Marine Mammal Stock Assessment Reports

Final 2023 Marine Mammal Stock Assessment Reports

• Alaska Marine Mammal Stock Assessments (PDF, 335 pages)
• U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments (PDF, 375 pages)
• U.S. Pacific Marine Mammal Stock Assessments (PDF, 420 pages)

NOAA Fisheries prepares marine mammal stock assessment reports annually, as directed by the Marine Mammal Protection Act. The reports are prepared in consultation with one or more of three regional Scientific Review Groups.

NOAA Fisheries currently maintains stock assessment reports for 261 marine mammal stocks, of which 66 new or revised reports are included for the 2023 cycle. The final 2023 Marine Mammal Stock Assessment Reports are published in the Federal Register.

Stocks are classified under two categories: “strategic” and “non-strategic.” A strategic stock is defined as at least one of the following:

• A marine mammal stock for which the level of direct human-caused mortality exceeds the potential biological removal level
• A stock which, based on the best scientific information available, is declining and is likely to be listed as a threatened species under the Endangered Species Act within the foreseeable future
• A stock which is listed as a threatened or endangered species under the Endangered Species Act, or is designated as depleted under the Marine Mammal Protection Act

We released the draft reports for public review and comment in January 2024. We evaluated all public comments, and the Federal Register Notice includes responses to the substantive comments we received.

Key updates from these final 2023 reports include:

• Revisions to the population structure for the West Coast harbor porpoise stock
• The proposed designation of a stock for a new species, Sato's beaked whale
• The change in status from “non-strategic” to “strategic” for the Western North Atlantic short-finned pilot whale stock
• A proposed revision to the Barataria Bay Estuarine System common bottlenose dolphin stock assessment report to incorporate recent publications regarding health assessment data and proposed outcomes for the mid-Barataria sediment diversion project
• A proposal to rename Pacific Island marine mammal stocks to align with the original Hawaiian places where these stocks reside in an ongoing effort to reflect indigenous knowledge