Compared to historical information, not much has changed in the spawning run of trout at William’s Lake. The last time IDFG operated a weir on Lake Creek was 2006. That year, the weir ran for a shorter period of time, but captured a similar number of adult trout (300). One thing that stood out was that the average length of fish was actually the same as what we observed in 2023 at 16 inches! From the 1940’s to about 1970, the weir operated frequently on Lake Creek to collect eggs and milt for hatchery stocking both in Williams Lake, as well as other fisheries throughout the region. Looking back to 1967, one of the last years the weir was operated for hatchery purposes, reveals that even after 60 years not much has changed! The weir operated for seven weeks and trapped 393 Rainbow Trout with an average length of 13.5 inches. Most interestingly, the catch in 1967 was 66% female, almost identical to what we observed in 2023 at 65%. The similar trends in the data from 1967, 2006, and 2023 reflect positively on the Rainbow Trout population today, especially when considering that Williams Lake was stocked regularly prior to 1984 and Bridgelip Suckers now occupy the same space. If we had seen a noticeable decline in the numbers or size of Rainbow Trout trapped at the weir this year,  it may have been an indication of limited resources or a decline in spawning activity. Luckily this was not the case. In fact, average fish size in 2006 and 2023 was larger than the most recent historical account, which is great news for anglers.

The weir was a useful tool to monitor the status of the spawning population of Rainbow Trout in Williams Lake, and compare to past trends.  Since the Bridgelip Sucker population has only been recently documented, it will be important to continue to monitor any changes in the Rainbow Trout population. IDFG staff are planning on conducting a variety of additional fish population surveys on Williams Lake throughout 2023 to gather as much data as possible, so stay tuned for the next blog! In the meantime, if you catch a fish with an orange T-bar tag, please be sure to report at tag.idaho.gov or use the phone number listed on the tag!