I have a 15 acre pond in NC. I stocked 300 hybrid striped bass about seven years ago to cut down on my populations of stunted crappie and brim. The hybrids have been fed with fish food pellets from day one. It is an unbelievable sight to see these fish come up to the surface to take this food. However, the only people that seem to catch these fish are kids fishing worms or someone fishing for catfish with liver. It is almost impossible to get them to hit an artificial bait. I wonder if this goes back to what they were raised on in the hatchery. Has anyone who has stocked hybrid stripers in their pond had any luck catching them with artifical baits? I know that in the lakes the state stocks with hybrids, they will hit just about anything you throw at them. However, that does not seem to be the case in a pond environment. Any comments on this subject by anyone who has stocked hyprid stripers would be appreciated.

bob i think what it really depends on is what the fish have been able to forage on their entire lives....if they are forced to eat brim and crappie...then you may try an artificial lure of that nature. however, from personal experience i know the hybrids that i have caught, the ones above 5lbs normally come off of a white/gray Stump Jumper...they sell them at BPS. however i have also found that sometimes catching pond reared fish is alot harder in ponds than in lakes...especially the big ones. when fishing for them when, where, and from what(boat or land) do you fish? this could also have a significant effect.

Have you tried using a pellet that you feed them for bait? Most of the trout in my trout pond are so conditioned to eat pellets that you have to match the hatch. Since the pellets are too hard to put a hook into we stretch a little panty hose over the pellet and tie it off. Then you run a small hook into the hose and you're in business. If you feed floating feed you should be able to put two or three together this way and cast out without even using a weight or float. You want it to float anyway and it will for a while if you do not add any weight.

Some like to add a regular float or clear float up the line a ways for extra casting weight or even use a fly rod. Either way as soon as the pellet gets engulfed set the hook and hold on for dear life.

I have taken trout in the 11 pound range this way. BTW, I have had people tie up or paint pellet imitations and most of the trout will ignore it. It seems they can smell the pellet.

This is very very interesting!! so you use strippers to forage your crappie population down...has this been sucessesful so far?

Thanks for the responses. I must admit, I am really a bass fisherman trying to catch these hybrids on artifical lures with little luck. I did try using the pellets as bait this past summer, and I can tell you that trick also works on hybrids. In regard to using hybrids for crappie control, I feel I have been pretty successful. The first two years I had my pond (which was built in 1920), I caught and released over 75 bass between 6-8 pounds. However, I had no natural bass reproduction to speak of because of the large numbers of stunted crappie. I can tell you first hand what crappie can do to a bass fishery in even a 15 acre pond if they are not properly controlled. Since my objective was to manage my pond for numbers of decent sized bass rather than an occasional large bass, the state fish biologist recommended I stock the hybrids to help reduce the number of crappie in addition to removing all the crappie that I caught. Seven years later, I am catching large numbers of decent sized bass (with an occasional lunker), as well brim and crappie the size of your hand. In fact, I am at a point where I am harvesting all bass under 14 inches. I really feel the hybrids played a key role in helping me attain my pond management objectives.

Bob,

I have a profound interest with stocking hybrid stripers, especially to control crappie. Can you please tell me what size the hybrids were when you stocked? What time of year did you stock them? Did/do you have shad in your pond (if so, gizzard or threadfin)? On average, what's the water clarity? Thanks.

I stocked hybrid stripers and catfish in a tiny pond with no other forage. Last spring we tried to catch the catfish which had grown a little faster and caught stripers on worm pieces and liver. We also caught them on various small lures. Then later in the year we quit catching them when we were after catfish so I tried several lures and didn't catch a one. Last fall I tried to catch the stripers to see how big they were and couldn't. Catch them in spring and not in summer and fall? I guess I'll know next spring.
My only guess is that the feed make them fat enough by early summer so they are more selective.

Shawn,
I would suggest not stocking any hybrid stripers less that 6-8 inches. They will be more expensive, but the survival rate at this size will more than offset the additional cost. I would stock them during the coldest part of the year because the mortality rate can be high if they are not properly transported and handled. This seems to be less of a problem during the colder months. In NC, I stocked mine in Feb seven years ago and again this past year. They have a life expectancy of not much more than seven years and that is why I re-stocked them. However, I do know there are still a lot left from my original stocking because I see numerous fish in the 6-10 pound range when I feed them from my dock. They actually school around the dock at feeding time. I do have a good population of gizzard shad in my pond, and the water clarity is slightly stained. Not only do the hybrids help keep my crappie population in check, but as a gamefish they are as strong as a largemouth bass and so much faster. I just wish they were easier to catch. Good Luck.

