View Full Version : Crappie Populations

05-31-2009, 10:30 AM
Crappie are a very popular freshwater gamefish in much of the United States. Wherever they are found, crappie populations seem to fluctuate noticeably, with good catches some years followed by years of very poor catches. This cycle seems to be more common in manmade lakes and reservoirs than in rivers.

But even in these areas a population cycle may be noted. Biologists in Iowa have attempted to determine if environmental conditions may explain some of the variation. They towed a very small mesh net in 11,000-acre Rathbun Lake and compared their catches of larval (newly hatched) crappie against lake water levels, water clarity, temperature, wind, and bottom firmness. Like many fish after hatching, larval crappie are nearly free-floating in the water until they grow enough to swim well.

The results of this investigation were very interesting. The two main environmental factors affecting the number of larval crappie were water levels and water clarity. Almost without exception, high water levels in the lake during the spawning period resulted in high numbers of larval crappie. The only exceptions to this relationship were in years of low clarity (muddy) water. Larval crappie were never found when waters were very muddy during spawning season. Based on previous research, biologists felt that adult crappie abandoned their nests when muddy water created low light conditions on the bottom. They did note that actual suffocation of the eggs may also have occurred.

Temperature was an important, but not overriding factor. Crappie begin spawning when water temperatures reach 61 degrees F. A gradual steady temperature rise, with few ups and downs during the spawning season seemed to produce the most spawning success. The rate of temperature rise did not seem to influence the length of the spawning season, which lasted between 27 and 47 days during the 9 year study.

Wind played a small role in catches of larval crappie. Larger catches always occurred under low wind conditions, but many poor catches were also taken under low wind conditions. High catches never occurred under high wind conditions. This may be due to nest destruction in shallow spawning waters by fetch (wind-produced waves).

The final factor studied was firmness of the lake bottom. While it was a minor factor in larval crappie production, areas with very soft or very hard bottoms did seem to produce less larvae. Other studies have indicated that crappie prefer to spawn on hard clay, usually near some sort of water plants.

During the 9 years of the study, greatest catches of adult crappie by fishermen were made 2 to 4 years after a year of high larval crappie numbers.

05-31-2009, 11:01 AM
Thanks for posting this as I have been arguing with Texas Fish & Game people here for years about the water levels during the spawn and what it does to the fish. This was the first year in very many that the SRA (Sabine River Authority) let the lake stay full this time of year as usually if the lake reaches full pool they would bring it down right away and fast for fear of more rain coming or something that had not happened yet.

It also too years of fighting to make the SRA stop generating when the lake hits 4 feet below full pool. Use to they would just keep sucking it out until they had generated all they wanted with no real care for what happened to the lake, fisherman or even the economy which takes a hit when the lake is too low.

Thanks again,

05-31-2009, 11:09 AM
If muddy water inhibited crappie spawn, There would be no fish in my lakes!

05-31-2009, 06:33 PM
Muddy water definatley inhibits crappie spawn. I've seen crappie run from Muddy water whenthey're trying to spawn.


05-31-2009, 08:13 PM
Thanks NIGHTPROWLER64 very interesting post. Just a note on muddy water(concerning other posts) its a relative term, that is to say what I may think is muddy for one lake could really be its normal color/or stained water.

05-31-2009, 09:27 PM
Muddy water definatley inhibits crappie spawn. I've seen crappie run from Muddy water whenthey're trying to spawn.


Not when the water is always muddy.;)

05-31-2009, 09:42 PM
I have found that bigger/healthier crappies run a 4 year cycle after a banner spawn season. Actaully i didnt find it out, was told by an old-timmer, and twice now its proven correct. 5 years ago, we had excellent spawn conditions, and last year, we caught a larger number of big fish compared to what we normally catch.
For my area(IN/OH/Ky), we have had great spawning conditions(for the fish, not so much the fishermen), and mark my words, 3-4 years from now, you'll catch some big ones.
Thanks for the post, if you ask 10 different people about the crappie spawn, you'll get 12 different answers, sometimes more. Ive also found 20 miles away, fish spawn differently, some lakes the fish are very late spawning, others very early. The only real constant ive found for my area is the blacks spawn very early, when the water hits 62-64 like there spose to, but ive got places round here that the whites havent spawned yet, and the water is closing in on high 70's, and some parts 80 degree's, im sure these are just the late bloomers.