Where did all the sea otters go?

I read recently that sea otters are being reintroduced into places where they once thrived. Thousands had swarmed around the coves and shoreline of San Francisco Bay where they were hunted for their thick luxurious fur. The indigenous people first took the furs for their winter clothing. When Spain ruled Alta California, the Spanish agreed to allow the Russian navy to anchor in the Bay in winter and bring Aleut hunters from Sitka to trap the animals. The pelts brought high prices and were sought by wealthy Russians for fur coats. Spain and later the Mexican government collected a hefty tax for each pelt. Tax collection for these furs evolved into one of Captain William A. Richardson’s duties.

Sea otters are now protected wildlife. Because their numbers were so reduced, their favorite food, sea urchins, overpopulated the kelp forests along the western North American coast. Without their otter predators, sea urchins devastate their environment and create what biologists label an urchin barren. In Canada, along the coast of British Columbia, sea otters are increasing and so the coastal ecosystem has improved significantly. The kelp forests are rebounding. Otters are now re-entering the Oregon and California coast, not in numbers as they were in the 1800s, but enough to help the ecosystem recuperate.