Henrys Lake provides a unique opportunity for anglers to catch trophy-sized trout through the ice. It recently produced two catch-and-release state records for brook trout. On Dec. 11, Kazen Cromar caught, measured and released a 22-inch brook trout while ice fishing on the lake, surpassing the previous catch/release record set by Kordin Miller on Dec. 2.
The lake has long been known for producing monster rainbow/cutthroat hybrids and brook trout. Up until 2011, the season closed at the end of the November, but since then, Fish and Game extended fishing to allow for an abbreviated ice fishing season with a two-fish limit (fishing on the lake is closed to all angling Jan. 2 through Friday before Memorial Day weekend).
Regional fish manager Dan Garren tells us more about ice fishing at one of Idaho’s most famed fishing lakes.
Q: Many anglers equate ice fishing with an opportunity to harvest lots of perch or a six-fish limit of trout, or both, but not a two-fish limit. Explain why fisheries managers decided to open this unique opportunity.
Garren: Henrys Lake provides one of the best opportunities for anglers to catch trophy trout in Idaho. Trout growth rates are among the fastest we’ve been able to document across the state, but this fast growth is offset by a high natural (non-angling related) mortality rate.
As a result, most trout don’t live long, with most dying at ages 3 or 4. Very few fish survive to reach 5 or 6 years, and we rarely see a trout live to 7 years old. The combination of fast growth and a high natural mortality rate allows managers to provide a lot of opportunity for anglers, which can be high bag limits, longer fishing seasons, or both.
In the case of Henrys Lake, we have chosen to increase the fishing season, but leave the bag limit at two fish. Anglers have told us that they value the opportunity to fish Henrys longer into the winter, and the quality of the ice fishing opportunity is rare.
Q: The timing of these two record brook trout is interesting considering the catch-and-release records started on Jan. 1, 2016, which meant ice anglers only had one day to fish the lake. Did it surprise you to see these two record brook trout come out of the lake early in the ice fishing season considering others anglers had months to catch them?
Garren: I’m slightly surprised that the record for brook trout wasn’t set earlier during the open water season on Henrys. For several years running, we’ve had some very healthy brook trout being caught. Anglers have reported many brookies in excess of 20 inches this season, but according to the record book, the biggest brook trout registered up until November was only about 7 or 8 inches.
I think that it took an astute angler to recognize the potential for getting their name in the record book, and after the word got out about the new record fish program, others took note and participated as well.
It’s worth noting that the Yellowstone cutthroat trout record is only at 21.5 inches, and there isn’t even an entry in the rainbow/cutthroat hybrid trout category yet. Those are low hanging fruit if an angler wanted to release a big fish and get his or her name in the record book.
Q: Henry’s obviously has a reputation for big fish, but what’s the average size, and does it change in winter?
Garren: The average size of each species varies, and it can vary by year, too. Trout size in Henrys Lake can change depending on how many fish are out there competing for the food resources that are available.
Our most recent population survey was done in May, and we found mean size of cutthroat to be 14 inches, brook trout to be 13 inches and rainbow/cutthroat hybrids to be 18 inches. By winter, those fish have added another 2 to 3 inches in length.
We maintain a stocking program to support the fishery, and routinely stock between 750,000 and 1.5 million fingerling trout (brookies, cutthroat and hybrids). Adding to this, Fish and Game along with our partners, such as the Henrys Lake Foundation, Trout Unlimited, Fremont County, local landowners and more, have worked to improve spawning conditions in the tributaries around the lake.
These efforts have resulted better conditions, but inconsistent natural reproduction adding to the population. When we have good survival of our stocked fish and also get substantial natural production, we end up with too many fish competing for the food that’s out there. This ends up slowing growth, and after a couple years, we see the mean size go down.
Right now, we have slightly lower densities of trout than we want, and this has caused mean size to increase, and has also contributed to the trophy trout that are being caught this year.
Q: There was some concern early on about possibly over harvesting trout when ice fishing started, and we’ve now had five years of ice fishing. What have you learned about its effects on the trout populations in the lake.
Garren: On many waters, ice anglers have a reputation as being harvest-oriented, which can cause concern for overharvest, or the perception of overharvest. We’ve done several studies on Henrys both before the ice fishing opportunity increased in 2011, and after to monitor how many fish anglers catch, and how many they keep.
We see release rates during the ice fishery that are identical to those during the open water season. In general, both open water anglers and ice anglers on Henrys release 80 percent or more of the fish they catch.
In part this can be attributed to the fishing rules we have in place that require anglers to stop fishing for the day once their harvest limit has been reached. For an angler fishing a trophy water like Henrys, this means they need to be selective on what fish they harvest.
If you keep a nice one during the first half-hour of your trip, and then catch a giant on the next cast, if you decide to keep it you are done fishing for the day. So anglers seem to be reluctant to harvest trout quickly at Henrys. Along with that, we can see some extreme weather in December in eastern Idaho, and that can limit the number of people willing to go fishing on any given day.
But in general terms, we are very confident that the current level of effort and harvest experienced during the ice fishing season is not having a negative impact on the fishery. For comparison, we see as many fish harvested during the opening week of the fishing season as we do during the entire ice fishery.
Based on the studies we’ve done to date, the number of fish in the lake has a much bigger impact on fish size and catch rates than do the impacts of increased fishing pressure and harvest.
Q: After Henry’s Lake closes for ice fishing on Jan. 2, what other ice fishing opportunities in the region should be anglers know about?
Garren: Unfortunately, we don’t have a lot of lakes that can compare to Henrys in terms of trophy trout fisheries, but we do have other waters that are worth considering. Island Park can produce rainbow trout up to 20 or more inches, but it can also be a fickle fishery.
Ashton Reservoir is one of the more overlooked opportunities we have, and it can be entertaining with high catch rates for smaller trout. It’s worth noting that the current brown trout record was caught out of Ashton. If the weather stays cold, Ririe Reservoir should freeze, and it will also provide a great opportunity for kokanee and rainbow trout.