Pond Boss Forums INTRO Questions & Observations Questions about RW in different sized LMB

In a 1/4 acre pond there are around maybe 8 LMB in the 18" class. They appear to be in good condition and we frequently catch them. There are probably a similar number of smaller LMB in the 9" to 11" class. These look poor. I see smaller LMB and occasionally catch them but few LMB YOY are surviving. The piece that confuses me is why do the smaller LMB look so much poorer? My first hunch would be that small LMB would be the best fed fish in the pond. But they do not look to be fed well. Is this just the difference between males and females where males are relatively lower RW?

Have you weighed them to see what their RW actually is?

Wow, in a 1/4 acre pond, that's a lot of predators! Back to basics...do you have adult BG too large for the LMB to eat and spawn? Cull the LMB population

First thought is the bass size class of 9" to 11" are not getting enough of the "good" sizes of food to catch and eat whereas the biggest bass are finding enough of the food sizes that allow them to eat more and maintain a higher RW. Another possibility is the smaller bass may need to expend more energy to catch their food compared to the larger bass. Bigger bass might be more efficient in catching their food compared to the smaller small bass need to a lot of swimming to catch foods .

As Theo suggests it is a very good idea to actually weigh some representative of each size class of bass. Results may be enlightening because the visual appearance of average bass in each group may look to be fatter when in reality they are not in as good of body condition as outwardly apparent. Optical illusion?

The smaller LMB look poor because last yrs yr class of BG have out grown them. I'm sure there are other forage items but obviously noy enough to make a living on.

Eastland, yes too much LMB biomass but also too many intermediate BG. I need to cull some of the largest LMB. The populations of both BG and LMB are out of synch with the goal of growing some 9" to 10" BG. Way too many BG also. I have been culling BG in the 4.5" to 6" range.

Snipe, that makes sense. There is presently a bloom of YOY BG that are a hair bigger than a postage stamp. I think these were probably spawned early June. I'll watch to see if the condition of smaller LMB improves.

Bill, regarding efficiency of the different sized LMB. Would vegetation affect this parameter? The pond is shallow (probably 6' at the deepest) and it suffers from immense blooms of southern naiad. Earlier it had something like 70% coverage to the surface but that stuff grows everywhere submerged. I was concerned enough by it to rake some out. Every year the naiad dies back (or maybe settles back?), usually in August but it was earlier this year (over the past week or so). Most of the pond is now clear at the surface and there is a pretty dark green phytoplankton bloom with visibility to 2.5 to 3 feet.

Bill, another question of efficiency just regarding prey availability. I wonder to what extent their range of consumed prey overlap. IOWs. The larger fish need more maintenance ration and would necessarily need to consume greater numbers of smaller prey (even if not ideal). It may be no problem for the larger LMB to consume prey that are relatively more difficult for the smaller LMB to consume. I am just not sure but it is an interesting thought.

Theo, I haven't weighed them. I measure lengths with marks on my pole. I don't keep released fish out of water very long. The condition of the smaller LMB are obviously poorer. Much more so than the larger ones. The heads are disproportionately large on the smaller LMB. I have lots of pics of the bigger ones my son has caught but none of the smaller ones (just not memorable enough). I'll take pic or two of the smaller fish to demonstrate. Also, I think this fall (after the water temp cools a bit). I will get some good relative weights to compare against subsequent years.

OK so I know some of the larger LMB need to be culled. Because the BG are not controlled well enough to grow large I feel like I need to maintain culling of BG in their absence. Where culling the larger LMB would work best is if some of their diet overlaps with the smaller LMB. IOWs some of competition would be removed allowing the smaller LMB to consume more than they otherwise are/would.

I am thinking about removing 2 to 4 of the larger LMB. I am uncertain as to the optimum timing and interested in other's thoughts on that question. Is the lower number better than the larger? Also, should I wait until fall or spring or just do it now when there is crop of YOY coming on?

Do you own this pond to be able to control all management?
Lots of naiad could be part of the bass problem - too many naiad sheltering too many small BG and not allowing certain LMB to adequately harvest BG. Southern naiad is an annual and will die completely back, leaving only seed behind. It regrows each year, I would consider using just enough GC to allow it to grow to about 5%-105 OR maybe 15% of the pond area. Once the naiad is reduced the fish balance I think be different. Then reevaluate. I'm not sure but I think tilapia at a higher density will help the GC to in warm water season help control the naiad esp the smallest plants.

About Southern Naiad
https://www.mossyoak.com/our-obsession/blogs/conservation/southern-naiad-is-a-common-underwater-weed

Diquat can also be a good tool to spot treat for naiad or maybe even try and eliminate it. It should definitely regrow from dormant seeds each year. Then see how the BG-LMB fishery and balance develops.

""efficiency just regarding prey availability"" - IMO the larger bass will eat anything to survive but eating too small of BG that are preferred sizes by 9"-11" LMB will not allow the big 18" ones to grow much if any each year. Ideally,,, those bass could in a TX climate be growing 1-2 lbs per year if they are getting appropriate foods. So next year those 18" bass could / should be 19.3" -20". Postage stamp BG for them means surviving (RW 70%-85%) but no growth. This is determined by taking RWs. Less than 90% to me means inadequate foods for best growth. RW I think needs to be 85%- 90%+ (as a maintenance wt) to be able to grow or make added poundage.

IMO a 1/4 ac pond with reproducing forage specie/s of BG or maybe YP, the pond should have only 1 LMB over 18" long if we want that bass to be noticeably bigger next year. This one bass is capable of eating 30 lbs of BG IF we want that bass to grow optimally or be the best it is capable of being.

