NEGAUNEE TOWNSHIP (AP) - On a recent sunny, unseasonably warm afternoon at the Yellow Dog River, just off of the Marquette County Road 510 bridge, more than a dozen people were in the water looking for bugs.
Macroinvertebrae, to be exact. Having donned waders and separated into teams of three and four, and armed with 5-gallon buckets and sturdy nets, the crews spent half an hour in the water doing a "river dance," using their feet and the nets to stir up cobble and sand to get at where the creatures like to live, according to The Mining Journal of Marquette.
By collecting these macroinvertebrae - a variety of species of fly larvae, nymphs, snails, snipes, crayfish, clams and worms - and tallying their number and diversity, Big Bay's Yellow Dog Watershed Preserve is able to get a rough understanding of the level of the river's pollution. The YDWP then disseminates the information, in coordination with the Michigan Clean Water Corps, to the public.
The group, most of whom are volunteers, first went through about an hour-and-a-half-long training session at the Powell Township School in Big Bay, learning not only the different species of creatures they're likely to encounter in the water, but also how to note a plethora of other river characteristics, including water color, substrate, morphology, in-stream cover, potential causes of erosion or environmental degradation upstream and even whether any sheen or slime in the water is due to oil or naturally occurring bacteria.
"It really gives you a sense of community empowerment to know what's in your water," said Christy Budnick, program coordinator for the watershed preserve who conducted the training session.
If, for example, the groups find Caddisfly larvae, or mayfly nymphs, it's probably a pretty good indication that the river is healthy, as those two species are among the creatures most sensitive to pollutants. Alderfly larvae, crayfish and dragonfly nymphs are listed as being somewhat sensitive, while aquatic worms, leeches and pouch snails can thrive in even the worst environmental conditions.
Adding the species whose numbers are rare - meaning fewer than 10 were found - with those that are common from each of the sensitive, somewhat-sensitive and tolerant groups gives a total stream quality score that indicates the general health of the site.
The preserve has been conducting environmental monitoring on the Yellow Dog for a number of years, collecting and counting macroinvertebrae each spring and again in the fall. In 2012, with the help of a grant from MiCorps, several sites on the Salmon Trout River were added to its monitoring efforts.
"In each river you get a two-week sampling period for the spring or the fall," Budnick said. "And we do them within those two weeks so that our results are really accurate between all the sites."
Budnick said the two rivers are generally pretty clean and free of contaminants, but there is a system in place if problems arise.
"What we would do is we would go to the site and determine if there's something happening right at that site that we can see - whether there was some construction or a new culvert that went in upstream, and that's why the habitats are a little changed and we're not finding as many bugs," Budnick said. "Sometimes erosion can be the issue and sometimes it's actually from pollution entering the water from somewhere upstream. ... So we would look at all the different factors and determine our next step from there."