Several thoughts, here.
In 1981 we surveyed a 35 acre lake near the high plains of Texas, east of Lubbock. Found thousands of stunted white crappie, 4-6" long, slightly thicker than a postage stamp. The fishing club had a limited budget, couldn't afford to rotenone and start over, so we went shopping for hybrid stripers. We calculated the average crappie in this lake would fit into an 8 inch hybrid striper's mouth, so we bought $2,000 worth of 8-10" hybrid stripers, and stocked them. As I recall, it was 1,000 fish.
The next summer, club members were catching 4 pound hybrid stripers, and 8 inch crappie.
The second summer, folks were catching 7-10 pound wipers, along with 10 inch crappie.
At that point, the club decided to start harvesting the hybrids.
They did, and bluegill numbers began to rise. Once the forage base recovered, the club restocked with largemouth bass, which was their long term goal anyway.
All told, they harvested more than 650 hybrid stripers, as large as 12 pounds, and re-created their largemouth bass fishery. So, this lake is evidence hybrid stripers will eat crappie (as long as the crappie fit into a hybrid's mouth).
Another note...the hybrids weren't fed pelleted fish food during their stay in this lake.
Here's another thought to motivate your hybrids to bite a hook.
Take away their feed for a few days, and see if they bite any better.
Fish become conditioned to environmental parameters such as feeding, cover, habitat, water quality. Change the conditioning, you may change the behavior. Plus, if your hybrids are being fed to satiation, they won't bite your hook, because they aren't hungry.
Add hunger, see what happens.

It sound like these Hybrid Stripers are just what the doctor ordered when it comes to Crappie :rolleyes:

So...what about this stocking senario...Redear, Coppernose bluegill, red reasted sunfish, Crappie, F1 LMB, Blue catfish, and Hybrid striped bass. All mixed in an 8.25 acre lake 25 feet deep... would this work?
Of course the three top predetor species would be treated as "one group" when it comes to stocking rates. For examle 50 F1 LMB, 50 Blues, and 50 stripers, which would make a total of 150 predetor fish per acre.
any comments?

provided ample forage will HSB grow just as large if pellet trained....does anyone know the numbers on this..

ie...how many pounds per year one can put on with just forage and also pounds per year of some that were pellet trained

also i was wondering....could i start my hybrids on a pellet trained diet to start them out growing fast...and then after a couple years (once they've reached more than 5lbs) could i take them off...this way you stil

sorry about the mistake above...the last paragraph was going to ask something along the lines of can you feed your HSB and then take them off of it after an extended period of time

i know this i not recommended with bluegill because there population size is dependent on the amount of food available, but with HSB you only have as many as you stock...and recommendations?

Over the past 5 weeks, I've been taking delivery on several fish I ordered in late Sept (sbm, lmb, perch, shiners, fatheads).

While they were loading up at their shop, they called to see if I wanted anything else. They had 8-10" hybrid stripes. I wasn't looking to put any of these in my pond; I'd done no research, and from the little I'd heard, the stipers were fairly aggressive and would eat a hell of a lot (I do no feeding/pellets).

Anyway, when the fish truck comes around, the supply is right there (Like the Schwan's Food Truck), so I just got (5) of 'em and put 'em in the pond. My pond is about 7 acres (in past posts, I know I've called it 8-10, but after doing some rough sizing, I'm thinking 7) with existing lmb, sunnies, crappie, cats, perch, and shiners & fatheads.

The INTERESTING thing is when the fish people made their last delivery, various types of fish came in one tank, so we got everything out except for the stripers. Then the fish dude put clove oil in the water & in a few minutes, the stipers were laying around. When we put them in the lake, they just went to the bottom on laid on their sides. It took over 10 minutes for them to revive and swim away.

wipers are eaters , that means any thing they can catch , even largemouths.

So..what is the difference between a hybrid Striped Bass and a plain Striped Bass.

Gregg,
What are the big fish we catch in these public lakes like Lake Linear? are the Hybrides? or just plain Striped Bass? Can you stock just plain striped Bass? why or why not?

thanks

The Hybrid stipers are sterile and can't reproduce. I think "triploid" means they have three chromosomes or something like that, so they can't spawn.

