Pond Boss
Posted By: heybud Do Fish Keep Growing? - 10/19/09 11:32 PM
I was wondering, as the water temps get colder and colder, do fish keep growing. Say, will a 4 inch BG keep growing all winter and be 6 inches by spring? Since they slow down eating, I would suspect at the minimum their growth rate at least declines somewhat.
Posted By: ewest Re: Do Fish Keep Growing? - 10/20/09 01:00 AM
It depends. I bet you knew that was the answer. Water temps effect different species differently. It also depends on the minimum water temps. At about 60 F BG metabolism starts to noticeably slow and shortly thereafter their eating starts to slow. At some point energy use is channeled to maintenance of body functions and away from growth. Then in late winter/early spring energy use is diverted to gamete development. If there is excess energy then some growth will continue but not at warm water rates.
Posted By: Cecil Baird1 Re: Do Fish Keep Growing? - 10/20/09 01:41 AM
 Originally Posted By: ewest
It depends. I bet you knew that was the answer. Water temps effect different species differently. It also depends on the minimum water temps. At about 60 F BG metabolism starts to noticeably slow and shortly thereafter their eating starts to slow. At some point energy use is channeled to maintenance of body functions and away from growth. Then in late winter/early spring energy use is diverted to gamete development. If there is excess energy then some growth will continue but not at warm water rates.


Eric,

The author of that bluegill book you sent me maintains that bluegills grow in winter here in Indiana. We are talking water temps at the maximum in the upper 30's in winter here. I find that hard to believe don't you? Otherwise it was excellent reading and I really appreciate the book, but that part I found hard to swallow. It just seems to go against everything I learned in fisheries class.

Thoughts?
Posted By: Bob Lusk Re: Do Fish Keep Growing? - 10/20/09 11:50 AM
My bluegill, in Texas, feed all winter, except when the water temp drops into the 30's.
But, if fish won't eat in the cold, why do you guys fish for them under the ice?
I contend that if the food source is plentiful, growth continues through the winter, albeit more slowly.
We saw some outstanding individual growth rates with bluegill in North Carolina the last two winters. There were several feeders where they were pretty aggressive, even on the coldest days.
Posted By: heybud Re: Do Fish Keep Growing? - 10/20/09 12:11 PM
Great info. I am planning on adding a bunch of 2 to 4 inch BG in November to the pond. I was hoping that with feeding as whole slowing down, that they would big enough come spring to avoid predation and also be close to spawning.
Posted By: Dave Willis Re: Do Fish Keep Growing? - 10/20/09 01:26 PM
I wonder if fish tend to grow a little more in weight when its cold, and not as much in length? That is a really slippery topic, and if I really knew anything, I would say so rather than "wonder." \:\) When studying fish population seasonally, including under the ice, we do see more weight gains and length gains seem pretty rare or at least pretty small.
Posted By: Cecil Baird1 Re: Do Fish Keep Growing? - 10/20/09 02:08 PM
 Originally Posted By: Bob Lusk
My bluegill, in Texas, feed all winter, except when the water temp drops into the 30's.
But, if fish won't eat in the cold, why do you guys fish for them under the ice?
I contend that if the food source is plentiful, growth continues through the winter, albeit more slowly.
We saw some outstanding individual growth rates with bluegill in North Carolina the last two winters. There were several feeders where they were pretty aggressive, even on the coldest days.




I don't know Bob. Standing on two feet of ice here with sub zero temps I'm just not convinced of any growth. I'm not countering your years of fish experience and knowledge that dwarfs mine, just having a healthy debate here. ;\)

As far as why they bite under the ice I don't have a problem with them eating for maintenance, but the growth thing in really cold water (30's) has me skeptical. Furthermore fish do bite on reflex do they not? When we ice fish for bluegill, bass, etc. we pretty much have to drop that bait right in front of their noses. Many times you can see them but they are not interested in biting. Monster redears in the local lakes are notorious for that.
Posted By: Cecil Baird1 Re: Do Fish Keep Growing? - 10/20/09 02:12 PM
 Originally Posted By: Dave Willis
I wonder if fish tend to grow a little more in weight when its cold, and not as much in length? That is a really slippery topic, and if I really knew anything, I would say so rather than "wonder." \:\) When studying fish population seasonally, including under the ice, we do see more weight gains and length gains seem pretty rare or at least pretty small.


That's plausible. On the other hand is it possible they are eating and not digesting the food very fast which leaves their stomach and intestinal tract more full of food, hence they weigh more?


Posted By: Dwight Re: Do Fish Keep Growing? - 10/20/09 02:13 PM
I think Northern Pike grow in length all year around. Something to add to a slippery topic.
Posted By: Cecil Baird1 Re: Do Fish Keep Growing? - 10/20/09 02:24 PM
 Originally Posted By: Dwight
I think Northern Pike grow in length all year around. Something to add to a slippery topic.




Do you have any scientific evidence of growth under the ice of northern pike? Northerns are active under the ice and may even build up their gametes under the ice. Northerns even spawn under the ice at times. However this doesn't necessarily mean they grow under the ice.


Here's something to add to the slippery slope. I've seen it stated in scientific literature several times, that even trout, that are a coldwater fish, cease to grow below 38 F. even if they still feed. According to literature, the feed goes to maintenance of weight and any excess is wasted. I even know one trout farmer in Harrisville, Michigan that was livid a neighbor that was growing out trout for him in his pond, had fed the trout when their was a brief ice out during the middle of winter. He was sure the neighbor had killed some of the trout doing that. He claimed it was really bad to feed them during the winter. He may be wrong of course (wouldn't be the first time a myth has been perpetuated among fish farmers and accepted as fact) but he sure believed it.

In trout, the minimum temperature
for growth is approximately 38°F. At
this temperature and below,
appetites may be suppressed and
their digestive systems operate very
slowly. Trout will require only a
“maintenance” diet (0.5 percent to
1.8 percent body weight/day, depending
upon fish size) at these temperatures;
more than this will result in
poor food conversion and wasted
feed.


http://ag.arizona.edu/azaqua/extension/Classroom/pdffiles/223fs.pdf
Posted By: ewest Re: Do Fish Keep Growing? - 10/20/09 02:51 PM
Heybud often asks questions that result in some of the best discussions here. As a result I try to help them along by being sure my first answer is short and without too much detail. I wait to see how things develop to encourage everyone to get in on the discussion. I will post a few items from a new study (saving some of it for upcoming PB Mag.“Cutting Edge” articles) . This study looked at BG across 23 impoundments with “ extensive latitudinal (and therefore, ecological) variation and encompassing a broad range of factors known to be important to bluegill growth rates and population size structure “ within Ill. Keep in mind this is focused on the big picture not individual ponds. I will look for the data on metabolism ,and growth rate at temp. for BG to post. What I provided in the first post above is a generalization and you should remember that local adaptation exists (in one population of BG in Ohio growth may continue at 45 F temps while in another in TX it may slow to almost none at 48 F while in south Fla all BG growth may stop in one lake at 52 F ).

