Pond Boss Forums Thread Like Summary - What is the optimum ...

What is the optimum sized BG prey for LMB and how many do they eat every day during the growing season? For size use a proportion like 1/4 or .25 ... whatever feels about right.

I think that is the real reason most of us are on Pond Boss and do the pond work that we do!

Lusk sez 1/4 to 1/3 their size. It’s a matter of energy expended versus calories obtained

Conversion of Koi was measured in weight of koi. Length means nothing if the fish is average, below average or above average for it's length. Also matters how accessible those fish are, whether BG or Koi..
State uses Koi because average conversion is around 4.5 to 1 and are easier to raise than BG. But, that's a very controlled situation.
If you are going to study FCR of BG, you have to establish a RW standard of the fish being eaten.

That's a remarkable number of gross FCR for an adult LMB. The koi results are a little better than I estimated for carp which comes in about 6 for a 1 lb LMB growing to 3 lbs in 180 days. I wonder if the koi are possibly more energy dense than carp or perhaps some of the koi fed in the brood ponds manage to grow before being eaten. Do they feed forage daily, weekly, monthly?

Yes, I agree that length isn't what converts so I always use standard weights when estimating prospective scenarios. The question of length I think is important from the perspective of a predator's realized consumption. A predator can consume a variety of different sizes but what is it going to consume? Would what it consumes most be most optimum? If not, why would what it consumes most be less optimum?

Fishing with my son the other day we fished with a 4 1/2" BG and a 18" LMB seemed very interested. He chased it multiple times but never got his mouth on it. After about 10 minutes of this we fished for a different bait ... a 3 in BG ... and the 18" LMB took it within 10 seconds and the fight was on. I know the LMB could have eaten the 4 1/2" BG. It was, like the 3" one, struggling and obviously distressed and vulnerable. Yet the 18" LMB seemed cautious about taking the larger bait. At standard weight, the larger BG would be 4 times as heavy as the 3". The 3" BG is only 1/6 the length of an 18" LMB yet two of them is almost enough energy to sustain the 18" LMB for a day(assuming standard weights for BG and LMB). With three of them every day for 180 days it can double in weight (even though the FCR isn't that great 11.94). In a typical pond, getting 3 meals of 1/6 BG prey everyday for 180 days must not happen very often for LMB that are 18" long.

Standard fin Koi should be the same as std carp in FCR if close in condition.
Koi are dumped weekly into grow out ponds during summer which is not exactly a farm pond setting so it's not going to be the same as a normal pond, in which case all of the BG are not going to be the same length, condition or population structure. Some will even be more aware of their surroundings than others.
I think this is a great project to take on, but in my opinion, it's going to take 3 different ponds with like numbers of fish with consideration to fish health of both Prey and Predator, cover and ambush points available.
LMB will eat when it wants to eat and we've all seen when one has bigger eyes than stomach. I don't think Bass need a huge mouth-full every time, but I do think a couple of things have to be present...1, high forage numbers that increase frequency of encounters with little effort to ingest, and healthy, stress-free conditions.
I believe you can get close to an assumption, but to know the true growth, we need to know the density of the fish being consumed at the time it is consumed, and how much energy did it take to run it down on that specific feeding burst. I "think" every encounter would be a different measure, although an average could be established if fish are sampled often but we know this is a stress inducer.
I'm sure there's a way to do it, just not sure how but there are folks doing this much smarter than me that may have an answer.

jpsdad,

Was that bass foraging in open water?

If so, then your observation may show the importance of "ambush cover" for bass.

That factor could actually be more important than the size and quantity of available forage!

If a bass has to expend the energy of 50 attempts to catch a meal compared to a bass that only has to expend the energy of 3 attempts to catch a meal, then the latter bass could grow more quickly - even with less than optimal available forage.


P.S. How were you observing the bass from the high vantage point? I didn't know if a nice drone was part of your "pond supplies" since you have a son (or sons?).

It certainly frustrates me to take people fishing, and then have a very poor outing. I am pretty sure we presented lures to the fish - but the fish turned up their noses. I have little doubt that I would be a much improved fisherman if I could determine what I was doing wrong - especially on the days with no feedback from the darn fish!

