Pond Boss Forums INTRO Questions & Observations Do Fish Keep Growing?

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.

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.

First, try doing some metric to english conversions.

Hmmm, that begs a question. Do fish use the metric system?

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.

1 gram = 0.0352739619 oz.

Am I doing the math right? 143 grams = 5 oz?

Let's see. We all know that a pint's a pound the world around ...

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.

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.

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.

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.

Good stuff, thanks Gflo.

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.

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.

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.

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..."

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.

Someone with a couple of fish cages should do a winter test to see fed vs not fed growth rates thru winter.

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.

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.

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.

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??

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.

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.

in my case, I wonder about bluegill.