You may have seen the recent story about a massive catfish caught in C.J. Strike Reservoir that set a new catch-and-release state record, and now the story gets more interesting. Paul Newman’s giant catfish will remain a record – but with a twist – it is now the first-ever Idaho record for blue catfish rather than channel catfish. The previous catch-and-release record for channel catfish will stand.
It was a simple case of mistaken identity that stumped both the angler and biologists. The two species can be difficult to tell apart, especially when their coloration and features can be similar. Identifying species by looking at a photograph can be especially challenging – even for biologists – because subtle details often differentiate between two fish species. Considering the fish was released, it could not be closely examined.
The possibility of Newman’s catch being a blue catfish was raised earlier, but after investigating stocking records, Fish and Game biologists considered it unlikely because blue catfish are nonnative to Idaho (so are channel catfish), and have not been stocked for decades.
Fish and Game’s historic stocking records showed blue catfish may have been stocked in a small number of lakes and the Snake River as late as 1985, but biologists have never encountered them during fish surveys at C.J. Strike, and there are no records of blue catfish stocking since then.
So the origin of this fish remains a mystery. Catfish stocked in Idaho are typically channel catfish, and they often come from fish farms in the Southeastern U.S. It’s possible that a few blue catfish got mixed in with the channel catfish and ultimately ended up in Idaho.
It’s also possible one of Idaho’s commercial catfish producers near the Snake River had a blue catfish mixed with their channel catfish. Occasionally, those fish escape and make their way into public waters. Fish and Game staff have documented several blue catfish in the Snake River in recent years below facilities raising channel catfish, so it's a remote possibility that some blue catfish are out there, but they would still be very rare.
An angler’s chances of catching a blue catfish in Idaho remains slim, although it’s obviously possible. Most anglers are likely to catch channel catfish, which are still Idaho’s most common and widely distributed catfish.
The Snake River and its reservoirs will likely continue to produce big catfish. Brownlee Reservoir and the river immediately upstream are also home to giant flathead catfish, which currently hold the title for Idaho’s biggest catfish. The state-record flathead was 58.5-pounds and 48 inches long, which was caught in 1994.
Here's more about the difference between blue catfish and channel catfish.