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Fish Care - Disinfecting Nets, Mats & Slings


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I am involved with a fishery in Brittany, France and we have a rule about nets and unhooking mats. Anglers are not allowed to use their own gear.

Obviously that's logical because we have to avoid all risk of infection from other lakes but I am wondering if there is another way.

Additionally these days, there is some really good carp-care equipment around and it seems a shame to deny anglers the right to use their own gear when it's better than ours.

I once belonged to a syndicate in London that provided dip-tanks for such gear at the entrance, so I am wondering how safe this method it, what disinfectant to use and what concentration.

The first thing that comes to mind is Jeyes Fluid but that may only work on bugs that infect humans.

Does anyone have any ideas?

Thanks

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Simple - dry out all your gear thoroughly in sunlight.

 

I agree with Nige's sentiments, but unfortunately I know it isn't always practical.

 

A couple of years ago fishing in the winter with a week between trips my gear simply wasn't drying out, the bivvy was damp, and my landing net, slings and mats were still damp each trip.

 

Now I was lucky, I was fishing my syndicate water, and so the only place that the equipment used was this one lake, yet I know that some anglers do fish more than one water.

 

The bugs and bogies that get from water to water may not be instantly passable as the temperature is not warm enough for them to be active, or for the carp to pass them over, yet as it warms up they may then get passed on and become active. (Levigsp (Frank) knows far more about this than I ever do).

 

 

The other option is for the fishery to provide the nets, slings etc, but even then we have sticky fingers at various venues.

 

 

Therefore there has to be an effective way to clean your kit between trips, but equally it may not be practial or possible for the angler, so the theory of dip and rinse tanks is a good one, but they should be checked and replenished, and the active ingredients should be safe for the fish.

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I once was working at a salmon/trout farm and during my time there we were unlucky enough to be notified by the government that one of our tested specimens (allways before putting them out in waters) was tested positive for an Epizoo classed virus. That means virus with mortal possibilies that can transfer between animals and also to humans. In other words very nasty stuff to release that can affect humans and lots of wild animals.

 

That meant we had to totally put out all of our stock with electricity or large doses of tranq and then desinfect all of our gear, tanks and dry out and do the same to the ponds and even electrocute and do the same to the surrounding areas streams etc.

 

Not very pleasant. However for desinfecting the gear we used Virkon. A substitute for killing basicly any virus, bug or bacteria and it comes in various forms.

http://en.wikipedia.org/wiki/Virkon

 

The dams and the surrounding area we "killed" with this:

http://en.wikipedia.org/wiki/Calcium_hydroxide

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Simple - dry out all your gear thoroughly in sunlight.

 

The other option is for the fishery to provide the nets, slings etc, but even then we have sticky fingers at various venues.

 

Therefore there has to be an effective way to clean your kit between trips, but equally it may not be practial or possible for the angler, so the theory of dip and rinse tanks is a good one, but they should be checked and replenished, and the active ingredients should be safe for the fish.

 

The first problem is what chemical to use, so I would be interested in any other fishery owners who have hands-on experience.

Then the "dip and rinse" question. At my old syndicate we just dipped and laid the gear out to dry.

Finally: We have 4 lakes at Les Kaolins, which are spring-fed and all connect via tubes and ditches. Do we have to disinfect if an angler moves from one lake to the other?

IMPORTANT: My colleagues at Les K did the stocking before I got involved: 300 fish (mirrors, cats and sturgeon), just the main lake which is 16 acres. All the lakes had a resident stock of commons, pike, perch and silver-fish.

Just after this stocking a lot of the resident commons died, fortunately only small fish and only in the main lake.

Curiously now there are only large commons in the main lake, 30's and up, but still a lot of small ones in the other lakes. I witnessed scores of fish spawning in the Island Lake this year, mostly all in the 5lb - 10lb bracket.

 

So we need to think carefully about the best way forward. We purchased a few sets of gear which we provide against a cash deposit. It's early days for us but the fishery holds up to 20 anglers. We either have to buy more gear or go for the disinfection tanks.

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Also, any dip tanks must be maintained, cleaned out regularly and the concentration of disinfectant checked to ensure that it is still effective.

 

I have seen some dips that are just bacteria soup due to not being looked after correctly. This type of dip can actively spread disease rather than prevent it.

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May be a daft question but , has there ever been a documented case where it has been proved that a wet net has transported KHV or something similar from one lake to another ?

I think that we can dismiss this as being fairly obvious.

Part of my job is to maintain a number of swimming pools and I can say for sure that water is a far better medium than air for transmitting bacteria, virus and fungi.

