How many years a lake has been stocked and how many years of it this site can show you are two different numbers, and the “since [year]” figure on every lake page is the second one. It is real and computed from real events, but it measures the depth of the stocking archive behind the page, not the age of the fishery. Read it as a floor. The lake has almost certainly been stocked longer.
The two states are backfilled to different depths
Every Washington lake page here currently reads “since 2025”, all 75 of them, because 2025 is as far back as this site has loaded WDFW data so far. WDFW’s own catchable trout plant archive lists a separate report for every year from 2015 through 2025, plus a 2014 PDF, so the agency record goes back much further than this site’s copy of it. Mayfield Lake, a long-established Lewis County reservoir fishery, shows 43 plants and a one-year window on this site. Both are true at once, and only one of them is about Mayfield Lake.
Utah is loaded eleven years deep, 2016 through 2026, and Utah’s own stocking app is queryable further back than that. Strawberry Reservoir shows 561 stocking events across that window, which is a genuinely different kind of evidence than one year of Washington data can offer for any single lake.
What this means in practice
Do not read a short “since” date on a Washington lake page as a sign the fishery is new or unproven. It is a statement about this site’s data, not about the water. A Utah lake with a decade of plants on record is showing you something much closer to the fishery’s real long-term pattern: restocking frequency, seasonal timing, typical species mix, because there is more behind it.
The honest way to use this stat
Treat “plants on record” and “since [year]” as a measure of how much verified history this site can show you for that lake today. As earlier years of the Washington archive get loaded, that number will move backward, and the gap between the two states will close.