Pacific oyster (Magallana gigas) shells are thick and elongated with a rough surface texture and are highly variable in shape. Pacific oysters were introduced to Washington and British Columbia from Japan in 1922 for aquaculture, and are now also in the natural environment. It is the largest oyster in this area, and in addition to its size the undulating frills on the valves help with identification. The Pacific oyster is the most commercially harvested oyster in the world. This oyster can grow to 18 inches (45.7 cm) in length, and has a range that includes Siberia to Pakistan, central Alaska to central California, and also Europe and Asia.
References:
Cowles, Dave. “Magallana gigas (Thunberg, 1793)” Invertebrates of the Salish Sea, Rosario Beach Marine Laboratory – a campus of Walla Walla University, 2005, https://inverts.wallawalla.edu/Mollusca/Bivalvia/Ostreoida/Ostreidae/Crassostrea_gigas.html
Lamb, Andy and Hanby, Bernard. Marine Life of the Pacific Northwest: A Photographic Encyclopedia of Invertebrates, Seaweeds and Selected Fishes. Madeira Park: Harbour Publishing, 2005. (An online version of this book is also available to subscribers at https://knowbc.com)