I believe this is similar to a tiger muskee.

Depends on how big they are...most likely they are stripers. However, alot of times you'll find a school of hybrids mixed in with stripers. I haven't heard much on stocking plain stripers. Personally that's what I want, but I've heard a few say that a pond isn't deep enough to hold stripers....Has anyone ever actually tried this? There's nothing like a 20lb striper pulling a bass boat all the way down a lake

Chris

A hybrid striper is a cross between a striped bass (striper) and a white (sand) bass. I don't remember which sex of either is used. At the hatchery, one is stripped for eggs and the other 'milked' for sperm. It is mixed and the result is the hybrid striper. It can occur naturally in rivers but, I understand, is rare. Both parents depend on running water to spawn. My personal experience is that a striper pulls harder but a hybrid actively fights better. Like both parents, it is a schooling fish.

Expanding on Dave's comments:

Some states (not all) have enacted legislation requiring that white amur (grass carp) must be "triploid" (their chromosome structure modified during the egg fertilization process) when these fish are being stocked in public or private waters for vegetation management purposes. The odd chromosome sequence disables the fish's reproduction capabilities, which greatly reduces the potential impact of an exponentially-expanding population on desirable aquatic plant species (especially if these fish should escape their intended watery confines).

Hybrid stripers are entirely different. These fish are the result of crossing either female white bass and male striped bass (Sunshine Bass) or female striped bass and male white bass (Palmetto Bass). Crossing a donkey with a horse produces a sterile mule. Likewise, the hybrid striper is sterile. But, like the mule, the hybrid striper carries with it some very desirable qualities from both parents.

So, has any one raised or stocked any stripers? do they exibit the same wonderful charecteristics as the hybrid?
Do they eat peleted food?
Do they reproduce in small ponds? Where I'm from in SC the state had to stock them every year in Lake Murry?

They definitely do not reproduce in ponds and I do not know of any lakes where they can reproduce. One fact that many people do not know is that the striper is actually a sea-bearing fish that comes upstream into rivers to reproduce. Now they are bred and stocked into freshwater lakes - called landlocked striper bass. I think the world-record for a saltwater striper is well over 100lbs. So these guys to get big. The lake where I fish the record is around 50lbs. so I'm sure they consume huge amounts of forage, so it would probably have to be a fairly large pond in order to support them.

Chris

Some one mentioned that there has to be deep water in order to stock them...My lake will hpefully be 25 feet deep is that deep enough? Does any one know who sells the fish and how much they cost? do they eat pelleted food?
You are right I have heard that these were once salt water fish, its quite interesting these fish I really would like to know more info on them...

The feeding habbits of striped bass tend to parallel that of blue catfish. In fact, I have caught striped bass on stink bait intended for catfish, so they may be opertunistic enough to learn to take pellets. Who knows?
Another interesting fact about the hybrid stipers. I have read that although they cannot spawn with each other, they can back breed (meaning they can spawn with a white bass to produce white bass or spawn with a sriped bass to produce striped bass)

The situation described by Bob Lusk really caught my interest but I do have a question about it. Why were wipers used to contoll the crappie? Is there something about a wiper's behavior that that makes them a more effective crappie preditor? Or is it that hybrids of adequate size are less expensive than LMB of adequate size? I would assume (eventhough we all know what happens you assume) that LMB would be the optimal preditor due to increased mouth size and expert ambush skills. Is there something I missed or am I just thinking too deeply into it?

-Scott

jb it may deal with the fact that HSB have a contrained mouth size limit therefore contraining them to be able to only eat a certain size of crappie....this maybe the size that crappie tend to overpopulate and stunt at...bob probably knows more but that's just a guess.

Big Pond, I got my hybrid stripers from Keystone Aquaculture (John Sproch) near Harrisburg, PA, ph. 717-834-6772.

I know that they do ship some fish, but I don't know about South Carolina. Give a call and ask. If he can't help, he may point you in the right direction.

I was just in contact with the director of fisheries at Southern Illinois looking to get some hybrids for some strip mine clients and he suggested Mike Freeze in Keo Arkansas. I was wondering if anyone has any knowledge of him as I start my research. I contacted SIU because as a student, I knew they were doing alot with them as as table fare. He stated that as a cooperative in that part of the state, 200,000lbs were raised, mostly in coal mine lakes in pens.
Robert B

What is the definition of contrained or contrain as used in tritonvt's Nov 6th postpost?

