Outdoorsmen Adventures.com

Jon Thelen, walleye fishing pro from Crystal, Minn., knows the importance of properly measuring walleyes
before putting them in the livewell. Nearly every lake we fish today has some type of length limit on this popular gamefish.

Reprinted from the Sioux City Journal.
If you are fishing walleyes or bass on public waters now days, a ruler important a piece of equipment as your fishing rod.

Can you think of a lake which does not have a length limit on either walleyes or bass.

Well, sure. There are some.

But, not many.

If you don’t know how to measure a fish, you could find yourself on the wrong side of the law.

Jon Thelen, walleye fishing pro from Crystal, Minn., knows the importance of properly measuring walleyes before putting them in the livewell. Nearly every lake we fish today has some type of length limit on this popular gamefish.

That’s why we asked Jon Thelen to give us a short course on how to measure a fish properly.

Thelen makes his living fishing.

He’s a former PWT professional and now makes his living promoting fishing through his business Professional Angling Promotions.

There are few anglers who can measure fish as accurately as tournament fishermen. Bring in a fish a fraction of an inch over the minimum and you might suffer disqualification or a big penalty.

“There is nothing worse than catching a fish that is real close and just not being sure whether you should keep it or not,” Thelen says.

“You need to learn how to measure fish the same way the DNR’s measure fish,” he says.

It’s actually not very complicated.

“Close the fish’s mouth, push him to the front of the ruler so he is touching it,” Jon says. “Then pinch the tail closed and read where it falls on the ruler.”

“So what you need to do is get the fish at its longest possible length and that is the point any authority on the water is going to go by,” he says. “So make sure you are measuring your fish right and save yourself a ticket.”

However, there is close and closer in fish measuring, and we have all heard how fish seem to gain a quarter inch in length in the livewell.

What about that?

“You know what,” he continues. “There are plenty of fish to catch out there so throw it back and catch another one if you are not sure.”

It’s always best to error on the side of conservatism when measuring fish, but what do you allow? A quarter inch. An eighth of an inch?

“I’m going to go an eighth of an inch,” Thelen says. “I use a ruler called “The Judge” and like a all rulers designed for measuring fish, it has a 90 degree bend on the zero end. I’m gong to have the nose of the fish pressed against that and with my other hand I will pinch the tail and read the ruler.

“If you are using a soft ruler like a tailor’s ruler or a carpenters tape measure, you might want to allow a quarter inch because there is no way to know exactly; but, I’m pretty comfortable with one eighth of an inch as long as I’m doing it on a ruler that has a 90 degree end and I know I am touching that end.

“The other thing to keep in mind is to measure it on both sides because the authorities are going to measure it on both sides. Tournament officials are going to measure it on both sides.

“If it is over one one side and under on another, believe me it’s the wrong way for you,” he smiles. “That’s not a knock on our authorities on the water, that’s just the truth.

“Let’s just say I’m on Mill Lacs lake and I cannot keep a big fish under 28 inches,” he continues. “I need to make sure that fish is legitimately over 28 inches and if it’s over on one side and under on the other side, you know what? I’m going to throw that fish back and not take the chance.”

Thelen said every angler should buy a proper fish measuring device.

“There are a lot of different brands,” he says, “but at the end of the day the DNR in Minnesota is very fair and they are going to go by the ruler in your boat as long as it looks like a ruler, but I’d suggest getting something with a 90 degree bend to push the fish’s nose into.

“Be sure to read the signs when you pull into a boat landing,” he says. “Most states are posting regulations so take a minute and read those signs. Make sure your are legal.

“Those regulations are put in place to make our fishery healthy so abiding by them makes sense,” he concludes.