Killer whale
Information for offshore regions and warmer waters is more scarce, but widespread sightings indicate the killer whale can survive in most water temperatures. They have been sighted, though more infrequently, in the Mediterranean, the Arabian Sea, the Gulf of Mexico, and the Caribbean. Over 50 individual whales have been documented in the northern Indian Ocean, including two individuals that were sighted in the Persian Gulf in 2008 and off Sri Lanka in 2015. Those orcas may occasionally enter the Red Sea through the Gulf of Aden. The modern status of the species along coastal mainland China and its vicinity is unknown. Recorded sightings have been made from almost the entire shoreline. A wide-ranging population is likely to exist in the central Pacific, with some sightings off Hawaii. Distinct populations may also exist off the west coast of tropical Africa, and Papua New Guinea. In the Mediterranean, killer whales are considered "visitors", likely from the North Atlantic, and sightings become less frequent further east. However, a small year-round population is known to exist in the Strait of Gibraltar, mostly on the Atlantic side. Killer whales also appear to regularly occur off the Galápagos Islands.
Channel Islands National Marine Sanctuary
After populations of large whales were decimated by whaling in the last two centuries, several species are rebounding. Channel Islands National Marine Sanctuary is a seasonal home to several species of those large whales. From Early Spring to late Fall the sanctuary sees increasing numbers of humpback, blue and fin whales- with seasonally migrating gray whales transiting the sanctuary on their trips between the North Pacific and the lagoons of Baja California. At times, large whales aggregate in tremendous numbers, with as many as 186 unique photo identifications occurring in a single day. Understanding the causes of this aggregation, such as bloom dynamics of the krill the whales feed on, can provide valuable forecasting information to predict where whales are likely to be in the near term. This information in turn could aid in reducing whale-ship interactions. Ongoing work has focused on behavioral responses of large whales to close encounters with large vessels transiting the Santa Barbara Channel. This work is being extended to focus on two problems: how variability in krill depth is key to whale decision making, and how the whales are selecting specific sized prey within pools of mixed-age krill. To get after these questions, sanctuary staff and contractors are combining an ongoing program of tagging large whales with time-depth-location recording tags with systematic mapping of krill fields around the sanctuary. The sanctuary is assisting the work of partners from Cascadia Research Collective and Scripps Institution of Oceanography.