Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Managing Put & Take Predators

This thread is about predator size structure and the forage requirements to maintain the predators in a sustainable put and take predator production system. To be sure, the main incentive for having a BOW is the purpose of recreation and enjoyment. I don't intend to alter this main purpose but do want to demonstrate how having predator and prey in good condition (and at harvestable weights) critically depends on the harvest of and limited recruitment of predator fish. In this thread we are discussing the recruitment as annual fall stocking of a predator that does not reproduce in the BOW. This non-reproducing predator could be Female LMB, WE, HSB, or even FH.

Initially, we will discuss (and I am sure debate) the stocking and harvest of an altogether disdained predator for small recreational BOWs, the flathead catfish. Since the purpose of a private BOW is recreation and enjoyment, this initial example is for a minority that may enjoy flathead fishing most. The management plan is in form of an excel spreadsheet that you will find at the bottom of this post. The yellow cells are the results of the inputs and they reflect information about the outcome of the managed harvest. The green cells are where you can change the inputs, they include:

1. Size of the BOW in Acres

2. Standing Number in Fall Prior to Harvest. This reflects the maximum number of fish of the particular year class

3. Initial weight of Fall Stocked Predators. This is the average weight of predators stocked subsequent to the harvest.

4. Weight gained annually. This weight needs to be a reasonable estimate of predator growth from the previous Fall weight.

5. Predator and Prey Exponent. This number is usally a little over 3 and can be extracted from standard weights. It is used to calculate predator and prey lengths. This number is independent of units.

6. Predator and Prey Multiple. This number is proportional to the weight of fish and can be extracted from standard weights. It is also depends on the shape of the fish. This number depends on units. Units used are length in inches and weight in pounds.

7. Maintenance Weight per LB Predator. This is an estimate of the forage weight required to maintain 1 LB of predator weight for a year.

8. Growth Weight per LB Predator Gained. This is an estimate of the forage weight required to grow 1LB of predator Weight.

9. Median weight of prey as a percentage of predator weight. I assume 1% based on evidence of realized consumption of prey by predators. If you disagree with this you are free to change the parameter.

The management plan incorporates a harvest of 32 lbs of Flathead annually. It allows for the harvest of one 8 lb FH, two 4.77 lb FH, and seven 2.08 FH per acre. Success of the plan depends on the BOWs ability to produce a minimum of 368 lbs per acre of forage. The predator size distribution is constructed to allow the survival of large prey fish (>6"). In as much as this is true the management plan can allow a prey harvest also provided there is a surplus of production exceeding the forage requirement. At very least there remains a catch and release fishery for prey fish provided the BOW can produce 0 to 1 year prey in sufficient quantity to meet the forage requirement. Note the Spring Weight per Acre. This is the combined weight of predators in the Spring and also note how much smaller a number this is than the Fall preharvest standing weight of 45.09 lbs/acre.

This demonstrates how quickly a predator population can reach a pond's prey production limit. Though it certainly applies to FH, there are no exceptions for other apex predators. FH are simply geared to grow faster than most. You will note that by reducing annual growth numbers ... the prey requirement is lowered AND/OR the standing weight and number of predators can be increased. I think a fall harvest is essential to this scenario and it has benefits beyond just the food one gets. Reducing the large predators before stocking the recruits improves the likelihood that stockers will survive. Furthermore, in the Spring the first hatch of prey fish are able to get a running start and the prey fish brooders will be less vulnerable during their initial spawns.

Should Flathead be avoided? Probably, but this isn't because they are bad predators ... rather ... the reason may be that they are rather impractical to source in the appropriate sizes or that the commitment to management through harvest is lacking. To be sure, FH without a harvest will eventually eat themselves out of house and home. To have them means one must be committed to managing them and understanding their forage needs.

With regard to other predators, they, just like FH, need forage to grow and so the same principles apply. I will follow this thread with another that deals with achieving managed goals in systems where predators reproduce.

I think it all looks good on paper but from my 4.5 yrs of pond management I learned a pond is not the same as a laboratory environment. At my place, after two es. surveys in 4 1/2 yrs, I have learned it is pretty much a SWAG when it comes to the fish in the pond. The spreadsheet looks good but too many variables in a pond that is exposed to Mother Nature, I think. I noticed you are in Texas and because of the size of Tx there are many different weather patterns across the state. I have learned that weather does come into play. In the past 4 yrs I have seen floods and I have seen droughts. And that may dictate water conditions, it has at my place. Things like blooms, along with algae types and their blooms may also come into play. Just these two things can effect growth and survival rates of fish and fish reproduction rates of forage fish. There are other things like birds and animals that may come into play also. They have at my place. I think the spreadsheet is fine and good but just too many variables and I have only listed three. I could list several others that might interfere with growth and survival rates but this post would be much longer. Thanks for posting up though, it is some numbers to consider

I hear ya Tracy, many variables to consider for sure but a good starting point I would think

Tracy, your points are well taken. To be sure, our best laid plans often don't work out. Where predation by natural predators plays a role, to be sure, one should plan for it in a put and take system especially. The plan serves only a baseline. If mortality turns out to be only harvest, and the harvest beats the plan, then one learns that his BOW is capable of producing more than he assumed. The same applies in vice versa. Many different insights may be gained by relating actual results to the plan.

