It's that time of the year again, time when the weather and subsequently the water start cooling, which then starts the process of turnover. It's also the time when you start seeing questions and posts submitted to message boards asking about the process, and frequently incorrect information passed along about how it all works.
So for this year, a short and pretty straight forward, easy to read thesis on conditions before and just after turnover, as well as how water and conditions continue to change and react headed into winter. Relating Dissolved Oxygen Concentration to Fish Distribution in Jarecki Lake by Adam Sutton, University of Nebraska at Lincoln. Some nice simple graphs on dissolved oxygen and temperature comparisons included, and they even used a fish finder to correlate marked fish with the levels of the thermocline and oxygen content through out the water column. Nearly everything covered and discussed in the paper, which was carried out on a small sandpit lake in Nebraska, is identical to what occurs on the majority of our larger/deeper bodies of water here in central and southern Indiana.
For even more information, you can do a search for previous years postings on the subject using the Google site search feature on the right hand sidebar.
Turnover is one of those things I've read about but never made much effort to understand. If the oxygen level is so low at depth during the hotter months, then why so much effort in fishing deep? I'm clearly just missing a key ingredient. I've always done well by chasing some shallow fish when everyone swears you'll only catch them by crig or deep cranking during the dog days. I suspect the oxygen is better up shallow but guys are still catching them deep. I have luck both deep and shallow, and have seen some tourneys won on a shallow bite that no one expected.
Posted by: aaron | September 14, 2010 at 12:17 PM
It's not near as complicated as many people make it out to be. There are always going to be some fish shallow, and there will always be some fish deep. Deep is a relative term though, basically meaning only as deep as good oxygen content will allow. On many of our lakes that's about 18'-22' of water; sometimes more, sometimes less.
A very good general rule of thumb is that the best oxygen will always be shallow, typically within the first 5' of the water column. That said, from there to the thermocline oxygen levels usually don't change much and are almost always suitable for fish life, so bass will tend to stay located where ever they're at and won't necessarily go looking for "better" water conditions.
On a graph, you simply fish only as deep as you are graphing fish. For example, if you don't graph any fish deeper than 15', then you simply don't fish below 15' of water. You can fish shallower though, all the way up into inches of water. At that point it simply comes down to either eliminating patterns or fishing either your strengths or what you feel most comfortable doing.
As the lake turns over, or overly simplified as the surface waters cool down to the point of matching the deeper (cooler) water temps, then everything mixes and most all water becomes "good" water again. You will see this on a graph by marking fish at all depths from the surface to the bottom of the lake. This frequently occurs on Indiana waters when the water temps reach the mid-50's. At this point you can potentially catch bass in any depth of water.
Posted by: Big Indiana Bass | September 14, 2010 at 01:27 PM
I am new to this sight and wonder why I can't find any more current postings. At least some 2013 stuff. Were do I look or are there just not any!
Posted by: Al | June 16, 2013 at 06:04 PM
Al, welcome. You can either click the link where the word "main" is at the top center of this page, or simply use this link to take you to the mqain page. Over 6 yaers worth of stuff, inlcuding a lot from 2013.
https://bigindianabass.com/
Posted by: Big Indiana Bass | June 16, 2013 at 09:07 PM