Ultimately, the USFWS release strategy for sea otters following an oil spill will depend upon the geographic location of the spill, the geographic extent of oiled habitat, the severity of habitat damage, the biological risk to the affected sea otter stock, and the number of affected animals. Consequently, release strategies need to be tailored to each situation where sea otters are captured. To that end we offer the following general recommendations:
1) Rehabilitated sea otters should be used to fill any demand from aquaria before release to the wild is considered.
2) Holding time should be minimized for rehabilitated sea otters that are to be released.
3) In those situations where the extent and severity of habitat damage is limited, releasing sea otters in the general vicinity of the point of capture should give rehabilitated sea otters the best chance for survival. This strategy will also result in the least amount of risk to wild sea otters from disease transmission.
4) In those situations where the capture location and surrounding habitat are severely contaminated and may remain so for many years, sea otters should be relocated, preferably to areas already occupied by sea otters.
5) New techniques should be developed and tested to enhance the probability that relocated animals will remain in the release area.
6) Sea otters from different subspecies should not be mixed.
7) Because of potential management conflicts, rehabilitated otters should not be used to expand the existing range of sea otters, except perhaps in California, Washington State, or British Columbia, where no other alternatives may be available.
8) At a minimum, released sea otters should be individually marked with brightly colored hind flipper tags and a uniquely coded transponder chip.
It is presently difficult to recommend a specific distance to relocate sea otters. Relocated sea otters have traveled hundreds of kilometers to return to areas where they were captured (Monnet et al., 1990; Rathbun et al., 1990; Ralls et al., 1992; USFWS). Thus, it is conceivable that some relocated sea otters will find their way back to contaminated habitat. The advantages of relocating sea otters at distances great enough to discourage homing may be offset by the higher risks associated with relocating sea otters to unfamiliar places.