In the end, the Spreadsheet shows what is possible when the world is as rosy as he planned. Even so, it can help one to plan and to prevent one from managing for an impossible goal.

"Plans are useless. Planning is invaluable." Dwight Eisenhower

True in my pond experience.

That quote sounds just like something Winston Churchill is credited for saying. I am not sure how one does planning without plans so I think Dwight means that plans must include contingencies and adapt to changing conditions and failures along the way. Here are few other great quotes about planning.

“A goal without a plan is just a wish.” Antoine de Saint-Exupéry, writer and pioneering aviator

“By failing to prepare, you are preparing to fail.” Benjamin Franklin, Founding Father of the United States

“If you don’t know where you are going, you’ll end up someplace else.” Yogi Berra, former New York Yankees catcher

“Unless commitment is made, there are only promises and hopes; but no plans.” Peter F. Drucker, author and educator

“Plans are of little importance, but planning is essential.” Winston Churchill, former British Prime Minister

I'd like to share my thoughts on this because it follows a similar pattern of how we deal with "planning" in a State run situation.
My thoughts and beliefs are that this is very well written and the way it's laid out in a format I understand and am familiar with.
There are constants and variables-always...the understanding comes when a manager understands the value the "constant" represents must be changed some to fit the ever changing environment we deal with. And I will be the first to admit, I have a lot to learn, regardless of the people I work with.
Every BOW changes-ages-from day 1 on. The true constant is the ability to recognize and adapt to the variables by using learned knowledge.
You guys that work with WR's a lot have seen the changes (standards) that have changed through the years for various reasons, what it boils down to is either a trend has developed showing a lean in one direction or another and for the most part, this starts to show up as more and more data points are collected.
This is a well rounded, excellent series of point(s) to start the data for each specific BOW.
Adaption comes with many data points of observation on each particular situation, added and calculated into the "averages" based on how that BOW reacts to changes made.
This is really an exceptional document to me and looks to be a great tool in anyone's hands that is willing to apply the principles outlined.
Very nice to see this.

Thank you Snipe. That is why I posted it and I do hope a few find it useful. It would be great to see it show up in a post from time to time where another has shaped his vision in it.

Given the warm reception ... ... I think I'll pass on posting anything regarding the reproducing predator scenario unless I see questions about it in the context of plans that another has constructed with the tool.

I, for one, am extremely interested in the reproducing predator scenario. That's why we're here! to soak up all the info!
Post when you have time, can't have too much of that kind of stuff.

Warm Reception Not to worry! I have seen several good and informative post you have made here. So keep up the good work. I would say, everyone most likely has a goal when building their pond and so a plan is the next step. The problem is "The Plan" and what Mother Natures plans are different. The other problem is it depends on water clarity. You can't see under water to monitor the PLAN. And electric shock surveys may only provide a small sample of what is swimming down there. A sein survey may do a similar small sample. And you may never see or catch to confirm those put and take fish are there. I don't mean to be so negative, I really don't. But not only have I experienced this but have read here where others said they have never seen theirs either. With all this in mind, I might use a put and take plan but I would add more or double up on these type of fish if I planned for harvest at some point.

No worries Tracy, and I am totally OK with everything you mentioned.

Of the quotes above my favorite one is Yogi's. What I think he meant to say is this "If you don't know how your are going to get there, then you'll end up somewhere else." At least that is my interpretation of his quote. That's all a plan is. Doesn't mean there won't be bridges out and detours along the way.

Anyone traveling from Missouri to Minnesota will have to travel in a northerly direction. Same thing follows in the example plan. Anyone wanting to maximize FH production and avoid FH from eating themselves out of house and home will have had a grand annual harvest each year. The "harvest", when you think about it, is no different than "planning to travel North from Missouri to get to Minnesota".

To be sure, this isn't the only way to use FH and one's goals may not be geared around FH production but rather the production of harvestable prey fish. These differing goals lead to changes in planning and I had hoped there might be discussions around other types of scenarios.