Pond Boss Forums STOCKING A NEW POND Creating the food chain Small LMB Gape and Proper forage size

I was reading a bit on the forum tonight (Trophy Bass Concepts - BC) and I'm curious about small LMB proper forage size. I've read and participated in a couple of discussions relating to the subject for larger LMB and supplemental forage but haven't seen anything (probably in the archives and missed it) about the youngsters on initial stocking. I think the general rule of thumb is the optimal forage size for LMB is typically 30-50% in length. Lower values for taller forage and higher for values for something more fusiform. Does this also apply to the 2-3" May/June stocking fish as well or is this something they "grow into"?

In the concepts link:

2. Do not buy those 5 month old bass that are 2”-3” long fingerlings when you want to grow the biggest bass possible for your water.. Don’t do it. IMO 2”to 4” fingerlings are only valuable as TROPHY stocker sizes used in July –early August. High quality fast growing fingerlings should be a full 3 inches long or bigger in August; smaller than that they were over crowded and sub-par trophy potential. Real high quality genetic bass fingerlings should be growing close to 2mm per day when raised the best ways. May 20 to Aug 10 = 80 days X 1.25mm growth per day = 100mm(3.9”), 120 days (May,Jun,Jul.Aug) X 1.25mm/day = 150mm = 5.9”. Fingerling bass of 2”-3” in October thru April are the slower growing bass with less than exceptional genetics of that year class of bass. October yearling LMB should be a minimum of 5.3” and the “Jumpers” could be or should be 7”-9” long. Remember we want to grow not just big bass but grow trophy class bass. Choose your stockers wisely. See next.

Fast growing best genetics bass at 5 months old (October) should be at least 5”-6” long and MUCH better if they are 7”-9” long IF they were ALWAYS well fed daily with plenty of forage. These bass are called “jumpers” aka "shooters". Some 6-12 month old “jumper bass can be 10” long. Those young bass with less size than those 5 month old 6”-8” lengths of bass, IMO when wanting trophy stockers are the “runts” and will never reach trophy status. They can be big bass but never achieve trophy status They had too little food, were too crowded, and will never become trophy bass. True trophy 10lb+ bass are unique aggressive eaters and fast growers and HAVE to be 9”-10” long at one year old.

How long do the LMB maintain 1.25-2mm per day growth rate? My gut says there's a slowing in the winter and again when they are able to spawn / sexually mature.

Boondoggle, i cant speak to lmb. Im very intrested in following your post to see how it may apply to my smb.
But i can tell you what ive been seeing in smb so far this season. May 15th i moved smb fry into grow out ponds at about 6 to 7mm long. 30 days sampled 15 qty. Average was 45mm.
now nearing 60 days i will be pulling another sample. From what ive seen in my z traps samples in the last week i can say that ive seen them up to 4" (100mm). And what i visually see to be an average around 3.5"" (90mm). I feed these fish 3 times a day for optimal growth. I can see a few shooters that look to be about 5" long. I still see fry in the ponds that i took those fry from and they are not on feed. Average current looks to be around 35 to 40mm. Without feed.
With feed. They seem to be 1.25 mm per day maybe a little more. Not sure what average should be for smb per day. To answer your question, i think this may apply. (At 60 days they seem to be filling out more and slowing in length a bit.)

Ron, Sounds like you are having some great responses with your SMB on growth! I'm curious, what size mesh are you using on your traps? Did I read correctly that you are hand feeding your smallies?

Fast fish growth of non cold water fish does become gradually slowed as the water temperature drops below 60F then 50F down toward the 39F. This is because the fish are cold blooded. Growth of cold blooded animals slows as the temperature drops and amount of food the animals are willing and able to eat. Optimal temperatures for the species encourages and enables growth for fish.

