Anyone have any idea how much wild reproduction there is in Pyramid Lake?

If you're talking about LCT - none. All LCT are spawned at the hatchery. The dams on the Truckee river upstream of the lake prevent the fish from reaching spawning territory. It's a completely hatchery-fed lake.

Is there any hope that creating fish passage at the dam would lead to fish reproducing in the wild?

This story implies that Lahontan cutthroat trout were never extirpated (local extinction) from Pyramid Lake when, in fact, they were driven to extinction by a number of causal factors.

The construction of Derby dam diverted most of the Truckee River's flow into the Truckee Canal to support irrigation in the desert and away from Pyramid Lake. With reduced inflows, the level of Pyramid Lake dropped precipitously and the Truckee River began down cutting to match the lake level.

The down cutting led to a large amount of sediment being transported into the lake and formed a delta in the lake that resulted in increased temperatures and acted as a barrier to upstream spawning migrations of Lahontan cutthroat trout (LCT). The last spawning run of LCT was around 1939 and by that point it was only a matter of time before all LCT were gone from the lake.

Today, the only remnant populations of LCT are in Summit Lake and Independence Lake. LCT were giant lake predators and occurred in streams as obligatory stream spawners or stream residents (smaller and slower growing) in the Humboldt basin outside the Pleistocene Lake Lahontan boundary or in limited numbers in the tributary streams of remnant lakes left behind as Lake Lahontan receded (Pyramid, Walker, Carson, Tahoe, etc...).

Despite the history of LCT as a massive lake predator, relatively little has been done to preserve the 0.4% of remaining lake habitat for remnant LCT populations. More money goes into producing hatchery LCT for put-and-take fisheries than goes into understanding and mitigating non-native impacts to remnant populations in Summit and Independence Lakes.

The story of this fish is long and troubled. Angler's who fish Pyramid today are mislead into thinking that the reintroduction of the Pilot Peak strain into Pyramid Lake is the end if the story when it's really just the beginning. The dams constructed on the reservation (one to stop the down cutting of the Truckee River and one for agricultural diversion) present the first major obstacles to upstream migration, yet many otherwise well-intentioned anglers cite Derby dam as the major obstacle.

If the fish get past the two dams on the reservation, they have to make it through the warmer lower reaches of the river where they'll face a functional, but non-operating, fish passage structure at Derby dam that marks the end of the upstream journey. The passage is closed due to the absence of fish screens on the diversion that takes water out if the Truckee River and delivers it to Lahontan Reservoir where it is used to support agriculture and towns in an otherwise barren desert. The screens are needed to keep Cui ui, an endemic and listed fish in Pyramid, from becoming entrained in the canal and lost to the reservoir while in the Truckee to spawn. So, until the screens are purchased and installed, passage above Derby dam is impossible.

But I said Cui ui make it up to Derby...

Yeah, so this part is mostly hearsay on my part. I've heard that the elevator at the Marble Bluff dam used to pass fish upstream is only operated when the Cui ui spawn and isn't run when it's just LCT. If LCT and Cui ui are there at the same time then they can both move up, otherwise it's just for Cui ui. Marble Bluff was built in 1975 to stop the down cutting of the river, but it also diverts water into a channel used to bypass the large delta and facilitate upstream migration. This channel is a pathetic alternative to the river that resembles a ditch used for agricultural purposes, has little to no cover and bares no resemblance to a trout stream.

It would really be nice if the angling community got together and pushed for a more natural system that connected to the Truckee River and supported natural reproduction. It boggles my mind how wild trout advocates and conservationists lose all perspective when given the chance to catch a 20-pound hatchery fish. The Pyramid Lake Tribe has done some phenomenal work in getting flows allocated back to Pyramid and they would more than capable of solving the problems of their awesome lake, but they have no incentive to invest in natural reproduction if nobody cares.