The United States National Marine Fisheries Service is listing a population of rare dolphins living near Hawaii as endangered.
It's also issuing new rules for Hawaii's longline fishermen to prevent them from accidentally hooking the animals.
The agency says it's acting in response to two separate court orders.
The dolphins - which are called false killer whales - have been getting caught in longline fisheries at high rates.
This is because the dolphins like to eat tuna, mahimahi and other fish the fishermen are catching.
The agency is listing false killer whales found in and around the waters of Hawaii's eight main islands as endangered.
There are just 150 of these dolphins remaining.
The agency expects both measures to be published in the Federal Register next week.