If we use esshup's BG weight chart this equates to
just that one 18" LMB eating 4260 2" BG/yr or 330 5" BG/yr or 750 4" BG/yr. What would you rather spend your time doing? 2"ers or 5"ers?

Now if we multiply those numbers above by 8 for your 8 18" LMB in your 1/4 pond,,,,, can your 1/4 ac pond produce these numbers of BG and still have about 20% -40% BG remain uneaten as broodstock and numerous BG available to continue feeding our hopefully plump LMB for the next growing season? I think not. Plus too many submerged Naiad weeds are preventing the LMB from easily catching eating all the BG they need to do the good "growth thing" even if enough BG were present for each to get the amount of food needed for "good" RW. Remember activity and catching BG takes energy. Energy means more needed food intake.

If you are removing large BG - remember to remove mainly the females if you are wanting to grow. 9"-10" big BG. This female harvest method likely means fewer BG produced to feed aggressive hungry bass. Thus IMO skinner slower growing bass.

Thank you Bill. I appreciate your thoughts and advice. I got tied up yesterday but will try to answer before heading out.

This is not my pond. The pond is shared with many others and supplies far better LMB fishing than I would suspect given the fishing pressure it receives. I've never harvested LMB from it and I think this applies to practically everyone enjoying it. The limited surface area of course makes the pond very vulnerable to overharvest even if only one person were meat fishing.

The naiad is very problematic and I think a great deterrent to the growth of the existing population of BG as well where when it grows it greatly inhibits the food chain potential at the base. The BG fishing has declined as the naiad has worsened. Unfortunately, my only remedy is to rake what I can reach tossing a rake and pulling it back. Naiad isn't so much volume once removed from the water and I just put it in tidy place where it didn't interfere with mowing. The pond is small enough I think the effect was worth the effort.

I would like to influence the pond to grow larger BG. Presently, the population is predominantly 4.5"-6" in length with a few fish larger up to about 8". Almost all of those are male as females are all culled. I think that 4.5" lies just outside the limit of consumable prey. A similar situation is present in an adjacent pond that is about 3 times in surface area. Both are plagued with naiad and other than my recent efforts to reduce the predominate size of intermediate BG they are not harvested.

Bill, I know I need to reduce the number of larger LMB ... I just want to be sure I do not overdo that. The standing weight of >16" LMB exceeds 70 lbs acre and comprises a great majority of the LMB Biomass. I want to be cautious about removing them because I don't want to make such a dent that matters for the BG are made worse. IOWs I think as you mentioned above, the large LMB are consuming very large numbers of less than optimum prey. The maintenance for 70 lbs of LMB is around 350 lbs of BG annually. I think there are an insufficient number of smaller bass to take up the slack if all but one of the ~18" LMB are removed. For whatever I remove, I would like to see improved condition and growth of the smaller LMB and better LMB recruitment without seeing a substantial increase in the numbers of intermediate size BG that are too big for LMB to eat. I would like to remove just enough over three or four years to change the population to more but smaller LMB focusing on influencing the production of larger BG. Hopefully then the LMB exceeding 16" will number only 1 or 2 and the BG will be larger. I would like to be as aggressive as prudent but feel like that involves maybe 2 to 4 of those larger LMB annually. In a pond this small each of those bass is a substantial LBS/Acre.


I don't know how interested you might be in this but over the past year I have researched as much as I could find available on LMB energetics. One of the things I have learned is that specific consumption (consumption per unit weight of the predator) falls off with age. A 1 lb bass will consume 10 lbs of forage for each pound of its own weight in a year and will grow 1 lb. However, a 3 lb bass is just not inclined to consume at that specific consumption. If it could it would double in weight just like the 1lb bass doubled in weight (at 10 lbs of specific annual consumption). There are probably some LMB at 3 lbs that would consume 10 lbs of forage for each pound of its own weight. These would be exceptionally fast growers putting on 3 lbs in 1 year growing from 3 lbs to 6 lbs. When an LMB consumes at 10 specific consumption, the FCR is 10 lbs forage consumption per pound gained if the forage is BG. Other forages are more energy dense and the conversion is better. To gain 1 lb, A 3 lb bass must consume 20 lbs of BG forage and this corresponds to an FCR of 20 to 1. The gain actually comes from just 1.47 lbs of consumed forage where the rest consumed was just for maintenance. Keep in mind that a 4 lb LMB requires 20 lbs of forage for maintenance and that is all the fish consumed in that year. As it grew its daily maintenance needs increased. Now Swingle over 70 years ago proposed that the limit of standing weight was limited to maintenance and this ... based completely one energetics equations ... clearly demonstrates this principle. An LMB will grow into the maintenance provided by forage produced but no more. The standing weight of LMB in a pond ... if unharvested ... gives one very good estimate of the annual production of consumable prey.

Do you have age data on the small LMB (with big heads)? Obviously that size class is not getting enough to eat. If they are old and in that class, you need to take them out. Males while smaller do not have lower RWs (should not have) unless you are sampling post spawn.

This ,from Dr. Anderson who literally wrote the book on PSD and RW may help (from an old thread).

Read these threads on PSD for guidelines which include comments from the Prof who developed the concept Richard Anderson.

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=23612&page=1



http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=23960&page=1


Dick Anderson


Registered: 18/09/06
Posts: 5
Loc: TX, MO, WI

Keep taking <12 in bass until the number 8-12 equals number 12-15. Ideal pond structure is 40% 8-12, 40% 12-15 and 20% 15+