Phillip's Natural World: Sea Otter Conservation

Sea Otter by Ryan Wolt

I recently spent a day on Sitka Sound (Alaska) searching for Northern Sea Otters (Enhydra lutris kenyoni). I was not disappointed. This area of Alaska is one of the most scenic in the world, and we found lots of sea otters to admire and photograph.

These sea otters are the largest member of the weasel family. Their fur is made up of a dense under fur, ranging in color from brown to black, and longer guard hairs. The guard hairs can be brown to black to silver. Their hind feet are webbed to aid in swimming, and their front toes are short and stiff.

Sitka Sound

Adult Sea otters grow to 5 feet in length. The males average weight is 80-100 pounds but individuals can weigh much more. Females are smaller, weighing 50-70 pounds. Sea otters' average life span is 15-20 years. Breeding begins at age 2-5 for females and may continue until age 20. Males become sexually mature at age 4-6 but may not hold breeding territories until several years later.

Sitka Sound

Historically, sea otters occurred in near shore waters around the North Pacific rim from Hokkaido, Japan through the marine coastal areas of the Russian Far East and the Pacific coastal areas in the United States as far south as Baja California. The world-wide sea otter population was drastically reduced to just a few hundred individuals between 1742 and 1911, due to commercial harvest by the Russian and Russian/American fur trades.

Three populations of sea otters exist in Alaska today. The statewide population is believed to number around 70,000 individuals.

In the United States, the Northern Sea Otter is protected from hunting and harassment by the Marine Mammal Protection Act of 1972. The U.S. Fish and wildlife Service is the federal agency responsible for maintaining healthy populations of sea otters. In the early 2000s Northern Sea Otters in southwest Alaska were listed as threatened under the Endangered Species Act.

The primary threats to sea otter are generally human-related, and include: competition for shellfish, mariculture, oil and gas transport, logging activities in coastal areas, and commercial fishing.

A Sea Otter Mom and large pup riding on her belly

Conservation Success for Otters on the Brink of Extinction

All over the world otter populations have been hanging in the balance, but two very different approaches have been successful in saving the species

Loveable, playful, inquisitive, tenacious, energetic, versatile, charming and undeniably cute. These are just some of the words that can be used to describe an otter. If you’ve been lucky enough to see one of these shy semi-aquatic animals in the wild, you’ll instantly understand why.

But despite all their lovable qualities, otter populations all over the world hang in the balance.

Because they haven’t always been appreciated (at least not alive), sea otters were almost hunted to extinction for their warm and luxurious pelts. More recently, many species including the common, or Eurasian, otter have been hunted and trapped because they were seen as threats to fish stocks and competition for our food. Sometimes they were even killed for fun.

It is not just deliberate hunting, trapping and persecution that cause otters to suffer; they have to cope with shrinking habitats and a shortage of food, are vulnerable to chemicals, pollutants and (for some species) oil spills. Getting caught in fishing nets, parasites and infectious diseases are yet further causes of fatalities.

These are big problems and a tall order for any group of animals to deal with.

Despite all these challenges, they are fighters with a range of skills and behaviours making them superbly adapted to life on land and in water.

Found on every continent except Oceania and Antarctica, not one of the 13 species has yet become extinct.

This says a lot about the tenacious nature of these members of the mustelid family, but also about the efforts many organisations and individuals have played in their conservation. The approaches and use of technology may differ vastly in different parts of the world, but the long-term survival of the species is what matters.

Sea Otter by Ryan Wolt

Sea otters in California

It was a close call for the incredibly cute sea otter (Enhydra lutris) though.

During the fur trade of the 1700s and 1800s, the worldwide sea otter population was reduced from as many as 300,000 animals to as few as 2000, explains Andrew Johnson, Monterey Bay Aquarium’s Conservation Research Operations Manager.

They were relentlessly hunted for their pelts. With around a million hairs per square inch, it was regarded as one of the most prized animal furs in the world.

