LEWISTON, Idaho — In three decades of capturing and tagging white sturgeon, researchers with the Idaho Department of Fish and Game have handled more than 4,000 fish. Of those, fewer than ten have measured longer than 10 feet, and the people taking part in the sturgeon-sampling work hadn't caught one that big in more than five years.
As the year 2021 wrapped up, that changed in what regional fisheries biologist Joe DuPont called an "amazing week" on the Snake River in Hells Canyon.
In a recent IDFG blog post, DuPont writes that his group was having difficulty hooking a sturgeon one day, as the fish were biting very lightly and, "if you didn't get to the rod quickly, you missed your opportunity."
DuPont said the team adjusted their strategy by staying focused on their rods, so that when the rod moved, they did not wait to set the hook. It's a strategy that soon paid off.
"When it launched itself into the air, we all gasped at its size," DuPont said of the sturgeon on the line. "An hour and 15 minutes later, we boated this monster that measured 10-feet, 1-inch long. Not only was this fish long, it was also fat. It taped 50 inches around its belly!"
DuPont said researchers had never caught and tagged that particular fish before, "which was surprising seeing it has been around a long time."
After tagging and recording data about the fish, which they released, the group headed downriver to meet up with a group in another sampling boat for lunch -- and maybe a little bragging, but it turned out that whopper of a story had another chapter.
"When we found them, they were hooked up into a large sturgeon of their own," DuPont said.
That team landed the fish about an hour-and-a-half after hooking it, DuPont said. It measured 10 feet, 4 inches, and was 54 inches around. Like the first fish, DuPont said this one was also a sturgeon researchers had never caught and tagged before.
That's not all.
Over the rest of that week, DuPont said the group landed another 10-footer twice.
"This was the sixth and seventh time we have landed this particular sturgeon. The first time it was caught was in 2010 and it measured 9-feet, 10-inches. Eleven years later, it now measures 10-feet, 4-inches. It was not as fat as the other two, but massive none the less," DuPont said.
White sturgeon reside in the Snake, lower Salmon, and Kootenai rivers, according to the Idaho Department of Fish and Game website.
Each year, DuPont and other researchers with Idaho Fish & Game, Idaho Power and the Nez Perce Tribe spend time fishing on the Snake River in Hells Canyon so they can measure, tag, scan for previous tags, and evaluate the condition of the sturgeon they catch. This takes place between Hells Canyon Dam and Lower Granite Dam. DuPont said that work helps increase understanding of the growth, movement and mortality of the fish, and helps highlight areas of concern where the researchers may want to do more focused work in the future. One example of more focused research relates to the growth rates of juvenile white sturgeon.
However, one of the most frequently-asked questions is, "just how big do sturgeon get?"
DuPont said the biggest sturgeon researchers have sampled was 10 feet, 8 inches long and bottomed out a 500-pound scale.
White sturgeon can live to be more than 100 years old. DuPont said it's difficult to tell if the big fish from his most recent research trip are that old.
DuPont said, based on the growth rates researchers are seeing now, their age is largely dependent on whether they lived in Lower Granite Reservoir for part of their life or not.
"If they lived in the reservoir, they are likely around 70-90 years old," he said. "But if they lived in the river their entire life, they would be over 100 years old!"
DuPont has the following tips for anglers who want to go after big sturgeon:
- Use heavy line. We like to use 60-pound test mono for the main line with 80-pound test leaders. Although you can fish with heavy braid (150-pound plus), I don't like to use it because when it wraps around fish it can cut into them.
- If you hook a big fish, it is important that you follow it closely with the boat. It is almost impossible to land a 10-footer from shore. You will often have to fight fish of this size for over an hour, and if you don't keep the boat above it to keep the line off the bottom, the repeated wear on the line as the fish hugs the bottom will eventually cause you to break it off.
- Use big hooks. DuPont says, "I prefer to use 12/0 circle hooks or 'J' hooks 10/0 or larger. I have found that with smaller hooks you often don't get a good bite into their lip, which will make it more likely that it will eventually pull out.
It is illegal to keep sturgeon; those caught must be released.
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