Pond Boss Forums INTRO Questions & Observations Fish Bioenergetics - the basic rule of energy use

A key fisheries science concept that is key to understanding the working of the entire system. Energy in = energy used + growth. Read then comment.


Welcome to the world of fish physics. Many of us understand basic fish behavior and can reach logical conclusions about where the best place to throw a fishing line is. But when we don’t think much further than that we are missing out on some very interesting details of fish behavior. We can never fully understand why we find some fish in one location and some fish in other locations until we consider the concept of fish bioenergetics. Ultimately, fish behavior is a product of bioenergetics, ... this concept to demonstrate how interrelated physics is with fish behavior. First, ... take a look at basic fish bioenergetics, understanding the underlying quantitative principles. Then, ... look at some examples of how physical forces, thermodynamics, and light characteristics are specifically related to fish bioenergetics.

BASIC FISH BIOENERGETICS
Fish bioenergetics includes components of physical forces, thermodynamics, and light characteristics, and follows energy laws and theories describing any other closed system. What it all boils down to is the net rate of energy intake. If this rate is positive a fish will grow and if it is negative then a fish will begin to undergo the stresses of losing biomass.

Fish bioenergetics is really a matter of efficiency. Potential profit for a fish at any given position ... (is) ... the amount of energy coming into its system as prey minus the cost of staying at that position.

Bioenergetics
the biological study of energy transformation.
Bioenergetics is the subject of a field of biochemistry that concerns energy flow through living systems. This is an active area of biological research that includes the study of thousands of different cellular processes such as cellular respiration and the many other metabolic processes that can lead to production and utilization of energy in forms such as ATP molecules. All biological processes including the chemical reactions of bioenergetics obey the law of thermodynamics.



Thermodynamics

First Law is the conservation of energy: energy can neither be created nor destroyed.
Second Law states that the degree of disorder or entropy (S) of a closed system or of the universe as a whole can only increase.[1


Overview
Growth, development and metabolism are some of the central phenomena in the study of biological organisms. The role of energy is fundamental to such biological processes. The ability to harness energy from a variety of metabolic pathways is a property of all living organisms. Life is dependent on energy transformations; living organisms survive because of exchange of energy within and without.

In a living organism chemical bonds are broken and made as part of the exchange and transformation of energy. The chemical bonds in carbohydrates, including sugars, are important for the storage of energy. Other chemical bonds that are important for metabolism include the terminal phosphate bonds of ATP and the energy-rich bonds of fats and oils. These molecules, along with oxygen, are important energy sources for many biological processes. Utilization of chemical energy from such molecules powers biological processes in every biological organism. Bioenergetics is the part of biochemistry concerned with the energy involved in making and breaking of chemical bonds in the molecules found in biological organisms.

Food molecules are sources of chemical energy for many organisms. Not all metabolizable energy is available for the production of ATP.[2]

Wikipedi

Boy, I need to absorb this for a little bit. I have never formally studied this and if I did, it was by accident.
It seems to me this concept is suggesting a fish may convert energy in ways much larger than simply eating something, digesting it and converting its food.
Eric, I missed the bioenergetic talks in the lobby at the conference. Heard about it, but didn't partake.

Life goes on forever and the learning never ends...Robert Earl Keene's next song.

The concept is part of and related to Bruce's threads :

"My Friend Ray"

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=18845&fpart=1


Pond carrying capacity

http://www.pondboss.com/forums/ubbthread...ite_id=1#import


Here are a couple of posts that touch on the idea from a thread about Grass Carp but it applies to all things . http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=57227&fpart=1

Todd-

I would contest that what is left over from grass carp digestion process does not directly or indirectly encourage filamentous algae or macrophytic growth. We've seen grass carp enrourage planktonic algae growth, but that is exactly what we want for fish growth. Cellulose, being the major structural component of plant cell walls, is indigestible to all single-stomach animals, including fish. In addition, undigested cellulose, is not a readily available nutrient for direct uptake by plants. It must first degrade into basic nutrients.

I think that the efficiency of the grass carp digestion is interesting, and have read that they can grow to several hundred lbs in their native environment. They may be inefficient eaters, but most plant-eaters are inefficient. Consider the economic efficiency of grass carp in comparison with herbicides, labor, time, etc. The alternatives to grass carp may include chemicals and countless hours of mechanical removal which has to be repeated throughout the season and every year.

