There's an interesting new story that just appeared in Minnesota Outdoor News. Researchers with the Minnesota Department of Natural Resources say that in 900 lakes they've surveyed in that state, numbers of yellow perch are down significantly.
Over the years, I've noticed the same thing while diving and photographing fish in Wisconsin lakes... there just aren't as many perch as there used to be. The news report says in part that DNR researchers are looking at not only what might be holding back yellow perch, but also potentially dragging them down.
"A new study looking at yellow perch is being led by DNR research biologists Jeff Reed, of Glenwood, and Bethany Bethke, of Duluth. Related research conducted by Bethke during the past couple of years pointed to a likely decline in perch numbers; in more than 900 lakes studied, perch numbers had dropped on average, from about 10 fish per gill net to around five fish per gill net during DNR surveys.
“When you see something going in half over a 25-year period, it’s something you want to look at,” Reed said.
Examination of netting data yields some clues regarding why perch might be declining in some places. High water levels have created fertile breeding grounds for northern pike, and a corresponding increase in the pike population could be putting a bigger dent in the perch population, Reed said. Also, invasives – such as zebra and quagga mussels, and spiny water fleas, where they exist – could be reducing the foods available – like zooplankton – for very small perch.
One other factor could be in play, too. Longer growing seasons in lakes are helping species like bluegills, which compete with yellow perch.
Bethke adds yet another item to the list of possible culprits for perch decline: the loss of near-shore habitat, which could be lakeshore property owners removing woody debris or bulrush."
To read the entire article, go to this link.