What is this caramel colored brown stuff attached to our oysters?
Seems to me this has to do with spawning during the warm weather months...
From an LA Times article July 19, 2006:
WHEN it's a real scorcher outside, slurping icy-cold oysters and sipping a crisp Chablis sounds like the perfect refresher. But eating oysters in the summer isn't always a winning proposition. At some restaurants, the oysters are always fantastic, so firm and briny you're tempted to order more. But in other places they might seem unpleasantly flaccid and creamy, a result of warm-weather spawning...Eating a spawning oyster won't make you sick, but it's not a pleasant experience, either. When fertile, their texture is soft and creamy, and not in a good way like cheese or ice cream.