Examining Interpopulation Variation in Bluegill Growth Rates and Size Structure: Effects of Harvest, Maturation, and Environmental Variables
R. JOHN H. HOXMEIER, D. DEREK ADAY, AND DAVID H. WAHL Transactions of the American Fisheries Society 138:423–432, 2009


“Consistent with previous investigations of bluegills and other species, temperature had a pronounced effect on growth and body size; based on our models, temperature may be the most important environmental factor for explaining variation in bluegill size structure. The effects of Secchi depth and prey abundance were also generally important and were consistent across metrics; good growth and large body size were associated with warm, clear lakes and abundant prey resources. An exception to this pattern was observed in juvenile bluegills, for which larger body size was associated with relatively low Secchi depth (i.e., turbid water). Size at maturation was important in determining the body size of adult males but was relatively
unimportant to female body size. Conversely, bluegill density and harvest mortality did not contribute much explanatory power beyond the effects of prey abundance and temperature in any of our models.”

“However, the relative importance of temperature compared with other abiotic and life history factors is interesting and indicates the value of this approach when considering the multivariate nature of influences on population size structure. Latitudinal clines in growth resulting from changes in temperature have previously been demonstrated for a number of freshwater fishes. “

“ In a test of Bergmann’s rule for freshwater fishes, almost all of the fish species reviewed had smaller lengths at age in northern latitudes than in southern latitudes (Belk and Houston 2002). In a review of largemouth bass growth rates across North America, McCauley and Kilgour (1990) found that half of the variability in growth of largemouth bass was related to temperature. Similarly, bluegill growth was positively correlated with air temperature in Minnesota lakes . Our study provides a relatively unique perspective because we were able to quantify the importance of temperature relative to other environmental factors in its effect on variation in population size structure.”
Posted By: Bob Lusk Re: Do Fish Keep Growing? - 10/20/09 05:38 PM
Cecil,
With your ponds, you should be able to run some experiments to prove whether or not fish will grow in the cold.
I contend that bluegill will grow, even in the coldest of winter, as long they have an adequate food supply. While their metabolic rates are much, much slower in colder water, that doesn't mean they won't gain weight. If a bluegill eats half a pound of insects over the winter, it should gain at least an ounce of weight, maybe two ounces. With a slower metabolism rate, it has better food conversion rates than in summer, when its system is running full force.
Yes, fish bite because of reflex reaction, but they also bite because they're hungry. If an ice-fisherman must stick the bait in front of a fish several times before getting a strike, is that really reflex? Or, defense?
Either way, I have seen evidence in ponds and lakes that I manage that, if we feed all winter, the bluegill come out on the other side larger than when we went into winter.
For many, many years, I believed that we just shouldn't feed in cold water. I still believe that for northern ponds. I expected the fish to not gain weight...I also believed that they would actually lose weight...which they did, because I didn't feed them.
As I tried a few different management techniques, it dawned on me that these cultured fish HAD to lose weight if they had no food. But, I justified it anyway because I didn't want to compromise water quality with excess feed.
But, as I watched people catch fish under the ice and then watched the fish behavior on a camera, it dawned on me that those fish would eat. So, we devised a method of feeding fish, bluegill, crappie and bass in particular, where we would "chum" an area under the ice with fathead minnows. We would push a pvc pipe through the hole in the ice and pour fatheads down the pipe and they would swim out in four or five feet of water. Within a few days, game fish began to congregate in that area. That made be believe they were hungry. Catch rates went up and everybody was happy.
Regarding all the studies...here's my thoughts. Each study has a purpose and the conclusions are based on good science and good technique (in theory). Therefore, the data is good. At the same time, I have learned that managing a fishery is figuring out what variables have the greatest influence on that particular body of water and then do what we can to offer a positive influence on those variables.
Studies don't do that.
Studies are set up for a set of criteria, planned out and then the plan is executed and the results are properly documented.
I've read studies until I'm blue in the face. They are good, helpful and promote deeper thought (at least for me).
At the same time, I don't see any studies as "gospel". I get paid for results, not research.
It is easy to make the argument that temperature is absolutely a variable that inhibits growth rates in bluegill (and most all warmwater fish). But, what if we supply an adequate food chain to those fish? Do they still not grow? Do they lose weight? If that's the case, then I'll buy into the concept that temperature is "THE" variable at play. Right now, I don't believe it. Even though the studies suggest it, and I don't do any research to disprove it, my clients are often tickled pink and surprised to see fish with better relative weights, fatter tummies and chunkier-looking bodies going into the spring months than they did in the fall.
I won't dispute the science.
I also won't dispute the fat bluegill each spring.


Posted By: Dave Willis Re: Do Fish Keep Growing? - 10/20/09 06:04 PM
Good call from Dwight on northern pike. They truly are a coolwater fish species. In South Dakota, they grew in length over winter and in spring/fall but did NOT grow in the summer when it got too warm.

Neumann, R.M., D.W. Willis, and S.M. Sammons. 1994. Seasonal growth of northern pike in a South Dakota glacial lake. Journal of Freshwater Ecology 9:191-196.

You can't get that journal online. So, if anyone "needs" \:\) a copy, send me an email and I'll get it to you. It's also available on our department web page publication list.

http://wfs.sdstate.edu/wfsdept/Department%20of%20Wildlife%20and%20Fisheries%20Publications.htm

Oh, and one other tidbit. Rob Neumann is now the managing editor for In-Fisherman magazine. Cool, eh?
Posted By: esshup Re: Do Fish Keep Growing? - 10/20/09 10:27 PM
I believe that fish feed under the ice, and don't just strike out of reflex. If the reflex part were true most of the time, then what color of ice jig or fly wouldn't matter, would it? I read somewhere, and believe the BG target copopods (sp?) during the winter (iced over lakes). The BG seem to follow their rise and fall in the water column as it relates to ambient light. Matching the hatch seems to work. I've used a #28 fly tied above an ice fishing jig and have caught more fish on the fly than on the jig.

In regards to pelleted feed, does anybody know how long a fish takes to digest a pellet at "X" number of degrees water temp? i.e. a BG will digest a pellet in "X" hours in 70* water vs. "X" hours in 40* water.
Posted By: Cecil Baird1 Re: Do Fish Keep Growing? - 10/20/09 10:31 PM
Interesting Dave. So pike have been documented as growing in the winter but trout are not supposed to grow below 38 F. I wonder how much of the trout info is documented through research like the pike data is, or is it just accepted as the truth?

A good example is how it was always accepted smallmouth bass are a coolwater deeper fish than largemouths in large lakes and reservoirs when it turns out they are just being pushed out of the litoral zone by the more aggressive largemouths.


Posted By: adirondack pond Re: Do Fish Keep Growing? - 10/20/09 11:32 PM
When it comes to brook trout, they must be feeding and growing during the winter, they spawn in the winter and yet most of the BRKT I catch in early spring are in great shape.

I like Bobs method of feeding fish thru the ice, I can just see the fish lining up by the feed pipe like a fast food restaurant.
Posted By: Cecil Baird1 Re: Do Fish Keep Growing? - 10/20/09 11:51 PM
 Originally Posted By: adirondack pond
When it comes to brook trout, they must be feeding and growing during the winter, they spawn in the winter and yet most of the BRKT I catch in early spring are in great shape.

I like Bobs method of feeding fish thru the ice, I can just see the fish lining up by the feed pipe like a fast food restaurant.


