The instructions were explicit: Don't waste time with the big ones.
Simple enough. In plain talk it meant that as a crew member on the night-time fish study of the Green River below Flaming Gorge Reservoir, duties required netting fish, not trophies.
Standing on the bow of the aluminum boat, holding onto the safety rail and looking down at several dozen fish as they surfaced, the smallest about the size of a man's hand and the largest big enough to make a snack of the smaller fish, the temptation was too great.
Down went the dipnet toward the head of a fish much longer than the net was wide, up came an empty net.
Ignoring other fish, down went the dipnet again, then up it came — empty. Down it went again, for a third try, and the result was the same. By now, the boat had passed the backwater cove and what should have been a cache of fish.
Then it became ever so clear: There was good reason to ignore the trophies. Fish too big for the nets are impressive but impossible to study if you can't catch 'em. Still, I tried.
Biologists back on the launch ramp, where a makeshift laboratory had been set up, needed fish for their study, and on that one pass I contributed not a single fish.
Over the next 10 minutes, however, I scooped up, sometimes two and three at a time, between 50 and 60 fish — browns and rainbows, mostly, with an occasional whitefish in the pool. I lost count of the total in the hurry to swing the long-handled net between the surface of the water and the large livewell in the center of the boat.
Once a year, volunteers and staff from the Utah Division of Wildlife Resources conduct a two-night electro-fishing study on the Green River below Flaming Gorge Dam.
The first night, crews worked along a one-mile stretch below the dam. The second night they moved to Little Hole and netted fish downstream for about a mile and a quarter.
These same two sections have been sampled since 1986, "Which means that from our studies we can pretty much tell what's happening on the river," said Roger Schneidervin, project leader at the Gorge for the DWR.
The seven-mile stretch of Green River below the dam is one of the most heavily fished sections of river in Utah and is recognized as one of the best trout-fishing waters in the country.
People come from all over the world to throw a fly or spinner at the fish in the Green. There are days over the summer when it's nearly impossible to find casting room.
It is therefore important, said Schneidervin, "that we know what's happening on this river."
He set 800 fish as a target for each night's catch. Crews work at night because fish aren't as spooked by the movement of the boat and come into shore under the cover of night to feed, so it's easier to hit quotas.
Back in the 1990s, population counts showed there were between 20,000 and 21,000 fish per mile through the seven-mile stretch. It's a number chipped in stone, said Schneidervin. "I still get people asking if those numbers are right . . . but, conditions change and numbers change. But, no, there are still a lot of fish in this river."
In this study, fish popped to the surface like corks, as many as 20 or 30 at a time.
"We do this annual collection for population trend assessments," Schneidervin said. "Information we gather we use for management. For example, we access the survival of the seven-inch rainbow we stock at the tail end of high flow released in May. It's a chance to see how they came through the summer.
"This information was particularly critical during the real high flows of 1997 and 1999, and to see the siltation effects in the river after the Mustang Fire. And, now, with the New Zealand mud snail and some siltation still coming from Dripping Springs, it's important we know the conditions of the fish."
The boat is equipped with a large floodlight and a generator that releases, through small probes, an electrical shock into the water which stuns the fish. As they surface, some of the fish are netted and placed in a livewell. They are then transported back to the makeshift lab on the ramp, where they are identified according to species, measured, weighed and released.
To help in identifying ages of planted rainbow, the fish were marked at the hatchery with a dye, which when placed under a black light shows up as one of three colors — green, red or yellow — each representing a year. This helps biologists monitor growth rate, survival and natural reproduction.
"What we found last year," explained Schneidervin, "is the condition of all age classes of fish, both for rainbow and brown, declined slightly at Little Hole, where we have mud snails and siltation, but remained constant at Tailrace, upstream near the dam. It's nothing to be alarmed about. The condition of all fish we checked was good. But if this trend continues for three or four years, then it will tell us we may have a problem."
A team of Utah State University biologists was at the ramp to check on the stomach content and condition of the fish.
Biologists are able to monitor the conditions of the fish by getting what is called a "plumpness index," which is a ratio of weight to length. All of the fish checked on the first night were plump; there was certainly no sign of a food shortage.
All the data collected from the 1,600-plus fish will be fed into a computer. The findings will then be compared to past samples.
It has also been found through these studies that lowering the amount of water released from the dam to more consistent flows has improved fish health and, equally as important, natural reproduction.
"Without the big differences in fluctuations during high spring flows, we've seen where it's helped the young fish and has resulted in better natural reproduction," Schneidervin said. "The past two years, nearly 10 percent of the rainbows we've handled in the fall are naturally reproduced fish, which is up from what was typically 1 percent to 3 percent through the 1990s."
It has also changed the distribution of fish in the river. Typically, the preponderance of fish around the dam has been rainbow, where most of those downstream at Little Hole have been browns.
During high-flow periods, the ratio near the dam was 80 percent rainbow and 20 percent browns. Currently, it's 60 percent rainbow and 40 percent browns, "and the numbers are getting closer and closer to a 50-50 split," added Schneidervin.
Preparations for the study began at dusk. The first collection site was about 100 yards up from the ramp, the second a couple of hundred yards downstream. It took only seven trips to collect the needed sample size.
In all likelihood it would have taken less if the netters, certainly myself included, had been able to focus their attention away from the trophy fish.
E-mail: grass@desnews.com