Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Caloric Densities for bass forage

Does anyone have a scientific study of caloric densities of bass forage?

For example Trout and insects are really high, yellow perch and threadfin are in the middle and crawfish are low. But want to fill in the gaps with BG, RES, Shinners, GS and tilapia.

Looking for hard data/proof as opposed to a hunch.

There have been a few threads on topics closely related to your question.

Unfortunately, I don't remember what the keywords would be for you to find those threads using the search function.

I believe "jpsdad" is one of the members that provides research data in that area.

You might try sending him a private message and see if he can direct you to any good past threads, or see if he will make a comprehensive comment in your new thread?

(I believe he is plenty busy with family stuff this time of year, so if you message him you should probably give him 1-2 weeks to respond.)


Good luck on your bass feeding project!

salex,

There is no study that I am aware of that focuses on the relative nutritional properties of LMB prey. There are, however, many investigations into the energy density and nutritional profiles of various organisms. Member ewest pointed me to a paper on Arizona NP growth rates where energy density of various species which comprised the diet of NP in the three lakes under study. The density units are in J/g wet instead of calories. This can serve as starting place into your own investigations.

Species................J/g Wet......Author
===========......======......================
Black crappie........4186..........Kitchell et al. 1974
Bluegill..................4186..........Kitchell et al. 1974
Common carp.......7524..........Cummins and Wuycheck 1971
Golden shiner.......4983..........Kelso 1972
Green sunfish.......4186..........Kitchell et al. 1974
Largemouth Bass..4186.........Rice et al. 1983
Northern crayfish...6153.........Stein and Murphy 1976
Northern pike.........3600.........Bevelheimer et al. 1985
Rainbow trout.........6069.........Rand et al. 1993

(I thought images were working? or still no?)

The other thing to take into consideration is the size of the fish compared to the size of the bass. It doesn't matter if the gams are 30% more the j/g of BG, if the LMB have to expend 50% more calories catching gams to equal the weight of the BG then the LMB is at a net loss. Size of forage matters too.

Its all about energetics - food energy in, minus food energy used, equals weight gain or loss. Even when cold there is still energy burned to maintain body functions like respiration, circulation, digestion etc.

One may not assume that LMB expend more energy on small prey than on large prey. This is simply not the case. Small prey have a very high probability of capture where large prey have very low probability of capture. LMB expend more energy to catch a single large prey than a single small one.

Slightly off topic, but slightly on topic.

I have caught large bass on tiny lures.

Since LMB don't have hands, do they strike at lures that invade their space? If so, is that phenomenon heightened during the spawn?

(I have caught more big bass on small lures during the spawning season, but I have caught more big bass overall during the spawning season too, so I can't evaluate my own observations.)

If they will strike at intruders large or small, might they "take a meal" if it was purely for defensive purposes?

FishingRod,

Provided prey is large enough to be retained by gill rakers and small enough to fit in a predators mouth and be passed into the gullet ....it constitutes potential food. If an LMB takes food in its mouth, it makes sense to swallow it if it can be swallowed in order to get the energy return of an energy investment. I would think that LMB which are guarding nests typically do not get a full daily ration and that such LMB may be declining. There is incentive to feed from that stand point if it does not risk the nest. IOWs it makes sense that it isn't purely for defense but a blend of defense and some needed energy for the task of nest tending.

I will mention that on most days that I fly fish I will hook up with a >16" LMB or >22" CC. The CC are much more rare however and it seems I only hook up when the light is very low near dusk. I have caught several >16" LMB this year on a size 14 copper john. That's ultra tiny. On Saturday, I shouldn't have went out because I was coming down with Covid and it was dang hot ... but I netted some GAM and fished for small LMB to stock a pond and for >16" LMB to remove. I am trying to shift the population structure in favor of BG growth. Anyways the gams ranged in size from 3/4 in to 1 1/2 inches. I caught 8 LMB ranging from 3" to 8" ... but guess what? I also caught a 12" LMB and an LMB > 16". I deliberately fished for both casting to them and both spotted the GAM and moved in to investigate. Stopping just short. Then each opened its mouth moving forward a little with a small flick of its tail engulfing their respective GAM. The GAM that caught the 16" LMB was less than 1 inch long and was a negligible proportion of its daily maintenance need. I don't know why fish that large take size 14 copper johns and little GAM ... but ... if we return to optimum forage theory we might come to the conclusion that the LMB taking these baits anticipated a net gain in energy.

My efforts to remove 16" LMB from the little pond didn't go as well. There is a huge bloom of BG in that pond from 1/2 in to 1.5in in length and it is very difficult catch BG that small for fishing but I did manage two but was broke off by two that were the size I wanted to catch. The roughly 1.5" BG I was using were near the lower limit of what is considered consumable (10% proportionate length). I was unable to catch BG at the optimum length. That segment of the population is not very numerous right now.

Do you have a throw net?

I am not very good with mine because I use it so rarely. However, it is fun to watch people bring in the fish when they are good with it. A few throws might get you a big haul of BG, including some in the size range you want.

I have found a "Z" trap is extremely effective at catching the size of BG you want, jpsdad.
No bait, the trap does all the work.

I really like this discussion. Very good information that helps me with some food benefits for LMB. Many Thanks to all,

Salex,

Don't count out crayfish just yet. Notice their energy density. In that NP study the lake that recorded the most growth contained carp and crayfish as the primary sources of prey for NP. The NP growth in that lake blew away the other lakes which recorded growth right along the path that was then thought to be the maximum possible. So carp and crays pushed the envelope that redefined what the maximum path could be and what high energy prey can do. NP have exceptionally low energy density themselves and are consequently more sensitive to variation of prey energy density than predators of higher energy density.

