In an effort to assess the health of our lake, the Covekeepers, under the guidance of Catawba Riverkeeper David Merryman, recently conducted a leaf-bag study of the aquatic life in Mountain Island Lake. A leaf-bag study is a composite of leaves, sticks, rocks and other natural materials inside a mesh bag suspended in the water column or on a streambed for a specific period of time. The material within the bag simulates the plant matter and other "stuff" that accumulates throughout the year in our lake water. Upon removal of the leaf-packs, the contents are inspected for insect larva and other non-fish macroinvertebrates.
Covekeepers inspect the contents of the leaf bags from Mountain Island Lake.
Lakekeeper Alice Battle and Assistant Lakekeeper Kathy Jaeck discuss aquatic insects and other "critters" they found living in our lake water.
Midge larva can be small, often
less than 1/8" long. Photo courtesy
U.S. Geological Survey
By counting the various kinds and numbers of snails, aquatic insects and so forth that take up residence in the leaf-bag, we can get biological indication of water quality in our lake. Combing through the detritus in our study, we found mayfly nymphs, snails, aquatic worms, dragonfly nymphs and a few specimens that defied identification. The bag with the highest "critter count" came from Gar Creek Cove near the Latta Plantation kayak launch.
We found a number of mayfly nymphs in our sample from Gar Creek. In late July there was a very significant hatch of mayflies from Neck Cove down to the Big Island across from the dam. Photo courtesty of North American Benthological Society; www.benthos.org, contributed by Geoff Leclair
Catawba Riverkeeper David Merryman and MIL Lakekeeper Alice Battle examine specimens from the Covekeeper leaf bags.
Based on our study Riverkeeper David Merryman feels the quality of our water here in Mountain Island Lake is tettering between fair and good. Merryman states, "Our leaf packs harbored species indicative of good water quality in some locations, but we also found a high prevelance of midge species throughout the lake. This tells us there is definite room for improvement."