Just because a fish is feeding doesn't mean it's growing though. Could be more of a maintenance thing.
Posted By: Bob Lusk Re: Do Fish Keep Growing? - 10/21/09 01:41 AM
Cecil,
I don't see your logic. Please explain further. I'm not getting it.
Admittedly, my fisheries management style is based on good science (but not specific science), which makes much of it an art, which is based on what I perceive as common sense.
My common sense tells me that when a fish eats, it eats because it needs to. If the food chain is available and the fish is hungry, it eats. I have not seen a fish just trying to "maintain"...if they have plenty to eat. I have watched them grow like little fat sumo wrestlers, even in the winter.
My "common sense" approach tells me a fish only maintains when that's the only choice it has.
I haven't grasped the concept that any bluegill that has copepods, insect larvae or fish food...or any favorable food chain... available at times when that fish is hungry, that it will turn its nose away and swim off, just because it wants to maintain. If a fathead minnow swims near and the bluegill is hungry, I contend it will eat it, regardless of the temperature. And, I also contend that when that sunfish eats that minnow and its nutrition is more than the bluegill needs to "maintain", that it will gain weight.
So, would you be so kind as to enlighten me? I'm just hard headed enough to stay in this fracas, but also intelligent enough to realize there are plenty of people out there that know more about it than I do. Really, all I have to show for it are the ponds and lakes I take care of, and they may be exceptions to the rule(s).
So, I am really interested in your side of this friendly little debate.
I guess I am asking you to cite some real world examples (beyond some specific study we can read) or some idea that I can wrap my mind around that will help me embrace your idea.
If I am thinking in the wrong direction, I need to shift it.
Thanks, buddy.
Posted By: Cecil Baird1 Re: Do Fish Keep Growing? - 10/21/09 02:02 AM
O.k. Bob here's my take on this and I sure don't have all the answers, and probably not making my point clear, but I did stay at a Holiday Express last night!

Seriously, aquaculture text literature says from several sources the following more or less regarding trout which are a coldwater fish:


In trout, the minimum temperature
for growth is approximately 38°F. At
this temperature and below,
appetites may be suppressed and
their digestive systems operate very
slowly. Trout will require only a
“maintenance” diet (0.5 percent to
1.8 percent body weight/day, depending
upon fish size) at these temperatures;
more than this will result in
poor food conversion and wasted
feed.


My thoughts are (and I sure could be wrong) that if a trout, a cold water fish, stops growing at 38 F. even while eating, why do we think a bluegill would continue to grow under the ice in northern Indiana as the author of the text I was referring to says?

I'm all ears if someone can show evidence of growth in those frozen lakes even if it's a millimeter all winter. Or evidence that the above information about trout is false. Like I said in a previous post it could be false about the trout, and is one of those things that has been accepted and repeated over and over again but not necessarily proven.

So I'm not talking about winter growth in general or winter growth in Texas or wherever. I was referring to the text Eric sent me that said there is bluegill growth in the winter in Northern Indiana lakes.

Perhaps when the author was talking winter growth in winter in Northern Indiana lakes he was referring to growth from the first day of winter to the last day of winter where on occasion we get unseasonably warm weather or a late winter? One year it was in the 70's on Christmas Eve here and many of us were out in our boats fishing.
Posted By: ewest Re: Do Fish Keep Growing? - 10/21/09 02:21 AM
Here is a little more. Like I stated early on I think it depends on several factors.

The Effects of Growth, Predation, and First-Winter Mortality on Recruitment of Bluegill Cohorts

Victor J. Santucci Jr and David H. Wahl
Transactions of the American Fisheries Society 2003; 132: 346-360

All sizes of age-0 bluegills grew during winter in our study, suggesting that starvation was not a factor influencing winter survival. In contrast, predation was a likely factor reducing bluegill survival overwinter.

* this was in Ill.


SEASONAL GROWTH RATES OF FISHES IN RELATION

TO CONDITIONS OF LAKE STRATIFICATION

Glen E. Gebhart and Robert C. Summerfelt

Oklahoma Cooperative Fishery Research Unit†,

Seasonal periodicity of growth has been reported which shows a reduced rate in

midsummer. This coincides with the onset of summer stratification and severe hypolimnetic oxygen depletion.

Beckman (5) found that 85% of the expected growth of bluegills in a Michigan lake was completed between the

end of April and mid-July. Sprugel (6) found bluegill growth in Iowa was most rapid in June and little growth

evident after July. Anderson (7) also found bluegill growth to be most rapid in June with most growth occuring

in May, June and July and the total growing season extending from 1 May to 31 October. Winter temperatures

are generally too low for optimum growth of most warm-water fishes, but even normal summer surface

temperatures can exceed the optimum range for warm-water fishes as ascertained from laboratory and field

studies of the preferred temperatures of fish (8).

The generally held view on seasonal variation in fish growth in North America is that growth is fastest in

the spring and early summer, slows in the late summer and fall, and virtually stops in the winter (7).

More later.
Posted By: DJT Re: Do Fish Keep Growing? - 10/21/09 03:24 AM
Great topic. I was thinking about starting a thread about something very similar before I saw this one. Mine was going to go something like this.

Since switching to Aquamax feed I have noticed the the BG have lots of fat deposits in their gut when cleaning them. It is like you can't even see the intestine through all the fat. Once feeding halts for the winter will some of that fat be converted to muscle/length or will it just be burned as maintenance energy?

I'm sure that body condition (RW) going into the winter would be another variable in this discussion.
Posted By: Cecil Baird1 Re: Do Fish Keep Growing? - 10/21/09 10:56 AM
 Originally Posted By: ewest
Here is a little more. Like I stated early on I think it depends on several factors.

The Effects of Growth, Predation, and First-Winter Mortality on Recruitment of Bluegill Cohorts

Victor J. Santucci Jr and David H. Wahl
Transactions of the American Fisheries Society 2003; 132: 346-360

All sizes of age-0 bluegills grew during winter in our study, suggesting that starvation was not a factor influencing winter survival. In contrast, predation was a likely factor reducing bluegill survival overwinter.

* this was in Ill.


SEASONAL GROWTH RATES OF FISHES IN RELATION

TO CONDITIONS OF LAKE STRATIFICATION

Glen E. Gebhart and Robert C. Summerfelt

Oklahoma Cooperative Fishery Research Unit†,

Seasonal periodicity of growth has been reported which shows a reduced rate in

midsummer. This coincides with the onset of summer stratification and severe hypolimnetic oxygen depletion.

Beckman (5) found that 85% of the expected growth of bluegills in a Michigan lake was completed between the

end of April and mid-July. Sprugel (6) found bluegill growth in Iowa was most rapid in June and little growth

evident after July. Anderson (7) also found bluegill growth to be most rapid in June with most growth occuring

in May, June and July and the total growing season extending from 1 May to 31 October. Winter temperatures

are generally too low for optimum growth of most warm-water fishes, but even normal summer surface

temperatures can exceed the optimum range for warm-water fishes as ascertained from laboratory and field

studies of the preferred temperatures of fish (8).

The generally held view on seasonal variation in fish growth in North America is that growth is fastest in

the spring and early summer, slows in the late summer and fall, and virtually stops in the winter (7).

More later.

Posted By: Bodock Re: Do Fish Keep Growing? - 10/21/09 01:11 PM
This is a timely subject. This begs the question whether one should stock a new lake with fingerlings in the winter or wait until early Spring. If fish don't grow in the winter it seems all your doing is exposing your investment to bird predation, possible winter kills, and more. Of course all the hatchery guys are pushing to stock ASAP regardless.
Posted By: Dave Willis Re: Do Fish Keep Growing? - 10/21/09 01:15 PM
Another tidbit. We sampled black crappies monthly in a fast-growing population in Lake Madison, SD. Following is the mean length of age-3 crappies each month.
Lengths in centemeters. cm/2.54 = inches
Mar 18.1 = 7.1 "
Apr 18.1
May 18.1
Jun 18.7
Jul 21.0
Aug 22.8
Sep 24.5
Oct 24.6 = 9.7"

Isn't that amazing? 7 inches to nearly 10 inches in just 3 months of growth. Crappies can really put on the feed bag.
Posted By: ewest Re: Do Fish Keep Growing? - 10/21/09 01:25 PM
Cecil I have been doing some checking. What reference (pg / ft.nt. # , etc) in the Bluegill book are you referring to? I reviewed the material along with some other info and the results are all over the place on BG winter growth and most , but not all , is latitude (temp) related.