I have caught some nice LMB on small lures and flies. The largest was around 5lbs with my dad many years ago on a crappie jig. I figure the jig just fell right in front of his face and he just opened his mouth ... sucking it in by doing so. How much energy does it take to open a mouth? No more than what a crappie jig sized minnow has in it for sure! LOL. But I am always pleasantly surprised to catch >12" LMB on BG popping bugs and other small flies. I catch a few in the 16" class each year and I can tell you that they will usually inspect closely before taking which involves a gentle rise and take that just sucks the bug in. To be sure, small prey, particularly prey that are less than 1/10 the length of a piscivorous predator are uncommonly consumed, even so, they are consumed about as often as 1/3 length laterally compressed prey which is also uncommon per multistate DOW records on realized consumption. Uncommon but both happen where each make minor contributions to the overall consumption of predators.

As for the little bait and the CC. I once caught a 9 lb rainbow on a salmon egg. Trout grow huge in the White River on sowbugs and in the Blue River on green drakes and stoneflies. We shouldn't underestimate what small food can do when it is abundant and easily consumed.

Snipe earlier mentioned that we all have seen what LMB can do when their eyes are bigger than their throats. There are risks to larger prey and I do think they are harder to handle and to get positioned so the throat teeth can begin pulling them into the gullet. BG have large spines and it seems reasonable that they can damage gills like fish hooks do. I do wonder if this might explain why LMB sometimes seem more careful to take the larger BG and the time the bait is on the hook tends to be substantially longer.

FishingRod,

As far as I know these are the two largest LMB in the 3/4 acre pond. They seem to have territories and I have seen them chase away other LMB. One hangs out around a bridge structure and the other near a dam (two ponds separated by the dam of the upper pond). The dam has a retaining wall on the downstream side. It is bricked and its about 5 feet above the water. (That was my vantage point). The dam area has structures related pond aeration (by pumped fountain) and the dam area has cattails along its edge. Both locations are in some of the deepest water of the pond.

There used to be an old cartoon where a buzzard says to another, "Forget this! I am going to kill something!" That may be the basis of the story above. There is structure it probably uses for ambush cover but it was probably impatient or just felt like chasing something down. I have heard there are two types, one that roams and one that claims prime real estate. I do think these two fish have staked claims.

Hey I am with you on having a successful outing. Can't always happen but I can't help trying. There is a lot of fishing pressure on the bass in these two ponds and every year I notice two or three morts of ~16" LMB. I try to be very kind to LMB when I personally catch them which is usually on flies fishing for BG. Fishing for LMB is kind of tough with artificials but they really take BG well if they are small enough. My son fishes with BG and likes to catch the bigger fish (the largest are CC). We have a pond with stunted BG (no decent predator other than CC) and its a cinch to catch a dozen or two 2" to 3.5" BG for bait. I mean like 5 or 10 minutes cinch releasing 2/3 of them as too big ... LOL. Anyways, James fishes with them while I cull BG. He is conscientious and careful in landing and releasing fish and asks for help if he is having any trouble. The problem I have is just getting him out and away from his online friends with whom he games. Anyways, when we go I make him and for the past year he complains the whole way there but on the way home he never fails to thank me for taking him fishing. I really enjoy making these memories.


Yes, I think this is true but I want to share something I have learned. We have all heard from Lusk, Eric and Dave that balance in a pond is knife edge. What I have learned is that once carrying capacity is achieved, the struggle seems to be to consume enough for maintenance. Swingle thought 2lbs per year was maximum growth. This seems to apply whether it is a 2" fingerling or a 6lb bass. After an LMB reaches an adult size it tends to consume a relatively small proportion above maintenance to achieve the maximum growth. IOWs Growth is VERY sensitive to even small increments of consumption above maintenance. For example, a standard weight 20" LMB can grow 2 lbs in a year simply by consuming 0.29% of its body weight in addition to the maintenance rate for 180 days (assuming the rest of the year it consumes only maintenance). Almost 90 percent of what it consumes is just to survive ... even when it is growing 2 lbs in year (from 4.71 to 6.71). STARVATION is the primary motivator I think. They work hard to survive and if they can get a small increment above maintenance they grow much more than one might suspect they would.

OTOH, the same applies inversely. IOWs when a fish consumes less than it needs for maintenance it declines more than one might expect it would. Even in the same pond, some may grow at the expense of decline in others. When fish are declining, mortality is higher and this is natures way of making room for the fittest survivors.