Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Ageing Bass

I'm sure it's in here somewhere, so could someone tell me how to age a bass by looking at the scales.
Do you need to remove the scale from a certain part of the body or anywhere.

Then can you tell age by looking with the naked eye or do you use a magnifing glass or microscope.

I cought five bass in my lake yesterday, all were between 8 and 12.5 inches.
I think my bass aren't getting bigger due to too many bass, so I want to start removing bass but would like to age them also.

There is a way to age fish by the scales but I can’t tell you how. We tried it when I was in college and I don’t thick any of us in the class could do it and even my professor was struggling. But what I remember is: it is not as accurate in the south because no distinct growing season (up north it is a little more accurate because of the distinct growing seasons), there are a couple of different areas where it is best to remove the scale but I can’t remember exactly, also I was told if you can get a image of the scale to where you can put that in a projector and project a large image of the scale on a wall it makes it easier to age the scale, and most importantly my professor told us it is not as accurate as aging a fish using the otolith and that it is very difficult. So that is why I age fish using the otolith. However you have to kill the fish to extract the otolith. I age the otolith by grinding down the otolith to where you have half a otolith, then I mount it on a microscope slide, then grind the otolith down to where I can see through it with a microscope. I’m sure an expert will chime in on how to age a fish using a scale. You may also want to just calculate the relative weights of the bass and use that to determine if you should harvest the bass or not. You can go to our website to get the formula on how to calculate the relative weight and I also have some pictures of extracting the otolith out of some bass. http://www.lakework.com

For Bass the scales should be taken from above the lateral line and below the dorsal fin.

What we did was place the scales on a plastic slide and put them through a press. This leaves an impression on the slide that you can place in an inverted microscope. That is basically the same thing as a projector but you can change the magnification.

Deerstalker -- we had an article in Pond Boss magazine a while back that had some good pictures of some aging structures for fishes. Send me a PM or email me, and I can send you a copy of the article via email.

Aging methods - get the article from Dave and read it. MMorgan is right about scales in the south - it will work but is hard and not accurate without help. Pics are in the article and provided by Dave Willis.



scale


otolith location


whole otolith aging


cracked otolith aging

Thanks to all for the informative information.