The mood of the Henry’s Fork community in May of 2010 was one of cautious expectation and optimism. With a new season directly ahead all visible 
signs were positive with regard to the health of the fishery.
2009 had ended on an amazingly favorable note with hatches and the resultant fishing opportunity being unanimously declared as being the best in more than a decade by locals and visitors alike. With Island Park reservoir at nearly 60% of capacity in early November, hopes for a repeat of the favorable winter flows of the previous year were realized as December arrived and releases from the dam reached 400 cfs.
For several decades, scientists had become convinced that adequate winter flows were the most critical factor in juvenile trout survival on the Henry’s Fork. With cooperation secured from irrigation interests by the Henry’s Fork Foundation, winter flows from earlier in the decade which were far short of optimal were gradually improved as more normal weather patterns began to replace several years of severe draught.
The revival of the Henry’s Fork fishery in 2009 was the result of three consecutive years of off season flows which allowed increased numbers of young rainbows to endure the harsh Island Park winter. The consistent release of 350-400 cfs this past winter were the best we had seen since 1997, and anticipation of another successful year ran high among Henry’s Fork outfitters and guides. But as spring drew near, it became apparent that diminished snow fall from early January through most of March had left the mountain snowpack at an alarmingly low level.
Despite general optimism for the immediate season, a cloud of gloom crept over the fishing community as concern for future winter flows began to mount. A continuation of dry weather extending through summer would assure severe draw down of the reservoir and the subsequent end of a positive trend in fish saving flows in the critical months that would follow.
In most years, a six to eight week period of near constant rain and below average temperatures would sour the disposition of any angler especially when it occurs at the beginning of a long awaited spring. But to we who depend upon the Henry’s Fork fishery for our existence, the soaking rains and snow preserving temperatures were a source of tremendous relief. By late May, the snowpack had reached normal levels and the farmlands of the lower valley were thoroughly saturated. And while two more weeks of unusually cool and wet weather provided extra insurance pertaining to water supply, it came at a price.
Losing nearly the entire Salmon Fly hatch in late May and early June was costly to Island Park businesses that rely on visiting anglers to stay afloat.A restless lot by nature, the river guides became especially grumpy as foul weather kept them confined indoors as the opening of the Ranch drew near. But as the skies cleared and temperatures reached more seasonable levels, it was as though a flood gate of bounteous hatches and rising trout had been released.
Almost overnight, fishing on the entire river from Island ParkDamtoSt.Anthony sprung to life with water conditions that were ideal and weather ideally suited for wading or floating the Henry’s Fork. While somewhatdelayed the Gray, Green, and Brown Drakes produced consistent fishing for large trout from mid June through early July. Golden Stones followed on the heels of the big mayflies and hatched simultaneously with theFlavs until the second week in August. Numerous caddis hatches joined March Browns, PMDs, Callibaetis and Tricos to provide the kind of consistency that can only happen on a truly healthy river.
Hopper fishing from mid August through an unusually pleasant September was even better than 2009 which everyone agreed as exceptional.
The warm weather of mid summer through early autumn was especiallyfavorable for the smallerterrestrials. Winged Ants in size 14-20 were a daily feature for more than two months. And despite their relatively small size some of the largest trout of the season were taken on this favored trout food. Beetles run strong competition with ants for the trout’s attention, and they were a daily feature during the period when land based insects dominate on the water.
While October was greeted with summerlike temperatures, a shift to weather more favorable to fall hatches occurred by the end of the first week. Baetis and Mahogany duns are now the main attraction as the end of another season draws near. Walking the open banks brings a feeling of amazement and gratitude as one considers the revival of life so strongly incontrast to what was observed only a few years ago. Trout of
all age classes are visible in the clear flows as they feed leisurely amid luxurious aquatic vegetation that had been devastated during the draught years.
With Island Park Reservoir approaching 50% of capacity, the prospect forcontinued favorable winter flows looks very good. This bodes extremely well for the fishery downstream of the dam which fisheries professionals estimate increased by 40% in 2010. And while a similar increase can not be assured, it is reasonably safe to assume that the positive trend of the past three years will continue into 2011. The future of the Henry’s Fork looks very bright.
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