Thanks Ron for sharing your information. Ron provides some excellent practical growth rate information for well fed cultured SMB and their siblings who experience "normal" pond foods and forms of regular crowding conditions that occur for many regular fish farms. Ron's overall range of growth rate numbers can IMO usually be applied to most LMB of less than one year old for similar conditions. If one can get LMB to grow at rates that match Ron's growth information consider that as excellent growth rates for LMB. If one can get 1mm of growth per day for LMB and SMB then they are doing something very good for raising fish. Any growth more than 1mm per day is IMO exceptional for sportfish..

Thanks Bill! Does the 30-50% rule on optimal forage play through even at the fingerling stage for LMB?

Boondoggle,

I think I am reading your blue highlight section differently than you are?

The important part (to me) is that if you buy undersized bass at the start of your project, you will never achieve trophy bass sizes with those stockers.

A human that was genetically destined to be 5'2" tall cannot be made taller by eating more food, they only get fatter. A human that was genetically destined to be 7'0", can be much shorter at adulthood if they were starved during their early life and puberty. Therefore, any LMB that you get that are far behind the growth curve for their age are either runts, or have been underfed (and will not recover fully).

Adulthood for humans (who stop growing taller) is clearly different than adulthood for LMB. However, there are lots of studies that stunted fish can never get back to their full growth potential, no matter how much you feed them later in life.

[I suspect you get that part, but I typed it out just in case.]

I think there may be some possible confusion over this sentence?

"Fingerling bass of 2”-3” in October thru April are the slower growing bass with less than exceptional genetics of that year class of bass."

That sentence seemingly must have a typo/error. It makes sense if you change the "thru" between October and April to "from".

Or, the sentence should have read, "Fingerling bass of 2-3" in April from October ..."

However, I think that is very unlikely. Even for warmer climate fish suppliers, I don't think you get LMB spawns in October.

Therefore, I am reading your blue excerpt as saying any 2-3" LMB that are available for stocking in May or early June are almost certainly "super runts" that may be almost a year old. [Experts reading this post, please correct if I am attempting to clarify and my post is BS!] However, if you were sourcing 2-3" LMB in early June that were spawned in the same year, then you would almost certainly be stocking the "shooters".



If that was NOT part of your question, then I apologize for the partial thread jack.


If the proper forage for the gape size of small LMB is your only question, then let me add this observation.

If you observe or seine a FHM-heavy pond or creek after their main spawning season, you will be amazed at the size disparity. There will be FHMs larger than the 2" LMB, and I have seen some FHMs that are actually larger than the 3" LMB. However, there will also be lots of tiny and small FHMs that are 30-50% of the size of the LMB fingerlings. Even if those are too large for the LMB gape, there are also FHMs that are 10-20% of the size of the LMB.

Now that I have typed all of this, I do see one concern related to stocking 2-3" LMB in a pond during May with FHMs as the main food source. If the FHMs spawn in that pond in June and July, then there are only going to be adult FHMs in the pond for the new LMB fingerlings - and those FHMs are going to be too large for the bass to eat!

The first BG spawn would probably be a little earlier than the first FHM spawn, so if the pond already had BG before the bass were stocked, then there might be optimal sized forage for the bass a slightly sooner?

However, I think the 2-3" LMB might have to eat insect larva, small crayfish, etc. until they grow enough to eat their fish-based forage.

I don't think I answered your question at all, but I did like your question. Hopefully, expanding the discussion will draw in some more good information.

FishingRod helps explain early growth and choosing fingerling LMB for pond stocking. If growing LMB to trophy sizes are one's goal then it becomes important to choose the bass stockers wisely from a reputable source. If just big average size bass are your goal for your region of the country then most any stocker bass from any fish farm can be used. Feed them well and they will grow well. Remember that close to 1/2 the bass you buy are males and the males grow slower and top out at a smaller size than female bass.

One point I want to make about FishingRod's comment: “The first BG spawn would probably be a little earlier than the first FHM spawn….”

According to the literature FHM begin spawning at 60F while the bluegill start spawning at 69F. Thus the fathead fry are usually available a food earlier in the spring compared to the first bluegill eggs that hatch.