Guys please don't pick out one data point (or comment) and assume it is universal. That would be a huge mistake and not justified by the science or actual data. As I stated early on this is a big picture discussion and the results depend on many factors.

Cecil you said " The author of that bluegill book you sent me maintains that bluegills grow in winter here in Indiana." The author also states " Based on the appearance of scale annuli, growth starts in May in northern Indiana and extends through September. Growth rates vary widely both by region and bodies of water with in regions , and variation within lakes can be as great as between lakes in the same vicinity." He also says about those near Kalamazoo Mich that BG " continued to grow through winter, in one pond adding 20% in length and 50% in mass." Keep in mind the nature of this book. It is in large part a survey and recounting of data and conclusions from many studies on BG. There are over 1300 footnotes and probably around 500 studies reviewed and acknowledged. There were 60 lakes examined in the one study above in IN.
Posted By: Bill Cody Re: Do Fish Keep Growing? - 10/21/09 01:29 PM
Normally I prefer a spring stocking so newly introduced fish coincide with the production of the new crop of foods in the spring. Over the years I have found that sometimes certain species or sizes of fish were all sold out in fall and then not available in spring unless one traveled further distances to get a specific species or size. Bottom line do a little homework in advance, know your fish supplier, and the availability and size of the species you want to stock. Often scarse fish in the spring are SMB, RES, walleye, pike, musky, pumpkinseed, and larger(10"-12")HSB. Larger SMB (6"-8") are always scarse and demand a high price (usu 2X LMB $). During hard winters (heavy snow cover) in the north even some common species and sizes such as LMB fingerlings (or 4"-6") are sometimes scarse and hard to find especially at the smaller local fish farms.
Posted By: Theo Gallus Re: Do Fish Keep Growing? - 10/21/09 03:02 PM
 Originally Posted By: Bodock
This is a timely subject. This begs the question whether one should stock a new lake with fingerlings in the winter or wait until early Spring. If fish don't grow in the winter it seems all your doing is exposing your investment to bird predation, possible winter kills, and more. Of course all the hatchery guys are pushing to stock ASAP regardless.

In addition to the availability points Dr. Perca made, fish stocked in the Fall are present and eating (assuming food is available in the pond) during late Fall and early Spring, even if no growth occurs in the dead of Winter.

I stocked 3" to 6" SMB 11 months ago (Nov 2008) into a new pond full of FHM and Gams. I was very happy with the growth they had managed by the time the usual Spring stocking season rolled around this year.
Posted By: Bodock Re: Do Fish Keep Growing? - 10/21/09 03:28 PM
[quote=Theo Gallus}
In addition to the availability points Dr. Perca made, fish stocked in the Fall are present and eating (assuming food is available in the pond) during late Fall and early Spring, even if no growth occurs in the dead of Winter.[/quote]

Interesting. So you're saying in addition to the risks of late fall stocking I previously mentioned also much of the feeding I'd likely attempt to do (with sinking feed nonetheless so I couldn't tell if it was getting eaten) would be largely throwing money away because the fish wouldn't grow much if at all? It seems waiting until March 1st is making more and more sense.
Posted By: andedammen Re: Do Fish Keep Growing? - 10/21/09 03:54 PM
The fish has a energibudget.
Absorbd energi is split beetwene, metabolisme,somatic growth, and reproductione.
The growth rate is then deteremined/efectet by:
1. themperature C/F and acses to Nutrientes.SEASON in NATURE
2. life sycleus (age)SEASON in LIFE

By nature this are given factors, each spicies has an ideal, and a upper/lower toleranse in habitat demands, furthermore a maximum lifespan.
Within these boundries we/you/me/? can manipulate.
The formula is a mix of 1. and 2. you prolong the optimal natural cross seasons, for gowth, with in the cost$/time limit you have.

PAUL
Posted By: Theo Gallus Re: Do Fish Keep Growing? - 10/21/09 06:06 PM
 Originally Posted By: Bodock
 Originally Posted By: Theo Gallus

In addition to the availability points Dr. Perca made, fish stocked in the Fall are present and eating (assuming food is available in the pond) during late Fall and early Spring, even if no growth occurs in the dead of Winter.


Interesting. So you're saying in addition to the risks of late fall stocking I previously mentioned also much of the feeding I'd likely attempt to do (with sinking feed nonetheless so I couldn't tell if it was getting eaten) would be largely throwing money away because the fish wouldn't grow much if at all? It seems waiting until March 1st is making more and more sense.

Nope, I'm saying that in exchange for the risks your fish take from being in until March 1, they get to grow some (if there is proper food for them to eat. I'm staying out of the Winter pellet feeding debate as well). Whether that includes during the dead of Winter or not, you can refer to the above discussion, but while temps are in the middle, they will be eating and growing some.
Posted By: ewest Re: Do Fish Keep Growing? - 10/21/09 07:06 PM
...and if they have food they will become acclimated to the pond and be ready to spawn at the earliest opportunity. That is a big + . In addition it’s a risk management choice. It’s one thing to risk a small amount of $ on FH or a few 3-5 inch BG and something entirely different to plan your entire stocking $ on the risk.

Here is the point. Do you want to pay for and stock 1000+ BG per acre in May/June - let’s say 3000 BG @ .25 = $750+ or do you want to risk $50-100 and buy 50 advanced 4-6 inch BG and stock them in November and watch them spawn in April/May @ +- 20,000 offspring per couple - that’s 500,000 potential new BG . Many will be morts but you will get a lot more to 3-5 inches by summer’s end than by stocking 3000 2 inch fish in May. Of course you can split the risk and do some of both and have several size classes by next fall. My usual choice.

I understand both methods and have used them and others successfully. I like the idea (Bob and Bill’s) of the fish growing up in the pond and thinking outside of the box about concepts. IMO the fish to bet your pond on are the ones born there not necessarily the 2 inch ones you buy and put in. That is a key difference. The first fall/winter stocked fish in low #s are not the ones I want to use up the ponds carrying capacity. It’s their yoy I want in that prime position. They will grow-up in a nearly empty pond from day 1 not day 90. In addition I can do a better selection for quality job on 4-6 inch BG than I can on 2 inch .

It’s all about the time , risk , availability , goals and planning.

