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Project Lab 

September 25, 2013

Sea Otter Awareness Week

This week happens to be the 11th annual Sea Otter Awareness Week (September 22nd to 28th). To celebrate, I figured I’d take a break from writing about marine invertebrates and write about this very charismatic marine mammal.    This week in the Project Lab we have a display of sea otter specimens including some skulls, pelts and study skins, so if you are at the Academy, stop by and check it out!

Growing up, sea otters were one of my favorite animals.  I remember seeing them at the Seattle Aquarium as a kid and thinking they were just adorable.  I mean, who could resist a face like this??

Sea_otter_cropped.2

Sea otters (Enhydra lutris) belong to the order Carnivora, which includes mostly carnivorous (and some omnivorous) mammals.  Within the carnivorans, sea otters belong to the family Mustelidae, which includes otters, badgers, weasels and others.  In layman’s terms, sea otters are cute marine weasels!  The species is subdivided into three subspecies:  the Southern Sea Otter (Enhydra lutris nereis), the Northern Sea Otter (Enhydra lutris kenyoni), and the Northern Sea Otter (Enhydra lutris lutris).  Each subspecies has its own distribution, as you can see in the figure below.

special_spp_otter_fig1.3

 

Sea otters live in marine habitats and can be found in protected bays, tidal estuaries and outer coasts, usually associated with kelp beds.  They range from 1-1.5m (3ft 3in- 5ft) long with the males larger than the females.  Unlike seals, sea lions, and whales, these marine mammals don’t depend on blubber to keep them warm.  Instead, sea otters rely on their thick fur that has up to one million hairs per square inch— the densest fur of any animal!    As a comparison, humans have a density of roughly 1000 hairs per square inch on their heads.

 

purple urchin

 

As you can imagine, sea otters are big fans of seafood.  They eat over 100 different prey items including a variety of marine invertebrates (turns out I’m writing about them after all!), such as sea urchins, clams, mussels, abalone and crustaceans.  In order to harvest and prepare their meals, they use tools such as stones to pry food off of rocks or to open up shells.  Interestingly, sea otters that specialize on purple sea urchins will have purple teeth and bones.  If you look closely at one of our specimens on display, you can actually see the purple coloration!

 

 

purple teeth

 

Sea otters are important members of kelp forest ecosystems.   Kelp provides a habitat and nutrients to many organisms, and sea otters play an important role keeping kelp healthy by feeding on kelp predators.   Sea otters are often referred to as a “keystone species” because if they are absent, this can have huge effects on these ecosystems, including too many kelp predators and a loss of kelp and kelp forests.

 

Sea Otter threats

Beginning in the late 1700s, Southern sea otters were harvested commercially, reducing the population in California from about 16,000 animals to the verge of extinction.    All of the current California sea otters are descendants of a small colony of 50 animals from the Big Sur Coast in the 1930’s.  Today, the Southern sea otter is listed as Threatened under the U.S. Endangered Species Act and protected by the California Department of Fish and Game.  The biggest threats faced by sea otters today include oil spills and diseases.  Oil can interfere with the ability of the fur to keep these animals warm.  It can also cause harm through ingestion or fumes.  Diseases are another threat to sea otters and can be strongly influenced by human activities on land.  For example, sea otters are susceptible to a parasite (Toxoplasma gondii) that breeds in cats.  This parasite can enter waterways when cat litter is disposed of improperly by flushing down the toilet.

 

If you are interested in helping sea otters, you can help by:

  • supporting efforts to control urban, industrial and agricultural runoff,
  • supporting efforts to minimize bycatch of marine mammals in fishing nets
  • supporting non-profits involved in sea otter recovery and research, such as the Academy.

 

Here at the Academy, we have the world’s largest collection of Southern sea otter research specimens, which are used by researchers to study these charismatic and important animals.   For the duration of Sea Otter Awareness week, you can see some of these specimens on display at the Project Lab.  Also, as a special treat, you can view sea otter skulls being prepared in the Project Lab and talk to biologists at a special sea otter table during NightLife on September 26 between 6:00-10:00 pm (for ages 21 and over).

