The U.S. Fish & Wildlife Service published a final rule on Tuesday officially ending the “no-otter zone” encompassing nearly all of the sea otters’ natural range in Southern California.

In 2009, the Environmental Defense Center sued the FWS on behalf of The Otter Project and itself, challenging the FWS’ decades-long delay in making a required decision on whether to terminate the Southern Sea Otter Translocation Program, an outdated rule from 1987 prohibiting threatened southern sea otters from California waters south of Point Conception (Santa Barbara County to the Mexican border).

Allowing otters to once again inhabit Southern California waters is considered critical to the recovery of the species. Under a 2010 legal settlement reached by The Otter Project and the EDC with the FWS, the agency was required to make a final decision on the fate of the program by this December. Publication of the final rule is the last step of the settlement between the FWS and the two environmental groups.

“Trying to tell a marine mammal to stay on one side of an imaginary line across the water was a dumb idea,” said Steve Shimek, executive director of The Otter Project. “This rule will not only protect sea otters from harm, but because of the otters’ critical role in the environment, it will also help restore our local ocean ecosystem.”

“Southern sea otters have been largely absent from their historic Southern California habitat for far too long,” said Brian Segee, EDC staff attorney and lead attorney in the litigation and subsequent settlement. “This decision is a critical step in efforts to recover southern sea otters, by formally allowing this charismatic and intelligent species to naturally return to waters south of Point Conception.”

Under the decision, sea otters are now legally free to float the sunny Southern California waters without the threat of being trapped and “deported” to Northern California. Sea otters in Southern California will have the same protections under the Endangered Species Act and Marine Mammal Protection Act as otters to the north, including being protected from harm from any new development plans that could impact their recovery.

The southern sea otter population numbers around 2,800 in a range that once supported 12,000 to 16,000 sea otters and is listed as threatened under the ESA and depleted under the MMPA. Sea otter recovery is impossible with the “no-otter zone” in place.

Beginning in 1987, when the no-otter zone was established, the FWS moved 140 southern sea otters to San Nicolas Island, the most remote of California’s Channel Islands, in an attempt to establish a reserve population and protect the small and struggling mainland population from a catastrophic event, such as an oil spill. Shellfish fishermen, the offshore oil industry and the Navy objected to the plan and as a result the no-otter zone (officially called the “management zone”) was established.

Unfortunately, the relocation plan failed immediately when all but about 11 of the 140 otters swam away from San Nicolas Island and back to their home waters or perished. In spite of the failure, the no-otter zone stayed in place and wandering otters were trapped and deported for many years.

The mainland population began to expand its range into 1995 and in 1998 152 otters swam nearly en masse across the line. Fishermen sued the FWS, demanding the otters be trapped and removed. That lawsuit failed. In 2001, the FWS declared that it would no longer move otters out of the zone but left the lower level of protection of sea otters in the zone in place. The failure of the FWS to protect the otters in this area led to the lawsuit filed by The Otter Project and EDC.

— Betsy Weber is the communications director for the Environmental Defense Center.