Just to add an anecdote. I have personally observed 9" LMB grow to over 13" over the winter months (in Texas climate). They were moved from a stunted pond to a pond with no LMB. About 10 of them to a 1/4 pond. The pond they were moved to was loaded with stunted GSH. So plenty of forage. I presume most of growth occurred during the warmest part of the spans (at the ends of the period) from late September to late March/early April. So around 180 days to grow 100 mm (an average of .55 mm/day). This may be close to the maximum potential growth for length increment for ~9" LMB through the temperature profile they experienced over that 6 months. Of interest, it is unknown how old these fish were but they may have already expended most of their life potential (in years) at the time of the stocking. LMB grow throughout life and growth will be function of prey availability and the individual LMB's motivation to consume.

The motivation to consume is in part related to the length of LMB. When shorter, they will consume a higher percentage of their body weight daily than longer LMB. They are just hungrier. So a 2" LMB will consume around 15-20% of its body weight daily but a 7" LMB will not consume that much. I once worked out a maximum consumption by length curve. It suggested a maximum consumption of 3.9% of body weight daily for the 7" LMB. I worked out that function from a very basic premise. The maximum LMB weight gain in a 12 month span is 2 lbs (per Swingle) AND daily weight increment is constant (an anecdotal observation of Swingle an many others). In the paper on energetics I have referenced before, their maximum observed consumption for 7" LMB was 3.6% when feed to repletion. So the agreement isn't bad. So why do short fish want to consume more? I think the answer is built in to them to improve survival. The shorter they are ... the more likely it is that they will be eaten and so they have more growth hormone raging and are motivated to consume a larger proportion of their body weight. This helps them grow longer faster improving their chances of survival.

Boondoggle, it is certain that we over-emphasize gape when talking about optimum lengths. The part we miss is the difficulty of capture and time between successful captures during which LMB are expending energy which are thus part of the energy cost of consumption. If we assume that realized capture reflects optimum energetics, then the prey with the highest frequency of consumption is the most energetically optimum. It is not prey between 30% and 50% the length of the LMB. For fusiform prey, it is between 25 and 30% of the LMB and for BG it is between 16 and 20% the length of the LMB. Why is this important? Let say you want to supplement forage. Let's say you have 20" LMB and use 30% the length BG to feed them. You will be stocking 6" BG and I can assure you that very few of them will be eaten beyond the first day or two. This stocking will make matters worse actually because the will survive and compete with other adult BG for limited resources reducing the production of BG fry. Furthermore, they will compete with LMB for BG by eating BG < 25mm in length. Sounds good under the premise of gape to define "energetically optimum" but it will never work because LMB do not in reality consume > 30% length BG as a high proportion of their diet. Not enough of them will be consumed.

A forage pond is probably by far most affordable way to add forage. IMO the forage size should be greater than can be consumed by BG. So at least >30 mm. With this arrangement, the forage feeds only LMB. As you previously mentioned they will grow in the pond. Their length at time of consumption will depend in part on the length of the LMB that eats them but each LMB will eat a distribution of sizes where the most frequently consumed BG forage is less than 20% the length of the LMB.

We put a lot of emphasis on the first year of growth. I would not say that it is not important. For example, if the first year growth is slow, then by default so also will be the second year. But what limits growth isn't just the first year .... it is a subsequent year where the LMB reach a forage limitation. The cause of this forage limitation will always be production numbers of >30 mm BG as this number relates to the number of LMB. Each LMB needs between 400 and 500 BG for maintenance (and more for good growth).

1/4" coated mesh is what i make my z traps from. I hand feed my smb fry 3 times a day. I have 4 grow out ponds with different size fish. Ponds with smaller numbers of fish are a little larger. Average size 2024 fry class are around 3 to 3.5" with the small end around 2 " with some shooters up to 5". In the last week they seem to have really filled out. Very healthy looking. Pretty happy.

