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Thread: Aging crappie project

  1. #1
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    Default Aging crappie project


    I’m certainly no expert at aging fish. I’ve done it once before in a biology class in Alaska but that was it. This is actually something pretty easy that I think anyone could do. I found a very easy way to remove the otoliths from crappie after a few attempts at doing it like you would on larger fish like salmon. The easy way is to open the under side of the head, remove the gills and the transparent case containing them will be right there, you can even see them. Crack it open like a nut and they fall out like loose teeth.



    You can just about see the growth rings with the naked eye but a little magnification does make it easier. You don’t need a fancy microscope or anything to see them, a simple 5 dollar magnifying glass will do. So with 30 seconds time and a cheap magnifyinglens and you will know what age your fish are.



    The microscope I use for wound tract survey's goes from 20-100x so it doesn't show the whole otolith when counting rings. I plan to oder an adapter that will nock it down to 10x and hopefully open the field of view for better pictures.

    The next time I collect them I’ll do a video on it so if anyone were to be interested in aging a fish, it will walk you through the process.

    Otoliths are a crystal that continues to grow on itself. During the winter you get a slowed growth so these areas are more distinct and show as a line just like a growth ring in a tree. They are supposed to be much more accurate than using a scale, especially in the south where the slower growth of the winter season is much shorter. Supposedly they can produce much more information if you crank up the power and look close but for now I’m satisfied with age information.

    What got my interest going on this was a thread a couple weeks ago about crappie management. Some indicated a 10” minimum limit state wide and some a 12“ to increase general size. I’ve go no problem with “Trophy” management if it works, I like big fish too, so it got me looking into it online and as usual I didn’t find much for answers. There are a lot of other variables involved here other than just age but I would think age would be a key variable. I haven’t fished alot of NC yet but I have fished enough places to see a significant difference between the quality of fish at Jordan Lake and other places.

    I’ve heard of overpopulation stunting growth, quality ofhabitat is unquestionably a factor but the main question on my mind was justhow long does it take to grow fish of this size and where? The 10” measurement I’m using as a base line just because it’s a state limit and it seems like a good place to start. I’m real interested in seeing how it progresses from therein the “Slab” category.

    This will not be a short term study. I’m the type of guy that likes large sample sizes and since it’s a side project it’ll get done as I can do it but any input from others is most welcome to increase sample sizes and add regional information. I’m not looking to influence crappie management, this was just started out of a lack of information to understand management. Hopefully any outcome just helps alleviate that for anyone else looking for answers.


    I started with Jordan lake and really consider the beginning a good one. I brought home six fish for measurement that I will add to throughout the year. I am recording length, weight and age for this, so it will show time of year and weight for a fish’s size as well when its all said and done, which will hopefully give some indication as to quality of habitat in regards to food sources.



    The six fish ranged from 10.25” to 10.75”. All weighed within a 3oz range with the 10.25” being 8oz and the rest 10-11oz. I know I should use cm and grams here but I’m keeping this easy for most to visualize. 5 fish showed to be of the same age group but one and it wasn’t the smallest fish. It was a 10.5” 10oz fish that showed to be a year younger than the rest.


    5 of the fish showed to be going on their third winter.



    One showed to be on its second (this fish fell into the middle of the size group and was not the smallest)

    It’s a small start but down the road when there is 20-30fish for a size group and location and things get all graphed out, I hope there could be some worth while information. We’ll see how it goes.

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    Likes bassaholic, BigDawgg, fishjunky, SEA DANCER LIKED above post

  2. #2
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    Thanks for your work Woody. This is great information.

  3. #3
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    Nice work Woody. I'd like to see these results later on down the road as you build up specimens a broader range in size and maybe different lakes. I know where a ton of 8 inch fish are that never seem to grow. I'd like to know how old they are.

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    Thanks for the support guys. I know where there are some of those 8" fish as well. I really can't wait to find some 10-15 year old fish either.

  5. #5
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    Thats interesting for sure. I'd be curious to see how old the 8in fish are aswell as ones that are 12in plus.

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    I have some, OK a bunch otolith ageing too and for the older fish the rings start to stack up on top of each other so it makes it difficult, however i found that if you lay the otolith down flat and press down with your thumb it will crack into 2 pieces. Next wet sand the cracked pieces so that you will have a cross sectioned view on the otolith. you will need a microscope for this however. just make sure when you crack it cracks in the middle so the nucleus(or when first born) is in the middle as your starting point and then count outwards i have a bunch info from Lake wylie, sc side and a ton from lake wateree, sc that i will try and dig up next week after the holidays.

