Wednesday, March 28, 2012

Time to take a few fish?

I recieved this from a friend regarding the Driftless of Wisconsin, and sounds like we can help

Gill Lice in the Driftless

All Concerned,

I wanted to bring this up as I'm sure a lot of the folks on here enjoy fishing for trout in SW Wisconsin. Unfortunately, Gill Lice is becoming more prevalent in the driftless area and is taking its toll on the brook trout as it directly affects the respiration, oxygen and carbon dioxide process. Below is a response from Susan Marcquenski, a Fish Health Specialist, to a gentlemen’s email that lives in SW Wisconsin.

I am the Department's fish health specialist and Mike Staggs asked me to respond to your e-mail regarding gill lice affecting brook trout in Wisconsin streams.

You are right, gill lice (a parasitic copepod called Salmincola edwarsii) can cause significant physical trauma to the gill filaments, causing deformities which affect respiration and the efficient uptake of oxygen and the release of carbon dioxide, ammonia and other metabolites. Fish that are heavily infected cannot obtain sufficient oxygen when they are exercised, such as when they are caught by angling.
Gill lice have a direct life cycle- when the egg sacs release nauplii, they immediately molt and become the first copepodid (larval) stage and they have about 24 hours in which to find a new host and anchor onto the gills and continue their development. After several molts, the copepods reach maturity and remain permanently anchored in the gill tissue. This is a significant stress especially when more than one parasite is attached to a gill arch.
In streams with dense brook trout populations, the success rate for the larvae to attach to gills increases due to the greater chance of contacting a fish within the 24 hour "post hatch" period. Streams with faster water flow (velocity) can make it harder for the larvae to successfully attach. So fish density and water velocity are two factors that affect the prevalence and intensity of infection by Salmincola edwardsii in a stream. A third factor that may play a greater role in the future is temperature trends. Gill lice are invertebrates and therefore their development is proportional to the water temperature of the stream. If water temperatures increase, the parasites will develop to maturity faster and will then be able to reproduce one or more extra "generations" each year. Because the copepods remain on the fish, the affect of more generations of parasites is cumulative and we may see far higher numbers of gill lice on individual fish in the future.
So rather than not fish the streams where gill lice are present, I would encourage people to fish and take fish home (reduce the density of the fish) as long as the fishing regulations allow this. Anything that can be done to keep water moving (faster velocity) may also help reduce the probability of larvae to successfully attach to fish.
It would take a special study to do this, but it would be interesting to compare the prevalence (percent of fish infected) and the intensity of infection (number of gill lice per fish) of gill lice in brook trout streams that have high densities with those that have low densities; those with faster velocity vs those with slower; and slightly warmer vs colder streams.
Thank you for taking the time to share your concern with us, and please let me know if you have any questions.
Susan V. Marcquenski
Fish Health Specialist
WI Department of Natural Resources
Box 7921
101 S. Webster St.
Madison WI 53707

Saturday, March 17, 2012

Return to the "Driftless"

It's been too long, a year to be exact. I certainly wont make that mistake again.  I went back to an old stretch of river that I've fished many times, and like welcoming home an old friend, it was bliss from the moment I walked through the door.
I picked a rock to see what was going on for bug life, a few crawler mayfly nymphs , midge larvae all over the place,  a few sow bugs, and a freshwater shrimp. This made my selection of 'old reliable" fairly simply. I tied on my olive tungsten scud trailed by a juju midge, and by my third cast, I had already hooked into a plump little foot long fish.
This could have very well been the theme of the day. It seemed like we couldn't go five or ten casts without hooking up, and we weren't complaining, but yet we were a bit puzzled? This river had normally housed at least a few line breaking , muscle bound Browns, that made you realize the need for fluorocarbon a few times during the day. Where in the world had they gone?
Was it simply this crazy warm spring, and they weren't up in the normal holes? Or, was it simply that our cast, mending, and acumen wasn't up to par with getting the right to hook one of these fish yet? My guess is it's a combination of the two. A quest to the DRIFT LESS ANGLER afterwords made me feel a little bit better about the lack of larger fish. Matt had said this particular river had been fishing that way this season, and he had no idea why? Could it be there were to many takers last season, or a fish die-off, to many little guys for competition? I had no idea why, but to put that many tugs on the end of my four weight was just too great to put into words.
Nothing was truly "coming off" today except for a few sporadic egg laying black caddis, but I suspect that the next coming weeks it could really go off down in SW WI. I plan on being there when it does!
So for you readers of the blog, I'm always looking for fishing partners. It seems we all get way to busy in life, whether that be because of work, kids, yard chores, etc etc, DON'T LET THIS SPRING AND EARLY SUMMER GET AWAY! I let ALL of last year get away, and I'll never forgive myself!