Observation and Investigation
By John F. Comes
Editor, NorthWestTrout.com
 

"In the field of observation, chance favors only the prepared mind."
Louis Pasteur (1822 - 1895), lecture 1854

Prior to his retirement Edgar Martinez, long time Seattle Mariner designated hitter, took his role on the team seriously. The DH is a specialized role in the American League. Martinez worked very hard to be one of the games best. His training regime included taking batting practice with tennis balls. One might ask how tennis balls helped a Martinez become one of the greatest designated hitters in the position’s 31 year history. Martinez’s training routine would vary but one part involved a special machine firing colored and numbered tennis balls over the plate at 150 mph. Martinez would alternately make contact with a bat or, just as hard, read the numbers on the balls as they flew by him. Martinez recognized the need for elevated observation skills to identify different pitches quickly, adjust his swing, make solid contact and thus lead the league in many categories throughout his career.

While at a much, much slower speed, keen observation can greatly improve your fly-fishing.

Many factors add up to a successful fishing day. Some, like the forces of nature, are out of our control. However if ones pays attention to nature and investigates a bit, their luck can improve.

Early into the sport, I often solely depended on fishing reports and hatch charts for fly selection when targeting trout. My success level was good as I got by on standard patterns. Still there were plenty of times when other anglers were consistently getting more strikes. Etiquette sometimes frowns on asking another angler what fly they are using. Rather, you hope they see your lack of success and offer a few friendly tips. During one float trip, a guide floating by - and possibly sensing our frustration - passed over a handful of well-received nymph flies to our group. Our success rate dramatically improved. What did he know that we didn’t? Well, I am sure the list is long as it is his job to know what is working. We bumped into him later at the take-out and asked. “I hadn’t been out in nearly a week,” he replied. “I managed a nice trout yesterday morning. I did a stomach pump on him to see what he was feeding on. That told me the trout were actively feeding on march brown nymphs, aquatic worms and fresh water shrimp (scuds).”

While some find the use of stomach pumps questionable, there are many other less invasive ways to identify what sub aquatic food source trout might be keying on.

Flipping Rocks
This is one of my favorite and I have learned much from it. As you wade into a stream, reach down and turn over a rock or two. This will not only tell you what aquatic insects are active in a watershed but where they are active.

Turning rocks in the slower slack water areas typically reveal little if any insects. The water is usually warmer, slower moving, and thus less oxygenated. These factors add up to less than ideal conditions for not only fish but also their insect food source. Finding better water in riffles and the like will turn up more insects clinging to rocks and seeking shelter under them.

During a recent trip to the Yakima River in February, I waded out into the water before tying a fly on. I flipped a few rocks and found a variety of aquatic insects. The two that caught my eye were cased rock worm caddis and small nymphs, possibly blue winged olives or march browns. I am not an entomologist. I am more concerned that I have something in my fly box that approximates the naturals.

I did. I pulled one of the cased caddis off a rock and carefully squeezed it out of the case, the brilliant green body and dark head were very reminiscent of a chartreuse Copper John fly. For the march brown nymph (remember, I am not an entomologist), a small dark Hare’s Ear or Pheasant Tail nymph would be a good match. I opted for a Hare’s Ear and Copper John dropper. I fished this setup for a bit and was reward with a solid hook-up. A whitefish. While not the trout I was after, I was glad to see he went for the chartreuse Copper John.

With this section of river covered, I headed back to the vehicle to explore other sections. While walking in the shallow water I saw a skwala stonefly sunning itself on a rock. Being attentive, I looked for others but it appeared to be an early riser. I flipped some rocks close in hoping to see some of these stonefly nymphs waiting to emerge. Even with the warm winter, it seemed a bit early for the skwalas. I did not see any nymphs. “Maybe another week or two,” I thought. Something to put in the memory banks in case I get back out.

Seine nets
Flipping rocks will show you what is hanging on or trying for cover. A seine net will show you what is floating free in the water column. Nets come in a variety of styles from one-person butterfly nets and dip-style nets to two-person poled nets. The larger the net, the larger the sample. However, carrying a separate seine net is not always convenient. One nice compromise is Quick-Seine. The Quick-Seine attaches to landing net at the junction of the handle and the hoop. The net stretches over your landing hoop frame, effectively turning into a seine net. The net is made to dry while tucked away in its pouch after use.

Also available are products from Wind River that include a seine system similar to the Quick-Seine along with a “catcher’s mitt” seine net and an insta-seine net kit.

For those that want to store samples for transport home, TYT-LNZ from Buxton, OR offers a very nice entomology kit. Known as BugBagz the kit consists of lightweight case, four twist-cap double-sealed vials, forceps, a seining kick-net, magnifier and water resistant log sheets for on-location recording of collection info. They also offer other items that are useful in obtaining information such as a temperature gauge.

A few words of caution on using seine nets. Some states have laws forbidding the use of seine nets on certain waterways as well as the collection and transportation of insects. Check the regulations. While these laws typically apply to seine nets used in the capture of fish, a misinformed wildlife agent might take exception to their use. In regards to the collection and transport of insects, the same cautions taken to prevent the spread of invasive species and disease (New Zealand Mud Snails, Whirling Disease, Zebra Mussels, etc) should apply. If you are transporting in water as opposed to denatured alcohol, be sure to correctly dispose of the water. Also, be sure to properly clean the seine net.

Stomach Pumps
My son was rooting through my fishing gear one day and wondered why I had a small turkey baster in my fishing gear. I explained it was not a turkey baster but a stomach pump. His eyes grew a bit larger until I explained the procedure and its use on fish.

The first part can be the hardest - and that is catching a fish. Once completed successfully you can proceed.

Start by rinsing the stomach pump in the water to lubricate it. Wet your hands before handling the fish. Keeping the fish close to the water, turn it upside down on its back.

Squeeze the bulb about half way and carefully insert the tube into the fish’s mouth and into the stomach. Release the bulb, drawing the stomach contents into the tube. Remove the pump from the fish. Keeping the open tube end pointed up set it aside for a moment. Turning back to the fish, release it when it is revived and ready. If you plan to keep the contents for examination later, have a container filled about ¾ with water. Insert the pump tube into the container and draw in some water. Swish it around and then squirt it and the stomach’s contents back into the container. Close the container and rinse out wash the stomach pump.

If you are not intending to save the contents, simply draw in some water fromthe river, stream or lake, swirl and carefully empty the contents into the palm of your hand. The contents should be easy to identify and match.

When using a stomach pump it is important to avoid injecting water or air into the fish’s stomach. In addition, some larger terrestrial insects will be difficult to extract. If you are unable to retrieve any contents, do not try again. Repeated attempts can be harmful to the fish.

Walking the Banks
Early I mentioned a skwala sunning itself on the rock. This is another way to observe that does not require getting wet to find the insects. Walking along the banks will show you what has emerged. You might find insects that are in the process of shedding their exo-skeleton in preparation for mating.  In warmer months, you will also find more terrestrials insects such has grasshoppers and ants tempting fate clinging to shoreline blades and bushes.

These are a few of the more popular methods when it comes to determining the sub-aquatic life forms in your favorite river, stream or still water. Take the time to observe, collect and investigate and your trout fishing will likely improve.