 

To learn more about sea otters and Sea Otter Awareness Week, visit http://www.seaotterweek.org/.

 

That’s all for now!

Vanessa Knutson

Project Lab Coordinator

 



Filed under: Uncategorized — project_lab @ 4:32 pm

September 18, 2013

A Threatened Species

Codie last wrote about the effects that plastics can have on bird species. As we all know, there are many more ways that we can have negative impacts on animals of all shapes and sizes. I recently prepared a study skin of a Western Snowy Plover (Charadrius nivosus nivosus), a bird you might be familiar with if you frequent the California beaches that they breed on.

 plovers_photo1 copy

The Western Snowy Plover is a small shorebird that nests and raises its young on beaches. Between the months of March and September, beaches along the Pacific Coast become the territory on which these birds find a mate, establish a nesting site, lay and incubate their eggs, and raise their young. Beaches are obviously a very important part of the life cycle of this species. As we all know, beaches are also important to another species: humans! We use beaches for recreation both for ourselves and our dogs. Between human recreation, urbanization, and the introduction of invasive plant species, suitable beach habitat for Snowy Plovers to breed on has diminished.

plovers_photo2 copy

plovers_photo3 copy

 

What does this mean for the plovers? As you might imagine, habitat loss means less area on which to successfully breed. Even in areas where plovers still nest, humans, predators, and other animals scare adult birds away from their nests, leaving eggs and young vulnerable. This inability to breed can lead to endangerment of a species and, in the worst case, extinction. The Western Snowy Plover has been listed as a threatened species under the Endangered Species Act since 1993, meaning that the species is likely to become endangered within the foreseeable future (endangered meaning that the species is in danger of extinction throughout all or a significant portion of its range). It’s obvious that we need to find a way to allow these birds to breed while still being able to use beaches ourselves.

There have been and continue to be many restoration projects along the Pacific Coast that focus on removing invasive plant species, restoring native plant species that attract beach-dwelling animals, and setting aside protected areas where humans and dogs can’t impact breeding birds. These kinds of projects are crucial to species’ survival!

 

plovers_photo4 copy

 

Am I suggesting that we all keep ourselves and our dogs off of beaches? Absolutely not! I’ve lived the majority of my life in California and love going to the beach (with my dog, as well). We just all need to make sure that we share the beach with native plants and animals. That may mean paying attention to signs pointing out sensitive areas, keeping our dogs on leash, and keeping our beaches clean. It’s a small price to pay to ensure that Western Snowy Plovers, as well as other species, get a chance to survive.

 

Laura Wilkinson

Curatorial Assistant and Specimen Preparator

Ornithology & Mammalogy


Filed under: Uncategorized — project_lab @ 11:01 am

September 12, 2013

They call me Melo yellow…

Most weeks I write about my research subjects: nudibranchs.  This week I thought I’d learn something new and write about some shelled marine snails.

One of the highlights of my trip to Papua New Guinea last year was finding the largest live snail that I’ve ever seen in my life.  I found the snail on a night dive while looking for nudibranchs.   As I approached a large structure, a coral head or perhaps it was a coral-covered boulder, I remember seeing a snail nearly the size of a football.  It was brown in color and its foot was spread out from under its shell like a thick carpet as it moved up the side of the structure.  I remember being overwhelmed with excitement having come across such a large snail, especially as I was looking over sand grains in search of slugs the length of grains of rice!  I immediately decided to collect this live snail, since I couldn’t recall anyone collecting anything quite like this yet on our biodiversity survey.  I grabbed it by the shell and placed it in my catch bag.  It took up a majority of the space in the bag and added a fair amount of weight!

 

Melo in hand cap

While diving in in the field, our team had an in-house competition on each dive to see who could find the most interesting or beautiful specimen, clearly this time, I had won the “shell of the show.”  When we returned to the lab, everyone was excited to see such a large snail, and I was told that it was a member of the group commonly called “bailer” snails.  Our shelled snail experts identified this particular species as Melo broderipii.