I note andedammen’s use of the bioenergetics model. Good point which we should all learn to use and think more about. It really fits this thread on winter growth. Here is the last time it was discussed.

http://www.pondboss.com/forums/ubbthread...true#Post126419


Posted By: andedammen Re: Do Fish Keep Growing? - 10/21/09 08:35 PM


Here is the point. Do you want to pay for and stock 1000+ BG per acre in May/June - let’s say 3000 BG @ .25 = $750+ or do you want to risk $50-100 and buy 50 advanced 4-6 inch BG and stock them in November and watch them spawn in April/May @ +- 20,000 offspring per couple - that’s 500,000 potential new BG . Many will be morts but you will get a lot more to 3-5 inches by summer’s end than by stocking 3000 2 inch fish in May. Of course you can split the risk and do some of both and have several size classes by next fall. My usual choise

It’s all about the time , risk , availability , goals and planning.[/quote]

I think an esentiale pharametre,is to be honest/realistic in assesment, off costs/risk/effort involved, and that vill allways have to include the naturale Advantadges/Dissadvantedges within grasp/reach, an play along with them, at the best off your own knoledge/exsperience, wich vill keep growing for as long you are up/in to it.
So put in a stake you can afford to loose, in balance with, lesson learnd I`d like another go.
Posted By: Bodock Re: Do Fish Keep Growing? - 10/21/09 11:46 PM
That's some good advice y'all have just given. Thank you and thank Pond Boss. Perhaps fewer #s of larger CNBG and a full stocking of FHM & golden shiners this fall then add some 2-3" CNBG along with Threadfins in early Spring. Then LMB in June.
Posted By: Cecil Baird1 Re: Do Fish Keep Growing? - 10/22/09 02:02 AM
 Originally Posted By: ewest
Cecil I have been doing some checking. What reference (pg / ft.nt. # , etc) in the Bluegill book are you referring to?


I couldn't tell you Eric. After reading the book I gave it to Bill Cody.

One thing I have not seen addressed here unless I missed it is, fish are in better condition in the fall after a summer of growth vs. coming out of winter. I've seen fungal problems from seining fish early in the spring.
Posted By: Bill Cody Re: Do Fish Keep Growing? - 10/22/09 02:26 AM
Eric, On page 123, last parag. of the BG book you and Cecil are discussing, it says in reference to Cecil's winter BG growth comment: "Those(BG) near Kalamazoo continued to grow through winter, in one pond adding 20% in length and 50% in mass(1004). Some of these fish reached 150mm TL in 17 months." Ref: Krumholz 1946, TAFS 76:190-203.
Posted By: Cecil Baird1 Re: Do Fish Keep Growing? - 10/22/09 02:30 AM
I believe there is something about winter bluegill growth in Kosciusko county lakes in northern Indiana. Shoe Lake comes to mind.

Why aren't you wading into this Bill? Not chicken are you?

Baak, baak, baak!
Posted By: ewest Re: Do Fish Keep Growing? - 10/22/09 02:28 PM
Bill I will check it tonight. To be clear - my point is that the part of the book on growth provides good info over a large area from many studies and many more lakes/ponds and the results are all over the place on BG winter growth even in just IN.

Eric - All I was doing for this topic was providing the reference in question. It will be interesting to see your review of the article and its methods. I am curious if this is an average growth rate or taken from the fast growing fish in the population.

Bill - check your mail. The study has extensive stats and methods and models. I am not going to address them as they are way too complex to explain in PB Cutting edge space restrictions. Not sure I would try that even with unlimited space - only a statistician would enjoy that.

Posted By: 2trackin Re: Do Fish Keep Growing? - 10/22/09 07:55 PM
Hey I'm in Kalamazoo Michigan! Hopefully my bluegills (and trout) keep growing \:\)
Posted By: ewest Re: Do Fish Keep Growing? - 10/23/09 02:34 AM
A bit more info from Handbook of Freshwater Fishery Biology Vol Two , Carlander pg 112 "Feeding occurred in winter in Buckeye L. , OH, ... with fat accumulating in the tissue. ... In aquaria no feeding occurred below 3.3 C ,and feeding in ponds has been found at 3.9 C. In ponds there was no growth and little feeding at temperatures below 10 C. In a Michigan lake , bluegills fed little in winter , and caldocera where the major food in mid-winter. "

10 C = 50 F
3.3 C = 37.94 F
3.9 C = 39.02 F
Posted By: Bill Cody Re: Do Fish Keep Growing? - 10/23/09 04:27 PM
Cecil says: "fish are in better condition in the fall after a summer of growth vs. coming out of winter". Cody thinks this is definately true for those fish that have minimal amounts of food available during winter.

IMO fish will readily feed especially on natural foods in winter if items are abundant and avaiable. Ample natural foods in winter result in well fed fish, likely fat fish and in some cases slightly larger fish (growth). I emphasize natural or moist foods for winter feeding because several fish farm people have had fish mortality of some species of fish eating dry pellets in water colder than 50F. Cold water fish such as trout would the the exception here.

Cecil mentions that he has seen fish ingore his bait when ice fishing and concluded that fish was not hungry. I have seen the same behavior of fish in summer. IMO hunger is not always the main factor that a fish ignores a bait.

Water temperature, species of fish, and as mentioned by Hoxmeir et al (Eric above), "latitudinal clines in growth resulting from changes in temperature have previously been demonstrated for a number of freshwater fishes". I think populations of fish for example BG and their ability to grow at one specific temperature can be somewhat different at diffferent latitudes depending on the particular acclimatization and adaptability of those fish. Numerous factors determine fish growth during winter and the other seasons. One of the main ones is temperature as discussed here.
More later.
Posted By: andedammen Re: Do Fish Keep Growing? - 10/23/09 07:13 PM
 Originally Posted By: ewest
A bit more info from Handbook of Freshwater Fishery Biology Vol Two , Carlander pg 112 "Feeding occurred in winter in Buckeye L. , OH, ... with fat accumulating in the tissue. ... In aquaria no feeding occurred below 3.3 C ,and feeding in ponds has been found at 3.9 C. In ponds there was no growth and little feeding at temperatures below 10 C. In a Michigan lake , bluegills fed little in winter , and caldocera where the major food in mid-winter. "

10 C = 50 F

It seems to me that this is your dep. ewest?????

Her you have a link to a lecture on energetic on brown/brook trout study on local tribes from Greenland and in Norway.
On page 12 you can see that the studies are based on brook living in a temp. environemente that has rised from a averge of
C 4,9 to C 9,1 at the peek/hotest of summer(august)

http://dok.ebl-kompetanse.no/Foredrag/2008/Fiskesymposiet/Fjeld.pdf

I could not fine a english version hovever I did fine translation on the particulare studie from Greenland

http://www.biomedcentral.com/content/pdf/1472-6785-6-10.pdf




3.3 C = 37.94 F
3.9 C = 39.02 F

Posted By: ewest Re: Do Fish Keep Growing? - 10/23/09 09:04 PM
Thanks Andedammen I will take a look !
Posted By: Gflo Re: Do Fish Keep Growing? - 11/13/09 05:05 AM
Forgive me if I am totally off base, but it is my understanding that fish in general only "slow" their feeding in the winter when it is cooler because the lower temperatures take their digestive tracts out of the optimal temperature range for reactions to take place (the optimal pH / temperature balance).

This would effectively lead to a decreased rate in digestion (depending on the protein source / type).

Their digestive tracts are not processing food items optimally, so they don't eat as often because their digestive tract can only hold so much food, and process it only so quickly in sub-optimal conditions.

So what effect might this have on growth rate in the winter?

Well, for one we would need to take into account the type of protein / foodstuff being provided. What is the digestibility of the said food item?

Using common sense I would surmise that a fish (bluegill, bass, whatever, just arbitrary at this point) may not grow very quickly or very much at all if it is eating natural forage, and breaking down complex proteins.

It might be able to process the prey items just quickly enough with a lowered rate of digestion to maintain its current body weight, and maybe put on a little weight or grow a bit.

