in the book 'freshwater fishes of southern africa' it is stated that moggel and vaal river mudfish have been found to interbreed.
middelbek ? never heard of such a thing.
Wil the then have to join www.middelbekchat.co.za or kan they still be on this site
Mario Geldenhuys
Smallstream fanatic, plus I do some other things that I can't tell you about
"All the tips or magical insights in the world can't replace devotion, dedication, commitment, and gumption - and there is not secret in that" - Glenn Brackett
FOSAF
THE FEDERATION OF SOUTHERN AFRICAN FLYFISHERS
PROCEEDINGS OF THE 12TH YELLOWFISH WORKING GROUP
CONFERENCE JONKERSHOEK 14 – 16 MARCH 2008
Edited by Peter Arderne
• Anglers started catching “weird” looking yellowfish for the last 3 to 5years.
• It has become famous as “middelbekke” (middlemouths)
• Two distinctive characteristics of these “middelbekke” are the positioning of their eyes and the form of their mouths. The eyes are placed higher on the skull, and the mouths are bigger and a somewhat harder structure with the incisors (lips) coming together further behind the nostrils compared with what is common in smallmouths.
• The socalled “middelbek” has been caught on small nymph patterns through to bulky streamer type flies. This shows an adaptation to a variety of different types and size of food.
• Normal small and largemouth yellowfish are also being caught in the dam.
• The “middelbek” is by no means a smaller breed, as fish in access of 2 kg are being caught in the dam.
• There are two bodies of opinion on the theory of the evolution of the “middelbek”. One group sees this as a hybrid, between the two species, as they were forced to spawn together on the scarce mining gravel found in certain parts of the dam. This was left many years ago when alluvial diamonds were being prospected for along the river. A local fisherman/club member has been fishing the dam for a decade now, and has told me that spawning can start late August to early September in the dam, due to the strong winds blowing at that time. It should also be taken into account that the area is always warmer than in the Highveld (38 C warmer), and it seems possible that the shallows could warm up quicker.
• The second group sees the “middelbek” as an adaptation towards its surroundings/environment. The dam does not have much insect life compared with the Vaal. It seems the dam lends itself more to a more predation/ piscivorous lifestyle as there is an abundance of smaller fish. There is also plenty of rock & tree structure and very clear water with 23 metre visibility at times. It is believed that part of the smallmouth population has adapted to this type of lifestyle, and are breeding because small “middelbekke” (300500g) are also being caught.
• It should be noted that fishing on this dam is difficult at best of times, and a guide is a prerequisite, and even then the fishing can be heartbreak and neck break.
• Request has been made from the NCYWG for a genetic analysis of these species to confirm the origins of these fish. "
Well nobody REALLY knows for sure, therein lies the problem.
Technically speaking the SmallMouth and LargeMouth spawn at completely different times in the year so even though it's possible, the chances would be slim. Then again you never know when a big SM starts living under delusions of being a LM.
Even so, I don't for one second think that this would be a 'new' development, it's not like SM and LM havn't been occupying the same waters for thousands of years, so there would have been cases of hybridisation predating the current ones by a few millenia.
It would be interresting to find out wether the Middelbekke are sterile if indeed they are a hybrid.
"Hierdie drol het baie vlieë" - Ago 2014.
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