Monterey Bay is one of the most diverse marine ecosystems in the world, and is home to a variety of fish, invertebrate, seabird, and mammal species, including sea otters, harbor and elephant seals, bottlenose dolphins, and turtles. It is also famous for its fish-processing industry, which grew up in the early part of the 20th century around Cannery Row. The bay is the site of one of the longest undersea canyons in the world, Monterey Canyon, which reaches a depth of more than 9,800 ft (3,000 m) and runs 60 miles (100 km) offshore. A mud volcano north of the canyon is the source of cold hydrocarbon seeps, which support an ecosystem based on metabolizing sulfide compounds, rather than using sunlight for energy. Similar deep-sea communities are found at hydrothermal vents on the mid-ocean ridges.