Hmmm. I'm not sure where exactly I came across the 30-50% on optimal forage size and will do some work to try to track it down. I remember some discussions on the topic relating to supplemental forage and rainbow trout use in the fall but that was more for mature fish and trying to push some bigger/trophy type monsters. Perhaps my memory was a little faulty and inflated the numbers on accident. I'll keep digging to see if I can get a link to add in.

I did come across this info though by the American Fisheries Society as it relates to Juvenile LMB and forage (what I'm trying to track down). AFS - Predator and Prey Size

It appears as though in the article they mention Juvenile LMB taking on GS from 33-65% and BG/FHM from 25-48% of the LMB length with a preference toward larger GS in comparison to BG/FHM.

1/4" coated mesh is what i make my z traps from. I hand feed my smb fry 3 times a day. I have 4 grow out ponds with different size fish. Ponds with smaller numbers of fish are a little larger. Average size 2024 fry class are around 3 to 3.5" with the small end around 2 " with some shooters up to 5". In the last week they seem to have really filled out. Very healthy looking. Pretty happy.

Size Selection of Prey by Young LMB

" Size selective predation by largemouth bass Micropterus salmoides and other
centrarchids has been documented (Lawrence 1958, Wright 1970, Pasch 1974,
Werner 1974, Timmons et al. 1980, Howick and O'Brien 1983, Michaletz 1988).
In most cases these studies have provided data that confirm size selection by large
mouth bass but not always at the expected energetically optimum size, i.e., the
maximum size which could be consumed.
'Present address: U.S. Geological Survey, 2280 Woodale Drive, Mounds View, MN 55112.
1993 Proc. Annu. Conf. SEAFWA
Size Selection in Bass
597
Largemouth bass have generally been found to consume fish prey that are 30%
to 50% of their total length (TL) depending on the body depth or girth of the prey
(Lawrence 1958, Timmons et al. 1980, Howick and O'Brien 1983, Michaeletz
1988). Most of these studies have, however, investigated size selective predation in
bass that were age 1 or older which, then, were confirmed, habitual piscivores."

Quoted from the above link.

Down around page 5 & 6 it also looks like there is a shift in percentage to prey size. Smaller fish preferring larger prey and then shifting to larger YoY LMB showing preference to smaller meals.

I guess the answer is best described as "it depends".

Bill,

Thanks for correcting my spawning dates on BG vs FHM.

I was going on sources that cited estimated calendar dates (which are obviously dependent on many factors.) You based it on water temperature, which is certainly much more universally applicable.

Cody Note: spawning times are also dependent on day length and water temperature especially for spring spawners. This is a very good and interesting forum thread. Maybe I can get the PBoss editor to use some of it for an article in the magazine. Bass predation is always an interesting topic.

I have read all those papers ... and yes ... smaller LMB tend to eat prey which is a larger proportion of their length. One hypothesis proposed by one author is that the risk of taking prey that they may choke on is outweighed by the need to grow fast. So small fingerlings take that risk more frequently. Rather than "it depends", I would say this. There isn't an optimum size that has to be fulfilled in order to optimize growth. There must be sufficient forage consumption to support optimum growth. In the reference you noted above, the author(s) talk about the maximum sizes depending on the body shape of the prey.

If a prey item has a similar shape, 1/2 the length results in consumption of ~10% to 12% the weight of of the predator. This greatly exceeds normal daily consumption for all but the smallest of LMB. It is much more normal for predators that swallow prey whole to consume prey less than 1% of their body weight. So consider a 2" LMB that one stocks in June that needs to consume 18% of its body weight daily for maximum growth. It would take two 1" FHM to meet its daily needs. Or it would take 12 1/2" FHM (about 1 per hour during daylight hours). So which is better? IMHO, it doesn't matter so long as the LMB is consuming what it needs for the day's maximum growth. Most of the energy burned will not be in the taking of individual prey. It will be burned between those encounters . In general, LMB consume a range of prey sizes that fit a log normal distribution. How a daily ration is filled by this size or that is less important than just consuming the ration by whatever means possible.

