When, where, and how sea otters are released after rehabilitation from oil, injury, or illness depends on what is safest for the sea otter. 


release-monitoring2Factors affecting the decision about the release method include distance/time to release site and proximity to capture/stranding site.   When otters are released from a beach, the transfer box is carried into the water by a team of people and tipped on its side with the opening facing the water.  When everyone is ready the door is slid up and the otter is free to swim into the water.  When otters are released from a boat, a team of people lift the transfer box onto the side of the boat with the opening facing the water.  All boats used for release are low to the water so the otter has a short distance to move to reach the water.  Again, when everyone is ready the door is slid up and the otter is free to swim into the water.  Personnel continue to monitor the otter until it resurfaces after the initial dive and  make sure that normal behaviors and swimming abilities have resumed.

release-monitoringSea otters are tracked using VHF telemetry.  Observers on shore use a VHF receiver and antenna to locate sea otters that have been instrumented with VHF transmitters, which each have a unique frequency.  The receiver is tuned to the frequency of the otter they are looking for, much like you would tune your radio to pick up your favorite radio station.  If several otters are of interest, the receiver can be programmed to scan through the frequencies of interest. The observer attaches an antenna to the receiver and holds the antenna in front of them, moving it from side to side until a frequency is detected.  Detection of a frequency is indicated by high-pitched “chirps,” which indicates the tagged otter is in the area and at the surface.  Although the frequencies can be detected several kilometers away if the observer is at high elevation such as on a bluff or cliff, they can only be detected at the surface, as the signal attenuates in water.  Once an otter’s frequency is detected, observers use high-powered spotting scopes to try to locate the animal.  Most instrumented otters also have colored flipper tags to aid in location and identification of specific animals, but some tags are chewed or fall off over time.  For otters without flipper tags, the observer can match the pattern of the “chirps” with the activities of otters in the area to confirm the identity of the otter of interest.  For example, when an otter with a transmitter dives, the “chirps” will abruptly stop.  If the otter is grooming or rolling at the surface, the “chirps” will get louder and softer as the otter’s body gets higher and lower out of the water.  Once an otter is positively identified the observer can make detailed behavioral and foraging observations, which adds to our robust database of sea otter behavior and foraging patterns.