If that fish on the other hand were fed a high quality, highly digestible pellet based feed (Assuming that many of the same principles of livestock and companion animal nutrition are used in fish nutrition), then I would expect those fish to process those pelleted feeds at a higher rate than they would natural forage. I would expect to see a measurable amount of growth even during the winter on pellets. But then again, this is a gross generalization. Not everyone has the same intensity winters or water temperatures.

Sorry for bringing this topic back from the dead. It is a topic I am very interested in academically, although I'm more of a companion animal / ruminant nutrition kind of guy.

I could be totally off and have wasted your time. I don't know anything about fish really, I just assume from my studies that there is significant overlap between species and the principles of digestion. There are a lot of confounding factors like Genetics and probably all sorts of "crap", for lack of a better word, that I don't even know about.
Posted By: ewest Re: Do Fish Keep Growing? - 11/13/09 03:49 PM
Gflo its never a waste to have questions asked. You have ask a very good one. I will do some checking. One point I note is you addressed one side of the growth question - energy in. The energy out (used) part is equally as important and furnishes the demand side of the equation for energy in. It’s not only a digestive function but also a metabolism question. Keep in mind that unlike many livestock type animals most fish are cold blooded and their energy demand slows greatly in cold conditions where as in warm blooded animals it increases to keep body temps up. This effects digestion and energy demand as well as other biological functions.

Another thought is the comparison of fish feed to live fish and other forage. While feeds are good and live forages have different nutrient results (not all forages are equal or the same) I don't think that feeds offer as much as live forage for growth. The best feeds are designed by doing an analysis of live prey (optimum diet) and trying to match them. They are good but not quite as good as the real thing. That is the main reason that the major ingredient in better feeds is fish meal and oil mostly from menhaden. These comments are for predator fish (LMB , HSB , BG , YP , trout etc) and there is some difference as to the omnivore types ( catfish and GShiners ) and even more difference as to the herbivore types (tilapia , shad , carp etc) at least as to the diet requirements for feed vs. live forage. Not all fish need more protein or fish as a source. That is one reason for the different types of feed. More later.
Posted By: jeffhasapond Re: Do Fish Keep Growing? - 11/13/09 03:57 PM
No need to apologize for bringing back an old thread Gflo, besides that thread was from October, heck I have pizza in the fridge that's older than that.

 Originally Posted By: Ewest
Another thought is the comparison of fish feed to live fish and other forage. While feeds are good and live forages have different nutrient results (not all forages are equal or the same) I don't think that feeds offer as much as live forage for growth.


Interesting, I shall wait impatiently, fingers drumming on the desk top until further clarification is posted.
Posted By: Gflo Re: Do Fish Keep Growing? - 11/15/09 08:02 AM
After reading up for like 5 hours in our university scientific articles online database, my brain is in a world of hurt.

Basically,

This is what I have learned. The short story from well over 100 pages of text from like 20 or so articles (forgive me if I don't reference them... I pieced these thoughts together from a lot of fragmented studies...).

As far as the comparison of commercial fish feed to live forage.

There is evidence that there is a difference between commercial feeds and live forage (theoretical, unmeasured).

It has to do with the nutrients that make up those food sources.

Protein levels, for example, have been correlated with growth hormone levels. And other micro-nutrients and amino acids have had an elevating effect on hormones such as T4, and the deionization to T3.

I know I am being vague as far as specifics of which hormones specifically, and in what species of fish. Right now, that isn't important (and is extremely boring).

What is important is that studies are showing that levels of specific nutrient(s) components (such as protein, carbohydrates, lipids), and their ratios, may have an effect on circulating hormone levels (Growth Hormone Specifically).

So what does that mean?

This tells us that fish nutritionists could potentially formulate diets that will have an effect on the endocrine system, and increase circulating hormone levels that are directly correlated with growth.

Instead of looking at what feeds convert better, we could be looking at what feed compositions actually increase feed conversion on the physiological level. This goes beyond digestibility as it pertains to particle size of ingesta, surface area, etc. This is analogous to increasing growth via exogenous (injected) hormones like we do with cattle, except the hormones are endogenous (naturally occurring) through nutritional manipulations.

There are also a lot of confounding factors (problems) that need to be addressed.

There are boatloads of environmental factors that have been shown to affect circulating hormone levels, growth, and feed conversion in fish.

The first is the time in which the fish are fed, and the frequency.

In one study looking at trout in particular, those fish fed at night had higher growth hormone levels than those that were fed during the day at a frequency of one feeding every 24 hours.

In other species, it was totally backwards, and in others there was no difference at all. This makes this information not so useful at this point in time if we are talking about managing the growth of a variety of species.

The only important tid-bit that came out of this portion of the reading was that fish that are fed more than once a day had a higher circulating level of Growth Hormone (pretty much observed in most studied species). Basically, to maximize growth feeding more than once a day is ideal (theoretically... Real world results are what count!)

Whether or not those gains are really worth the extra hassle, I couldn't really say. I have no experience in the fish management arena, and the studies just stated that there were statistically significant differences, rather than stating weight gains (It was a review article talking about other primary research articles).

Another confounding factor is that for every hormone like Growth Hormone, there needs to be an active hormone receptor, like "Growth Hormone Receptor" (for our purposes).

Even if there is a change in endocrine function and level of Growth Hormone and other Insulin Growth Factors (Other junk that contributes to actual growth), that doesn't mean that it will be put to use.

Think of it this way. Lets say I have 5 basketballs. Lets also say that I have 3 hoops.

In this example...

Basketballs = Growth Hormone Circulating In The Fish.

Hoops = Growth Hormone Receptors (Where the points are scored, and actual change, or growth, is initiated).

If you shoot all 5 basketballs at the exact same time, then you will only score 3 baskets. You had an excess of basketballs (growth hormone), and not enough hoops (growth hormone receptor sites).

In this example, the fish's body doesn't react to having a high level of growth hormone. It ultimately only really matters how many receptors there are. That is the limiting factor.

Basically this means that even if nutrition can change circulating growth hormone levels in a fish, it may not even cause them to grow. Or maybe it will... Who knows... (Remember, hormones are not given to cattle because they don't work... They seem to have more than enough hormone receptors to make use of the excess hormone and grow).

There is a lot of other stuff, but my brain started hurting so I stopped.







So, if you want skip all that junk, here is the conclusion I have come to..

Commercial fish feeds have the potentially to overtake live fish and other forages as far as measurable growth is concerned. The keyword is potential. From what I've read there isn't really an indication that today, this is the case.

There is no reason to discount live forage. The main advantage of pelleted feeds when compared to an equally nutritious live fish prey item is that the pelleted feeds are designed so that an increased surface area of nutrients comes in contact with the digestive tract. This theoretically would increase feed conversion efficiency.

Commercial fish farming is really starting to take off, and I am confident that there is going to be a lot more research published in the next 10-15 years than there has ever been on freshwater fish. The quality of nutrition really increases exponentially when that happens.

I think its kind of funny how we know more about cattle, and take care of them better nutritionally than we do horses. A lot of people treat their horses better than members of their own family, yet nutritionists still don't know where horses are absorbing their vitamin K from. Its pretty important, and no one really has a clue, just theories. No one is really investigating it because no one is really throwing money at them, horse farming as far as growth is concerned isn't a substantial industry.


Anyhow, back on track.

