I have noticed it takes about 3 to 5 days for a good bloom to be noticed on most of the nine lakes I fertilize. I use water soluable 10-52-4. Now the question I have is this. On the "third day" the fish bite will shut down. (Very Noticable) Then it will gradually pick back up in the next three to four days. What is your opinion as to the cause of this Shut Down. I have several theories, but would like to here from some professionals. Thanks in advance.

Here's my opinion.

Bass are sight feeders. Clear water aids their ability to see to eat.

When a lake/pond is fertilized, visibility is dramatically reduced and bass can't see nearly as well.

Since bass don't have the ability to think or reason, they depend on instinct and conditioning to survive...a Pavlov's dogs situation.

When their conditioning is altered, they need time to adjust their conditioning. Hunger often dictates the time frame it takes for them to adjust to water with less clarity.

That's why the bite is off for a few days. Bass can't see and can't figure out why. At some point, hunger overtakes the change in conditioning and their other senses kick in...bass can detect movement through their lateral lines. When they sense a vibration in the water, they'll move toward it, until they can see. Then, they attack.

When water clarity is reduced, use baits that make noise...buzz baits, crankbaits with ball bearing, spinnerbaits, etc and you'll likely have a change in bass behavior and get more bites.

How does the bloom effect the dissolved oxygen in the lake, if at all?

Thanks Bob for your answer. I believe you are dead on with that answer. It just makes sense that any sudden change to a fish's environment will cause them to react accordingly. I thought also that with the darkened water, the temperature would raise somewhat, also contributing to the bite shut down.

Hellbenderman. I will try to answer your question. A bloom is the foundation of the food chain and is a good thing to have for any lake in my opinion. However if the bloom becomes too dense it can restrict sunlight to the point that it will literally kill itself. The dying bloom (decay) then is what can deplete the oxygen in a lake possibly causing a fish kill. Especially in hot weather where oxygen depletion due to a thermacline is already present. It is important to understand how adding fertilizer to a pond or lake can effect it and how to monitor the visibility of a bloom for best results. All lakes are different and should be treated as individual lakes. Many things can vary from one lake to the next such as the rain runoff, streams or creeks that feed it, wind or lack of it, depth, silt, weeds and the list goes on. This is a short answer and I hope it helps. The more you read on the subject and the more you play around with lakes, the puzzle becomes more clear. I must admit it can sometimes be confusing and biologist will have different opinions on the same subject sometimes. I am a self taught student of the fisheries management deal but I have had some great results so far, but with help from a good friend or two that are biologist. It is great that I can come hear and get a response from guys like Bob Lusk. Good Luck.