For seventy years the Britannia mine ran acid drainage into this water: zinc, copper, cadmium, straight off the mountain and into the Sound. By the time it closed in 1974 it was one of the largest sources of metal pollution on the North American west coast, and stretches of shoreline held almost nothing. Remediation started in 2002. Pacific herring came back to spawn in the late 2010s, in numbers nobody had recorded for sixty years, and in 2019 the glass sponge reefs on the bottom of these inlets became protected marine refuges.
You can see the return without being told about it. Plumose anemones stand a foot high on the Porteau wrecks. Nudibranchs work the shallow boulders at Tuwanek in numbers that make a sixty-minute dive feel short. Even the shrimp hold their ground long enough to be lit properly.
The recovery is real and it is not complete. The sunflower star, twenty arms, a metre across, the predator that held the urchins down, was wiped out along this whole coast by wasting disease from 2013 and has not come back. Researchers named the bacterium responsible in 2025 and the first lab-reared stars went into Salish Sea water the following summer. You can dive this place on any day of any month, from a car park, and watch which way it is going.
