Sea otter Distribution, Status and Taxonomy

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Sea otters, originally native to Japan, Alaska, Canada, Russia, Mexico and the United States, now have established populations in southern California, Washington state, British Columbia, Alaska and the east coast of Russia.  Recently, there have been sporadic sightings along the Oregon coast seeming to indicate the species is attempting to expand southward.

The sea otter is classified by the IUCN as endangered with a decreasing population, one that is that is believed to have declined over 50% in the last 30 years, equating to about three generations.  Their populations, once numbering 150,000 to 300,000 animals worldwide, decreased to approximately 2,000 when the commercial fur trade ended in 1911. 


Sea otter range map courtesy of www.iucnredlist.org

Sea otters have many threats in the modern day. Their greatest threats are from oil spills, either small or large like the Exxon Valdez catastrophe of 1989, pollution in their native habitats and the resulting diseases, conflicts arising from commercial fisheries, as well as boat strikes.  There has been an increase in orca and shark predation in recent years.

The taxonomic listing for the sea otter is as follows: Kingdom: Animalia; Phylum: Chordata; Subphylum: Vertebrata; Class: Mammalia; Order: Carnivora, Family: Mustelidae; Subfamily: Lutrinae; Genus: Enhydra; Species: Lutris.  The sea otter is further divided into three subspecies, depending on its range.  Enhydra lutris lutris ranges from the Kuril Islands north past the Kamchatka Peninsula to the Commander Islands in the Western Pacific, Enhydra lutris kenyoni’s range is on the eastern side of the Pacific in the Aleutian Islands and Alaska. Finally, Enhydra lutris nereis inhabits the central coast of California.

Hairy-nosed otter status and distribution

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Hairy-nosed otters are listed by the IUCN Red List as endangered with its population trend decreasing.  In fact, its population is believed to have declined 50% in the past 30 years.  The species was thought to be extinct, but has been rediscovered in Southeast Asian counties of Thailand, Vietnam and Cambodia.  (range map courtesy of IUCN Red List). 

 

Hairy-nosed otters have significant threats in their range. Otters in Southeast Asia, including the Hairy-nosed otter, are the subject of intensive poaching and are hunted for illegal wildlife trade, medical use and for bushmeat.  (Otter News will explore more about this topic during Hairy-nosed otter month).

The official taxonomic listing is: Kingdom: Animalia; Phylum: Chordata; Subphylum: Vertebrata; Class: Mammalia; Order: Carnivora; Family: Mustelidae; Genus: Lutra; Species: Sumatrana.

Otter News sends sincere appreciation to Carol Bennetto for the use of her photograph in this post. 

Mazu's beginning

 Article by Jo Myers Thompson, Ph.D., original publication date - 2010

(full article available, click here)

 

 Follow Congo Clawless otter month daily on Otter News.

Enjoy this article on Mazu's early days



A newborn Mazu

Early in February 2010…[after killing the adult mother of a Congo Clawless otter pup, a hunter, named Mundweni, brought the newborn pup to two missionaries serving in the Democratic Republic of Congo (DRC), Africa.]

Glen and Rita Chapman are missionaries who have both lived most of their lives serving in the Congo. Their mission station is a small pastoral training center called Kikongo. About 170 kilometers east of Kinshasa, the capital city, their idyllic home village lies on the bank of the Wamba River (a tributary to the Kwango River) in Bandundu Province, DRC. Rita has a special gift for successfully raising wild orphans. So, Mundweni presented Rita with the newest addition to her menagerie.
 
The Congo Clawless Otter (Aonyx congicus) range corresponds to the Congo river basin. It is one of the least known otter species in the world. It has a patchy distribution across its range of occurrence and a very low density of occupation where it is found. Within their previous range, their population numbers have been reduced and they have been extirpated from areas where they may have previously been assumed to occur. There is a desperate need for conservation action and research.
Threats to Survival:  

• the escalating demand for bush meat and skins
• habitat loss and degradation
• steep decline in fish populations due to overfishing by humans with improved technology and nylon fishing nets
• pressure from development of hydro-electric power projects
• under-representation of otter habitat in protected areas
• pollution and deterioration of water quality resulting from large scale deforestation throughout their range
• growing proliferation of weapons and munitions such that now otters can be shot from pirogues and river banks
• dramatic depletion of other species (such as the hippo) who play an integral role in the food chain on which otters depend and contribute to the aquatic-ecosystem functioning that supports otter food supplies.