Grass carp are an integral part of some of our management programs. They help us to feel comfortable with fertilization programs where macrophytes already exist, and they improve the efficiency of fertilization programs.

I agree that grass carp can cause problems, but I also must insist that they are a valuable tool for pond and lake management when stocked responsibly.

Bruce -

I obviously am not saying that GC have no use in pond management, given the fact that three of my ponds have been stocked with them. I'm just concerned with the misconception that GC are a inexhaustable nutrient sink. The math is really simple and indisputable. The dry weight of your grass carp mass increase will be about what your plant weight dry decrease is. You can't make something from nothing...or nothing from something for that matter. If your twenty grass carp have a net annual weight increase of sixty pounds, and the fish are comprised of 75% water, then you have only "created" 15 pounds of mass from the nutrients digested from plant life. Try to explain to me how you can lose any more than 15 pounds of dry plant weight in the process. One exception to this rule is in ponds with good flow-through. If the plant biomass is occupied in smaller organisms, like single-celled algae then your pond is more likely to see a net decrease in biomass in a rain event by allowing nutrients to be ejected through your overflow.

Todd -

I disagree. The system is not that cut and dry. Assume 1 grass carp gains 3 lbs in a single year. Your explanation would lead us to believe that the carp ate no more than the equivalent of 3 lbs dry weight vegetation to gain that 3 lbs. What happens to the dry weight of vegetation that has to sustain metabolism, immune system function, and to provide basic energy needs? That dry weight is burnt as fuel and not released back into the system. I don't know the numbers, but am positive that actual weight gain can only comprise a fraction of total dry weight eaten, even in consideration of dry weight not digested by fish. Assuming filamentous algae did not develop with grass carp present, even undigested plant material that degrades to nutrients and is reassimilated into vegetation and can be processed by grass carp again.

Bruce -

Todd, you're right. Metabolic needs have to be met, the GC has to swim about and run it's various organ systems, immune system, etc. The difference between plant mass and GC mass is dissipated as heat energy. The water becomes a little warmer due to these functions taking place within the fish. My only contention is that even with this taken into account, don't you think that some of your clients have the perception that the GC eat the macrophytes and "poof", they're gone? Energy and mass interact in a closed system. The plant material just doesn't disappear. It becomes fish mass, plus, as you pointed out, heat energy, but then what? If you're lucky your pond moves nutrients out through the overflow, but besides that, you can account for every single calorie into a pond equaling every single calorie out. Which by the way, I guess we need to include fish harvest as an energy outflow. Still, let me be concise about my point. I am ONLY saying the following:

Any nutrients that pass OUT of a grass carp are at least temporarily available for creation of new plants.

I promise you, I am not indicting your use of grass carp in pond management. They work quite well in many circumstances but I would like to make this second statement:

People with ponds often believe that stocking grass carp will solve all of their vegetation problems. Sometimes these people need to be made aware of possible ramifications to this stocking, such as possible increase in simpler plant forms.

This is incredibly fascinating stuff. It will take me time to digest it.

Is there any way to get Melissa Wuellner involved? Her knowledge on this subject is pretty amazing.

Highlighting by EW . A little on how it works.

Applications of Bioenergetics Models to Fish Ecology and Management: Where Do We Go from Here?
MICHAEL J. HANSEN, DANIEL BOISCLAIR, STEPHEN B. BRANDT , STEVEN W. HEWETT, JAMES F. KITCHELL, MARTYN C. LUCAS, and JOHN J. NEY


Bioenergetics models have been applied to a variety of research and management questions relating to fish stocks, populations, food webs, and ecosystems. Applications include estimates of the intensity and dynamics of predator–prey interactions, nutrient cycling within aquatic food webs of varying trophic structure, and food requirements of single animals, whole populations, and communities of fishes. As tools in food web and ecosystem applications, bioenergetics models have been used to compare forage consumption by salmonid predators across the Laurentian Great Lakes for single populations and whole communities, and to estimate the growth potential of pelagic predators in Chesapeake Bay and Lake Ontario.


