FWS proposes critical habitat for DPS of Northern Sea Otter
73 Fed. Reg. 76454 / Vol. 73, No. 242 / Tuesday, December 16, 2008 / Department of the Interior; Fish and Wildlife Service; 50 CFR Part 17; Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Southwest Alaska Distinct Population Segment of the Northern Sea Otter (Enhydra lutris kenyoni); Proposed Rule
SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to designate critical habitat for the southwest Alaska Distinct Population Segment (DPS) of the northern sea otter (Enhydra lutris kenyoni) under the Endangered Species Act of 1973, as amended (Act). In total, approximately 15,225 square kilometers (km2) (5,879 square miles (mi2)) fall within the boundaries of the proposed critical habitat designation. The proposed critical habitat is located in Alaska.
As a species, sea otters occur only in the North Pacific Ocean. The range currently occupied extends from southern California to northern Japan, with extralimital sightings in central Baja California and near Wrangel Island in the Chukchi Sea. The northward limits in distribution appear related to the southern limits of sea ice, which can preclude access to foraging habitat. Seasonal and inter-annual variation in the southern extent of sea ice results in constriction and expansion of the sea otter’s northern range. Sea otters, by limiting populations of herbivorous invertebrates such as sea urchins and large gastropods, played a keystone role in preventing kelp forests from being overgrazed. Photo by C.Brown from USGS
EXCERPT: Within the geographical area occupied by the southwest Alaska DPS of the northern sea otter at the time of listing, we must identify the primary constituent elements (PCEs) laid out in the appropriate quantity and spatial arrangement essential to the conservation of the DPS (i.e., the essential physical and biological features) that may require special management considerations or protections. Based on the above needs and our current knowledge of the life history, biology, and ecology of the species, we have determined that the southwest Alaska DPS of the northern sea otter’s PCEs are:
(1) Shallow, rocky areas where marine predators are less likely to forage, which are waters less than 2 m (6.6 ft) in depth,
(2) Nearshore waters that may provide protection or escape from marine predators, which are those within 100 m (328.1 ft) from the mean high tide line and
(3) Kelp forests that provide protection from marine predators, which occur in waters less than 20 m (65.6 ft) in depth.
(4) Prey resources within the areas identified by PCEs 1–3 that are present in sufficient quantity and quality to support the energetic requirements of the species.