views updated May 14 2018


Do fish really see leaders and shy away from them, or is it more often an unnaturally moving fly that they avoid, or both? I believe fish notice the drag or unnatural motion imparted to the fly from an unnecessarily stiff leader rather than the visibility of the leader. The late Charles Brookss experiment using highly visible size A white winding thread as a tippet supports this theory. So called leader shy fish readily took Mr. Brookss fly when he fished it with size A thread. The thread was highly visible, but it was extremely flexible.

The new fluorocarbon leaders interest me. Underwater they seem to disappear. Consequently, I can get away with using a heavy leader, which is an advantage in fighting a fish. A loop knot tied to attach the fly to the tippet allows the fly excellent freedom of movement. Perhaps their other advantage is that fluorocarbon leaders are denser than monofilament leaders and inherently sink. A floating leader seems to disturb the surface film because its movements reflect light and cause waves. A sunken leader does not disturb the surface. In short, when fishing for highly educated trout I opt for either a long flexible tippet or a fluorocarbon tippet with a loop knotted fly.

Sinking line leaders are simply three to five foot sections of tippet slightly tapered and attached to about one foot of heavy leader attached to the fly line. Leader Test: A leaders test refers to its relative strength and size.

I prefer to use heavier tippets than most other fishermen. I like to forcibly fight my fish so that they can be quickly released unharmed by fatigue. I get away with heavier tippets by using a very flexible material such as Dai Riki Velvet or a fluorocarbon tippet with a loop knot fly attachment. My tippets generally average about four feet in length. This system gives me adequate strength for fighting fish, pulling out snags, and abrasion resistance.

The general rule about leader length is occasionally broken when fishing sinking lines in lakes that are weed infested. Under these conditions, I use a long leader that buoys upwards somewhat and allows me to retrieve line out of the thick weed beds. I also use a slightly faster sink rate line than ordinarily needed with this long leader. The buoyed fly is pulled downward during the retrieve; likewise the fly buoys upwards during the pause. The faster sinking line gets my fly down quickly and saves time. The rise and fall of the fly is an effective retrieve. A slightly buoyant fly pattern accentuates this motion. Flies tied with deer hair such as Werner shrimp and Muddler minnows are effective. The leader length I use varies between 8 and 10 feet.

When fishing a dry fly, I lessen water splash due to casting by using a longer than normal leader. Fifteen-foot leaders carry fewer water droplets and are useful in very calm, clear water conditions. They make transparent false casting above the fish less noticeable and less likely to cause alarm. Lake fishing with midges and a floating line may require extraordinarily long leaders. When retrieved towards the surface, these long leaders permit flyfishers to imitate the slow ascent of midge pupa. The extreme

lengths allow these leaders to sink to the bottom.

Loop to loop leader connections are popular because they facilitate easy and fast changes to a new or different sized tippet. Their disadvantage is that the loops may hang up a fly cast with a tailing loop.

Wind knots severely weaken leaders. When I discover one, I replace the wind knotted section of the leader or untie the wind knot if it hasnt yet pulled tight.

The butt section needs to be a next size lower than fly line diameter. Leaders taper towards the tippet in progressively finer diameters to permit the casting loop to unfurl the leader on delivery.

Heavily wind resistant flies call for stiffer materials to straighten out the leader. Casting a tight loop increases the flys momentum by increasing the line speed. Small flies require smaller diameter and more flexible leaders to cast properly.

Its best to become a proficient caster: a well cast leader will always straighten upon delivery. Controlling line speed and loop

size are important casting skills. The most demanding conditions are those of crystal clear waters with smooth surface flows and mini current disturbances caused by weeds and minor obstructions. Fishing the surface under these conditions demands the most from a leader. You can overcome these adversarial conditions by using as flexible a leader as possible. A stiff leader causes the fly to float unnaturally.

I like my leaders to sink just under the surface. When leaders float, they disturb the surface by reflecting light and causing ripples. Leader sink products are useful, and so are techniques like pre-wetting the leader prior to casting or rubbing mud or weed slime on the leader. Just prior to fishing, you can also soak a leader in a water-filled zip lock bag.


views updated May 21 2018


Visibility generally refers to the quality of vision through the atmosphere . Technically, this term denotes the greatest distance in a given direction that an observer can just see a prominent dark object against the sky at the horizon with the naked eye. Visibility is a measure commonly used in the observance of weather in the United States. In this context, surface visibility refers to visibility determined from a point on the ground, control tower visibility refers to visibility observed from an airport control tower, and vertical visibility refers to the distance that can be seen vertically into a ground-obscuring medium such as fog or snow.

Visibility is affected by the presence of aerosols or haze in the atmosphere. In the ideal case of a black target on a white background, the target can be seen at close range because it reflects no light to the eye, while the background reflects a great deal of light to the eye. As the distance between the observer and the target object increases, the light from the white background is scattered by the intervening particles, blurring to some degree the edge between the target and the surroundings, since light from the background is now scattered into the line of sight to the black target. In addition, the whiteness of the background is decreased by the scattering of light out of the direct line from the background to the eye, and by the absorption of some of the light by dark particles, principally carbon (soot). Finally, particles in the line between the target and the eye scatter light to the eye, decreasing the blackness of the target as seen from the distance. At any distance greater than the visibility, then, all these actions degrade the contrast between the object and its background so that the eye can no longer pick out the object.

Some light is scattered even by air molecules, so visibility through the atmosphere is never infinite. It can be great enough to require correction for the curvature of the earth, and the consequent fact that atmospheric density is less (fewer scattering molecules per unit of distance) at the end of the sight path than at the location of the observer.

Air pollutants now produce a haze that circles the globe, significantly reducing visibility even in places as remote as the Arctic. In areas of industrial concentration, haze may consistently reduce visibility by as much as 40%. In addition, gaseous molecules scatter light; and some gases, most notably nitrogen dioxide, absorb light in the visible range, thus changing the apparent color of the background. The effects of air pollution on visibility are quite well understood, unlike some other effects of this pollution on human health and the environment .

See also Arctic haze; Photochemical smog; Smog

[James P. Lodge Jr. ]



Middleton, W. E. K. Vision Through the Atmosphere. Toronto: University of Toronto Press, 1952.


Lodge Jr., J. P., et al. "Non-Health Effects of Airborne Particulate Matter." Atmospheric Environment 15 (1981): 449458.


views updated May 21 2018

vis·i·bil·i·ty / ˌvizəˈbilitē/ • n. the state of being able to see or be seen: a reduction in police presence and visibility on the streets. ∎  the distance one can see as determined by light and weather conditions: visibility was down to 15 yards. ∎  the degree to which something has attracted general attention; prominence: the issue began to lose its visibility.