The Congo Clawless Otter is the most terrestrial otter species in the world and is therefore much more vulnerable to snares set on land. They are not protected by traditional taboos across their range. Some of these threats can be considered major, but more importantly is the dramatic combined effect of threats on otter populations.

 

Today (as of late 2010), the little pup is now known around the world as "Mazu" in deference to her persistent vocalizations recognized in the world of otter husbandry as the "nursing hum." Mazu means "noise" in the tribal Kikongo language. Mazu has united the interests of people around the world and in her home village. Locally and abroad Mazu has become a symbol of Congolese natural heritage and a global treasure. Through the efforts of the International Otter Survival Fund (IOSF), Mazu has been introduced to the world and on this global stage has become an unparalleled ambassador for African Otter Conservation.

 

Mazu helping to teach future conservationists

The Future for Mazu: it will be inappropriate to release her back into the wild. Congolese do not have experience distinguishing between wild animals and tamed wild animals when they are hunting. So, with the support of a group of caring individuals and organizations, Glen will be providing a safe and stimulating enclosure to meet Mazu's growing needs, Rita will continue to provide the nurturing and sensitive care under which Mazu thrives, the local community will reap the benefits of global attention and Mazu will continue to teach us all.

 

Special note: Mazu was originally thought to be male so references to Mazu's gender in this article have been updated from the original publication. 

Congo Clawless otter Distribution and Status

During July 2013, follow Otter News for Congo Clawless otter month

 

Photo courtesy www.pressdispensary.co.uk, Mazu caretakers & IOSF

The Congo Clawless otter is listed by the IUCN Red List as a species of least concern, however little is known about its population tread.  It was originally thought to be, and at times still described as, a subspecies of the African/Cape Clawless otter (Aonyx capensis).

Congo Clawless inhabits the rainforests and swamps within the Congo River basin (see map below).  As mentioned during African Spotted-necked otter month in May, Congo Clawless otter habitat overlaps some with Spotted-necked otters as Spotted-necks are present in the Congo basin as well. 

Per the IUCN Red List, Congo Clawless otters are not considered to have major threats at this point; however, they still face habitat loss and are hunted for bushmeat and their skins.
  
Some common names include: Cameroon Clawless, Small-toothed Clawless and Zaire Clawless otter.  The official taxonomic listing is: Kingdom: Animalia; Phylum: Chordata; Subphylum: Vertebrata; Class: Mammalia; Order: Carnivora, Family: Mustelidae; Genus: Aonyx; Species: Congicus.

Range map courtesy www.iucnredlist.org

Marine otter distribution and status

Follow Otter News daily for Marine otter month, June 2013

Photo courtesy www.seapics.com

The Marine otter is listed by the IUCN Red List as an endangered species; its population tread is decreasing. Native countries are Peru, Argentina and Chile (see map below) and their habitat is oceanic sea, with preferences for rocky shorelines with high winds.  They are the only Lontra genus to exclusively live in marine habitats.  

Marine otters are extremely susceptible to habitat decline, pollution, excessive poaching and hunting.  Otter News will explore their threats in more depth during awareness month.  

The official taxonomic listing is: Kingdom: Animalia; Phylum: Chordata; Subphylum: Vertebrata; Class: Mammalia; Order: Carnivora, Family: Mustelidae; Genus: Lontra; Species: Felina.



map courtesy http://maps.iucnredlist.org

Denver Zoo's North American river otter, Otto

Written and Submitted by Diane Tomecek

 

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Otter News briefly introduced you to Otto, the North American river otter (NARO) at Denver Zoo, in December during our feature on the Asian Small-clawed otters, Asha and Barry Kirin, of Toyota Elephant Passage. Returning to Otto, we wanted to introduce you to this charismatic North American river otter who has spent most of his life at the zoo enjoying the fine enclosure within Northern Shores.

In October 2012 when Otter News visited with Ashley Snow, one of the staff zookeepers, she spoke first about Ariel, the 18-year-old female NARO who had passed away the previous evening. Ariel had come to the zoo in 2005 and was a rescue from Florida; she had spent time at the Florida Aquarium. Otto is 14 and was feeling a bit out of sorts during our visit; likely not sure where Ariel, his long-time exhibit partner, had gone. Otto is a rescue from Louisiana where he was caught by a trapper and then given to a rehabber. You can see the probable damage caused by being caught in a trap at approximately 3-years of age because he has some nerve damage on his right front paw as well as a few missing toes (as seen in the photo above).


