Friday, April 27, 2012

I'd call this crab Wartimer

No need for the Freeze Away®, folks. You're going to love this Crabday's wart-riddled crab:

Warty Crab
Eriphia verrucosa

This crab was brought to my attention by one of the Snow Crab Love followers on facebook. Despite its name, the warty crab is quite pretty. It's also known as the yellow shore crab but gets the warty reputation from the tubercles found on its claws.

see the awesome tubercles?

This rocky intertidal crab (living on the coastlines up to 15 meters in depth) can be found in the Black Sea, the Mediterranean Sea, and the Atlantic Ocean. However, the warty crab has decreased in the Black Sea, being listed as endangered in the Ukrainian Red Data Book. This is not only bad for our little crab friend, but also for the rest of the Black Sea community. Warty crabs are the only native animal strong enough to crack the shells of invasive snails, Rapana venosa, who have made their entrance into the Black Sea due to warmer water conditions. (Remember learning about the ongoing battle between crabs and snails here?)

"Bring it!"
(you can see more amazing pictures of these snails here
and the crab photo was from here)

Aside from invasive snails, the warty crab likes to eat polychaetes, bivalves, and even hermit crabs! While not eating, they use rocks and anemones to hide and protect themselves from becoming eaten.


OK, I guess that's enough! I hope you enjoyed learning about this beautiful bumpy crab!

Read more:
Ozcan, T., T. Katagan, and A. Kocatas. 2005. Brachyuran crabs from Iskenderun Bay (Southeastern Turkey). Crustaceana 78: 237-243.

Rossi, A. C., and V. Parisi. 1973. Experimental studies of predation by the crab Eriphia verrucosa on both snail and hermit crab occupants of conspecific gastropod shells. Bolletino di Zoologia 40: 117-135.

Tuesday, April 24, 2012

Aging crabs

Last week was an exciting one with three defenses in three days! Congrats to my fellow successful defenders (theirs were doctoral dissertations! yikes!):

Ben Daly and Kray Van Kirk

Sherry and me before my presentation with our mugs

amazingly delicious cupcakes made by Gretchen Geiger
(the eyes are green just like snow crabs!)

During my presentation, I explained that I use the visual condition of snow crab shells as a rough estimation of how long it has been since they molted (see Step 1 here). The darker and more marked up a crab may be, the longer it has been since molting. While determining a crab's shell condition is not an exact science, shell condition index is the only way to get an estimation of age in these crusty guys.


That's right, there may be a way to age crabs after all! You see, we can use the bones of fish and mammals to get their ages since they often will lay down annual markers (much like trees). But because crabs molt, they lose that hard part that may otherwise have retained signs of growth and aging over time. And because snow crabs terminally molt over a wide range of carapace widths, size frequency distributions don't work well in estimating age groups. However, researchers think that they can measure lipofuscin, a waste material retained within the brains of crabs, in order to age them!

if he only had a brain!

Lipofuscin granules can't be degraded or exocytosed (removed from the cell), so they accumulate over time. Scientists have gotten age estimates in crayfishAmerican lobsters, and blue crabs using lipofuscin as an age index. What about snow crabs? Allain et al. (2011) measured lipofuscin from the olfactory lobe cell mass in new- and old-shell immature and mature snow crabs.

snow crab brain! (watch out for zombie crabs!)

The scientists found higher levels of lipofuscin in old-shell crabs compared to new-shell crabs, indicating the aging process! Unfortunately, snow crabs retain very low levels of lipofuscin compared to other crustaceans, and their immature animals had unmeasurably low levels, making a lipofuscin index for opies difficult to calculate. These lower levels may be due to snow crabs' cold water environment, as temperature has an effect on lipofuscin accumulation rates.

arctic sea ice extent (with the Bering Sea in the red star)=

Overall: use of lipofuscin is NOT useful for aging snow crabs, which may be bad (or just sad) news for us, but good news for those lady snow crabs who don't want to divulge their age. So don't worry, female opies, you can celebrate your "9th" birthday as many times as you want - we won't call you out on it!