There are a couple big hatcheries in the Carolinas that raise Hybrid striped bass: Ridgeway Aquaculture SC, Southland Fisheries Corp.SC, TCA International SC, Carolina Fisheries NC, Castle Hayne Fisheries NC.

Sorry for the mix up guys but I am living in the Atlanta area. But I grew up in SC, and pretty familure with the area.
I know a few ample suppliers of Hybrids. I was look for some info on the "actual" Striper! not the Hybrid.... I was looking for someone who sold Stripers, and what would be the draw back to the Striper as aposed to the Hybrid. Yes I did here that the feeding habits of Stripers are similar to the Blue cat this makes me think they will eat pelleted food. But is there any other draw backs ?? Any reason why people stock the hybrids over the Real thing?

Big_pond..several thoughts here. Stocking 50 each of three different species of predator fish doesn't mean they all perform similarly. Each species has its own habits. Largemouth bass are top line predators, designed to ambush and eat other fish. Hybrid stripers are designed for open water patrolling, looking for schooling baitfish, but trained from birth to eat fish food. Blue cat are nocturnal, skittish fish that are finicky eaters, that can be trained to come to floating fish food.
So, expect them to perform differently in your pond. Your project will be fun. People stock the hybrids because those fish are readily available in the marketplace and there's fewer regulations surrounding hybrid stripers.
Robert B....I know Mike Freeze. He is an outstanding fish producer, an outstanding citizen and a great guy, the leader in hybrid striper production in the U.S.
To everyone...we chose hybrid stripers to correct the crappie population in the high plains lake for several key reasons.
We wanted a voracious feeder to eat crappie quickly. We wanted a fish that would grow much more quickly than largemouth bass. And, we wanted a fish that wouldn't quickly reproduce. That's why we picked hybrid stripers.
There were several goals.
First, we wanted to eliminate as many crappie as possible. Second, we wanted to keep control of the population of fish until crappie became manageable.
Third, the ultimate goal was to reestablish bluegill, and largemouth bass.
So, hybrid stripers had a specific job. They did that job, and we opened the season on them. Crappie numbers plummeted, then hybrid striper numbers plummeted, then bluegill and bass became the "new" population.

Bill what I meant by constrained was that a HSB's mouth opening doesn't get that big...I don't know the exact numbers, but say that average opening is about 3 inches...which might be a 20in fish(?). Then think about the crappie...a crappie with a vertical length of 3in(able to fit in the fish's mouth) might be about 5in. As I've heard from many people on the board, most crappie stunt between 4 and 6 inches...which would be obtimal forage for a hungry HSB. So I figured instead of needing to massive amounts of catching and killing or the overstocking of bass you create an environment where BIG fish can be caught as well as being able to have a healthy crappie population.

Mr trivnot, thats seems like a good idea hopfully one day I will be able to try that my self! Mr. Lusk thanks so much for answering my question on the three preditor fish..This is my Ultimate goal is to have all there of these species of fish at once along with crappie i knew they all had completely different foraging charecteristics. I was viewing this purly by the numbers. I knew I had to have around 15 to 20 bait fish perevery predetor fish, (at least thats the way it seems by the stocking ratios I'v seen).
I am just hoping to get some ideas from people on making this work

If I stock crappie to my pond and they get out of control it sounds like all I have to do is introduce some hybrid strippers and the problem will be handled. It can't be this easy can it?

To Bob Lusk: Bob, in one of your last posts in this topic, you mentioned that you wanted a fish that "wouldn't quickly reproduce" refering to the hybrid stiper.

Does this mean that they can or will reproduce (within a soley "hybrid" population)?

Thank you.

These Hybrids might be just what the doctor order for these Crappie! Maybe we sould think about stocking Hybrids along with Crappie from the 'get go' is there any reason why this would not work?

I will let you know in couple of years, because that's exactly what I am getting ready to do. Only 3/4 ac pond though. I am going for the tasty crappie and with my size pond, it should be easy to fix if it doesn't work.

You know I wish there were more people or agencies that would experiment around and do studies on this type of thing..It really would be good if we could do more than the same'ole Bluegill bass set up...it seems that what most people are forced to do...

