Cutthroat Confusion Resolved

A Yellowstone Cutthroat stocked this summer

THE Norfork National Fish Hatchery has switched to rearing Yellowstone Cutthroats for better survival rates, despite some confusion with progeny of the Trout Unlimited #698 Bonneville Cutthroat rearing program.

AGFC trout management program supervisor Christy Graham told the Journal yesterday that some anglers were having a hard time telling the two subspecies apart. But as the Yellowstone cutties aged the differences could become more apparent.

The AGFC has also pledged to fin clip future Yellowstone Cutthroat stockings.

The Yellowstone cutthroat and Bonneville cutties both have bigger spots and a sparser pattern than the familiar Snake River Finespots. But the Yellowstone cutties spots are more densely packed towards the tail.

Christy said the higher survival rates with the Yellowstone’s this year meant 65,000 cutties could be stocked this year below Bull Shoals, almost double what was intended

The stocking program also included 12,000 brookies in the first 2 miles of the White and 6300 in Norfork Tailwater.

The AGFC is hosting an information meeting Thursday night to outline program with the two year old management plan . The meeting will be held at Arkansas State University, McMullin Lecture Hall (Room D200 in Dryer Hall) on Thursday, August 15th from 6 pm to 8 pm.

Hey Steve,
Thanks for your email.  I’ve received several other inquiries regarding Cutthroat recently, so I’m happy to be able to provide some more information on this new opportunity.

This year, the Norfork National Fish Hatchery made a switch in the cutthroat trout sub-species that they raise and stock, from the Snake River Finespot Cutthroat Trout to Yellowstone Cutthroat Trout. 

In years past, the hatchery would receive Snake River eggs in the summer (~ June).  It usually takes the eggs about a month-two months before they get to a size when they can convert the fish to feed (~ August).  As many folks know, August-September is the time of year when water quality in our reservoirs begins to decline.  During that period, water quality in the hatchery also begins to deteriorate (since the water supply comes from Norfork Lake), which results in poor dissolved oxygen and high nitrogen levels.  Both of those factors can have severe impacts on fish survival and quality.  There were some years where Finespot Cutthroat Trout survival was extremely poor and very few fish survived until they could be stocked. 

Now, the hatchery has switched to Yellowstone Cutthroat Trout because they can get their eggs earlier in the year (~April), which means they can raise the fish to bigger sizes before the water quality begins to decline.  The bigger the fish, the better they are able to withstand those stressors in the hatchery.  This was the first year that they were stocked and the hatchery had a much better time getting those fish to survive.  Approximately 5,000 were stocked in Norfork TW in May and approximately 64,000 were stocked in Bull Shoals TW (between the dam and Buffalo City) in July.  The plan was to only stock ~35,000 in Bull Shoals TW this year, but the Yellowstones did so well we stocked double the number. 

Due to the similarities in appearance between Yellowstone (stocked) and Bonneville (egg-planted) Cutthroat Trout, some anglers are having a hard time telling the two sub-species apart.   Right now, they are easily distinguished by the fact that the hatchery fish have eroded fins (hatchery-nubs for pectoral fins), while the Bonneville fins are in perfect condition.  As they grow, we hope that they become more distinct from one another. 

In general, the major difference between the two is a tendency for spots on the Bonneville cutthroat trout to be larger and more evenly distributed across the body, while Yellowstone spots will have a greater concentration of spots toward the tail.  That’s not a perfect identifier, and we understand the confusion. 

To avoid this in the future, we will be sure to fin clip stocked fish so the two sub-species can be easily identified by the angling public.  Rumors are going around that AGFC initiated this confusion on purpose (to have an effect on the successful evaluation of the Bonneville project), but that is simply not the case.

  It was all related to the hatchery’s ability to raise the fish and figuring out a way to continue to provide anglers with the opportunity to catch Cutthroat Trout in these tailwaters.

Hope that clears some things up!