Along the Californian coast, the southern sea otter (Enhydra lutris nereis) was persecuted particularly badly, where numbers in the early 1900s were down to around 50 individuals (from 15,000) and were close to being wiped out.

Thankfully, they are now protected and their numbers have recovered to around 125,000 - though they remain an endangered species.

Healthy populations have a profound effect on the overall health of kelp forests, estuaries, and coastal and ocean ecosystems, because, Johnson says, “When sea otters are absent, those systems often fall out of balance and become less diverse and resilient.”

Monterey Bay Aquarium in California has worked with sea otters since it opened in 1984 and now operates a successful sea otter rescue and release programme, using state-of-the-art facilities and tracking implants to help them in their vital work.

To help stranded sea otters, they have an Intensive Care Unit and multiple enclosures filled with filtered seawater with the capacity to hold 10 animals at one time. To monitor their progress once back in the wild, they use radio transmitters.

“We implant the transmitters so that we can track each otter and watch its behaviour following release,” he says.

Because the batteries last at least two years, young animals can often be tracked until they reach adulthood and reproduce, allowing the team to document the significant impact releasing sea otters into an area has on the ecosystem.

Largely due to legislation and the conservation work of dedicated organisations and charities such as Monterey Bay Aquarium, there is good news for California’s southern sea otters, as numbers are now up to 3000.

“This charismatic and vital species would not have survived without these protections.

“We need them to survive so they can exert positive effects on kelp forests and estuarine habitats, making those areas healthier and more ecologically diverse,” Johnson says.

A large group of Sea Otters near Cape Edgecumbe

The female otters and pups move in large groups through the nearshore kelp while the males are found floating far out in the middle of Sitka Sound

Hairy-nosed otters in Cambodia

Not all approaches to conservation are so well funded, but this doesn’t mean they are any less successful.

The hairy-nosed otter (Lutra sumatrana) is one of the rarest and most endangered species of otter. In the 1990s, it was thought extinct throughout its range in Southeast Asia due to habitat loss, poaching, local consumption of otter meat and a loss of its sources of food.

However, surveying between 2006 and 2013 at possible habitats confirmed the presence of several small populations. In Cambodia, for example, it was found in four areas; one of the largest populations being around the flooded forest surrounding the Tonle Sap Lake.

Now the species has been ‘rediscovered’, it needs to be protected so that the populations can be allowed to grow. And that’s where organisations such as Conservation International have worked to protect and conserve the area and the species.

As Sokrith Heng, Conservation International’s lead researcher for the survey, explains, even though there are a number of laws and regulations to protect the species, enforcement on the ground is weak and limited and local people’s awareness of the importance of the wildlife and ecosystems they live in is very limited.

Poverty in areas such as rural Cambodia can also be a problem and often pushes local communities to use natural resources in unsustainable ways.

In response to this, Conservation International took action at Tonle Sap Lake. Their approach was to restore critical habitat, raise awareness in local communities and schools, and suggest laws and regulations to better protect the species. They also established conservation zones, protecting these through collaboration with government and community rangers as well as helping local community fisheries to development alternative livelihoods.

Key to this was directly engaging local community members in otter research and forming a group of ‘otter ambassadors’ who help spread awareness resulting in stronger support from locals.

This is important Heng says because; “Educating local people means they can share their knowledge to other community members.”

An important part of the successful conservation here is ensuring that local communities are able to sustainably use and manage their resources, and that the communities are financially stronger, explains Heng. For example, some community fisheries now have better protection for the otters: they are patrolling the area to stop illegal activities and teaching otter conservation in the local area.

At Tonle Sap Lake, these approaches resulted in fewer otter traps and skins being recorded by officials and researchers, both signs that fewer animals were being killed. While ongoing habitat restoration combined with less hunting and greater awareness is helping to ensure a brighter future for the hairy-nosed otter.

Although the technology maybe very different to that used at Monterey Bay, this method of conservation has been just as successful, as hairy-nosed otters now have at least one stronghold in Cambodia.

It is a good result for the country and for a species that was once thought extinct.

By Jeremy Coles for the BBC, 2017