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-   -   Holiday Inn Express Guide to Macro Study (http://www.theflyfishingforum.com/forums/entomology/318270-holiday-inn-express-guide-macro-study.html)

stenacron 05-02-2013 05:19 PM

Holiday Inn Express Guide to Macro Study
 
There has been a lot of "bug talk" around here lately and at least one Forum Poll on seining, so I thought I would share some of the processes used to determine the health of coldwater streams and rivers.

The projects are called Benthic Macroinvertebrate Bioassessment Studies, or "Macro Studies" for short and the collection methods are surprisingly primitive. After samples are collected is where the amateur nerd anglers (like me) separate from the Professional Biologists. The angler samples to see "what kind" and "how many" different insects are present that the trout may be feeding on (or may be hatching), thus they simply examine what has been caught in the net (streamside) and then move on from there. The Biologist will return the net contents to a laboratory where an applied methodology is employed to closely examine the contents and determine the overall "health" of the coldwater environment.

Sounds simple enough, but if you're extra nerdy (like me) you can be a bit of a hybrid and employ some of the lab methods and calculations to accomplish both (although not to perfection… which is basically the difference between doing it for fun, and getting PAID to do it). :D

I've done a few Macro studies back east on behalf of small conservancies that just don't have the funding to pay for such a study. I got as much - if not more - out of it than they did and my daughter usually joined me which always made for an interesting day afield. Below are some of the things you would have to take along, how you would use them, and (optionally) what to do with the results.


Things You Will Need
--Pitchfork: Just a simple “garden variety” 4-pronged type, used for dislodging rocks and gravel from the stream bed during sampling.
--Sein: Fiberglass screening (as that used to repair screen windows) fastened to a pair of wooden broom handles, used for catching the dislodged organisms.
--Stream thermometer: Used for recording water temperature (optional)
--Yard stick: Used for measuring current speed (optional)
--Thin-bladed knife or spatula: Used for coaxing specimens off of the screen.
--3-ring Binder: Used for recording data… we keep our tally sheets in here, as well as some “cheat sheets” (pictures of various nymphs), maps, notes, and other reference material.
--Several small jars: These can be used to take specimens home for further analysis or identification.
--Other misc. items: Camera, hand towels, magnifying glass, reference books, and a small shallow dish (for photographing specimens streamside).


Method of Collection
We sampled riffle areas where surface speeds exceeded 0.3 ft/sec using a “kick/screen” method where as my daughter would position herself in the current flow facing upstream with the broom handles held firmly to the stream bed and net stretched between them… then I would disturb the substrate from approximately 4 feet upstream down to the base of the net using the pitchfork as well as my wading shoes. Once the clouded water filtered through the screening area my daughter would raise it in with slow, upstream scooping motion.

Back on the shoreline I would spread the net out and sweep back and forth from top-to-bottom examining and identifying the contents. I would call out the organisms as I removed them from the net while my daughter recorded them on a pre-prepared tally sheet.

As per methods used on other studies of this nature, we ONLY sampled riffle areas as the species that live here are typically the least tolerant of poor water quality. While sampling deep runs and pools (in addition to riffles) would give a better indication of the overall insect diversity, it does change the results as many of the organisms found here are highly tolerant of poor water quality.

Here are some of the areas that are of high importance to Biologists, and also moderate to high importance for Anglers (depending on your love of – or tolerance for - this kind of stuff).

Biotic Index (BI)
Most aquatic species have a number assigned to them which represents their tolerance to organic pollutants. The BI scale is 0-10 with lower numbers representing lower tolerances for pollutants. The overall Biotic Index for each sample station is calculated by multiplying the numbers of individual species by their assigned BI number... the sum of these numbers is then divided by the total number of organisms for that station. The resulting Biotic Index is judged against the table in Figure 1 below indicating the quality of the water and degree of organic pollution.
http://farm9.staticflickr.com/8136/8...c75c1d6f_b.jpg

EPT Index
Interestingly enough, the aquatic insects of most interest to anglers and trout, are also the insects of most interest to sampling Biologists. The insect orders of Ephemeroptera (Mayflies), Plecoptera (Stoneflies), and Trichoptera (Caddisflies) are grouped together for an EPT Index. These insects are generally considered to be pollution sensitive, thus higher totals of EPT’s among the total numbers of species collected represents healthy biotic conditions.

