Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations managing fish populations

thanks bill cody,i will try to explain my question.i have a 5.3 acre pond that is 3 1/2 years old.i am trying to learn how to manage this body of water with the help of this site and alot of reading.my question is i put 500 bass in this lake,is there any general rule to know many bass would be in this body of water.i was wondering just how many times my bait went past a bass,this past weekend we were fishing and one of the guys thought i should post this question.not really asking how many pounds of bass per acre but the total number of fish that you think might be in there.to date i have not removed any bass,i will start doing this next spring.thanks for responding yesteday,fish

You have not really given me enough information about water fertility, water clarity and management practices to give you a real good
estimate.

First a little background and ground work as a basis for your question.

Generalities are:
As we have mentioned here numerous times previously, fish biomass / numbers in a pond are directly related to the pond’s fertility. Pond fertility is often measured by how much phytoplankton & zooplankton is in a known volume of water. Typically clear water has less plankton and cloudier – greener water has lots of plankton. Fertilizer i.e. nutrients make the plankton become more dense or abundant. Waters with higher plankton amounts produce more fish biomass / numbers.

In balanced systems, panfish and small fish are always more numerous in a pond than number of predators because each predator needs to eat quite a few panfish each year to survive. If the predator is to be pump and get bigger,,, then the number of panfish eaten each year needs to be more than the amount for just a survival diet.

Also just because one stocks 100 bass per acre, it definately does not mean that 100 bass per acre will survive to be big fish (16"+). Nature does not work that way and will not allow that to happen with the natural food sources available.

Some past data:
A study was done in the mid 1970’s in 8 central US states by a group of fishery biologists. The group sampled all fish in 38 “average” ponds (0.5 – 4.1 ac).

Total weight of bass in the ponds ranged from 3 to 100 lb per acre; average was 36 – 41 lbs / ac (2 yrs) . Biologists like to talk about the amount of fishes present as pounds per acre because sizes of fish present can be real variable from year to year but the total group weight tends to be similar from year to year.

Total numbers of bass larger than 8” per acre ranged from 2 to 106. Numbers of bass larger than 16” on a per acre basis ranged from 1 to 16 per acre.

Estimates for you:
SO based on this information, I guess that your pond, if it is in the best condition, and has been managed properly, it has at best 15 to 17 bass larger than 16” per acre or a total of around 90 larger sized bass (16"+) in the whole pond (5.3ac) 17x5.3=90.1. Total number of bass 8" or longer would be signficantly higher based on info above (up to 500). Many ponds have bass densiers a lot less than these estimates.

You did not ask for estimates of numbers of catchable bass. I assumed (maybe incorrectly)you meant the category of fairly large bass.

Newer ponds such as yours with its original stock of bass could in best conditions have a few more larger sized bass in it than 90,, maybe 100 to 140 per 5 acres. But as these originally stocked fish are harvestd or die from old age and the system develops a more realistic steady state the numbers of large replacement bass per acre typically tend to decrease from optimum "new pond condition" densities. This is due numerous things but primarily to improper fish management in terms of usually the variablity of fertilities, loss of plankton biomass, and improper distribution of sizes of the forage fish and predators.

Bill, excellent info as always, where do you dig up studies from the 70's ?

Here's my question about your post. Let's assume 5 acres, fertile A+ management, 90 LMB 16"+ total. How do you manage the 90 LBM ? Is it time to base catch and release on relative weight ? They can't all go back in, or pretty quick the 90 LBM will be 100+ . Or is there a top end where stunting will occur, and they're better off harvesting 25% annually. In a nutshell, is there a "formula" for making room for up and coming generations ?

Eastland -- Digging up old data. I have lots of fishery literature about topics that interest me. I have been collecting these since the 1960's. This data was from an AFS special publ. about New approaches to Mgmt of Small Impoundments.

Subsequent management techniques when the top end bass reach 16"-18" will depend on your goals. Good management always involves monitoring relative weights and condition factors. These data are how the bass talk to you. One just has to be smart enough to understand their language.

This topic should have some additional input from guys such as B.Lusk, Shawn, G.Grimes and a couple others actively involved in managing bass populations. I don't consider my self a true expert with lots of field experience on tis topic. These other guys are all probably real busy now with field activities. If you really want a full spectrum of advice about this topic make yourself a calender note and bring or dig this thread back up this winter when they are active here.

Here's my brief opinion. B.Lusks book, Trophy Largemouths, should also cover this topic. 1. If you are happy catching quite a few 2 to 4 lb bass then selective harvest most all bass caught over 19"-20". This will cause the population to be dominated by 2 to 4 lb fish. Also monitor the forage so bgill are common in the 5"-7" range. This keeps this 16"-18" group of bass well fed. 2. If your goal is bass over 5 lbs then accept you will catch fewer but larger bass then harvest all or lots of bass less than 12" or 13" and probably a few 14" to 16" each year. Bass over 4 lbs - 6 lbs will probably need additonal larger sized forage speices than just bgill such as shad or shiners. The big bass will also be eating some of the smaller 8"-10" bass.

Managing for a constant supply of fewer trophy bass will probably need in additon to keeping good paper records of catches & fish body condtions, an occasional professional survey to monitor the status of the fishery. The survey will help get a better estimate of numbers of bass in each size group. So the harvest can be fine tuned and help to keep the proper number & sizes of well fed bass present.