Science Question

[gunflint]

If fish are dependent on a certain amount of oxygen (x amount of parts per million) then how is it that shooting 02 (oxygen) into a minnow bag does anything? Isn't 02 a gas and therefore lighter than water? Does it really do anything?

I'm looking at doing a road trip for minnows, maybe 200 miles round trip and want to keep them healthy. Would it be better to stop a couple of times on the way back and change water?

When the walleyes are hitting on 3 to 5 inch minnows and all you can get is minnows under 3 inches and over 6 inches a 200 mile road trip doesn't seem extreem. Does it?

[hanson]

You gotta do what you gotta do, eh?

Here's what I'd do. Get yourself a cooler of somekind and bring it with you, maybe 2 if you are buying lots of minnows. You could either fill it with water before you leave and treat the water with chlorine drops, or have the bait shop fill it up for you if they are willing.

Then get a battery operated or 12v airpump with airstone, like you'd find in an aquarium. Either that or one of those Frabill Min-O-Life air pumps. It'll keep your minnows alive for days with changing out a portion of the water daily.

I rigged up a livewell recirculating pump into a cooler to keep my catfish bait alive. The pump runs on 12v so I just have to connect it to a 12v power source. I've kept 6-8 large sucker minnows in this cooler for 4-5 days without killing them.

[irvingdog]

Oxygen is pumped in because it increases the ratio of Oxygen in the bag. Air is composed of a lot more than just Oxygen.

As was said, if you want to keep your minnows alive, agitate the surface of the containers, do-not-overcrowd-the-bait, and change a bit of water when you arrive. Make sure the water you replace is the same temperature as the water you removed.

[GoodToGo]

Oxygen in the water and in the air exist in a certain ratio called equilibrium. It is a natural balance, if you add more oxygen to the air in the bag, some of this oxygen will get driven into the water in order to maintain its equilibrium. When you open the bag, the extra oxygen in the air (bag) escapes, and the extra oxygen in the water will also escape.

[Mr. Bear]

Oxygen can dissolve in water to a certain extent. The amount depends on the temperature of the water. Colder water can hold more oxygen than warmer water. The presence of aerobic bacteria in the water will decrease dissolved oxygen as they use it to decompose organic matter, so you want to keep the minnow water as clean as possible. The main source of oxygen in the minnow bucket is the atmosphere. You want to stir/aerate the bucket to help speed up the process of dissolving oxygen (like making Kool-aid, if you let the sugar sit it will eventually dissolve, but it is a lot faster if you stir it). However, in the case of minnows in a bucket, the oxygen is constantly being depleted, so periodic stirring is needed to keep the rate of oxygen being dissolved greater than the rate it is lost or consumed.

As far as using pure oxygen, I think that is overkill and an unneeded expense. Air is about 20% oxygen and water can only hold a fraction of a percent of oxygen. This concentration difference is plenty enough to drive the diffusion of oxygen into the water. So while it is necessary to aerate a bit, you are right that if done excessively it won't make any difference as the maximum holding capacity of the water will be reached.

So in summary, the keys to keeping dissolved oxygen levels high would be:

- keep the water cold

- keep the water clean

- keep the water aerated (at least periodically)

[Deitz Dittrich]

Great First post MR. Bear!!!!

Welcome to FishingMinnesota.com

I look forward to reading more of your posts in the future!

[Mr. Bear]

Thanks. I've been a reader here since I moved to the state this spring. I guess it took the right bait to get Mr. Bear out of hibernation. I've really appreciated all the knowledge shared here, and it's been a blast learning the Minnesota lakes. Hopefully I can contribute a bit more in the future.

[gunflint]

Thanks Mr. Bear and welcome. Now can you explain that whole E=MC2 thing? Just kidding. It sounds like a couple of stops on the way home for fresh water should do it.

[ChuckN]

I don't think you will have a problem. I bought an $8 battery operated aerator system that includes a lid for a 5 gallon bucket.

I catch my own bait being redtails, creek chubs and shiners and I've kept them for many hours/days in the same water even with warm weather.

The main issue is if the minnows are fresh out of a creek they tend to deposit more feces and the water goes bad quickly, but if the minnows are trapped a couple days before containing them the water can go for a couple days in a 5 gallon pail. I run an AC aerator when at home and use battery power for trapping. I rarely lose a minnow in under 2 weeks time.