This has got me curious. I am going to look into seeing if I can get an experiment going injecting some trout, bass, or bluegill with amino acids in an effort to see if any of them have an marked increase in circulating hormone levels.
Posted By: esshup Re: Do Fish Keep Growing? - 11/15/09 12:31 PM
Gflo:

Thanks for taking the time to research this. It's interesting!
Posted By: Theo Gallus Re: Do Fish Keep Growing? - 11/15/09 01:55 PM
 Originally Posted By: Gflo
A lot of people treat their horses better than members of their own family ...

You'd understand, if you'd ever met my BIL.
Posted By: ewest Re: Do Fish Keep Growing? - 01/18/10 01:55 AM
Some additional info via Bass Times - Jan 2010 by Dr. Keith Jones director of Fish Research at Berkley about LMB in winter.

For every drop of 18 F in body temperature a bass' metabolic rate is reduced to 1/3rd its previous rate. Liver and digestive processes are hit especially hard. A meal of shad that at 70F took only 2 or 3 days to digest , at 60F may need 4 or 5 days to complete. The bass is beginning to struggle physiologically.

Around 60 F the outward behavioral signs of cooling may be marginal. From 60 to 50 F , however they become readily observable as the animal grows increasingly more sluggish. Dropping from 50 to 40 ... full fledged winter , the behavioral changes are major. At temperatures below 40 F ,bass essentially enter a state of dormancy. ...a large portion of the bass population will be resting with their pelvic fins and tails in contact with the bottom , wholly inactive with gill rates measuring about one breath per minute.

Cold bass can't swim very fast , long or far before tiring.
Posted By: Gflo Re: Do Fish Keep Growing? - 01/18/10 08:21 AM
All the stuff that contributes to fish growth like water quality, water movement, temperature, ph, nutrition, and Elevation*** (Hadn't thought of elevation before. Something to do with atmospheric pressure.) is confusing, but interesting.

I decided to take an aquaculture class this quarter, and I'm discovering what before should have been obvious. All of the above criteria vary between pretty much every species (even those subspecies closely related)... I'm having trouble keeping up.

With that said, I had a nice little tidbit of information in lecture the other day.

In trout and other salmonids it takes 330 grams of protein from a modern hatchery formulated diet to produce 1 pound of fish.

A natural forage diet however only takes 143 grams of protein in order to produce 1 pound of fish.

What does that tell us when we are talking about fish we currently know the most about nutritionally (followed closely by catfish of course)?

It tells us that we still are not getting the formula right, and there is a tremendous amount of room for improvement.

Ewest,

I think I am going to start bringing a thermometer with me and if the water is at around 40 degrees I might not even bother fishing. Then again, based on the intel you have provided I might just drag a night-crawler across the bottom reeeaaaallly slowwwww.

Do you know if that article was published just in the bass times, or is it going to be in a peer reviewed journal as well? I want to read up on that. Cool stuff.
Posted By: ewest Re: Do Fish Keep Growing? - 01/18/10 02:12 PM
I bet if you contact Dr. Jones through Berkley he would provide the material. I don't know if he plans to publish it elsewhere or his sources. Berkley , having its own research facility ,has a lot of their own data they might share. They have done series of articles like this over the years on most aspects of LMB biology.
Posted By: jeffhasapond Re: Do Fish Keep Growing? - 01/18/10 03:26 PM
 Originally Posted By: Gflo
With that said, I had a nice little tidbit of information in lecture the other day.

In trout and other salmonids it takes 330 grams of protein from a modern hatchery formulated diet to produce 1 pound of fish.

I thought that most of the fish food had a higher conversion rate than natural forage.

A natural forage diet however only takes 143 grams of protein in order to produce 1 pound of fish.

What does that tell us when we are talking about fish we currently know the most about nutritionally (followed closely by catfish of course)?


Is this specific to "trout and other salmonids" or does this principal hold true LMB, BG and other more commonly used pond species?

What does this tell us when we are talking about fish we currently know the most about nutritionally?

I guess I should be able to draw some form of conclusions here but am having trouble connecting the dots.
Posted By: Sunil Re: Do Fish Keep Growing? - 01/18/10 03:31 PM
First, try doing some metric to english conversions.
Posted By: jeffhasapond Re: Do Fish Keep Growing? - 01/18/10 03:46 PM
Hmmm, that begs a question. Do fish use the metric system?
Posted By: Greg Grimes Re: Do Fish Keep Growing? - 01/18/10 03:51 PM
ewest working on article now for PB about tagging. The motivator for the articel is that you can learn soem stuff abtou your ponds. IN this case it appears the bass in GA/SC grew MUCH better in cool months than warm months. If you like I can get you the article or data for your thoughts.
Posted By: esshup Re: Do Fish Keep Growing? - 01/18/10 04:40 PM
 Originally Posted By: Sunil
First, try doing some metric to english conversions.

1 gram = 0.0352739619 oz.

Am I doing the math right? 143 grams = 5 oz?
Posted By: Theo Gallus Re: Do Fish Keep Growing? - 01/18/10 07:14 PM
Let's see. We all know that a pint's a pound the world around ...
Posted By: ewest Re: Do Fish Keep Growing? - 01/18/10 11:59 PM
 Originally Posted By: Greg Grimes
ewest working on article now for PB about tagging. The motivator for the articel is that you can learn soem stuff abtou your ponds. IN this case it appears the bass in GA/SC grew MUCH better in cool months than warm months. If you like I can get you the article or data for your thoughts.


Cool not cold. Best growth at water temps between 70 to 80 F . Above and below it slows. Send the info. I will dig out the studies on LMB growth. Several threads here about fast growth in the deep south in spring and fall not summer and winter. You do have to factor in when the weights were taken due to weight loss from spawning. There is a difference between growth rate and max weight.
Posted By: ewest Re: Do Fish Keep Growing? - 01/19/10 12:49 AM
There is a lot to this as the thread suggests. Keep in mind its energy in = energy used + growth and - loss. Its not just energy in = growth. For example natural food is better nutritionally but there is an energy cost to catch it. Pellets are easy to catch with little energy cost to acquire. Here is one point from a study that will be in PB soon " supplemental feeding is a logical tool to improve the condition of fish in small impoundments as the energy cost for bluegill to feed on pellets is small relative to the high caloric intake, which can be 4-5 times greater than those fed natural foods (Schalles and Wissing 1976)." Contrast that to the info above about how much in pellets it takes to match the nutrition of live prey.
Posted By: Gflo Re: Do Fish Keep Growing? - 01/19/10 06:25 AM
 Originally Posted By: jeffhasapond
 Originally Posted By: Gflo
With that said, I had a nice little tidbit of information in lecture the other day.

In trout and other salmonids it takes 330 grams of protein from a modern hatchery formulated diet to produce 1 pound of fish.

I thought that most of the fish food had a higher conversion rate than natural forage.

A natural forage diet however only takes 143 grams of protein in order to produce 1 pound of fish.

What does that tell us when we are talking about fish we currently know the most about nutritionally (followed closely by catfish of course)?


Is this specific to "trout and other salmonids" or does this principal hold true LMB, BG and other more commonly used pond species?

What does this tell us when we are talking about fish we currently know the most about nutritionally?

I guess I should be able to draw some form of conclusions here but am having trouble connecting the dots.


Well Jeffhasapond,

that data is specific to only trout and other salmonids; however, the one thing that I take away from it is that if we can not even get the science of nutrition zero'd in properly on the species of fish we know the most about nutrition wise in aquaculture, then we sure as hell don't know jack about LMB, Bluegill, or other game fish (excluding catfish, trout and salmonids).

