Channel Cat Growth Charts

[TubeDude]

[#0000FF]Just finished a few exchanges with Chris Crockett of DWR about catfish growth rates and length to weight ratios. Thought fellow cataholics on the board might like to take a squint at a couple of tables I dug up during some original research. (Both of these tables were from In Fisherman)[/#0000FF]
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[#0000FF]When queried by Chris as to my observations of Utah Lake catfish growth rates, I provided my own personal guesstimates...based upon several decades of fishing that pond. I have noted young cats of about 4-5 inches by the end of their first season...second season cats growing to about the footlong category...third season kitties reaching the mid to upper teen-inch range...and then about 2-3 inches a year after that...depending on water levels, food resources, etc.[/#0000FF]
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[#0000FF]The length to weight ratio chart seems to be pretty much in line with UL cats also. But as we have all observed, it can vary widely by gender, time of the year (spawn and post spawn), etc. Still, a good basic rule of thumb...as long as you don't get a catfish spine in it.
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[Justaguywaworm]

7 years to get to 20'' - We got to speed that up. Start feeding the cats to get them bigger faster.
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[Tin-Can]

Worked with a guy in south Georgia, his parents ran a Catfish Farm in Cherry Creek Florida. They had automatic feeders at all the various tanks. A set times each day, the feeder would kick on and spray food out over the water. The Cats would go into a real feeding frenzy, really boil up the water. The food turned out to be dried dog food. Those cats would get pretty big in just 2 years. At the 2.5 year mark they would sell the fish to small community ponds and some farmers that had private Catfish ponds on their property.
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[Piscophilic]

Thanks for posting! It looks like the few places that reported fish over 30" seem to have growth rates of 1 to 1.5 inches per year in that lenght range. I thought even 1" per year for fish that age was optimistic, but I guess not.

Fall cats are coming!
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[TubeDude]

[quote Justaguywaworm]7 years to get to 20'' - We got to speed that up. Start feeding the cats to get them bigger faster.[/quote]

[#0000FF]Tin Can's comments support your theory. The fish will grow in direct proportion to the amount of food they get...and the length of the active/growing period. In other words, catfish in Florida...with year-round warm temperatures and regular feedings...will grow much faster than catfish in cold states with several months inactivity and marginal food supplies.[/#0000FF]
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[catchinon]

I've done a lot of similar research and was amazed that it took so long for our cats to grow to the size that we even start to get interested in them. That's about the time I started releasing (almost) all my cats. If I were to take home a really nice-sized cat it would take over a dozen years to replace it. Fifteen years to grow a chart-topper is a long time. Wonder how much I'll weigh 15 years from now at the rate I'm going.
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[wormandbobber]

[quote catchinon] If I were to take home a really nice-sized cat it would take over a dozen years to replace it. Fifteen years to grow a chart-topper is a long time. Wonder how much I'll weigh 15 years from now at the rate I'm going.[/quote]

IN a healthy system, though, that is not at all true. To replace that fish, you would only need the next year class of fish. IN other words, the 15-year old fish, assuming it spawned successfully (regardless of whether it is male or female) will have laid the foundation for future year classes of fish. So, a 14-year old fish will quickly take its place.

The idea that it would take 15 years to replace it is only true if there are no other fish out there.
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[wormandbobber]

Just an FYI...growth rates of channel catfish in Utah Lake have been conducted. But, I don't think it has been done for many years. I am reading one such study done where growth rates were listed this way: "The following lengths at ages on through 12 years based on the the body length (total length)-spine radius relationship: 64, 146, 197, 256, 320, 365, 402, 457, 474, 487, and 489 MM. The length-weight relationship is expressed by the equation Log W = -4.814 + 3.025 LogL." It was also determined that fish in Utah Lake reached sexual maturity as early as age 4 and all by age 8. So, if the catfish population is healthy (which seems to be the case) harvest of fish 8 years of age and older is ok because enough remain to continue replenishing year classes of fish.

But, that data is fairly old and the lake has changed since that study was completed. Nevertheless, I wouldn't be surprised if those numbers are still close to actuality.
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[TubeDude]

[#0000FF]I'm pretty sure that Chris Crockett had access to those numbers. He merely asked for my input on the growth rates I have observed from a lot of years of on-the-water experience. And he agreed that my observed growth rates of today are pretty much in line with previous studies.[/#0000FF]
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[#0000FF]He also has copies of individual studies done on other waters in other states and is surprised at the variance. Of course, the aforementioned longer growth periods in warmer states and a greater abundance of Purina Catfish Chow will both have positive influences on growth rates.
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[PBH]

What all of you need to remember is that you are looking at an average. A major problem with an average is that often times there are no individuals that actually fit the average!


You guys are assuming that fish growth is determinate, and that fish will always grow larger over the course of their life. In a good, healthy, system they should. The problem with most of this line of thinking is that anglers want size to be the result of time. ie: a fish will grow to x inches in y years.

This model is flawed. Because fish are indeterminate growers. They experience periods of growth, which might be + and might be -.

So, how do you grow large fish if you don't manage them based on time?

You must look at those growth rates, and figure out how to maximize how much time a fish spends in that period of maximum growth. This doesn't mean that you have to "let the small fish go so that they can grow bigger". What this means is that you have to manipulate the overall population so that the entire population - both small fish and big fish - are in that zone of maximum growth.

the overall system must be healthy to accomplish this. You cannot accomplish this simply by "feeding" the fish more food. If the population is out-of-whack, then adding more food simply compounds the out-of-whack problem (ie: more food = better reproduction = higher densities of fish = slow growth rates = more small fish).

Look at this growth curve:


You want your fish populations somewhere in the middle, in that zone of maximum growth. This is where fish sizes explode. Fish are growing like crazy. You have enough harvest, but not too much (either by anglers or other natural means of mortality).

Think about trout lakes for a minute. When they get overrun with chubs growth rates of trout decrease significantly. If you add more food for the trout, you just increase the carrying capacity of fish and increase the population, which drives average size down. So, instead, you poison the lake and eliminate all the fish (chubs + trout). Now the lake has 0 fish, and the lake has a boom in nutrients, zooplankton, aquatic insects, etc. Now you restock it with trout -- and guess what? Growth rates explode! Those trout, as we've seen in places like Yuba, Piute, Panguitch, after a rotenone treatment, grow big fast!

We see this all the time with brook trout on the Boulder. After a partial winterkill the remaining fish experience fast growth rates and get large fast! What we do NOT want with these fish is for them to get "old". If they are getting old it means their population numbers are staying high, which means more fish survive, which means growth rates slow, which means average size goes down -- and those trophy sized fish disappear. We do not want old fish. We want fish that are growing fast!


So, the real question that you guys need to figure out with the catfish isn't how old they are, or what their average inches per year over the life of the fish is. The question you need to find out is: what are their current growth rates? Find out the "K" factor.
Find out what can be done to increase the growth rate. Most likely the answer would be to remove more fish. Any fish. White bass. Carp. Suckers. Catfish. Any of them. Harvest more -- I'm pretty sure those fisheries are currently not overharvested. Take more fish out and increase growth rates. Increased growth rates = big fish.

Than, like wormandbobber said, the space occupied by that 15 year old fish that you just harvest will immediately be replaced by another fish that experienced high growth rates, which means another big fish.
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[wormandbobber]

And, that's just it...why are catfish growth rates relatively lower at Utah Lake than other lakes across the country. I would say it has nothing to do with the growing season and everything to do with the analogy that the aquarium is too dang full of fish.
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