Development and Test of a Whole-Lifetime Foraging and Bioenergetics Growth Model for Drift-Feeding Brown Trout
John W. Hayes, John D. Stark, and Karen A. Shearer



We developed and tested a combined foraging and bioenergetics model for predicting growth over the lifetime of drift-feeding brown trout. The foraging component estimates gross energy intake within a fish- and prey size-dependent semicircular foraging area that is perpendicular to the flow, with options for fish feeding across velocity differentials. The bioenergetics component predicts how energy is allocated growth, reproduction, foraging costs, and basal metabolism. The model can reveal the degree to which growth is limited by the density and size structure of invertebrate drift within the physiological constraints set by water temperature.



Bioenergetics Modeling in the 21st Century:

Reviewing New Insights and Revisiting Old Constraints

STEVEN R. CHIPPS*

U.S. Geological Survey, South Dakota Cooperative Fish and Wildlife Research Unit, Department of Wildlife
and Fisheries Sciences, South Dakota State University, Brookings, South Dakota 57007, USA

DAVID H. WAHL

Illinois Natural History Survey, Division of Ecology and Conservation Science, Kaskaskia Biological Station,

Rural Route 1, Box 157, Sullivan, Illinois 61951, USA



Bioenergetics models provide a sound theoretical

approach for estimating energy allocation in animals by

partitioning consumed energy into three basic components:

(1) metabolism, (2) wastes, and (3) growth

(Winberg 1956). Because the models are based on

mass-balance equations, they are often used to estimate

growth or consumption given information on other

variables. Bioenergetics models are particularly attractive

for estimating food consumption by free-ranging

fishes because of the time and effort required for more

traditional approaches (Kitchell et al. 1977). Today

these models are widely used as a tool in fisheries

management and research; the availability of userfriendly

software has led to the popularity of

bioenergetics models (Figure 1; Hanson et al. 1997).

Nonetheless, the proliferation of bioenergetics modeling

has not been without controversy (Ney 1993).



Model Development

Like other mathematical models, bioenergetics

models are simplifications of reality. How well they

describe the real world depends on appropriate

parameterization of the model and the accuracy of

input data used to drive them (Bartell et al. 1986).

Consider, for example, the variables used to estimate

fish respiration. Respiration rate is usually measured

across a range of fish sizes and water temperatures and

then expressed as a function of these two variables. In

most cases, such formulations provide reasonable

estimates of respiration rate. But what if other factors,

such as dissolved oxygen concentration, also affect

respiration rate? Applying the model under variable

oxygen concentrations, we might find that respiration

rate is poorly defined because our parameter estimate is

based on incomplete data.





Model Evaluation

Because bioenergetics models are based on a sound

theoretical footing (e.g., thermodynamics), they provide

a useful template for evaluating energy flow.

Indeed, there is no evidence that conceptual models for

mass-balance energy budgets are wrong (Ney 1993).

When model output poorly represents observed data,

one of several things may be true: (1) the model is

incorrectly parameterized, (2) the input data used to

drive the model are inaccurate, (3) the independent data

being compared with the model results are wrong, or

(4) some combination of the above.

Youve completly boogled my mind.Ill be worthless for the rest of the day

The concept is not hard to understand. The sun is the basic source of energy for the pond plus anything you add (extra forage fish or pellets). Here is a good site with basic info.

http://www.aqualex.org/elearning/fish_feeding/english/bioenergetics/intro_biogen.html


"The flow of energy through a biological system and the system's inherent energy requirements are covered by the term 'bioenergetic'. In biology energy is required to maintain life, grow and reproduce. From a fish farming point of view, growth is the main area of interest. The main energy source for consumers (as opposed to producers such as plankton and plants) is their diet or food. This provides the energy to drive chemical processes giving rise to new tissues, to help in osmoregulation, to aid digestion (the means by which consumers unlock energy stored in food) and so forth. [Note: energy cannot be made or destroyed but can only be converted from one form to another].

Energy taken in by fish through digestion of food is used ultimately in one of three ways - that is for growth, metabolic processes and that lost to the fish through waste. During digestion the main components of the diet (protein, fat, carbohydrate) are broken down into carbon dioxide and water with heat as a by-product, the latter being rapidly dissipated to the surrounding water. The energy liberated is temporarily stored in special 'energy compounds', the main one being adenosine triphosphate (ATP), which become cellular level energy sources for functions such as protein manufacture (i.e muscle growth), swimming and so on."

