Glen Elder Crappie

[DroptineJoe]

Craig,
Is there something in the water; more nutrients, more protein, more invertebrates(scuds, fresh water shrimp etc) that makes the white crappie at Glen Elder so much deeper(top to bottom) and thicker than the white crappie at Milford of the same length? The 13" crappies that I caught at the Glen seem to be almost twice as heavy as the 13" crappies I'm catching at Milford? Just wondering if there is a biological reason for this?

Thank you so much,
Joe Kitchens

[Craig Johnson]

Joe,

Scott will be along soon to answer your questions.

Thanks,

Craig

[Crappie Chatt]

Geez Joe,,, Everybody knows it's the magical waters coming from the sacred 'Waconda Springs' that make them spread out! <*)}}}><

[Scott Waters]

Joe, Craig alterted me to your question and I thought I'd try to provide some information.

To give you an idea of how healthy or thick the white crappie at Glen Elder are, I should describe how we determine the condition (fatness) of fish. Relative weight is a term used to describe the relationship between fish length and fish weight. The higher the weight for a given length, the better the condition. Most biologists consider a condition factor in the 70's to be fair, 80's to be good, 90's to be very good, and over 100 to be excellent. Here is a summary of the white crappie condition values from the fish sampled each fall for the last 5 years at Glen.

Year 8-9" 10-11" 12-15"
2008 113 114 108
2009 98 108 115
2010 96 106 109
2011 107 113 115
2012 105 108 103

These numbers simply provide quantitative verification to what most anglers know. The crappie at Glen are in excellent shape, but it also shows that this isn't a one year anomaly, but rather a consistent trend.

This all goes back to the productivity of a system and Glen Elder is one of the more productive systems because of the watershed. Being located in this part of the state, the majority of the watershed is comprised of agriculture with some native pasture mixed in, and a limited amount of riparian habitat. As everyone knows, today's agricultural practices involve the addition of lots of fertilizers which make their way into the system. Not to mention the livestock which grazes the pastures and provides additional fertilizer for the reservoir as well. This extra amount of nutrients starts the base of the food chain which allows higher production of phytoplankton, zooplankton, planktivores (shad and small sportfish), etc. Without the extra nutrients at the bottom of the food chain, there would not be as much to travel through the system and result in a smorgasbord for the crappie and other adult fish in the reservoir.

I conducted an age and growth study in 2011 using the otoliths (ear stones) of 100 harvested crappie. These give a very accurate picture of the age of a fish. Age-1 fish averaged 6.5 inches, age-2 were 10.6 inches, age-3 were 12.6 inches, age-4 were 13.7 inches, and age-5 were 14.6 inches, on average. These are very good growth rates for white crappie in this region.

Another positive factor working at Glen is the lack of zebra mussels and white perch. As you probably know, these are undesirable, in part, due to the fact that they compete directly with sportfish for these nutrients. As far as we know, Glen Elder does not contain either of these ANS species which, in turn, allows for that many more nutrients in the food chain.

Finally, these condition values are a great indicator of growth problems, "stunting", or overcrowding. When this occurs, food is limited and the fish begin to become thin while their growth slows. In this case, there is a strong need to reduce the numbers in a system by harvesting a certain percentage of them. One tool we use when looking at new regulation options (i.e., 20/day creel at Glen) is whether or not this situation exists. Obviously, the white crappie condition values illustrate that food is not limited and overcrowding is not present at this time or has it been in the past 5 years, thus the thick, healthy fish we enjoy catching out here.

Although, I do like Chatt's theory as well!

[ragnar]

Thanks Scott.

[DroptineJoe]

Thank you so much Scott! I knew that I wasn't imagining this!

[fishlessDan]

Scott, since the values are currently very high, could the newly imposed 20 fish creel have a negative impact on the fishery? Just curious, as I am not familiar with the Glen, but do remember a couple southern lakes that had a few real stellar years of productivity, but have seemed to have fallin off of late. Just curious as to your thoughts.

Thanks,
Dan

[Scott Waters]

Dan, I wouldn't expect to see a decline on the Glen Elder crappie relative weight values. Glen is blessed with an overabundance of food for these fish, and most years we actually have an excess number of shad that either winterkill or carry over to the following year. Another result of reducing the crappie creel limit is leaving a few more mouths out there to work on these shad.

Plus, there will still be plenty of fish harvested throughout the year, even with a daily creel of 20 fish.

Of course, I will keep a close eye on the situation and monitor relative weight values in case they do decline significantly, but I don't expect that to happen.

[fishlessDan]

Scott, great answer, I just it that our biologists genuinely care about the fisheries! Thanks for you and your fellow biologists do for us fishing fools.Dan