The Pacific Marine Ecozone is home to about 3 800 species of invertebrates, a mixture of oceanic, subpolar, neritic (living in the tide waters and landwashes), and benthic (bottom-dwelling) plankton. These populations make up 3.5% of all marine invertebrates in the world. The large invertebrate populations provide rich food sources for the 220 species of fish living in the ecozone. The Pacific Herring is the most abundant, while Salmon, Halibut, Steelhead, and Dolly Varden, among others, form the backbone of commercial fisheries. Over the years, salmon and herring stocks have been overfished, and although herring stocks are rebounding, the health of salmon stocks remains precarious.

Marine mammals include Steller Sea Lions, Sea Otters, Northern Fur Seals, Orcas and Gray Whales. Large breeding bird populations include ducks and geese, Petrels, Guillemots, Murrelets and Auklets, with some Puffins and Murres. Several species of raptors, including Bald Eagles and Osprey, feed in the near-shore wetlands and rivers. All of the B. C. breeding populations of Brandt's Cormorants live on the west coast of Vancouver Island.