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    What are the chances for genetics being the reason a 2 year old fish may be bigger than a 3 or 4 year old fish, such as the case with Whitetail Deer? I know that habitat, which directly affects the amount of carrying capicity a parcel of land has, is key to Whitetail growth, but could it be the same in fish? In essence, if a lake doesn't have the habitat to grow big crappie but has a limit imposed of 10 inches it will surely be overrun with small fish. I have seen this happen in smaller impoundments such as ponds. Couldn't it happen in larger reservoirs as well? I don't have any particular bodies of water in mind, but Woody's research has me intrigued. When I get intrigued I ask a lot of questions.

  8. #8
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    Quote Originally Posted by bioguy View Post
    I have some, OK a bunch otolith ageing too and for the older fish the rings start to stack up on top of each other so it makes it difficult, however i found that if you lay the otolith down flat and press down with your thumb it will crack into 2 pieces. Next wet sand the cracked pieces so that you will have a cross sectioned view on the otolith. you will need a microscope for this however. just make sure when you crack it cracks in the middle so the nucleus(or when first born) is in the middle as your starting point and then count outwards i have a bunch info from Lake wylie, sc side and a ton from lake wateree, sc that i will try and dig up next week after the holidays.
    These pictures, other than the one of the pair were taken at 20x with a microscope. The larger fish (salmon) I aged in AK were done by cracking the otolith as you can not see the age rings from the side when they are so large. I'm really interested to see how big an otolith gets in a crappie and when you would have to go to a microscope to age. I would love to see your data from SC and compare to it down the road as well.

    What are the chances for genetics being the reason a 2 year old fish may be bigger than a 3 or 4 year old fish, such as the case with Whitetail Deer? I know that habitat, which directly affects the amount of carrying capicity a parcel of land has, is key to Whitetail growth, but could it be the same in fish? In essence, if a lake doesn't have the habitat to grow big crappie but has a limit imposed of 10 inches it will surely be overrun with small fish. I have seen this happen in smaller impoundments such as ponds. Couldn't it happen in larger reservoirs as well? I don't have any particular bodies of water in mind, but Woody's research has me intrigued. When I get intrigued I ask a lot of questions.
    Thats a question that came up in my mind that started this project. Having worked in the hunting industry for quite a few years I've see quite a bit of diversity of genetics in whitetails. I've shot 140" 2.5 yr olds in Kansas and a 5 yr old 60" here in Smithfield. A neighboring property to me here is trying to grow those Kansas deer. He may improve things slightly but he will never get those Kansas size bucks based on genetics alone. With that said, we do have poor soil here and that effects the food source. If that could be improved he could see an additional growth in his management goals.

    I think its going to be interesting to see age sample groups in small waters compared to over populated and then Jordan. If the growth slows so much that you have to go to a scope to age because the rings are so close together after the first few years, then this is where influences like genetics and habitat should really begin to show. But that will beg the question...is there something else we can do to increase general size other than just impose a minimum size?

    Oooooooh, its fraught with drama now.

  9. #9
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    Ok so looked through some of my spreadsheets from Lake Wylie and here are some results. I am not expert but I feel confident in my methods. I wish I had some true slabs from wylie to age but I guess im not that good of a fisherman. Ya’ll can draw your own conclusions from what I collected….i feel like it depends on 1. food available and competition for the food and 2. water temps that make the biggest difference.

    2005 123 fish collected all in November.
    Age Inches Average size
    2 5.1-9.8 8.6
    3 5.9-12.2 10.6
    4 9.1-12.6 11.5
    5 7.5-13.8 11.2
    6 7.9-13.0 10.7
    7 11.8-13 12.4
    8 14.2 14.2

    2006 260 fish from Nov and Dec
    Age Inches Average size
    2 6.0-10.3 9.4
    3 9.4-12.7 11.0
    4 8.0-12.8 11.4
    5 10.4-13.7 12.2
    6 9.2-12.8 12.0
    7 10.4-14.3 12.4
    8 9.0-13.2 11.8
    9 11.5-11.9 11.7
    2007 213 fish from Oct, Nov, Dec
    Age Inches Average size
    1 3.1-5.1 4.2
    2 6.8-11.9 9.4
    3 10.6-14.3 11.0
    4 13.1-13.2 13.1
    5 11.9 11.9
    6 11.5-13.3 12.2
    7 12.8-13.4 12.9
    8 10.3-13.2 11.4
    9 11.1-14.0 13.4

    ps if anyone has any big fish they would like aged and can pull the otoliths you can mail them to me!

  10. #10
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    Interesting results. Thanks for sharing. It will be interesting to see how other lakes compare.

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