Evaluating Potential Occurrence of Sound
NOAA provides the guidance below to assess potential for listed ESA marine mammal occurrences in project areas. Southern Resident killer whales occur predictably in Washington and Oregon waters, as well as Steller sea lions. Other Endangered Species Act-listed marine mammals and turtles can occur in Washington and Oregon waters, but are generally less likely to occur in nearshore areas. More information about these species is available in stock assessment reports and status reviews.
Southern Resident killer whales spend considerable time in the Georgia Basin from late spring to early autumn, with concentrated activity in the inland waters of the state of Washington around the San Juan Islands, and then move south into Puget Sound in early autumn. While these are seasonal patterns, Southern Resident killer whales have the potential to occur throughout their range, from central California north to the Queen Charlotte Islands, at any time of the year.
The Whale Museum manages a long-term database of Southern Resident killer whale sightings and geospatial locations in inland waters of Washington State. While these data are predominately opportunistic sightings from a variety of sources (public reports, commercial whale watching, Soundwatch, Lime Kiln State Park land-based observations, and independent research reports), these orcas are highly visible in inland waters, and widely followed by the interested public and research community. The dataset does not account for level of observation effort by season or location; however, it is the most comprehensive long-term dataset available to evaluate broad-scale habitat use by Southern Resident killer whales in inland waters. For these reasons, NOAA Fisheries relies on the number of past sightings to assess the likelihood of Southern Resident killer whale presence in a project area when work would occur. The Northwest Region developed a set of maps that reports the number of unique Southern Resident killer whale sighting days 5.1MB in inland waters per quadrate 94.5MB and month over a near 20-year timeframe.
Steller sea lions of the eastern distinct population segment occur in Washington and Oregon waters throughout the year. Occurrence in inland waters of Washington is limited to primarily male and sub-adult Stellers in fall, winter and spring months. Steller sea lions use haulout locations on the Washington coast 20.52MB and in the San Juan Islands. 3.1MB There are no breeding rookeries in Washington State. In recent years, a small number of Steller sea lion pups (15-20 combined total) have been recorded on Sea Lion Rock and Carroll Island. A seal and sea lion haulout atlas is available for Washington State.
Steller sea lions use breeding rookeries and haulout locations along the Oregon coast. 13.7MB The animals are not known to occur predictably along coastal reaches, in coastal bays or river systems of Oregon, aside from areas near their haulout and rookery locations and from their seasonal occurrence in the lower Columbia and around Rogue Reef 3.12MB and Orford Reef. 3.56MB
A few Steller sea lions travel up the Columbia River 3.94MB to the tailrace area of Bonneville Dam where they forage on anadromous fishes. Some individuals have been sighted in the tailrace area as early as fall; their numbers peak in winter to early spring and they depart by late spring. A few of the animals make foraging trips into the Rogue River estuary primarily during summer months, but do not occur in peak numbers until the middle of July when returning salmon become more abundant in the lower river.