The latest papers I have read on the subject ... the authors tend to agree ... that energy outflow is proportional to time and that the time between predation attempts is not negligible nor is the energy consumed in a predation attempt a significant proportion of expended energy. Conversely, it is appropriate to look at consumption as a time rate of energy consumed. The key to consuming at maximum rates of energy consumption is abundant prey of suitable size. The range of suitable sizes is broader than many think. It takes more of smaller prey but the chance for successful encounters is higher and the number of encounters are increased if the smaller prey is abundant. This balances smaller energy per individual prey.

It would be wise to keep in mind that there is a significant difference between a 2" LMB and a 28" LMB and the prey they eat. 2" LMB can eat much longer prey as a proportion of their size than a 28" LMB can. The main reason for this is that prey morphology changes as the prey grow longer. A BG fry at the stage of swim up are skinny and spindly. They do not have as much advantage of laterally compressed defense against predation that they will gain as they grow longer. A 3" LMB can consume a 1" BG but a 28" LMB will not be able to consume a 9 1/4 inch BG. The 1" BG is like a fat minnow to a 3" LMB where 9" BG is just a too big too fat 9" BG to 28" LMB. One might find a dead 28" LMB with a 9" BG in its mouth. But this just demonstrates the risk can vastly outweigh the reward contrasted with smaller alternatives. Three 5" BG is all she needs during the warm months to grow larger. Now I say "all", but the sheer quantity of prey she needs between 4" and 6" in length each year makes clear that there cannot be many 28" LMB in a farm pond without supplementing forage. In waters that produce this size of LMB with natural production of prey, their density is quantified by acres per fish and not fish per acre.

Generally speaking, in a newly stocked pond, if you don't get good growth during the first year then something went terribly wrong. Prey for small predators should typically be abundant during this first year. Some other reason than optimum prey size would carry the blame for slow growth. More likely the cause is insufficient quantities of consumable sized prey. IMHO, just making sure there are abundant quantities of smaller than perfectly optimum prey will ensure maximum consumption and growth.

from above:
Do we assume that the three 5" BG for the 28" LMB are 3 5"ers per day? Per every two days?. or Per every 3 days?. How long does it generally take at water temperature 65F-75F (ave 70F) for a 28" LMB who just ate three 5" BG to get the needed nutrition from them and to be ready for another two to three 5" BG????

Also - the standard weight of 5"BG is 1.41oz times 3 BG = 4.41oz. Whereas the SW for a 9" BG = 9.98oz. A 8"BG = 6.7oz and 7" BG is 4.32oz. LMB 8"= 4.0oz, YP 8"= 4.16oz
My question = Can the 28" LMB SW of 13.4lbs eat a 7" BG that weighs 4.3oz?

I meant daily.

But lets just use the average temp of 70F. Lets first consider the weight of BG an LMB needs to eat in order to maintain its weight (provide for metabolism expenditures of energy). At 70F an LMB needs to consume 1.56% of its body weight every day. So for a 13.5 lb SW LMB needs .015*13.5*16=3.24 oz of BG every day to meet metabolic demands and not gain anything. It can consume 1 fish to get that 3.24 or 2 or even 3 or more BG. There will be range of sizes that are consumed in real case scenarios. If the 13.5 LMB fails to consume 3.24 oz of BG it will metabolize its own body to supply the energy and lose weight that day. OTOH, if it exceeds consumption of 3.24 oz of BG, it will convert some of the excess energy to its body mass and gain weight that day. I really appreciate the question because it makes sense to answer the question of what is normal for an LMB to consume 70F. Does it eat one fish every 3 days? or possibly 2 or 3 day? At 70F, a 13.5" LMB might supply all of its metabolic needs for 3 days by consuming a single BG weighing 9.75 oz (something like an 8.85" BG). This is less than 1/3 the length of the 28" fish. Should we expect an LMB this large to eat no more than 1 fish every 3 days? If this is normal wouldn't this be the most frequent size consumed?