Percent Mayflies
Many environmental agencies view the percent contribution of mayflies in collection samples as an indication of high water quality. Mayflies are one of the least tolerant orders with regards to pollution. The "percent mayflies" is calculated by taking the total number of mayfly species collected divided by the total number of organisms collected.

In Closing…
Whether you're an aspiring Biologist or just an over-curious angler, there is much to be learned from simply researching and reading Macro studies performed by others (let alone getting out there and doing it yourself). And speaking strictly from an angler's perspective, it can often reveal populations on your local waterway that you didn't even know existed.

For example; the table below shows the results from a study that we did on a fairly small freestone stream back in PA. We sampled 7 stations with 1 being close to the mouth where it emptied into a large river and 7 being just below a warm water reservoir spillway near the headwaters. I had fished that stream for years and thought that I knew it quite well, but I had only really fished the areas from station 1 up to station 4.

When doing the macro study my daughter and I visited new sections further upstream than we had gone before and discovered that it had a very healthy Drunella lata (Blue-winged Olive) population. I fished this hatch on that stream from that spring until we relocated to Utah… all alone nearly every time!
http://farm9.staticflickr.com/8115/8...c99c4274_b.jpg

Tight lines and happy seining! :)

silvertip8k 05-02-2013 06:26 PM

Re: Holiday Inn Express Guide to Macro Study
 
I never finished college...but I somehow feel smarter after starting digestion that post!!!

thanks for putting some perspective and direction on the subject...

my question is this...are we looking for passive bugs...ones just streaming down with the current(which is what I have always done)...or by breaking up the stones etc and helping them out...is it the same really??

I always thought some bugs were just better at hiding out...and that they were most vulnerable when they actually hatched??( or on their way to doing it)

nymphs broken loose from their moorings are what I thought we were mimicking??

this might not have come out right...I just an asking to learn more...OK...t

fredaevans 05-02-2013 06:31 PM

Re: Holiday Inn Express Guide to Macro Study
 
My 'learning curve' just went straight up. Excellent information.

stenacron 05-03-2013 08:58 AM

Re: Holiday Inn Express Guide to Macro Study
 
Quote:

Originally Posted by silvertip8k (Post 552331)

my question is this...are we looking for passive bugs...ones just streaming down with the current(which is what I have always done)...or by breaking up the stones etc and helping them out...is it the same really??

That would depend on what you're goal is I suppose. If sampling the overall insect population then you will need to overturn rocks and kick up some gravel. If searching for exactly what's happening in the invertebrate drift, then some type of anchored drift sock or screen would serve you better. Gary LaFontaine goes into great detail on this in his book Caddisflies.


Quote:

Originally Posted by silvertip8k (Post 552331)

I always thought some bugs were just better at hiding out...and that they were most vulnerable when they actually hatched??(or on their way to doing it)

nymphs broken loose from their moorings are what I thought we were mimicking??

Most mayfly species are exposed and drifting for days prior to hatching. Nature's way of spreading things out. Going back to that Meet the Hendrickson's video, where the nymph wiggles to the surface and then drifts back down… all Ephemerella species go through this same false emergence for days prior to – and throughout – their hatching period. That's why a simple Pheasant-tail Nymph drifted 18-24" below a small indicator is so deadly during Hendrickson and Sulphur (PMD) hatch periods.

Other species hatch on the stream bottom (Epeorus) and float to the surface before breaking through and flying away, and this is where your winged wet fly will outfish a floating dry 10:1.

Some species (Isonychia) are terrific swimmers and you can (actually should) fish the nymph cross stream with short twitches.

Trout key on areas of vulnerability during heavy hatches. That's all part of cracking the code when you see surface activity; are they taking nymphs near the surface, emergers, floating duns, cripples, spent spinners, or ignoring them all together and chasing caddis pupae?