Read up on aging:
Allain, R. N., M. Moriyasu, B. D. Crawford, and S. C. Courtenay. 2011. Lipofuscin quantification as a potential tool for age estimation in snow crabs,Chionoecetes opilio (O. Fabricius, 1788) (Decapoda, Oregoniidae). Crustaceana 84: 1441-1463.

Monday, April 16, 2012

Meet Ophilia!

It's defense week! I'm not going to be posting again until next week, but for now please enjoy this mini-book craft:

This little book about Ophilia the opilio can be yours!

1. Print out this pdf file.

2. Fold in half, open, then fold in half the other way.

^ hot dog fold (folding the long way)

 ^ hamburger fold (folding along the shorter way)

3. Cut along the black line.

(parental guidance is handy here)

4. Here's the tricky part:

go back to the hot dog fold and notice that the hamburger 
creases will allow you to open the book where you cut the line

using that opening, you can push the paper into a cross or X shape

 another angle of the cross/X shape

find the front and back of the mini-book like above
and press the rest of the pages together, 
then make one final fold in half so that the book looks like below:


You now have a sweet mini-book about a happy little snow crab that you (or your kids) can color and enjoy!

Feel free to print out this picture of Ophilia and color her in or decorate her with more fun bows/jewels/sponges/algae (I mean, she is a crab, and decorator crabs like to use sponges and algae)! Be sure to send me a picture when you're finished if you'd like to share your artistic abilities!

Friday, April 13, 2012

Roses are red, this new crab is blue!

It's a new Crabday and a new crab! Christmas Island is known for it's crabby inhabitants and has been studied for quite awhile now because of the yearly red crab migration. So it's surprising that a new species has only just now been described, but better late than never!

Blue Crab
Discoplax celeste

What a beaut!

Much like the newly discovered crabs we learned about last week, researchers were well aware of these beautiful blue crabs, but simply thought they were a blue version of D. hirtipes (found in Fiji and are so elegantly described as "dark violet and the chela bright cinnabar red"). The trick was that D. celeste change color as they grow: small juvenile crabs are black and light tan, and don't become that brilliant blue until they reach 46 - 52 mm carapace width.

a color progression from small juvie (A) to adult (H)

Upon closer inspection of the carapace, male abdomin, and gonopods, the researchers discovered the blue version were in fact a completely different species from the dark purple/black one originally described, so they decided to name the new one after its sky blue color.

it makes me want to watch for animal-shaped clouds...

Our new D. celeste wasn't the only crab on Christmas Island thought to be D. hirtipes. This other sneaky crab  D. aff. hirtipes has the dark purple/black carapace known to D. hirtipes proper, but yellow chela (hence the "aff." in the name, which simply signifies the similarity to the original species while noting that, as a new species, it has yet to be defined)!

a lovely blue D. celeste next to a
flashy D. aff. hirtipes on Christmas Island

Those two will make a great color-coordinated pair next Leap Year Day! (Here's hoping they survive the next 4 years!)

Check out the paper:
Ng, P. K. L., and P. J. F. Davie. 2012. The blue crab of Christmas Island, Discoplax celeste, new species (Crustacea: Decapoda: Brachyura: Gecarcinidae). The Raffles Bulletin of Zoology 60: 89-100.

Tuesday, April 10, 2012

Waiter, there's a crab in my bivalve!

Last Crabday's shellback crab got me thinking (and hungry): how would a crab-stuffed clam taste? I'm just guessing, but I'd say AMAZING! And while I'm not about to head out and go digging for clams around here (call me Miss Cautious, but paralytic shellfish poisoning is pretty prevalent up here and kind of freaks me out), this recipe from Food Network caught my eye:

Stuffed Razor Clams with Alaskan King Crab Rice Filling

  • 2 tablespoons oil
  • 1 tablespoon finely chopped fresh garlic
  • 1 tablespoon finely chopped fresh ginger
  • 6 razor clams (make sure it's a real razor clam, and not a robot!)

a razor clam and its roboclam counterpart

  • 1/2 cup scallions, white and green parts, sliced 1/4-inch thick
  • 2 tablespoons chopped fresh cilantro
  • Salt and freshly ground black pepper
  • 1 cup short grained sushi rice, washed, cooked and cooled, as for sushi
  • 1 cup coarsely chopped Alaskan king crab meat
  • 1 1/2 quarts water mixed with a pinch of sea salt and 1 sheet of nori (the original recipe calls for actual sea water mixed with a cup of bull kelp... so go crazy if you can rock that ingredient!)

