About The Species
Hooded seals live in the cold waters of the North Atlantic and Arctic Oceans. Adult males are known for the stretchy cavity, or hood, in their nose, which they can inflate so that it looks like a bright red balloon. They have another inflatable nasal cavity in the form of a black bladder on their head. Hooded seals are also known as bladder-nosed seals due to this unique ability.
Hooded seal pups are called “blue-backs” because of the blue-gray fur on their backs. Pups are weaned off their mother’s milk only three to five days after birth, the shortest weaning period of any mammal.
Hooded seals, like all marine mammals, are protected under the Marine Mammal Protection Act. NOAA Fisheries is committed to conserving and protecting hooded seals. Our scientists and partners use a variety of innovative techniques to study, learn more about, and protect this species.
To manage hooded seals in U.S. waters, we have grouped them into a western North Atlantic stock. Based on the most recent survey, our scientists estimate that there are about 600,000 seals in this stock.
- Throughout Its Range
Male hooded seals are about 8.5 feet long and weigh about 423 to 776 pounds, while females are about 6.5 feet long and weigh about 320 to 660 pounds. Both male and female adults have silver-gray fur with darker patches of different sizes and shapes across their bodies.
Hooded seals have a stretchy cavity, or hood, in their nose. This cavity has two sections, or lobes. Adult males can inflate and extend this hood so that it stretches across the length of their face. Sexually mature males have a unique partition in their nose that, when inflated, looks like a pinkish-red balloon. They use this to attract females' attention during mating season and to show aggression toward other males.
Hooded seal pups have blue-gray fur on their backs and whitish bellies. This beautiful pelt earned them the nickname “blue-backs” and once made them a target for hunting. Pups shed their blue-gray coat when they are 14 months old.
Behavior and Diet
Hooded seals are not social. They migrate and remain alone for most of the year except during mating season. They are more aggressive and territorial than other seal species.
Hooded seals begin their annual migration cycle once they reach sexual maturity. They gather at their breeding grounds for two to three weeks in the spring. After pups are born, adults stay in the breeding grounds to molt. Once they have molted, they begin their migration period for the rest of the year.
On average, hooded seals dive 325 to 1,950 feet below the surface for about 13 to 15 minutes in search of food, but they are also known to dive more than 3,280 feet for up to 1 hour. They eat squid, starfish, and mussels. They also eat several types of fish, including Greenland halibut, redfish, Atlantic and Arctic cod, capelin, and herring. Newly weaned pups feed on pelagic crustaceans.
In the Spotlight
Hooded seals are protected under the Marine Mammal Protection Act. In the United States, NOAA Fisheries works to protect all hooded seals.
All marine mammals, including hooded seals, are protected in the United States under the MMPA.
Key Actions and Documents
Incidental Take Authorization: U.S. Navy Dry Dock Expansion Project at Portsmouth Naval Shipyard, Kittery, Maine
- Notice of Issued Renewal IHA 2021
- Notice of Proposed Renewal IHA 2021
- Notice of Reissued IHA 2019
- Notice of Issued IHA
- Notice of Proposed IHA
- Renewal IHA (pdf, 7 pages)
- Reissued 2019 IHA (pdf, 8 pages)
- 2019 Issued IHA (pdf, 8 pages)
- IHA Application (pdf, 183 pages)
- IHA Renewal Request (pdf, 4 pages)
- References Cited (pdf, 4 pages)
- Public Comments (pdf, 5 pages)
- Public Comments, 2021 Renewal (pdf, 5 pages)
- 2018 Monitoring Report (pdf, 19 pages)
- 2019 Monitoring Report (pdf, 41 pages)
- 2019 Monitoring Report Appendices (pdf, 95 pages)
Incidental Take Authorization: U.S. Navy Atlantic Fleet Training and Testing (AFTT) along Atlantic and Gulf Coasts (2018-2025)
- Correction to Final Rule
- Notice of Final Rule for 2 Year Extension
- Notice of Proposed Rule for 2 Year Extension
- Notice of Receipt of Application for 2 Year Extension
- Notice of Final Rule
- Correction to Proposed Rule
- Notice of Proposed Rule
- Notice of Receipt of Application for LOA
- LOA for Testing (pdf, 40 pages)
- LOA for Training (pdf, 36 pages)
- Revised Application for Extension (pdf, 132 pages)
- References for Extension (pdf, 6 pages)
- Notification and Reporting Plan (pdf, 4 pages)
- Final Biological Opinion
- LOA Application (PDF, 560 pages)
- Environmental Impact Statement
- Monitoring and Reporting
- Ship Strike Analysis (PDF, 3 pages)
- Draft Notification and Reporting Plan (PDF, 4 pages)
- Issued LOA - Training
- Issued LOA - Testing
- Revised LOA Application [pdf, 337 pages]
- Original LOA Application [pdf, 335 pages]
- Navy Strategic Planning Process for Monitoring
- Integrated Comprehensive Monitoring Program [pdf, 73 pages]
- Stranding Response Plan [pdf, 13 pages]
- Press Release [pdf, 2 pages]
- 2014 Monitoring Report [pdf, 27 pages]
- 2015 Monitoring Report
- 2016 Monitoring Report
Incidental Take Authorization: U.S. Navy Waterfront Improvement Projects at Portsmouth Naval Shipyard, Kittery, ME
- Issued IHA [pdf, 7 pages]
- Revised Application Jan 2018 [pdf, 104 pages]
- IHA Application [pdf, 106 pages]
- References Cited [pdf, 18 pages]
- Public Comments [pdf, 7 pages]
NOAA Fisheries conducts various research activities on the biology, behavior, and ecology of hooded seals. The results of this research are used to inform management decisions for this species.
Determining the size of hooded seal populations helps resource managers determine the success of conservation measures. Our scientists collect population information and present the data in annual stock assessment reports.
Monitoring Population Abundance and Distribution
Scientists observe hooded seals to record their numbers and distribution. By comparing numbers collected over multiple years, scientists can look for trends—i.e., whether the population is increasing, decreasing, or remaining stable during a given period.