Yea, I agree with big_pond alot of us are looking for a more diverse environment. I think once my new pond is built I will stock bass, bluegill, shellcrackers, and then try a combo of hybrid stripers and just plain stripers. I will probably end up trying to tag some of the stripers that way I can easily identify them. If the stripers die, oh well, I know they didn't work. It's worth a try.

I agree tritonvt, Heck! it is going to cost me around 40K or more!!! to build my 8.25 acre lake. You better believe I am goin to try it all! This is what I plan:
Redbrested sunfish, Coppernose blugill, Shell Cracker, F1 Large mouth bass, Crappie, hybrid striped bass, maybe a few stripers, maybe a few channels, and finally....BLUES!
Then feedres all over the place, and maybe threadfin shad

Does anyone know about the differences between the threadfins and golden shiners? How well do they last over a long period of time? Also, how big should a 'bait' pond be? Just one where I can let threadins, goldens, or fatheads reproduce that way I can stock a few thousand every now and then without any cost.

tritonvt - Baitfish pond:

That depends on a few factors incuding what type of baitfish, how you plan to get them out etc.

Don't know how cold it gets where you are but first step is to get it deep enough not to freeze. Then do you plan to feed these minnows or fertilize to provide 'natural' feed for them? If you just want to be able to pull out a few thousand per year then something in the 20x30 foot or bigger range would be sufficient.(If it is too small the water may not be able to 'feed' the minnow population and/or you will have high rates of canibalism/low production) Provide them with lots of cover and spawning area in the pond but keep in mind your layout of this cover when it comes to your removal method. (Using traps or seining them out). Then when you want to stock your larger pond try to remove about 2/3rds of the minnows from the small pond at a time... or more even. All it takes is a few spawning size/age 'leftovers' to start the process again. You may get multiple spawns each year as well. Just keep an eye on the bait pond and when the minnow density gets high then transplant them to the main pond, that way you can keep production high.

On the topic of Threadfin shad I can't add anything as I really don't know a thing about them.

P.S. Whichever minnow you chose make sure you provide it with the type of habitat, (Still water, moving water, plants to spawn on, objects to spawn on etc.), it prefers to get the most out of them.

To Noles58; You're right, it ain't that easy. We analyzed that particular lake from water chemistry to the details of population dynamics. We learned statistical details of the fish population, compared ratios, looked at relative weights. Then, we tried to make a thoughtful decision, based on the science of fisheries management and the art of experience. That decision happened to work better than we had planned.
To Sunil; What I meant was that hybrid stripers won't reproduce. Whereas we had chosen to stock advanced largemouth bass, they would reproduce, then we would have to deal with those consequences. Since we had no way to predict the consequences, we eliminated lmb from our short list of fish.
We knew lmb would spawn, but we had no way to predict success, based on the fact the lake was overwhelmed with crappie, which would prey on babies...maybe 100%, maybe not.
Plus, we knew we could project growth rates of hybrid stripers, even influence it with feed, if necessary. We couldn't readily predict growth rates of lmb in that particular situation.
To big_pond; I love the thought of trying something different from traditional thinking. That's how we learn, but sometimes it's tough to convince a landowner to do something different, for the sake of learning.
To Ed Richter; Go for it, track it, keep notes, and keep us posted over the next few years. You're absolutely right...3/4 acre...if it doesn't work, you can easily change it. There may be a Pond Boss story in the making here.
And to tritonvt; There's big differences between threadfin shad and golden shiners.
Threadfin shad reproduce several times yearly and their babies mature sexually in 40-60 days. So, they reproduce a lot. They are basically filter feeders, gleaning their food from the water column. Threadfins grow to 7-8". But, the biggest fact is this..when water temps drop below 42, they die.
Golden shiners, on the other hand, spawn once yearly, mature in a year. They are predator fish, limited only by mouth size. Golden shiners grow to 5-7".
Each fish has its own role in pond management, but those roles are totally different.

Thanks for the info Bob. Are golden shiners a schooling fish? Also...relating to threadfins, what is the average temperature of a pond during winter in my area...Southwestern Virginia? I know most ponds freeze over here, but normally it isn't over the entire winter. I know lakes nearby support both the threadfin and the alewife. So is it a matter of how deep the pond is? If so, how deep would it have to be in order to maintain these....

Also along with this list of questions, you mentioned each have their own role in pond management....what are those roles?

Chris

It sounds like the Hybrids are next best thing to sliced bread...Is there any draw back to these things? How long do they live?

