Answer: Because it's cold.
Another answer: Because global warming might be here and it might be real, but it in no way -- notwithstanding what Gov. Tim Pawlenty, his wife, Mary, and, especially, state Sen. Satveer Chaudhary might want you to believe -- justifies opening the fishing season a week earlier.
Take a look at the tables that accompany this column. Star Tribune researcher Roberta Hovde gathered weather data for the fishing openers 1997-2007 and also for a 10-year period a half-century ago, 1947-1957.
Comparisons aren't exact, because the day the Minnesota fishing season opened changed from one period to the other. But they're close enough.
Three locations were chosen: Minneapolis, Brainerd and International Falls. Hovde looked at the high and low temperatures on the opener for each location, as well as precipitation amounts.
See any big difference between the two periods?
Neither do I. In fact, the warmest temperature (85) was recorded in the earlier period. And the coldest (43) was in the most recent 10-year span.
This isn't to say global warming doesn't exist (save your e-mails). Nor am I making the case based on this rather cursory look at Minnesota fishing-opener conditions that spring is not arriving ever earlier in the state, and waters warming sooner.
In fact, both seem to be true. Ice-out dates appear to occur slightly earlier now than they historically have, and data compiled by the Department of Natural Resources in the Bemidji area indicate that spring spawning of walleyes is ending a few days earlier than historical norms.
That said, my "freeze my tail off on most openers'' method of determining whether the season should be opened a week earlier is probably all that should be needed to derail the idea.
Let's look at some facts:
• Minnesota is a north-south state, meaning its distance from north to south is much greater than its distance from east to west. (Each of the Dakotas, by contrast, is an east-west state.)
• Because of this, weather (and particularly water temperatures) can vary greatly from, say, Winona in the south to International Falls in the north. This alone makes uniform management of fisheries (and also wildlife) statewide very difficult.
• As the accompanying charts indicate, and more exacting data confirm, warming spring temperatures, such as they are, are neither marked enough nor consistent enough to predict with any certainty in a given year that spawning will be complete in the northern half of the state if fishing season is opened a week earlier.
• Already on most opening days -- which by law now must be two Saturdays before Memorial Day -- the DNR closes multiple spawning areas in the north to anglers. This is relatively easy for the agency to do because in nearly all instances spawning, if not complete, is nearly so, and places where fishing is prohibited are easily marked.
• Open the season a week earlier, and statistically the DNR will have to close more areas to fishing more often. Moreover, in some years the spawning and postspawning populations that will require protection will not be in rivers, inlets or other relatively easily defined areas, but on or near midlake shoals. Difficult to post against fishing? In many instances, impossible.
• Opening the fishing season a week earlier also would be risky for northern Minnesota resort owners and outfitters (who are likely to oppose the idea). Opening weekend of the fishing season is tenuous enough up there in some places. Some years, it's simply too cold to enjoy. Other years, ice is still on lakes or portions of lakes.
• Yet it's well known that at least half of the anglers who fish opening weekend count that angling trip as one of the few they make each spring. They want to have fun with their family and friends, and with luck catch a few fish. If the forecast suggests they'll be rained or snowed or iced out, they'll cancel their opener. And many of these fair-weather anglers are not the type who will come back the following weekend, whether conditions improve or not.
• DNR fisheries chief Ron Payer says lake spawning now concludes in northern Minnesota between May 2 and May 7. As any angler worth his or her Lindy Rig is aware, walleyes (particularly males) hang around spawning areas for a week to 10 days after that -- making them vulnerable enough.
• Open the fishing season a week earlier and the walleye harvest doubtless will rise. Yet most management measures taken these days are intended to conserve fish stocks, not further exploit them. Already about 60 percent of the annual walleye harvest on Mille Lacs occurs during the first six weeks of the season (during which anglers catch about 60,000 pounds of walleyes a week). About 70 to 85 percent of Upper Red's walleye harvest occurs during the same period. Open the season a week earlier and the increased harvest will pose a special problem for Mille Lacs, where walleye angling effectively was shut down last summer when anglers bumped up against their quota.
• Recall also the state already has tacked on an extra week to the end of the winter walleye and northern pike fishing seasons. Those seasons now close the end of February, instead of a week before.
• Another problem: Bait dealers already are challenged (depending on the weather) to supply enough minnows, leeches and night crawlers for the current opener. Move it a week earlier and the probability rises that some years there won't be enough bait to go around.
Finally, there's Mother's Day. Opening day of fishing now conflicts nearly every year with the day we otherwise reserve to honor Good 'Ol Mom.
That's unfortunate. But it doesn't justify changing the fishing opener under the guise of "global warming says we should'' (because it doesn't).
Perhaps Mom would rather be alone on her big day, anyway.
As Hovde, the Star Tribune researcher, is fond of saying:
"Give a man a fish, and you feed him for a day. Teach him to fish, and you get rid of him for a weekend.''
Dennis Anderson • email@example.com