Summary: There is nothing quite like staring out at the open Pacific and seeing a group of killer whales (Orcinus orca). Whether from a local whale watch tour out of Monterey Bay or from the cliff tops overlooking the open ocean off Point Lobos, killer whales are keenly sought by naturalists and visitors alike. The Monterey Bay National Marine Sanctuary and surrounding waters of the California Current ecosystem are home to three ecotypes, or forms, of killer whale. One may encounter endangered southern residents following seasonally abundant Chinook salmon, glimpse a group of rarely sighted offshores hunting deep-water sharks, or witness the dramatic hunt of a group of transient killer whales trying to separate a gray whale calf from its mother!

Transient (Bigg’s) killer whales are marine mammal-hunting specialists, and by far the most commonly encountered ecotype of killer whale in Monterey Bay. However, current information regarding their ecology in waters south of the Pacific Northwest is scattered and varied. Most of it can only be found in unpublished reports or conference abstracts. This publication, in conjunction with our 2021 published technical memorandum, Transient Killer Whales of Central and Northern California and Oregon: a Catalog of Photo-identified Individuals, focuses specifically on transient killer whales identified in the Monterey Bay National Marine Sanctuary (MBNMS). For a comprehensive catalog of transient killer whales that use the waters of the outer coast of California and Oregon, see our recently published technical memorandum.

From May 2006 to April 2020 Marine Life Studies and the Transient Killer Whale Research Project have collected data and photographs of killer whales in Monterey Bay and the surrounding waters of California. Here we provide information on our research findings, natural history, and a compilation of 134 different individual transient killer whales photographed during our surveys.