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Epizootic Ulcerative Syndrome in bass

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#1
FYI - article by Dr. Olaf Weyl

Epizootic Ulceritic Syndrome Now in South Africa
Olaf Weyl (South African Institute for Aquatic Biodiversity)

The fish disease, Epizootic Ulceritic Syndrome or EUS for short, was recently diagnosed by researchers from the Aquaculture Research Division of the Department of Agriculture, Forestry and Fisheries, in barbel from a farm dam near Stellenbosch. The disease is caused by a fungus that is originally from Southeast Asia but has been spread to many other parts of the world by the movement of live fish and, possibly by the transport of contaminated water.

While confirmed diagnosis requires histological examination of the tissue and genetic screening for the presence of the fungus, I have recently received an alarming number of reports of fish with ulcers from all over Southern Africa. Waters where suspect fish have been reported include Theewaterskloof Dam, Buffelsjagts and Arabie Dam in the Western Cape and more recently in Hartebeespoort and the Vaal Dam in Gauteng. I have also received photos of bass from Zimbabwe that appear to have similar ulcers and EUS has been present in the Upper Zambezi and the Okavango Rivers for a couple of years.

Once introduced, the disease is fairly indiscriminate and has been reported to affect most fish species including popular angling species such as bass, barbel, carp, nembwe and tigerfish. Infection of fish requires the breaking of the skin for the fungus to get hold and once infected, the disease manifests itself in three stages. The disease progressed as follows: first, pinhead sized red spots form on the body and fins of the fish; these develop into small (2-4 cm) ulcers which finally form large open ulcers which eventually kill the fish. The distribution of the disease in South Africa is currently unknown and we unfortunately do not know what its long term impact will on our native fish stocks. What we do know is that disease spreads aggressively through fish populations once introduced.

Unfortunately, there appears to be no feasible way to control this disease once it affects wild fish populations and the only control measure is to try to limit its spread in the country. It is therefore vital that all anglers understand that: THE ONLY WAY TO CONTROL THIS DISEASE IS TO CONTROL ITS SPREAD TO NEW WATERS. We can all contribute to this by the following:
• Do not move any fish, live bait or fish parts from one water body to another. Fish with no clinical signs may be carriers of the disease.
• Do not keep infected fish in your livewell is may result in the fungus being transmitted to healthy fish.
• Use knotless landing nets to minimize abrasions on the fish.
• Empty your live-well and bilges before leaving the launch site.
• Clean boats, trailers, fishing gear and drain live wells and bait buckets between fishing trips. If you have been outside South Africa, consider taking the extra precaution of soaking your live-well and bilge area with a solution of one 1 tablespoon of bleach (Jik or Jayes Fluid) to 5 liters of water for 10 minutes. Then rinse thoroughly to get rid of any remaining bleach (watch your carpets!).
• Help educate other anglers in the dangers of disease transmission.
• Please send photos of suspicious fish and GPS coordinates to me as I woiuld like to monitor this situation. My email is <!-- e --><a href="mailto:o.weyl@saiab.ac.za">o.weyl@saiab.ac.za</a><!-- e -->


Vaal Dam (Louis Cooper)
Banket Dam, Zimbabwe (Denham Parker)

Haarties (Rudi Dreyer)
Theewaterskloof (Guy Paulet)



I dont know how the images thing works and so have sent them to BM to have them added!


Zim Fish
[Image: banket-Zimbabwe.JPG]

Haarties Fish
[Image: Haarties.jpg]

Theewaters Fish
[Image: Theewaters.JPG]

Vaal River Fish
[Image: Vaal-Dam.jpg]
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BFSA
#2
Houston, we have a problem!
Thanks for the update.
[Image: big_fish_eat_little_fish.jpg]
BIG FISH EAT LITTLE FISH....
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#3
I have also seen a few ill fish in Kwaggas. Nothing as bad as this though.
Regards
Robert Jacobs
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#4
Its also in clanwilliam ;(

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#5
Ive seen these type of ulcers on fish since Ive started fishing for bass in 1993. All of the dams where Ive seen them still have strong populations of fish. I must be honest, Ive seen these type ulcers in basically every dam Ive fished in some time or another. Is everything EUS, or could there be a thing that looks the same but actually isnt?
One fish can change it all.....
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#6
I have fished Clan and Mofam a few times since the reported/alleged outbreaks of EUS and this is the only bass that myself or anybody that I have fished with has caught with any kind of sore on it.
This is a 1.6kg that I caught and by the looks of it the sore is healing well.
[Image: DSC07501.JPG]
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BFSA
#7
@ August
EUS has definitely been diagnosed for fish from the theewaterskloof system but I cant speak for the rest of the dams. There are a number of diseases that cause ulcers but due to the fact that this disease is also transferred by birds, it is likely that it has found its way into other waters in the area! EUS is a more recent disease than 1993 in this part of the world and so its possible that the ulcers just look similar...
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#8
If I catch a fish with this. Can I put it in my livewell and treat it with something for the day?
One fish can change it all.....
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#9
To my knowledge there is no simple way to treat the fish in a short time and I am sure it will just pick the disease up again when released. I will see what I can find out
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#10
Can anyone enlighten me as to whether stressed, undernourished and over populated fish are predisposed to EUS?
Is it also prevelant in completely natural, balanced ecosystems?
[Image: big_fish_eat_little_fish.jpg]
BIG FISH EAT LITTLE FISH....
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#11
stressed fish (for whatever reason) are always more susceptible to disease. Healthy fish will take longer to show the symptoms but are not immune
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BFSA
#12
if we rince our live wells out with a cup of salt will that also stop the spread or not
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#13
hi Tom,
Sterilising the livewell will definitely help reduce the spread. I would use some bleach in the livewell water (after fish removed) and then rinse thoroughly by flushing the livewells at the next dam. Enough salt would probably do the trick but you would need a whack in a large livewell
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#14
I have a bad habit in my freshwater indigenous fish tank. Snails, daphnia, plants etc. from the wild so inevitably I end up with a fungus infection of some sorts with the kurper. I’m sure everyone who has a tank has to use a fungicidal remedy at some stage, which works. Thus my question:

Shouldn’t it be standard practice in confirmed EUS dams that the correct dosage rates be compulsory in the live well so that at least some of the fish receive some treatment at least? Those fish which are recaught from time to time might be lucky and receive follow-up treatment.
This must be over & above non-iodised salt which should also be standard practice – it works!
[Image: big_fish_eat_little_fish.jpg]
BIG FISH EAT LITTLE FISH....
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#15
Morning guys - this matter is extremely important to our sport. Why all so quite on the disease front?
This Sunday we are going to keep 5 fish in the livewell in a salt / fungicide solution as a test.
[Image: big_fish_eat_little_fish.jpg]
BIG FISH EAT LITTLE FISH....
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