Caddis are a whole other animal. :eek:

silvertip8k 05-03-2013 07:03 PM

Re: Holiday Inn Express Guide to Macro Study
 
now thats what I call an answer! thanks so much for taking the time to make those points...

the fact that the drift is going on so long is incredible...that these insects are actually in a vulnerable state so long blows my mind...

also the fact that they do that cool little "surfacing move"repeatedly is also so cool...its like they are practicing...but also they are so vulnerable too...I understand what you are saying about the wet flies and the success ratio...catching trout with a dry is sort of the quintessential method...the height of angling with a fly...but in all honesty I have caught way more with my favorite wet...

actually my best ever public water trout was a slab brown on a drowned caddis in Cheesman...but really it could have just as well been a generic wet fly ...now I think I am starting to understand...probably it looked like a "practicing" emerger???who really knows...its just a good thing to cover as many bases as possible...

again...thanks for taking thne time to add some understndable aspects of all this...maybe consider writing your own treatise on such matters..if you already have not...


btw...here is my favorite wet...not as fashionable as those cute dry patterns...but I am starting to understand why they work so well...practice sessions...:)

http://i637.photobucket.com/albums/u...ps2bf091cb.jpg

actually they are some many patterns that "cross over"...some wet patterns that are basically emerging nymphs...then some caddis bugs that look so similar...

all the best...ted

PS...Mr Leisenring back in the 40's perfected a style drift I love so much! sort of a mix of a high stick dead drift and stack mend...I wish I could have fished with him!

stenacron 05-04-2013 12:06 AM

Re: Holiday Inn Express Guide to Macro Study
 
Quote:

Originally Posted by silvertip8k (Post 552680)

btw...here is my favorite wet...not as fashionable as those cute dry patterns...but I am starting to understand why they work so well...practice sessions...:)

That's a good looking soft hackle! I like the plump, tapered body. Tied with a bright green/olive body and dun hackle, that shape would probably do an excellent job of imitating the western Green Drake (D. grandis/doddsi).

My infatuation with the dry fly was fairly short-lived. Once I found out that I could cast to rising fish with wet flies, and still see the take... I just figured why force the dry fly... why not just feed them what they're targeting.

I still fish dries occasionally. Usually a Comparadun when they are clearly gulping hatched duns, or spent wing patterns following spinnerfalls.


Quote:

Originally Posted by silvertip8k (Post 552680)

PS...Mr Leisenring back in the 40's perfected a style drift I love so much! sort of a mix of a high stick dead drift and stack mend...I wish I could have fished with him!

The area where I grew up in Pennsylvania was 20 minutes from Leisenring's home stream (Little Lehigh River) and about 45 minutes from his favorite haunt (Brodhead River). So it was always particularly exciting for me to fish those streams thinking about how much effort went into his imitations and the insects he was mimicking. As they say, "Leisenring may be long gone, but his book is still here, and so are the insects he was trying to imitate, along with the trout species that he duped with them." :cool:

The Art of Tying the Wet Fly & Fishing the Flymph is a fascinating journey inside the mind of a man obsessed with fooling trout through the art of angling.

silvertip8k 05-04-2013 12:09 PM

Re: Holiday Inn Express Guide to Macro Study
 
Just googled that title...would love to read it...except 200 bucks is sort of steep for this carpenter for a book...no doubt its worth it...

maybe just keep dropping off little crumbs here and there....OK...LOL...:)


stenacron 05-04-2013 03:22 PM

Re: Holiday Inn Express Guide to Macro Study
 
$200 wow!

Must not be a lot of them floating around out there. I paid $50 for my copy about 6-7 years ago.

Wet Flies by Dave Hughes is a great book too. He's a follower of Leisenring, Hidy, and Nemes so while a bit modernized, the tying methods are straight Leisenring. Its probably a LOT more affordable too! ;-)

silvertip8k 05-05-2013 07:45 AM

Re: Holiday Inn Express Guide to Macro Study
 
there were some used ones for under a hundred...it would be nice if family members or folks that have a connection with some of the old timers who are passed...re publish some of those older works...

Im sure it will happen sooner or later...especially with the aspect of internet publishing available...

thanks for the names of those other titles...t


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