Fish affected by early spring, ice out
The 2010 open-water season has arrived with some interesting circumstances.
Ice on many lakes melted in record time, the 2010 walleye opener is a week later than usual and seasonal temperatures have been consistent and above normal.
This year's walleye opener is a little atypical too. Because the walleye and northern season begins two Saturdays before Memorial Day weekend, the 2010 opener will land on May 15, missing Mother's Day by a week.
Mother's Day weekend is Minnesota's annual Take a Mom Fishing event, where moms can fish without a current Minnesota fishing license.
This year those participants will have to concentrate on panfish instead of walleye or northern pike.
The warm and consistent spring temperatures have some people wondering how the circumstances affect walleye behavior.
Park Rapids Area Fisheries Supervisor Doug Kingsley offered some insight on the subject this week. "Fish spawning is triggered by a combination of photo period as well as water temperatures. So even though walleye spawning normally occurs at water temperatures of 38-44o F (typically ~40o F), and our water temperatures have already been in the high 40os F, we are just seeing walleyes starting to spawn."
Department of Natural Resources Large Lake Specialist Doug Schultz has already been netting spawning walleye.
Schultz assists with walleye stripping (gathering eggs and milt) at Boy River near Hackensack. The eggs are hatched in captivity and stocked in various bodies of water.
Last Tuesday was the first day DNR workers stripped walleye at the Boy River site. Last year that process started on April 19.
According to Schultz, most of the approximately 80 walleye in the nets on that first day were males, with only about 5 quarts of eggs gathered.
"Next week should be better," predicts Schultz.
Kingsley adds that there are positives and negative to an early spring. A shorter period of ice duration means less risk of oxygen depletion & winterkill on our lakes. For the walleye angler, an early spawn and late opener may mean that walleyes will be more recovered from spawning stresses and may be more actively feeding.
However, a shorter period of ice duration means less chance of oxygen depletion and winterkill on natural rearing ponds. Lake of winterkill means undesirable fish survive, prey on or compete with desirable fish that are being raised. Or there's a carryover of fish that were being raised the previous year(s) that prey on or compete with fish that are stocked to be raised this year. Result of either (or both) is less survival and poorer growth and condition of desirable fish.
An early warm up, then more seasonal or fluctuating temperatures often means fish begin spawning earlier, but then spawning often drags on. This makes things more difficult for DNR workers to gather the number of eggs they need and finish the stripping process quickly.
For the walleye angler, an early spawn and late opener means that walleyes may move out of spawning areas by the opener and may be more scattered and difficult to find.