I suggested 5" but there isn't a goldilocks length that only works. LMB consume prey of all consumable sizes. The 5" BG at SW is 0.69% of the body weight of the 13.5 LMB. Probably less than optimum but it is not far from optimum. 3 of them would be 2.07% of body weight and thus would exceed the 1.56% required for maintenance .... and so ... the 28" LMB at 13.5 lbs can grow on that ration. When I run the numbers at 70F, over 28 days the gain would be .88 lb (an FCR of 8.68).


Sure it can. But I will add this. It will much less frequently consume a 7" BG than a 5". 5" BG will be its bread and butter and if it had to consume 7" BG exclusively it may not consume enough energy to maintain it's weight.

This is interesting to me. Most everything I've read has used some sort of efficiency in prey size and that some forage was specifically targeted (size and shape) because of higher RoI. The study that I cited was providing information info on YoY LMB as they shift from zooplankton and insects to fish between 50-100mm (roughly 2-4") referred to shift sized bass. Not that they weren't still eating some of both or only targeted one size, but there was evidence of larger meals being taken in stomach content analysis. Figure 1 on page 3 showed this graphically for two basic size groups of less than 100mm (roughly 2-4") and 100-200mm (roughly 4-8").

"For these larger bass the maximum size prey eaten averaged 25% their own length. This appears to be different from the sizes preferred by the smaller fish which selected items 35% their length and had an upper limit at about 40% their own length."

I would be interested to read the article on risk of choking. Could you share a link?

I think my initial question/subject was to try to find information or quantify what the needs were for YoY LMB relating to forage. No doubt that there is a range that this fits into by species and body shape. I think the "generally accepted" 30-50% prey size works for the middle ground and not as much for the extremes like you mentioned on the 28" fish. First off, congratz to the manager/owner that raised this beauty. I guess I took it as a general rule not a requirement that fish are only able to target prey within a specific category. She's earned the privilege to eat whatever her heart's desire is imo.

I like this information - very informative.

And as jpsdad noted "LMB consume prey of all consumable sizes." and types of prey to TRY and get the amount of prey foods needed to satisfy its hunger.

I will keep a look out for that reference Boondoggle and when I find it I will post.

Meanwhile. Here are two references I think you would find interesting:

First, a reference that consolidates a multiple state DOW data on realized consumption of various predator fish.

Go big or … don't? A field-based ...scivore and prey fish size relationships

Second, A reference detailing consumption when LMB are given prey fish of differing length ranges simultaneously and each class equal in number. You can calculate the ratios of length but the findings found in this 1991 paper support the findings of the 2018 paper above.


LMB prey selection

Looked at the two links and I think there is some really good info in both of them. The first one was a little tougher to read in my opinion. Of the three cited links one of them notes the shift bass (50-100mm) as having a preference to larger prey, the second either didn't note this behavior or omitted it and the third didn't appear to test fish of this size. The Go big or study you linked sounded as if it was modeling some formulas in software that could be used throughout the life of various species. From what I could see between the one I sited and the Go big or study was they had similar findings on size of prey for the 50-100mm of prey.

The YoY LMG study said the LMB showed a preference to larger prey at 50 - 100mm x 35% = 17.5 - 35mm average for this slot only with an upper limit of 40% according to finding in the study from stomach contents.
The Go big or study Fig 1 the LMB 50 - 100mm had prey sizes noted from 5 - 40mm but the frequency wasn't listed. Guessing a little here based on the graph.
Your info you listed above in a previous reply had the values of 16-30% or 8 - 30mm for prey when the LMB was 50 - 100mm.

Appears as if all of these numbers are pretty close and we are kind of splitting hairs. The differences would no doubt be larger as the fish got bigger but really working on fish in two groups here - 50-100mm and 100-200mm.