If the water is not correctly balanced and the sanitizer present it only takes one person to infect practically all of the others, especially in warm weather. With large community pools we are dealing with a relatively small number of bugs in millions of litres of water.

Having said that, I also think that drying gear is not sufficient either.

Eventually someone will say that we have the risk from animals and even birds pooping as they fly over but these are things we can do nothing about.

I am really worried about this. Our "babies" are really beautiful fish, chunky, healthy, putting on weight fast, each one different from the other and it would really be a shame to start losing them in a few years after all the TLC, winter feeding, etc.

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johnplumb wrote:

May be a daft question but , has there ever been a documented case where it has been proved that a wet net has transported KHV or something similar from one lake to another ?

 

I think that we can dismiss this as being fairly obvious

 

Can we ? i have long thought that if you could transfer KHV via nets then surley birds , rats , foxes , otters must be able to do the same this artical below is quite interesting

 

 

 

Cormorants now being linked to the spread of KHV

 

By Angling Times

 

Fishery News

 

01 October 2010 16:00

 

 

For years the cormorant has been regarded as angling’s public enemy No1.

 

This week that label has been further justified as experts reveal that the feathered predators could also be responsible for spreading the deadly Koi Herpes Virus (KHV).

 

Following one of the worst years on record for fish-kills at commercial venues, the Centre for Environment, Fisheries & Aquaculture Science (CEFAS) has stated that fish-eating birds, such as cormorants and herons, have the potential to transfer the killer virus from one lake to another.

 

Until now KHV, which has been responsible for the deaths of thousands of carp across the UK, was thought to have spread via either the movement of live fish or by contaminated nets used by anglers.

 

But it’s now feared that the disease could be transferred by the droppings of birds that have eaten infected carp, or even on the feathers of waterfowl that have come into contact with fluids secreted from decomposing fish.

 

“It’s possible that birds such as cormorants have the potential to spread KHV from one water to another,” said Dr Kevin Denham, head of the Fish Health Inspectorate at CEFAS. “It could be carried in their faeces and also in the undigested fish often regurgitated by cormorants when they’re startled.

 

“Decomposing fish that have died from KHV release oils and fluids into the water which could be transferred over a short distance by a bird that comes into contact with it.” Even though CEFAS is currently conducting research to find out more about the disease, given this recent revelation, it’s now feared that it will be impossible to stop the spread of the killer virus.

 

Barston Lake in Solihull, West Mids, tested positive to KHV in 2007, and owner Nigel Harrhy is one of many who is certain cormorants and other fish-eating birds are to blame.

 

“I’m convinced that KHV can be transferred by cormorant droppings and I’ve spoken to countless fishery owners who all agree,” Nigel told AT. “I know one man who owns 18 lakes and, despite fishing being allowed on just four of them, the carp in every one have KHV. They contained different stock and different water supplies, so how did the disease get passed on if it wasn’t birds which are free to move from one water to the other?

 

“Research must be done, otherwise I don’t see how we can protect our fisheries totally from KHV.”

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I've heard from the secretary of my club that a legal cull of inland cormorants has finally been sanctioned due to lobbying by the Angling Trust. I too have noticed what seems to be a correlation between the spread of cormorants inland and the increase of KHV.

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I wrote to my colleagues at Les Kaolins last night, Title: "Does Terry own a Shotgun" also a link to this post.

Thinking some more about that. If Terry does see a cormorant on the lakes hopefully he knows what to do; then recover the body and burn it - in spite of the fact that they are protected!

However that may not be a problem because we have never seen a cormorant there. We do get the occasional duck but there are some, quite large, birds of prey; one actually make a investigatory pass at matey John Richard's bait-boat.

The real risk could be the herons and we often wake up in the morning to the sight of one on the other side of the lake, standing in the margins. But how can anyone shoot a heron? I know that I couldn't!

I think that the real problem is due to the fact that Les K is such a vast area and so remote; very often there are only a couple of anglers on the whole fishery.

 

I've done my brains in Googling for information but there just does not seem to be an answer at the moment. KHV is a virus, just like colds and flu and the only protection from it is the immune system, apart from vaccination - which has not yet been developed.

Us humans have cracked it fairly well and those at risk are advised to have a jab every year. As well as that a healthy persons's immune system develops antibodies to quickly combat the virus because the body has learned to do this from previous infections; but a carp lake is a closed environment and the fish's immune system never gets the chance until it is too late.

Mankind created the problem in the first place, by stocking the fisheries with non-indigenous species. So now mankind has to provide the answer.

