• Oyster Culture

    September 16, 2009

    Here are the oysters spawning earlier this summer:

    spawn1

    And now here are their babies!

    oysterset

    The black specks on this shell are miniature oysters, called spat. We’ll leave this cluster out on the beach for about 3 to 5 years so it can grow into a cluster of big guys. And then we’ll shuck em. And eat em.

    Oyster farmers in the Hood Canal are lucky to be able to farm wild oysters. It’s a really beautiful way to grow food: We just encourage wild oysters to set on our beach, and then harvest whatever nature brings our way. Over the years, we’ve used several different methods to entice oyster babies.

    In the early 1960s we used concrete-covered lath. The idea was that after about a year, you could knock off the concrete, breaking the oysters apart into clusters and singles.
    My beautiful picture

    But nothing attracts the larvae quite as well as oyster shell. This is kinda obvious… if one oyster has survived and thrived in one location, it makes sense for others to join it. In the late 60s and throughout the 70s, 80s, and early 90s we suspended bags of oyster shell (called cultch) from floating racks out in the middle of the Canal. Deploying the “seed racks” was a pretty big undertaking, one that took the whole family. It was a fun (albeit dangerous!) job on sunny August afternoons.

    Here are the racks up on shore:
    My beautiful picture

    Oyster spectator sports:
    My beautiful picture

    And here they are floating out in the water:
    My beautiful picture

    In the late 90s, the permitting for the seed racks got pretty complicated and we decided we’d rather not use so much styrofoam. Since then we’ve gone back to basics: in the springtime we bag shell up into cultch bags (we try to get this done before the Oyster Rama, and then we use the cultch bags for our Rama fence) and when the oysters spawn in July or August, we put pallets of cultch bags out on the beach in hopes they’ll attract larvae at high tide.

    cultchbags

    Sometimes this works. But nothing’s a given! Sometimes the wind picks up during the larval period, drops the water temperature, and everything dies.

    Here are year old oysters growing on cultch bags:
    cultchoysters

    And here’s a 5 to 7 year old oyster cluster, the end result of this process:
    cluster

    Since Hood Canal has such a prolific wild oyster population, Canal farmers were a little slow to embrace hatchery seed. Why pay for something you get for free? Of course, using seed produces a much higher quality product for the half shell market, more reliable in shape, size, and appearance. And for the past 6 years or so the wild oysters really haven’t reproduced in the Canal, so we’ve had to scramble to get our seeding operations up and running. The lack of a natural set may be normal (we did have a big set in 2012) or it may be related to ocean acidification… the Canal has seen some of the lowest pH ever recorded on earth.

    To learn more about how to grow oysters from seed, read this post.

    oysterseed

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