Otto with enrichment - a water jug filled with live fish

Denver Zoo practices enrichment for Otto at random times during the day. He receives burlap bags of varying size and shape, multi-colored plastic balls to play with in the water, as well as a large water jug filled with live fish. Otto’s favorite enrichment has to be the large water jug – he found and consumed the fish almost immediately after Ashley dunked it in the water for him. Enrichment is a key element for a captive animal’s quality of life and Ashley and other staff have developed a number of methods for the North American river otters at the zoo.

Ashley attended an otter keeper workshop and brainstorms with many other otter keepers to create new enrichment ideas to bring to curatorial staff.  At Denver Zoo, they have a curator of behavioral husbandry who oversees all training and enrichment at the zoo.  The zookeepers bring the curator lots of creative and fun enrichment ideas and then it is her job to approve them based on whether the enrichment will emphasize natural behaviors and be safe for the animals.  In fact, Ashley has just recently informed Otter News that a series of enrichment methods have been approved; these items include duck decoys, pvc endcaps, dog beds and aneGGe dog toy.

The enclosure for Otto is quite substantial and he enjoys his 8-foot-deep pool. As discussed in our feature of the Asian Small-clawed otters, the Toyota Elephant Passage exhibit employs a habitat sharing concept for the animals. Since the exhibit’s opening in 2012, staff have been brainstorming ways to potentially incorporate this shared habitat concept throughout the other areas of the zoo. Additionally, because the zoo is on city land, it has limited capacity to expand habitats for other animals, including Otto. Therefore, staff is getting creative, brainstorming many ideas for the exhibit!  To create a more natural feel, staff constructed a planter garden atop one of the concrete platform ceilings which goes over Otto’s den.

 

After discussing the outside habitat, we moved behind the scenes to see where Otto receives training and any necessary medical treatment. The otter keeper workshop and discussions with Denver’s Downtown Aquarium emphasized to Ashley and other staff the need to develop an interesting addition to the enclosure where Otto receives any necessary medical treatment. They took a pipe, cut it in half and attached it to the cage. Now, Otto is being trained to go into this section, which helps him feel more secure while receiving any needed injections or other medical treatment.

 

Otto is quite a fun otter to watch. In fact, Otter News has recently returned to Denver Zoo to see him again. He was out swimming and romping around his exhibit on that warm Saturday afternoon. Denver had experienced some very cold weather the week prior and the waterfall in the enclosure had become quite frozen. However, the warmer temperatures of the day had begun to allow the ice to melt away. Otto enjoyed the ice as it broke off - playing and entertaining the visitors with his ice wielding antics! It was good to see him again.

 

Otter News is especially excited to bring our followers the news that Otto will soon have a companion otter! Ashley and zoological staff have been working with the SSP (Species Survival Plan) program to identify an otter that will be able to call Denver Zoo home.  The companion for Otto is coming from a facility on the west coast.  Keep following Denver Zoo on Facebook, www.facebook.com/DenverZoo, and via their website, www.denverzoo.org for more information. Otter News will keep following as well and will definitely let everyone know when Otto’s companion arrives.  

Otter News extends its sincere appreciation to Ashley Snow and Denver Zoo for this interview as well as taking such great care of the otters we all love!!

 

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African Spotted-necked otter Status & Distribution

The African Spotted-necked otter is listed by the IUCN Red List as a species of least concern because of its widespread distribution; however, its population tread is said to be decreasing. Their habitat overlaps to some degree with both the Cape Clawless and Congo Clawless otters; more so with Congo Clawless as Spotted-necked otters are present in the Congo Basin. (see map below) They are considered possibly extinct in the countries of Burundi, Ghana, Lesotho and Togo.

 

Their common names are Speckle-throated, Spot-necked or Spotted-necked otter. The official taxonomic listing is: Kingdom: Animalia; Phylum: Chordata; Subphylum: Vertebrata; Class: Mammalia; Order: Carnivora, Family: Mustelidae; Genus: Lutra; Species: Maculicollis.

Spotted-necked otters face similar threats to other otter species, i.e. habitat degradation and being viewed by locals as competitors for food sources. However, they are also killed themselves as a food source. Additionally, biological contaminants have been discovered in the bodies of deceased animals.