Published: Mon Jan 24, 2005While some people like to spend lazy afternoons catching minnows from small, shaded streams, Tennessee Tech University biologist Hayden Mattingly is involved in a research project — funded by the U.S. Fish and Wildlife Service through TTU’s Center for the Management, Utilization and Protection of Water Resources — to monitor the movement patterns of blackside dace minnows.
Native to only eight southeastern Kentucky counties and three northeastern Tennessee counties, the minnows spawn from April to July in silt-free, gravel areas in upland streams of forested areas.
“Anything that contributes large amounts of silt to the streams where blackside dace live — it could be agricultural runoff, mining and logging practices, highway or dam construction or any other number of activities — could also affect the fish,” Mattingly said.
Because the fish’s natural range also coincides with the coal-rich region of Tennessee and Kentucky, surface mining is believed to have a significant impact on its population, according to one wildlife conservation web site.
Rather than trying to determine what factors are contributing to the blackside dace population decline, however, Mattingly’s research monitors the minnows’ movement patterns for signs of migration.
After gathering data from 72 sites within 28 different streams, Mattingly and his research assistant used backpack electrofishing — which brings the fish to the water’s surface for counting — to estimate blackside dace populations.
“We studied two streams for about a year, looking at each one every six to eight weeks, to track movement patterns, and we found that about 60 percent of the population in one stream was highly residential, while about 80 percent of the population in the other stream was residential,” he said.
That means a sizeable minority of the fish have likely dispersed and migrated to other parts of the stream or to nearby tributaries, and that is a positive sign. “Although the majority of blackside dace seem to spend their lives in the tributary where they were hatched, it’s healthy for a portion of the population to migrate because that increases the gene flow, which is generally positive for any species,” Mattingly said.
The next step of his research is to try to learn how far and how many blackside dace actually are migrating and use that information to create a dispersal model to show what percentage of the population might relocate to any given stream.
“The farther the relocation, the lower the percentage of successful migrations, of course.”
Mattingly said he hopes his research findings can be used to make better-informed decisions regarding species conservation.
“When you’re directly involved in this type of research, you really come to understand how important it is that we as a population must focus on how to meet our own needs in ways to keep natural habitats healthy for native animal species,” he said.