aquarium dumps from reintroducing the pest.

Brazilian elodea is a common aquarium plant that invaded the lake in the past.
Steve Cotter, the natural resources manager for the City of Bloomington Parks and Recreation department, said he cannot be completely sure, but there was significant evidence that the Brazilian elodea was introduced after aquariums were dumped into Griffy Lake.

Colorful aquarium rocks were found on Griffy’s shores, and the Brazilian elodea is a popular plant for home aquariums.

Invasive plant species such as the Brazilian elodea can affect the lake environment and make boating and fishing more difficult for visitors to the lake. The plant tends to clog boat motors.

“It can have a devastating effect on ecology and recreational potential of the lake,” Cotter said.

In 2004 and 2005, aquatic vegetation surveys were performed by the Indiana Department of Natural Resources. The Brazilian elodea ranked third in abundance.

The City of Bloomington Animal Shelter will accept aquariums and their aquatic plants and animals.

A press release from the City of Bloomington Environmental Commission, said it can be harmful to the environment to empty aquariums into natural or man-made waterways, including lakes, streams, rivers, wetlands, storm drains and toilets.

“It is our responsibility as stewards of our local environment to take necessary care to assure unwanted plant and animal species do not become established in Bloomington,” the release said.

Cotter described Brazilian elodea as being about the diameter of a cat’s tail with many leaves on the stem.

Because it grows in groups, the aquatic plant becomes very dense, which makes fishing and boating difficult.

“It looks like you can walk on it,” Cotter said.

Instances of people dumping their aquariums into Griffy Lake are difficult to track.

Cotter said he thought these aquarium dumps might happen at night and could happen anywhere on the lake’s shoreline.

“It’s a very hard thing to monitor,” Cotter said.

Many non-native species seem to be coming from the South, Cotter said. There are theories that the plants’ success is because of the warming climate.

The growth rate of invasive species seems to be increasing compared to noninvasive species.

Brazilian elodea generally grows better in warmer areas, Cotter said.

“Some believe that the speed of invasions is increasing because of increasing temperatures,” Cotter said.

IDNR reported finding Brazilian elodea at about a third of testing sites in Griffy in 2005.

Griffy Lake was the first public access lake in Indiana where the invasive species was found.

The Lake and River Enhancement Program, which is affiliated with the IDNR, funded a fluridone treatment in 2006 and 2007 to eradicate the Brazilian elodea.

The lake was surveyed again in August 2007 and no Brazilian elodea was detected.

The treatment implemented to get rid of the Brazilian elodea led to the growth of some fish species.

Originally, IDNR felt there was the potential for the native plant community to suffer as a result of the Brazilian elodea invasion, but the native vegetation has returned and re-colonized the area once inhabited by the Brazilian elodea.

“Despite exhaustive searches, no Brazilian elodea has been detected in Griffy Lake since spring 2007,” a report from the IDNR says.

As of the report’s publishing in 2009, efforts to control invasive species are targeted at the Eurasian watermilfoil and curlylead pondweed.

The Brazilian elodea could be re-introduced if any more aquariums are dumped.

The City of Bloomington Environmental Commission is working to take preemptive action to prevent invasive species from encroaching on native plants in the Griffy environment.

“It does change the biological community if it is allowed to persist in the lake,” Cotter said.