 

Whilst writing there is something else that I have noticed. When I visit my "home town" and look around the lakes and gravel-pits of London, I see a whole variety of water-fowl in huge numbers and the same situation probably exists all over the UK. They all seem quite tame and accustomed to the presence of humans. Meanwhile, travelling around rural France and Spain I see very little "bird-life" - at least the variety with feathers! :lol:

Perhaps an answer: UK angling groups should provide culinary courses for our eastern european fiends who fish for the table. Perhaps "Heron au Vin" or "Cormorant a la Orange"! 8)

 

This is getting right off the topic - sorry! I started the post looking for opinions regarding dunking tanks vs supplying fish-handling gear; also the sanitizer to use in the tanks.

Any further thoughts, please?

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Rightihooooo!

Drying your gear does not help except that it will destroy bacteria.

KHV is a virus. Viruses are not strictly alive anyway because they need a host cell to invade, thrive and multiply.

http://boards.straightdope.com/sdmb/showthread.php?t=326147

Logically KHV can survive for along time after the gear has dried completely.

So the only solution is proper sanitization but how and with what?

What I do know is that halogens e.g. chlorine and bromine kill viruses in seconds. These chemicals are used for sanitizing swimming pools, jacuzzis, hot-tubs etc. and are quite complicated to use because of their short life after activation.

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No mention of khv in your original question :wink:

That's quite right. It started out with the simple question: "What's best, disinfection tanks or supplying the gear?" Then others raised the point about KHV and cormorants, which was what made me start looking around.

I had hoped that other French fishery owners would come up with some advice.

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In norway they use Virkon against gyrodactulys.

A said earlier in the thread it kills any virus or micro organisms.

Well done! I don't know how I missed that, must have been having a senior moment. :oops:

Anyhow got it now. Made by Dupont and contains their Oxone which I use for swimming pool sanitation. I'll get in touch with Dupont right away.

Could be a big moment. We may have saved the UK carp population and the French as well. WATCH THIS SPACE.

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In norway they use Virkon against gyrodactulys.

A said earlier in the thread it kills any virus or micro organisms.

Well done! I don't know how I missed that, must have been having a senior moment. :oops:

Anyhow got it now. Made by Dupont and contains their Oxone which I use for swimming pool sanitation. I'll get in touch with Dupont right away.

Could be a big moment. We may have saved the UK carp population and the French as well. WATCH THIS SPACE.

I have written to Dupont technical support and will publish their response.

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If you google virkon there is a Wiki page on it ,from what i can tell it will work for up to a week and then needs to be changed and i fear that will be the biggest problem - fishery owners keeping the tanks clean and replacing the liquid every week . My guess is it will cost around £15 / week

to buy the amount of virkon required .

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If you google virkon there is a Wiki page on it ,from what i can tell it will work for up to a week and then needs to be changed and i fear that will be the biggest problem - fishery owners keeping the tanks clean and replacing the liquid every week . My guess is it will cost around £15 / week

to buy the amount of virkon required .

Yes, I have seen that one but £15.00 might not be cost effective for fishery owners who have to provide multiple tanks, plus there is all the hassle of servicing them every week. They might just as well do as Les Kaolins do right now i.e. supply the gear and prohibit anglers from using their own stuff.

Virkol is produced by Dupont and it contains their Oxone + other chemicals. I use Dupont Oxone + Sodium Bromine to shock (sanitize) swimming pools and it does not even cost £15 for 50,000 litres.

One problem could be that the water has to be correctly balanced but that is simple enough and all pool owners have to deal with it.

Another is that they may not be able to chuck it on the grass after use.

Then the concentration has to be correct.

What I do know is that this sanitizer kills, ALL bacteria, viruses, fungi and algae in seconds but, within 30 minutes, the water is safe for people to swim.

Possible problems could be -

a) They may need two tanks. The first with a detergent to remove the dirt because otherwise a lot of the sanitizing power would be lost.

b) It might not penetrate porous surfaces such as landing-net fabric.

Lets see what Dupont say, they put me on the right track before.

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I would say birds and wildlife spread more diseases then an angler's net.

 

I personally dont use the dips at any lakes and the reason for that is my net and weigh sling is always washed out and left soaking in bath for a short while at home with disinfectant and then is hung up in shed to thoroughly dry before next session it stops them stinking and i very much doubt anyone can find any bacteria on my net and weigh sling.

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I would say birds and wildlife spread more diseases then an angler's net.

 

I personally dont use the dips at any lakes and the reason for that is my net and weigh sling is always washed out and left soaking in bath for a short while at home with disinfectant and then is hung up in shed to thoroughly dry before next session it stops them stinking and i very much doubt anyone can find any bacteria on my net and weigh sling.

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