The same concepts apply to the pond as a whole ( plants like plankton or pondweed and animals like zooplankton , bugs and all others).

Ok, I've read through these posts twice and I'm following along so far.



I didn't see part 2 yet. Did I miss something?

Are you saying fish will migrate to a location in which their energy expenditure is the lowest when compared to food intake? Or to phrase it in accounting terms, a higher return on investment?

I think this is essentially a correct assumption. I believe that it's not so much that a fish thinks "hmmm, how do I get my best return on investment". I think it's more that species that don't intuitively do this end up in the evolutionary scrap heap.

Oh, Ok I get it. So we're not raising future Donald Trumps of the fish realm, we're just raising ones that are better at not getting eaten.

Yes, you'd better be good at growing rapidly, or you'll end up being dinner. Also growing efficiently helps you to increase your diversity of available prey items, since it is assumed that your mouth is growing as well.

Ah, but do you grow fast in length to avoid predators (perhaps), or do you grow fast in body weight (to survive prey-poor times such as winter?)? There's the sticking point.

But does just length help much in predator swallow-proofing compared to height/girth? Aren't the fastest growing fish (like Cecil's) shaped like footballs - putting on weight in the middle before adding much length?

Wouldn't reproduction play some role in this as well. I'm thinking along the lines that a larger more robust male is more likely to attract a mate. I'm assuming fish have much the same reproductive disposition as much of the mammal kingdom (say a lion for instance) in which a larger, stronger male is more likely to reproduce that an skinny wimp. Therefore would not a male fish have some "instinct" (not sure if that is the appropriate terminology) to become as large and as strong as possible? I realize that different species of fish have entirely different courting, nesting, spawing, care of young, habits but in general wouldn't this somehow play a role.

I think that all species have a certain optimal size, which is continually being modified by selective pressure--either bigger or smaller, over time. Presumably a fish's adherence to principles of bioenergents helps it find this size in the best amount of time, but as Dave implied, fish don't stop growing, so the need to "bank-account" resources may be the most influential factor.

JHAP's "return on investment" analogy may be counterbalanced for a need to "put resources into account".

Don't we all face these kinds of questions on a day to day basis?

You guys are good.

You guys have the hang of it now.

Sometimes the fastest growing fish get eaten first because they are a little to aggressive or don't get the food they need because the plankton is not there at the right time. But they are going to try to max their energy in vs. energy used.

Yes reproduction plays a big part in several ways. The biggest male BG get the prime interior nest sights and most female attention (eggs). The females in the best entergrtic condition will have the most eggs all things considered. Thus the best BG have the best chance of passing on their genes. But reproduction comes at a cost of less growth. That is one reason Bruce's all male BG ponds have such big males , delayed reproduction/maturity and thus longer period of initial growth. Why - good genes and less energy used in spawning = better growth maximization.

Jeff asks - Therefore would not a male fish have some "instinct" (not sure if that is the appropriate terminology) to become as large and as strong as possible? Absolutely. For several reasons 1) to avoid being eaten , 2) to max their ability to eat others/food , and 3) to pass on their genes and 4) to avoid (out grow) competitors. These are the basic drivers but in all of these the fish are trying to max energy efficiency as best they can.

The even more fascinating aspect is when its applied to the whole pond. It applies to all energy flow including plants , animals and their use of energy. Kinda like what Bruce and Todd were talking about WRT GC but on a larger more involved model.

Not so fast!! There is some research out there that suggests the smaller (girly-looking) male bluegills have a better chance of passing on their genes because of behavioral modifications. These fish, known as "sneakers", are fast and not so "manly" looking so they get in the mix and do the fertilization. The big males then become nothing more than cuckholds. So that overtime, the size structure of a given population will decrease. True or False??? I don't know, but the research exists and the theory is interesting in the evolutionary scheme of things. Makes you scratch your head anyways. I'm so far removed from the literature anymore, but try an AFS serach using cuckholdry, sneakers or satellites with regard to bluegill. I think the research came out of Illiniois....probably Dave Phillip.

By the way, if these types of questions intrigue you, I recommend reading Naturalist by E.O. Wilson.

Ahh, good point, Shawn. Of course, I've always wondered about the genetic advantage of maturing young and staying small in a pond environment filled with 50 pounds/acre of largemouth bass.

