Sapro Fact Sheet: That White Fungus

[jasonvilly]

Seen a lot if posts here and on Alberta outdoorsmen forum, I found that being informed is important before jumping to conclusions.

 

Found this on the SRD site.

 

http://www.srd.alberta.ca/FishWildlife/WildlifeDiseases/documents/SaprolegniosisFactSheet-MAR-2010.pdf

 

The only thing I was left wondering is why there seems to be a greater occurrence this year? Cyclical? More large browns spawning? Great spore survival?

 

 

[scel]

Seen a lot if posts here and on Alberta outdoorsmen forum, I found that being informed is important before jumping to conclusions.

 

Found this on the SRD site.

 

http://www.srd.alber...et-MAR-2010.pdf

 

The only thing I was left wondering is why there seems to be a greater occurrence this year? Cyclical? More large browns spawning? Great spore survival?

 

As a child, I had systemic yeast/fungal infections. My partner did her Masters in mycology. In medical mycology, apparently, once someone is infected, they will always be infected, it just takes the right conditions to bloom. I think that this year was an abnormally stressful year on the fish, 2 months of run-off coupled with heavy fishing might have taken their toll.

 

I think that it might be cyclical, because there is going to be an age category of fish that it seems to affect (10+ years old, for example), the young fry are going to be born into an environment with higher levels of the spores available, more likely to catch the fungus, and then express in 10 years (if that is indeed the age category) when/if the conditions are optimized.

 

I am guessing that the answer will be in the water chemistry. When my partner would make her media on which to grow the fungus, incredibly minute changes of the same compounds would allow one type of fungus to grow, but inhibit another.

 

I certainly am not ascribing to know the answer, but I am certain that it is more complicated than a simple cycle.

I think that the answers will lay in answering the questions:

Why brown trout? Why older brown trout? Why males? (Rainbows and whitefish seem unaffected, despite being salmonids)

Is this a systemic disease or is it acquired purely from the environment?

In a laboratory environment, what conditions optimize the growth of sapro, and how does that correlate to this year's environmental conditions?

[bowbonehead]

As a child, I had systemic yeast/fungal infections. My partner did her Masters in mycology. In medical mycology, apparently, once someone is infected, they will always be infected, it just takes the right conditions to bloom. I think that this year was an abnormally stressful year on the fish, 2 months of run-off coupled with heavy fishing might have taken their toll.

 

I think that it might be cyclical, because there is going to be an age category of fish that it seems to affect (10+ years old, for example), the young fry are going to be born into an environment with higher levels of the spores available, more likely to catch the fungus, and then express in 10 years (if that is indeed the age category) when/if the conditions are optimized.

 

I am guessing that the answer will be in the water chemistry. When my partner would make her media on which to grow the fungus, incredibly minute changes of the same compounds would allow one type of fungus to grow, but inhibit another.

 

I certainly am not ascribing to know the answer, but I am certain that it is more complicated than a simple cycle.

I think that the answers will lay in answering the questions:

Why brown trout? Why older brown trout? Why males? (Rainbows and whitefish seem unaffected, despite being salmonids)

Is this a systemic disease or is it acquired purely from the environment?

In a laboratory environment, what conditions optimize the growth of sapro, and how does that correlate to this year's environmental conditions?

 

 

Makes you wonder if we should be promoting less handling of fish (fewer glory shots) as its when the protective mucus is removed that fish are more susceptible to the fungus obviously we see more Browns because of the time of year with lower water levels and a fall spawning period and increased stress. Higher and colder water and a spring spawn may have to do with less Rainbows being affected with fungus.

[bcubed]

Makes you wonder if we should be promoting less handling of fish (fewer glory shots) as its when the protective mucus is removed that fish are more susceptible to the fungus

 

ding ding..

[Flyrod1970]

I think we should add one more factor into this, and that is that browns are a non-native species. I know that the rainbows are not native to the bow, but at least they are native to this part of the world, and as a result they could be more resistant to this type of fungus. Browns are not native to North America at all, and maybe that makes them more susceptable to deseases that occur here.

