Marine Mammal Stranding Facts
What Is a Stranding?
A marine mammal is considered stranded if it is:
- Dead (in the water or on land)
- Alive and is
- on the shore unable to get back to the water
- critically injured or ill (in the water or on land)
- in the water but unable to return to its natural habitat without assistance (for example, an animal entangled in fishing gear)
NOTE: Not all animals seen on the beach are in need of help. Seals, sea lions, and walrus come ashore to rest, regulate their temperature, molt (shed old skin and hair), breed, give birth, and nurse their pups. Seals and sea lions will often leave their pups on the shore while they feed offshore.
Keep this in mind when you see a seal or sea lion on land. Do not approach these animals and do not touch or move a pup. If you believe the animal is injured or malnourished, or if a seal or sea lion pup has been alone on shore for more than 12 hours, or a sea otter pup has been alone on shore or in the water for more than 2 hours, report it to the authorities and let trained individuals assess the animal.
Why Do Marine Mammals Strand?
Marine mammals strand for a variety of reasons.
- Sickness, including:
- Disease
- Parasites
- Starvation
- Pup abandoned by mother
- Predation and competition among other marine animals
- Oceanographic events, including:
- Harmful algal blooms
- El Niño weather pattern
- Human causes, including:
- Injuries from ship strikes
- Entanglement
- Noise pollution
- Gunshot wounds
- Environmental pollution
- Unusual weather events
- Natural death
What Can Be Learned from Stranded Animals?
Stranded marine mammals provide an opportunity to study animals that would normally be difficult or impossible to study. Both live and dead stranded marine mammals can provide information on:
- Where they live
- How long they live
- What they are eating
- How many calves/pups they have and how often they reproduce
- Diseases and parasites that could affect other marine animals and humans
- How pollutants are moving up the food chain
- Food safety for people who consume marine mammals
- Threats to marine mammals by humans, including frequency of interactions with humans such as ship strikes, entanglements, hooks, and other marine debris
Changes in marine mammal health can be a reflection of environmental changes. Studying marine mammals can therefore help us learn about the health of our oceans. This is of great importance because Alaskans rely strongly on the marine resources Alaska has to offer.
Marine Mammal Entanglements
Numerous objects, including fishing line and nets, rope, hooks, packing bands, rubber bands, and other marine debris, can entangle marine mammals. As a result of these entanglements marine mammals may become injured, develop infections, starve, be hit by vessels, or drown.
What can you do?
- Report any marine mammal entanglement you see.
- Reporting procedures are the same as for other marine mammal strandings.
- Removing marine debris from live marine mammals is extremely dangerous and should be left to trained individuals.
- Be proactive.
- Cut any loops that could become marine debris before you throw them away.
- Pick up any marine debris that you see in the ocean or on the beach.
- Educate others about the dangers of marine debris.
For more information on entanglement
- Sea lion entanglement in Alaska
- Whale entanglement in Alaska
Marine Mammal Protection
In the United States all marine mammals are protected under the Marine Mammal Protection Act (MMPA). In Alaska this includes seals, sea lions, whales, porpoises, walrus, sea otters, and polar bears. The MMPA prohibits unauthorized people from handling, feeding, disturbing or harassing, capturing, or killing marine mammals. This protects both the marine mammals and you from injury, illness, and disease. Do not approach live stranded marine mammals—view them from at least 100 yards away. Marine mammals are protected under MMPA regulations even after death.
Volunteer stranding networks in coastal states are authorized through Letters of Authority from the National Marine Fisheries Service (NMFS) to respond to marine mammal strandings. Authorized volunteers are permitted to collect and transport sick or injured animals for rehabilitation or to collect samples from dead marine mammals. Exceptions to the MMPA are also authorized for Alaska Natives. A violation of the MMPA can result in extremely costly fines and prison time.
More information about the MMPA.
Alaska Natives and Marine Mammals
The Marine Mammal Protection Act (MMPA) provides exemptions that allow Alaska Natives to hunt marine mammals and salvage any marine mammal parts. However, reporting stranded marine mammals is still important because samples and information about those animals are valuable for understanding multiple biological and environmental factors. This includes the safety of consuming marine mammal species. In more remote areas of Alaska, samples from dead stranded marine mammals are often the only source, or one of very few sources, of data for those animals.
