small mouth lips

[dollar]

for many years now i have scratched my head about them lips. i have been told or made to believe that fat lips and thin lips are the same species but i think otherwise. over the years i have caught similar size fish and their lips vary from a chisel point shape to a fat lipped rock hoover. could it be no one has made a concrete study like a dna test to prove otherwise. i would load some pics but i could be stepping on some toes and i think you all know to what i'm referring to

[yella]

Yes their mouths can vary widely. I thought something along the same lines the weekend when I caught a relatively large fish that didnt have rubber lips at all.

[core fly]

Its an interesting question and i think you will get many varied answers.
If you take the studies that were done on behaviour of largies and smallies many years back the one thing that might answer the question best is smallmouth behaviour.
They are by what was determined very habitual and remain in a very small area for long periods of time and only move as result of water fluctuations and temperature drops etc.
This could mean that in the case of rubber lips they tend to stay in a certain area/water type for longer periods and their feeding methods differ from the fish in a different environment.
Maybe an overuse of a single feeding method that being sucking foodstuffs off and under rocks forms the elongated mouths much like a guy in gym that does bench press 3 times per week has massive pecs and not much else.
And by skimming the rocks they tend to get a bigger fill of food than the fish picking off foodstuffs in faster water etc only and hence rubberlips tend to be much larger and heavier than the average smallmouth.

One starnge thing though is that a person rarely catches a smallish rubber lip and they tend to always be pretty big fish.So either they are just very few or the development of the lips increases quickly and dramatically a bit later in its life.

[tombosis]

There has been quite a lot of DNA study on large and smallmouth yellowfish by a chap from Wits some time ago. As I recall it created more questions than answers as he found that Large and Smallmouth yellows in the Middle Vaal (Parys-Potch) were more closely related to each other than smallmouth from that area were related to smallmouth in the lower Orange!

I forget the term, but it seems that yellows very quickly evolve distinct DNA profiles based on the area the population comes from.

The different mouth forms are due to feeding behaviour, and come and go on the fish. The scientist kept some rubber lipped fish in tanks and watched the lips reduce in size due to the way they were fed.

The Windknot Flyfishing club helped out with the study at Elgro River Lodge and Wag-n-Bietjie so there may be more info on their website.

[DJR]

Interesting.......I'm thinking.......thinking......thinking.........

[dollar]

wahaha DJR, been doing that for a long time
Core fly i did think of yellows feeding on a particular structure that could cause the big lips and naturally one could point it hard and heavy structure than mud or tiny small gravel. i also doubt yellows would move or push over a fare size stone to feed. there is just to many insects in the water and no need for a yellow to force or exert there lips in such a manner to have a deformaty. yellows are naturally designed with underswung mouth parts to easily pick up insects on any structure except for food items like sponges (sponteras - something like that, one of those latin names), where the fish is forced to spend time to suck or scrape then loose from the structure.
Tombosis, joh, there is something i have never heard and never gave it a thought, yellows were able to shrink or reduce there lips while in a holding tank. this could be true if one thinks of other species that change colour or shape in spawning stages, could it be a feature that yellows do when they ready to spawn?

edit = freshwater sponges = porifera and not spontera as mentioned above

[dollar]

something that has come light about rubber lips, does other species of yellows like the large scale or the natal scaly grow rubber lips considering they live in similar enviroments

[Andre]

There was an article published sometime back about a fish that was tagged and released after being photographed, and a year later he was caught again. the second time he was caught, he had big rubber lips which were not present the first time, also the colouration of the fish was different.

[core fly]

Dollar..I have seen yellows push over some really size stones in the vaal when conditions allowed you to see them.If you turn a rock in the vaal there is virtually always mayfly and caddis or bloodworm and I think a select few,namely rubber lips know this and hence they turn stones.
I remember quite some years back someone mentioned they camped next to the vaal on a quiet side channel and later that night they could hear rocks moving in the water..Shining their torches they saw smallmouth feeding amongst the rocks.....

[Korrie]

I have also witnessed how a shoal of SM yellows goes about feeding.
as mentioned, large rocks where moved.
The shoal of fish had a very distinct V shaped formation and the leaders continously changed. like birds flying.
The front fish or 3 nudged, moved, rolled over the stones, some the size of the balls they use in Old mans Bowls.
the fish behind, intercepted the nymphs that washed off, and grazed on the upside down stones, pebbles and rocks.
The group was very dynamic and new fish continously took the lead, working the rocks.
I even saw the odd scale washing off the fish in the process.
One factor to remember is that the stones are much lighter and easier to move in the water.