[browntrout57]

I walked about 200 yards of river yesterday and saw 1 half dead brown covered with this and 1 dead one. Both were large fish (22+- inches) and both were males. Sad to see.

[troutfriend]

EDIT: Has anyone taken photos of any juvenile / non-spawning Browns with Saprolegnia? Say any fish less than 16" or 17"?

How about Rainbows?

[Jayhad]

Has anyone observed any juvenile / non-spawning Browns with Saprolegnia? Say any fish less than 16" or 17"?

How about Rainbows?

 

Yes and yes. I was out last saturday and i saw several big browns as well as a couple small rainbows

[jasonvilly]

Hopefully the cooling weather will kill most of the spores, unfortunately spores are unusually hardy, so some will survive a cold winter.

[SilverDoctor]

A waterborne fungus like this from what I gather will attack a Trout that has had its protective slime compromised. Spawning battles will do it along with poor fish handling techniques. Please use care in catch and release.

[scel]

My partner is a mycologist. She thinks that the problem IS the cold water. I definitely saw sapro on the big browns in the August. While the spawn and handling exacerbate the problem, I do not think that it is the cause.

 

Her insight was mould in almost every form thrives in low-light conditions. Certain moulds will favour certain temperature ranges and chemical compositions. Sapro seems to favour hard water conditions with low temperatures. With that in mind, the optimized conditions were probably caused by the cold, dirty water during the super long run-off.

 

Even when the fish is dead, the sapro continues to grow and infect nearby fish.

 

While it is technically illegal, I think that any dead (or close to dead) fish should be removed from the river.

What do you think?

[SilverDoctor]

My partner is a mycologist. She thinks that the problem IS the cold water. I definitely saw sapro on the big browns in the August. While the spawn and handling exacerbate the problem, I do not think that it is the cause.

 

Her insight was mould in almost every form thrives in low-light conditions. Certain moulds will favour certain temperature ranges and chemical compositions. Sapro seems to favour hard water conditions with low temperatures. With that in mind, the optimized conditions were probably caused by the cold, dirty water during the super long run-off.

 

Even when the fish is dead, the sapro continues to grow and infect nearby fish.

 

While it is technically illegal, I think that any dead (or close to dead) fish should be removed from the river.

What do you think?

 

It is illegal but I really do wish we had more info on this and the opportunity to cull fish infected out of the system but right now the law doesn’t allow it. It seems to be a particularly bad year for the fungus; I have seen it most years but never as bad as this. It really does seem to rear it’s head during the fall in spawning fish, and I imagine other Trout pick it up from damaged spawner's. I remember seeing this in BC with the Kokanee during the spawn cycle on some of the inland lakes.

I’ve read that the instance is much higher among male large fish as males fight over females and territory. I would imagine if you are using a cloth mesh net you will encourage spread of the infection, something to think about.

[maxwell]

I think better fish handling is defined key to limit the odds on non infected fish! I've define tilt seen this on fish my whole life so I don't think removing the odd fish will eliminate the problem might slow some stuff down would be interesting to know if the low waters and higher condensed fish populations the last few seasons has something to do with a higher infection rate... I like the rubber nets far better than regular mesh I'm on board with doc and wettin your hands even during the off season fishing now to protect the slime is critical for sure in trying to limit the slime removed in tougher living conditions...

[RedBeard]

Tilapia caught on the bow = related to the increased sapro this year????

[maxwell]

I heard of one fish caught downtown and I would be more willing to bet it either got dumped from a tank in china town or fry are escaping from the hippo tank at the zoo.. I doubt they have anything to do with the fungus but super crazy to see that one was in the bow...

[Gil]

This outbreak for me suggests we need to be careful in not carrying this to other rivers. Make sure you clean your boots etc. before moving between rivers....

[dutchie]

this is ugly and sad , i think it will take a few years to build it back up , we were lucky as the last 3 years was epic fishing for big browns