MOUNT VERNON, Wash. (AP) — NOAA’s National Fisheries Marine Service is beginning a five-year review of the Southern Resident orca population.

Combining scientific and commercial data, the review will ensure the orca population is in good health.

NOAA Fisheries published a notice in the Federal Register about the status review last week, The Skagit Valley Herald reported.

The whales were listed as endangered in 2005 under the federal Endangered Species Act.

The Endangered Species Act requires five-year reviews to determine whether a species is recovering or remains at risk of extinction.

Since 2005, the orca population has decreased from 88 orcas to a recent low of 72, according to the Center for Whale Research and NOAA Fisheries.

As of February, the population was estimated at 75 with some recently identified calves.