Got back into fly fishing for trout on the east side this spring, Forgot how fun it can be. Started to check out the WDFW Hatchery Trout Stocking Plan for lakes around the state. Noticed the E. Wa lakes get lots of fingerling plants. My question is how long does it take them to grow to there max? Say to 18"-20". What is there life span? I understand a little about how they are victims of their environment, so lake size, water temperature and food supply play a role. But on average, how fast can they grow and how long do they live?

Depends on the lake. A fingerling is supposed to be about 8-10-12" for the next spring opener; larger east and smaller west. At least on the westside, the tapeworm Diphyllobothrium (sp?) tends to kill them all off the next summer so carryovers are few and far between on the westside. One the east they would be in that 18-20" range the second opener.

As more lakes now have spiny rays it has become way more difficult for WDFW to rotenone them to maintain a fingerling program. Consequently, they need to stock larger fish (costlier, fewer). At the same time, stocking (say) an 8" fish in the fall-and not catching it until the next spring-would give you a larger "yearling".

I know some of the management bios were working really hard to increase individual fish size in the stocked lakes but it does come at the cost of fewer to catch. But on the lakes I checked, there was a really noticeable difference in size (and even appearance) of these larger fish.

It becomes a difficult problem to balance the desire to take home a mess of fish (size rather immaterial) and one or two toads. Can't make everybody happy everywhere.

RUNnGUN-

Few planted trout in low land lakes survive past their second year (end of their third year). The potential size of such fish is depended on a couple factors; such as brood stock source, planting density and lake productivity.

On the west side as CM said shore line and the spread of warm water species (and interest in fishing for them) effectively brought the "lake rehabilitation program" to an end. Managing lakes as single species allowed that managers to create trout fisheries with both higher densities and larger sizes. The ultimate death knell to west side fingerling programs and an effective limit on the numbers of potential catchable planted was the rebound of the double crest cormorants during the early/mid 1980s.

Curt

Something to note about the "rebound" of cormorants. They (DC's, Brandts, Pelagics) did not nest in the interior waters of the Salish Sea (BC or WA) until the 20s or 30s, I believe. The recent papers I have seen have documented a spread into the inside waters and the primary reason given was the decline in egging by Indians. They used to nest on the inaccessible portions of the coast. So, they are an invader.

In my opinion, by far the biggest bows you'll catch in Eastern WA is on put and take lakes planted with fingerlings the third year after a rehab.
Whatever survives into that third year will be a memorable fish.
There is a picture of a 10 lb bow in Mar Don from one of the lakes we used to fish a lot.
Yes, our lakes produced big bows longer before the state started their stupid triploid program.

There are certain put and take lakes on the west side that tend to produce larger numbers of carryovers then other lakes.
SF

Fake news. The tribes have always lived in harmony with the ecosystem and would never harvest something enough to impact the population.

Wdfw could save money by managing lowlands like high lakes instead of giant aquariums with no food.
Throw a few fry in and hope for the best.

WDFW used to manage the lowland lakes by fry/fingerling plants. It worked really well until the essentially lost the ability/desire to use rotenone and the expansion of spiny-rays in the lakes. The little trout don't compete well with the exotics.

Put and take is now the only way they can, given the constraints they work under, get fish into creels.