What this tells me is that there is loads of room for improvement, and the commercial feeds will keep getting better and better as time goes on.

From what I have gathered, the main obstacle to better nutrition is going to be Money. Scientists live off of research grants, and because LMB are treated more like the family dog than a serious big money food item for human consumption, the quality of the feed is going to be sub-par in comparison to catfish and salmonid diets.

The equine industry has a similar problem believe it or not. Sure, it is big money, and people take good care of their horses, but we are not eating them in the U.S.

There more than likely will not be significant advances made in equine nutrition until horses are put into a feedlot type situation and become as commercially important as swine, or cattle. There needs to be a reason for the big wigs with the deep-pockets to invest in that research.

My guess is that the extent of LMB nutrition currently is just trying to formulate the diet of a trout as closely as possible. For a lot of our game species nutritionists may be just applying information across species.

We do this a lot with exotic species. We figure that if a horse eats this much feed, then a zebra probably eats a similar amount. Sometimes the best we can do is take educated guesses.

Aquaculture as a growing industry, despite being around for thousands of years, is really in its infancy. It really hadn't started to get big until around 2 1/2 decades ago.


And Ewest,

You are 100% right. It takes much less energy to eat a pellet than to chase down a baitfish. I view supplemental feeding as extremely important. I'm just interested in how much more efficient we will become in feed efficiency and conversion as we start to close the nutritional gap between natural prey and formulated diets. I think we could really create some monsters in a very short period of time.
Posted By: Greg Grimes Re: Do Fish Keep Growing? - 01/19/10 02:30 PM
Ewest I will flip you a rough draft. My gut tells me the bass continue to grow down to 50 instead of 60. We need more data to confirm.

There seems to be some thought that the commericial diet feed of aquaculture is a new science. WHile maybe not at the livestock level. Rainbow trout in NC convert at 1 to 1.12 on their silver cup feed. Not lots of room for improvement there.
Posted By: jeffhasapond Re: Do Fish Keep Growing? - 01/19/10 02:41 PM
Good stuff, thanks Gflo.
Posted By: burgermeister Re: Do Fish Keep Growing? - 01/19/10 04:26 PM
quote "In trout and other salmonids it takes 330 grams of protein from a modern hatchery formulated diet to produce 1 pound of fish.

I thought that most of the fish food had a higher conversion rate than natural forage.

A natural forage diet however only takes 143 grams of protein in order to produce 1 pound of fish."

I am more than a little confused here. What I am gathering they mean is that 330 gr. of, say 35% feed is about 1000g of feed, or near a 2 to 1 gain ratio.

Natural forage, being made up mostly of water, requires less protein, but much more weight in vs. weight gained for live forage.
Posted By: Greg Grimes Re: Do Fish Keep Growing? - 01/19/10 04:40 PM
BM I'm a lttle confused as well. I just know in the real world trout producers are getting 1 lb of gain from 1.12 lbs of fish food that seems impressive to me and much better than what I was taught in aquaculture class.
Posted By: ewest Re: Do Fish Keep Growing? - 01/19/10 04:44 PM
 Originally Posted By: burgermeister
quote
I thought that most of the fish food had a higher conversion rate than natural forage.


I am more than a little confused here.




Those type calculations are usually done on a dry weight basis. Apples to apples comparison. Natural food is what they have evolved to eat and best meets their needs. Pelleted food is good and improving but is not a complete substitute for natural forage. That is why it is called supplemental feeding.
Posted By: wbuffetjr Re: Do Fish Keep Growing? - 12/03/19 03:24 PM
Ten year old there here. Very interesting stuff to me. I am curious what the thoughts are these days and how/if thoughts have changed?? I have my own examples from my place, at temperatures significantly lower than anyone above was discussing, but my "data" is not very scientific.

Saw this quote on another thread discussing trout
"I think certainly species of fish will grow in the winter, but it will never be anything substantial. Perhaps a 1%-5% of the total length at most. Now trout in a spring fed creek may grow as the spring regulates the water and keeps it warmer that it might otherwise be..."
Posted By: 4CornersPuddle Re: Do Fish Keep Growing? - 12/03/19 04:54 PM
wbuffetjr, thanks so much for bumping this fascinating discussion. I've just finished reading the entire thread when I "should" instead be processing my deer. (Deer can wait; there's enough cut for dinner)

Gflo's and ewest's stuff have my brain feeling like I just had 5 espressos. I took animal feeding classes many years ago in college (60's and 70's). We never touched on aquatic stuff. More's the pity. I just may have followed fisheries research as a vocation.
Posted By: BrianL Re: Do Fish Keep Growing? - 12/03/19 06:19 PM
Someone with a couple of fish cages should do a winter test to see fed vs not fed growth rates thru winter.
Posted By: wbuffetjr Re: Do Fish Keep Growing? - 12/03/19 09:25 PM
4corners - it appears you and I got to the pond boss party a little late. Back in the day there seem to have been quite a bit more trout guys and many more Northern guys dealing with ice and snow. I am actually embarassed that I have been on pondboss for over 5 years and just figured this out. A lot of the learning I have done the hard way was already done.

Brian - It would be really cool to see some controlled experiments. I THINK the answer for trout is clear, but I'm no scientist.
Posted By: FireIsHot Re: Do Fish Keep Growing? - 12/03/19 09:47 PM
Originally Posted By: BrianL
Someone with a couple of fish cages should do a winter test to see fed vs not fed growth rates thru winter.

Just a TX observation, but using a shallower cage increases the amount of food a caged CNBG will eat. In cold water, CNBG usually retreat to the lowest part of a cage, and are not inclined to rise into the colder surface water. Those that are in that same water temp as the surface (shallow cage), seem to eat much better.

Just throwing this out there for anybody that want to try a winter cage test.
Posted By: Bill Cody Re: Do Fish Keep Growing? - 12/04/19 02:33 AM
Trout will feed well in winter even through holes in the ice cover. Cecil Baird has quite a bit of experience with this topic and would have some good information about it. He no longer participates in this forum. There might be some of his old posts here about this topic.
Posted By: wbuffetjr Re: Do Fish Keep Growing? - 12/04/19 11:19 AM
Bill I wish Cecil was still around or could come back. Interestingly, he was one of the ones in this thread arguing basically no growth only maintenance over winter. Maybe he changed his mind as time went on??
Posted By: ewest Re: Do Fish Keep Growing? - 12/04/19 08:05 PM
This is another it depends topic. Species - from cold water fish like trout and pike to warm water fish like tilapia. It is also a nutritional question as fish that are herbivores have a vastly different metabolic structure than predators like pike and some fish like CC are omnivores which are a combination of the others. IMO each species and even based on location within a species have different growth traits.
Posted By: wbuffetjr Re: Do Fish Keep Growing? - 12/04/19 10:02 PM
Ewest I totally get that and I agree. Just interesting to look back at these old discussions and see the thoughts from back then. The way I read it, it wasn't just a given that fish, including trout (the quote was from a mod back then), could grow all winter.
Posted By: BrianL Re: Do Fish Keep Growing? - 12/04/19 10:11 PM
in my case, I wonder about bluegill.
Posted By: wbuffetjr Re: Do Fish Keep Growing? - 12/04/19 10:13 PM
Brian if you read the entire thread Bob Lusk had a good bit to say about bluegills and winter feeding/growth.
© Pond Boss Forum