I have notice this is a very long post that alot of people want to get involved with. This could be because so many people are interested in having these fish but there is so very littel usefull information on them...

A few notes about Hybrid striped bass (HSB) and crappie. Also note that this is not an attack on B.Lusk's Nov. 04,2003 post, it is just additional information
that I hope you find useful.

1. Bob, in talking about the 35 acre lake near Lubbock, led me to think that since the lake had thousands of 4" -6" crappie, these sizes would fit into an 8" HSB's mouth. He said, "We calculated the average crappie in this lake would fit into an 8" HSB's mouth..... I assumed he was referring to the thousands of crappie sampled that were 4" - 6" long. Maybe not.

2. Anyway, FYI, I did some fishery science this week and came up with the following info.
8.25" HSB has a mouth opening of 23mm (0.9").
9" HSB has a mouth opening of 25mm (1.0").
13" HSB has a mouth opening of abt 29mm (1.14")
22 " HSB has a mouth opening of 43-46mm (1.7-1.8").

The vertical height(body depth or maximum body depth)of blk crappie in OH is:
4" long crappie is 31mm (1.2")high/wide
6" long crappie is 49mm (1.9")high wide

As can be seen, even a 13" long HSB would have difficulty eating a 4" crappie.

NOTE: fish mouth openings (gape)are somewhat subjective to measure. I did not forcefully stretch the mouth
open to the absolute maximum possible. But I did extend it open as to not damage the live fish and measured what I thought was a normal gape this fish would have in swallowing a fish.

DISCUSSION. I have no doubt that the HSB did do their intended job of getting crappie under control in the 35 acre lake Bob talked about earlier. I think the 8" to 10" HSB initially fed on smaller food items than 4" crappie. This is very feasable in a lake as big as 35 acres which could easily have a large complex food web that produces lots of appropriate sized food items for the 8"-10" size HSB. The HSB may have even fed on lots of crappie smaller than 4" (1"-2"). The HSB obviously grew and grew fast. When the fish were adequate size they could prey on the larger sized problematic crappie population, reduce the competition for food, allow more overall food to be available and remaining crappie&other fish would grow better.

The other feature of HSB and crappie that I think helps make them compatable is crappie (at least the larger ones) often tend to stay more in open water than say bgill. HSB frequent open water thus the two species come in frequent contact.

My point is when stocking a predator to thin a problem prey fish population make sure it will be able to immediately feed on SOMETHING so it can survive, grow and ultimately do the job you intended it for when you stocked it.

Long ago I made the mistake one time stocking fingerling LM bass to hopefully get an overabundant bgill (1.5"-3") population under control in a pond. Fingerling LMB needed to eat fry and 1/2" bgill but these were not present. Overabundant starving bgill were even robbing other bgill nests of eggs and fry. Newly stocked fingerling LMB had to survive on invertebrates which the overabundant bgill had also over eaten that food item. Very few if any of the fingerling LMB survived.

This is interesting..Bill Codey this a good piece of work and good research, When Bob L was measuring the littel crappie he might have been saying they were 4 to 6 inches in length....this would make them about 2.5 to 3.5 inches wide wich would then fit into a 10 to 12 inch HSB.

So what I gathered from this disscussion is that if I want to srtock crappie, then I better my success if I also stock HSB. I would also have Bass and blugill as well.

big pond - Since I do not have access to hy.stripers larger than 24", I calculated for a hybrid striper to eat a fish 2.5" wide the striper would have to be 27" to 30" long. And for a hy.striper to eat a fish 3.5" wide it would have to be 41" long.

Hybrid stripers basically have small mouths compared to LM bass. A LMbass 18.5" can eat the fish 2.5" wide.

Bill I'll give in and declare you winner if take a look at that big cat topic...

Bill when you talk about 'width' what exactly are you implying?

Are you talking about the height of the fish(the long vertical point from the belly to the top of the fin) or are you talking about the width of the shoulders of the fish?

Fish width is the maximum body depth. The widest distance from the BASE of the dorsal fin to the lower outline of the belly. Basically it amounts to how wide a fish has to open its mouth to swallow a fish;; this distance is called "gape". Distance does not include to the top of the fin; prey fins are compressed when being swallowed so they do not count when taking the measurement.

Whereas Thickness is how wide the fish is across the back; widest point from right to left side.