You may be interested in reading th...ve energy density of prey was discussed.

I'm trying to get at is conversion rates for LMB when eating a pound of forage of a given species. Which species of forage (Tilapia, threadfin shad, crawfish or bluegill) is likely to give you the biggest pound of gain? I understand lots of variables going into this analysis and we can say it "all depends" . But can anyone boil it down to which of the 4 listed species of forage will (Likely-educated guess) hhave the best conversion rate, without getting into expendable energy to catch it or how much more babies a tilapia makes, or how big the forage is. Its a ROI question.

The amount of energy it takes an LMB to catch each species certainly helps determine how much Investment the bass has to make to get a Return On.

"IF EATEN" Crawfish provides the highest return of the 4 you mention. BUT...the highest density of available forage could very possibly be another species.
Most abundant of the right size at the right time-which can change in any pond setting at any time through a season-will be most utilized.
Forage diversity provides best growth for LMB for never having to miss a meal at any given time of year.
Every single pond will have a unique forage to forage relationship and to have a high density of many types of forage requires thought into the diversity of the habitat and structure required to have abundant populations of all forage types. Availability will vary for many reasons.

This gives some answers to digestibility of shad and sunfish, along with how they relate to each other.

https://seafwa.org/sites/default/files/journal-articles/MIRANDA-153-163.pdf

If anyone were to give conversion numbers, they would not work for you. The problem is that conversion is a function of consumption that exceeds the maintenance ration.

Also what we pond managers are finding out is that the bigger the bass, the more weight of fish it has to eat to gain a pound.

I suppose you could equate that to the caloric requirement of a 6 year old to walk 100 yds vs. the caloric requirement of a 300 pound man to walk that same distance.

Caloric requirements would be needed to swim and when the fish try to catch a prey fish, they aren't successful every time. So, there are lots of calories expended without them being replaced.

Depending on location there might be some seasonality mixed in here as well that I hadn't seen mentioned. For us in the Mid-west....finding crawfish, tilapia, or threadfin in the dead of winter is likely a failed proposition. Likewise, without out cool water or higher DO trout in the summer probably won't pass muster either.
- Supplemental stocking I would think would add some benefits though in not only taking some of the pressure off the existing forage as well as potentially providing a higher quality meal that is only available at the right time of the year.

Esshup, the conversion of 6 to 1 is a decent estimate for all LMB in north Texas so long as one understands the conversion is for the excess over maintenance. In the example above the pond provides the maintenance. They won't grow without an excess of consumption above maintenance. Without the supplement the consumption is 6 times the weight of the LMB and the gain is zero. Because the gain is zero the FCR is infinite and is in fact meaningless. With consumption above maintenance, there can be conversion and a finite FCR.

Gains can be negative. Just take away some of their maintenance. They will decline to match what the consumption can maintain. Examples of taking away some maintenance? Stop fertilizing, stop feeding, use pond dye, fail to maintain alkalinity are a few examples. Even an exceptionally cloudy summer can adversely affect the production of food.

So, you are saying a 1# LMB there needs 6# of forage to maintain, and a 10# LMB needs 60# of forage to maintain? (per year)

In DFW, yes ( on average 5.8 lbs BG per lb LMB). Maintenance is temperature dependent. In Indiana, where you are, maintenance will be less.

I think jpsdad is correct in his weight maintenance and gain estimates. This generl guideline probably applies for probably every fish consumer. For weight gain the fish has to be at an adequate weight (maintenance wt.) that allows for the increased gain above the maintenance level to occur. Weight gain to a certain extent I think does depend on QUALITY of food consumed i.e. food conversion ratio (FCR). If one disagrees then show us the proof from research or the literature to refute those estimates that were determined from the literature.

One thing I haven't noticed mentioned in here is birds as a dietary source. Most of the my bass that I gut contain swallows in their gut. I have always wondered why in spite of having many of them each spring that they all disappear by mid summer. I am used to dealing with all the mud nests everywhere on all the farms and ranches I grew up but no such issue here.

Then we started catching our bass and nearly every bass we have ever caught in the 15 to 20 inch range contains this when I gut them..



One might consider some bird houses to bring in birds to the pond. Not only a good source of food but it is amazingly cool to watch a big bass track a bird flying low over the water and jump out of the water and take the bird right out of the air. It is crazy how capable they are of tracking the bird and knowing where they will be. Also cool to watch is the bald eagles diving down and picking a large bass from our pond.

Our bass subsist off of basically insects and birds, we put catfish in the pond years ago and they thrived the first two years and there were a great many of them but then the bass ate them all and by year 4 there were no more catfish. So we keep the catfish in the other 4 ponds. I would love to have some Koi in the bass pond but there is no way they would survive the bass.

MountainWard ,

Dang .... this is just awesome. You know swallow skim the surface for water and will also kind bathe on the fly. Your LMB are just going to town on them. LOL. Awesome stuff. I was watching a nature show about animal migrations. There are several episodes and one featured European barn swallow as one the migrations followed. Swallow in Britain go all the way to South Africa and return to Britain to breed. Anyways they show footage of tiger fish jumping to catch them at the water surface. Was awesome footage. I frequently see LMB jumping to catch dragonflies in flight but haven't yet had the thrill to see an LMB take a barn swallow.

Anyways, welcome to the forum. It's been fun to follow your resourceful projects.

Also wanted to mention. Your LMB only pond is something that interests me. I am interested in understanding best practices of harvest management under LMB only. I would like to understand how you are managing and the production your are getting of harvested fish. If you would like to start a thread, that would be great.