 

Melo is a genus of snails that belongs to the family Volutidae.  Many volutes have large shells and some of the largest shells in this family can be found within the genus Melo.   Some of the shells of certain species can grow to 50 cm (19.7 in) in length!  The common name “bailer” comes from the shape of the shell, which can be used to “bail” out water from boats or canoes.  Members of this group are carnivores and eat other snails and seem to live primarily on a muddy or sandy bottom.  They appear to bury themselves during the day and are active at night.

 

779px-Melo_broderipii_01wcap

An interesting thing I read about Melo snails is that they are capable of producing pearls.  Unlike the pearls that are found in oysters, these pearls are not iridescent because they do not contain nacre, which is what makes other pearls and parts of shells iridescent.  Instead, these pearls are yellow to orange in color and have a sort of “flame” pattern to them. To me, they look very much like marbles!

 

Melo_melo_01_by_Line1wcap1

 

These animals are eaten by humans and the shells sold for a variety of uses.  Apparently, they are sometimes used as horns in ceremonies or as ashtrays.

I never cease to be amazed by the diversity of organisms that live on our planet.  I think I might delve into these snails a bit more…

 

Until next time!

Vanessa Knutson

Project Lab Coordinator

Sources:

http://www.palagems.com/melo_myanmar.htm

http://www.sea-ex.com/fishphotos/baler-shell-commercial-fishery.htm

http://www.sea-ex.com/fishphotos/baler.htm


Filed under: Uncategorized — project_lab @ 12:28 pm

September 4, 2013

Spider Sex!

Why is it that biologists always seem to want to talk about sex?  The answer goes back to our understanding of what a species is, and how biologists can tell if animals are of the same species.  While there is more than one definition for what comprises a species, a general description for animals goes like this: A species is a group of animals normally found together that breed and reproduce, creating offspring the same as the parents, who can also reproduce.  In other words, cows mate with cows and produce more cows that can mate and produce more cows. This generalized biological species concept works well for most animals. For larger and more common animals humans have had plenty of opportunities to see mating take place and watch the resulting birth of offspring. People make babies who grow up to mate and make more baby humans, dogs make dogs, etc.  But here’s the catch… the vast majority of animal life on the planet is generally invisible to us most of the time, because it lives in the ocean, deep underground, or hidden from normal view. In fact, many marine and other organisms have had the males and females described as different species, because they look so different from each other. But most of these animals reproduce sexually, using eggs and sperm, and they must have very specific sperm delivery and fertilization organs. This allows scientists to identify males and females of the same species by carefully examining genitalia, because part “A” has to fit into part “B” for everything to work.  And so it is with spiders.

Aranae of the Hearst Philippines Expedition

Spiders often exhibit sexual dimorphism, where the 2 sexes do not look the same. One example is our California black widow spider, where the female is large with a shiny round black belly with a red hourglass marking, while the male is a tiny brown creature devoid of markings.  While not all spider species have such extreme differences, examining genitalia often provides the final answer in species determination.

 

Salticid_Face.2

All spiders have 8 legs, and in addition they have a pair of pedipalps, small leg-like structures originating close to the mouth.  Male pedipalps are highly modified to act as sperm transfer organs, with a thin tube for containing the sperm, and lots of species-specific spines and projections that allow it to mate only with females of its own species.  Sperm is deposited on a sheet of special silk on the ground, then the male touches the drop, which is sucked up into the tube, and he is ready to find a willing mate.

 

Aranae of the Hearst Philippines Expedition

The female has a sclerotized (hardened) area on her abdomen shaped to allow access only to males of her species. By carefully examining these structures, researchers can often figure out who belongs with whom.

CASENT9031589_Epig2

 (All photos taken by Vic Smith at Project Lab)

Until next time,

Vic Smith

Curatorial assistant and imaging specialist


Filed under: Uncategorized — project_lab @ 10:36 am

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