Agreed. Personally, I'd rather be a 10" bluegill. This way, bass would respect me, and my only fear would be a dentist from Nebraska.

Interesting arguments could be made either way when viewing the population as a whole. Is it advantageous to be big and survive predation, but have fewer members able to reproduce thus fewer spawning events? Or is it advantageous to bombard the system with smaller, early maturing members and play the numbers game? For bluegill, my gut says you better grow fast, particularly in a pond full of predators.

Another angle concerning not only fish.

With or with human intervention, large animals become threatened or extinct. They just don't have the reproductive capability of the smaller animals. However, even with technology, we have never eliminated even one insect species.

Mama Nature actually selects smaller sized species for survival.

Shawn -- I think the most important application of the cuckoldry research probably is effects of harvest. When the large parental males are harvested, younger males will then begin to mature at a small size, and their growth slows at that point. I've often wondered if the public impoundments with 7 inch bluegills are there for such a reason. We couldn't do this in a public water, but what happens if you release all males and only harvest females? The larger males should re-appear? I know that Philipp and crew actually stocked large, mature males into a water body with earlier-maturing males to see if the smaller males would then delay maturity. Fascinating behavioral stuff.

Shawn here is most of the info - from Theo's Long-Haired Hybridization thread -

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Main=6396&Number=60751#Post60751

http://publish.uwo.ca/%7Ebneff/papers/nestling_recognition.pdf

http://publish.uwo.ca/%7Ebneff/papers/genetic_paternity_analysis.pdf

http://publish.uwo.ca/%7Ebneff/papers/dna_fingerprinting.pdf

http://publish.uwo.ca/%7Ebneff/papers/microsatellite_evolution_in_sunfish.pdf

http://publish.uwo.ca/%7Ebneff/papers/nestling_recognition.pdf

http://publish.uwo.ca/%7Ebneff/papers/Solitary_nesting_in_bluegill.pdf

http://ag.ansc.purdue.edu/aquanic/ncrac/wpapers/Sunfish12-3-03.pdf

Neff studied BG extensively.

I believe the recent AFS Bluegill Book quoted Neff with an interesting perspective. I will find it and add it tonight. I need to check some of the following.

Several things are thought to greatly reduce the success of cuckoldry to very low %s in non-overfished ponds. They include all the advantages that a large BG male has (nest location , better condition , sperm differences) and the strong likelihood that BG males can tell their young apart from the young of others and eat them and the probable abandonment of their nest (thus no young survival) if they contain large amounts of eggs which are not fertilized by them. In addition it is though that cuckolder %s are further reduced because they remain subject to predation as a result of their reduced size.

Not to get away from the topic as it relates to BG reproduction. The alternative reproduction methods of BG are driven by the genetic comand to reproduce. However that command is controlled by energetics. If there is not enough energy then egg #s and all males condition will suffer and spawning may cease or be reduced to the point of no survival due to predation.

From Bluegills - Biology and Behavior - Spotte - AFS

"This disparity .. (about reproductive methods and ability)... has been called ' an evolutionary arms race between reproductive competitors ' . " Parens added by EW for clarity.

Eric,

Thank you for the links. Pretty interesting stuff. The energy spent guarding a nest is costly, especially when you find out that the babies aren't yours. I guess that eating the babies is a way to recoup some of that wasted energy!!

It's a good thing that humans are compassionate and can reason. My step-dad raised me. Following the bluegill model, he could have whacked me over the head and eaten me.

Dr. Willis, your thoughts about 7" bluegill are really interesting. It is easy to assume that slow growth is related to resource limitations and over-crowding. Environmental cues that stimulate earlier maturation could very well be the culprit in populations with mediocre size structure. Anglers cropping off the large breeders would probably do this. I'm wondering if the same response would occur if some huge, toothy predators such as muskies were to be released in a pond?

On another note, I fish a pond that routinely prodcues bluegill in the 9.5 to 9 and 15/16 size range. We cannot get them to 10". This has been going on for 3 years. We started throwing feed at them last year and still cannot break the 10" mark. Any ideas?

Fasinating stuff guys.

Great links Eric, I read through most of it (not all because I have to reserve some small amount of brainage for today's pending tax research) still I think I'm still following along.

I think I should get a certificate or something for just participating in this thread, I'm way out of both my league and comfort zones here.