Most experts agree that sight plays the major role in bass food acquisition.  Bass have remarkably well adapted eyes for the environments they inhabit. They see shapes, colors, movement and distance very well at mid and close range.  Eye arrangement in the skull allows for binocular and wide peripheral vision.  This enables bass to locate and study their prey and assess how to best attack it.  Sometimes a bass will study prey and stalk it for a matter of minutes before attacking.   However this stalking process can start long before prey could possibly be in visual contact.  Often you will see a bass start to edge toward your fly while it is still obscured from direct view by weeds or other obstructions.

This is because bass also have a very acute sense of hearing.  Sound travels more efficiently through water than through air.  Bass use this efficient sound transfer to locate prey in weeds, turbid waters or low light conditions.   They hear normal frequency sounds with an inner ear very much like our own.  They detect low frequency sounds with special nerves located along the lateral line.  It is believed that bass may very well be able to judge the size and kind of prey as well as relative distance through sound.  This is why flies and lures that pop, whir, rattle or gurgle are so effective.  The sound gets the bass' attention.   Bass are always listening for prey that is in distress and vulnerable.  When the bass is alerted by sound it will stalk by sound until visual contact is made.  Fine tuning the attack is done after the prey has been sighted.

(to be continued in 06/25/01 FFS Insider)

Why we love the Deschutes River

Pale Morning Dun Mayflies are very small.  Most species that hatch on the Deschutes River in July are size eighteen.  It can take vast numbers to make a meal.  Some trout feed on them voraciously.  They are obviously very tasty.  However, the trout concentrate only on certain stages of the hatch.  Some trout, especially during the early part of the hatch, hold tight to the tops of weed beds.  Here they take the slim red-brown and olive nymphs as they emerge from the vegetation.  These nymphs are so tiny that the fish work at extremely close range.  Often the feeding lane is less than a foot wide.  These lanes are always positioned in line with the maximum concentration of insects. 

Many holds are textured valleys worn away by the abrasion of the currents.  Often these weed beds are situated near the shore in soft smooth flows.  A sneaky approach and careful observation will disclose trout making sporadic swift attacks while rarely moving more than a foot in any direction.

            A size sixteen unweighted Pheasant Tail Nymph is a deadly imitation for this stage of the hatch, but only if fished precisely.  The fly must approach the fish with absolutely no drag.  It must be in the feeding lane and on the trout’s level to bring success.  Study the currents carefully before you cast.  Place your fly upstream, mend your line, and let the fly come to the fish.  This is most easily accomplished when fish are within close range and holding in relatively shallow water.  These fish are often spooky, and the angler gets few second chances.

            Once Pale Morning Dun nymphs leave the bottom and are dispersed among the currents, they become hard to see and are therefore difficult to catch.  The trout tend to ignore them and concentrate on the surface tension.  Here the nymphs fight their upper thorax through the meniscus.  Their backs split open and the adult insect crawls out on top of the surface film.  Some hatch easily, while others have problems making this transition.  All are helpless during the state of transition from water breathing to air breathing existence.  All are easy prey.   Many trout prefer to intercept these hatchlings at the exact moment they are most vulnerable.  They can neither swim nor fly.   
The rise form is a deception waiting to happen.       (to be continued in 06/25/01 FFS Insider) 

If you would like to read a detailed Deschutes River Fishing Report, click here.

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Sandy River Fishery Information Bank
Daily Fishing Report
Watershed Over-view
Sandy River Book
Biology Etc. 
Watershed Council Web Site

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