Figure 5 - Above Emerald Pool

Figure 5 - Above Emerald PoolGuest Blogger: Michael Vorhis, Fly Fisher & Author, FreeFlight Publishing

The Merced in Yosemite Valley gets 90% of the fishing pressure of the park’s streams, but still not a lot by most standards, and much of that pressure is novice or spinning/consumer in nature. It’s understandably fished more because it’s more accessible to most family trip anglers. The creeks, even in the Valley, have less pressure yet–and where creeks come into the Merced it can also be good–such as the confluence of Tenaya Creek (near the Upper Pines campground) as one of many examples.

The valley Merced is a classic trout stream–it offers every kind of water, from riffles to boulder-strewn pocket water to big pools to deep holes in the head of a dangerous, deafening gorge. There’s a section for every fisherman’s preference. Most of it is boot-hoppable or wadable, and in the summer months the water temperature isn’t so extreme that you can’t wet-wade (a big benefit to travelers unexpectedly ambushed by the river’s allure or whose luggage space was too jammed with badminton sets and picnic baskets to have room for waders). Those who like sight-fishing for rising fish in large calm pools can do that; those who prefer high-stick nymphing or tenkara can pursue their dream. All fish are essentially wild, and many smaller streams never see an angler all year.

Figure 6 - Vernal_FallsYosemite Valley is known for its waterfalls, which run day and night in timeless splendor, their mists creating rich zones of life–and, on sunny days, beautiful rainbows. But another kind of rainbow was originally found here as well, at least at the lower elevations; there are early reports that rainbow trout lived in some of these waters long before man arrived to covet them. Introduction of various species of trout by man into what was clearly pristine habitat began just after the Civil War, with fish initially carried in by hand in buckets and jugs. Such was the zeal felt for bolstering the noble salmonid’s populations. It’s probable that these stocking efforts, which later gave way to more concerted energies employing the pack animals and manpower of the U.S. Cavalry, focused on higher lakes where trout populations were in less evidence. Most sources say several species of brown trout were planted below the Merced gorge around the turn of the century (1897 – 1905) and tend to stay at those elevations…although there have been plenty of sightings of German browns upstream, within the Park, possibly due to roe spread by birds of prey. In general, although in past summers I’ve seen sixteen inchers holding in deep pools right below bicycle trail bridges, as is characteristic of mountain streams that experience real winters the trout in the Valley itself will tend to be rainbows, and on average probably a little smaller than the biggest of the browns lower in the watershed.

Grayling were stocked around the time of the Great Depression, but seem to have long since disappeared. Golden Trout, Eastern Brook Trout, Cutthroats and Dolly Vardens were all given their chance as well, mostly with short-lived results (although a very few Goldens and Cutties still remain, and some Brookies in a few high lakes). The noble and hardy Rainbow continues on, steadfast and eternal.

Figure 7 - Low Merced BranchThousand-meter-thick Pleistocene glaciers scraping their slowly violent course was surely not pleasant for any fish life that might have existed in the Yosemite area at the time, if indeed any fish had gotten there yet at all. Effectively the Merced and Tuolumne watersheds had to begin from scratch, after their canyons were created, to populate their habitats with sub aquatic life. High waterfalls and ultra-high-gradient gorges still thundering today further slowed the process of species colonization and adaptation. It’s little wonder than Man, as late as our species arrived to the party, played an active role in opening the streams and lakes to a trout’s possibilities.

Figure 8 - Micro_PocketsToday there are ecosystems thriving so brilliantly that it’s clear the original glaciers and rivers had trout in mind all along. The fisheries are looked after, of course, in attempts to ensure that Man’s visionary contribution is not cancelled by Man’s parallel instincts to colonize or prey. We live in a world where many millions of homes are within a comfortable drive of this divine wilderness, and the pressure to dam up more stuff is always dangerously hovering (and forever advocated by those incapable of appreciating the pure magic…the irreplaceable value…of a free-flowing stream). Yosemite Valley is in fact one of two such treasures, the other being the neighboring Tuolumne river’s own masterpiece, Hetch Hetchy Valley, which was reported by legendary conservationist John Muir to be the more beautiful of the two! …but which was nevertheless dammed up in 1919-1923…and now is nothing more than a reservoir we’re not even allowed to set a kayak into. The defeat broke Muir’s heart and should break ours, although anymore ‘Hetch Hetchy’ to most is just a name for electric power and lawn water. (Thus grieve the forgetful masses–the same folks who tend to vote for ridiculous nonsenses like AmTrak lines to pipe millions more day-trip party-goers in to natural wonders, in hopes those gems may become as overrun as Disneyland…thankfully such brainstorms haven’t materialized yet for this place…but watch and wait, because someone with a microphone will eventually think it a capital idea.)

Note from J. Stockard: if you didn’t catch it, read Part 1 of this series now. Preservation, fishing regulations, current habitat conditions and local guiding and advice is discussed in Part 3 of this series.


  1. Nice piece. Although I am much less familiar with the Central-West Sierra watersheds, the native trout of the Merced is the Coastal Rainbow Trout (Oncoryhnchus mykiss irideus). Am unsure whether their native range extended into the Yosemite Valley, but most likely they did. Today’s rainbows, although wild are most likely descendant of stocked fish from long ago which were not pure strains of Coastal Rainbows. There is only one species of Brown trout (as we know it in the U.S.) and that is Salmo trutta. As Robert Behnke likes to call it the American Brown trout (Salmo trutta trutta) which is an amalgamation of various strains of browns from England and Europe. It is a great wild trout no matter where you find it.

    The protection of wild versus native trout populations continues to be a touchy subject in the West as even as wild trout populations flourish through good water management and angling practices, native trout populations continue to decline. In the latest issue of Trout, the Trout Unlimited journal, a “State of Trout” article claims 13 of 25 unique species of trout in the U.S. occupy less than 25% of their historic range. Pretty scary.

  2. Thanks for the background Mike; very informative. Yes, native species are in decline around these parts, and I think between genetic dilution and habitat, the bigger of the two problems is the former…but I could be wrong.

    > Am unsure whether their native range extended into the Yosemite Valley, but most likely they did.

    They did indeed. The stocking was more focused on the high country where trout populations weren’t in evidence. Of course that brought roe over the various falls into the lower reaches too.

    The Valley stretch wasn’t (isn’t) accessible to fish from below either, due to the largely impassable El Portal gorge..but native Rainbows still populated the Valley streams and Valley Merced prior to stocking efforts (prior to white man stocking efforts anyway), so it’s likely that natural means prevailed (birds of prey, etc) for the lower elevations of the land encompassed by the park.

    The Ahwaneechee Indian tribe wintered in the Valley (and I believe summered too) for 4000 years or more. It’s pretty likely that fish got brought in by them, along with roe. They were an impressive community and definitely knew how to pick a home. The Valley was sheltered from wind, defensible, chock full of game, and…kinda pretty.

    – Mike

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