Shuck, clean, and chop the razor clams. Reserve the shells and about 1 cup of the clam meat.

(image found here, with another tasty lookin' recipe)

Wash, cook, and cool the sushi rice just like you would for sushi. You'll want about 2 cups cooked rice for the stuffing.

Heat the oil in a wok over high heat. Add the garlic and ginger and stir-fry for about 2 minutes until soft. Add the chopped razor clam meat, scallions, and cilantro. Season with salt and pepper, to taste, and mix lightly. Fold the mixture into the rice with the chopped crab meat.

Divide the filling among 6 razor clam shells (I'm imagining that you'll actually have a total of 12 things since you can fill each half separately). Pour water/nori mixture into a wok fitted with a steamer. Bring the water to a boil and place the stuffed clams in the steamer. Cover the steamer and cook until heated through, about 10 minutes.

how I imagine this dish might look
(baby crab picture by Jon Felis)

Let me know how it turns out if you try this recipe, or any other crab+bivalve combo!

Sunday, April 8, 2012

A message from the Easter Crab:


I hope you're having a great day, whether it's getting outside for an Easter egg hunt or getting outside for an adventure, or maybe staying inside with family and friends! These Calcinus hermit crabs, found around Easter Island, would also like to wish you a happy day (I'm not sure if these particular crabs are from Easter Island, but their genus is found there).

wouldn't you love a colorful Easter (Island) basket like this?

Why have an Easter Crab? It is kind of a family tradition to celebrate Easter with different animals: I grew up in northern Illinois waiting for Gladys the Easter Cow to come bring bull's eyes and cowtail candies. My dad even had a song for our Easter bovine:

(I feel like this video explains a lot about my own sense of humor!)

Friday, April 6, 2012

4 for the price of 1!

Do I have a deal for you today! (That statement feels exciting, hence the exclamation point, but it's so question-y that I really wanted a question mark. But I felt like that would ruin the momentum of the sentence. Much like this is right now. The dilemmas I face everyday...)

Exciting news, everyone! There are still new crabs to be discovered and met! You can still be an explorer and name things like
Georg Steller or Charles Darwin or Hendrik Freitag (the researcher who described the new crabs in question). FOUR new species of freshwater crab were discovered on Palawan, a Philippine Island known for its rich diversity and endemic nature of over 50% of its species! (That means that half of the species found on Palawan are not found anywhere else, so it's really quite a treasure.)

The researchers were aware of the crab presence on the island, figuring they were some sort of Insulamon crab (previously defined in islands north of Palawan) but closer examination revealed the 4 new species:

Insulamon palawanense, I. magnum,
I. johannchristiani and I. porculum

top on my list of Most Beautiful Crabs:
the I. palawanense

I. magnum packs a punch!
(sadly no mustache...)

I. johannchristiani going for a more orange look
(perhaps wishing it's at the Jersey Shore?? Hey-oh!
But seriously, it's probably thankful it's not.)

I. porculum, named so for it's pink snout and corkscrew tail
(OK, not really, but I couldn't find a picture of a living
I. porculum and I wanted to spruce up this specimen)

Aren't they beautiful? The researcher's next focus will be freshwater crayfish and I'm so excited to see what they discover there!

A link to their scientific description:
Freitag, H. 2012.Revision of the genus Insulamon Ng & Takeda, 1992 (Crustacea: Decapoda: Potamidae) with description of four new species. The Raffles Bulletin of Zoology 60: 37–55.

Tuesday, April 3, 2012

Ask A Grad Student: Raphaelle Descoteaux

It's been a while since we've had an interview with a grad student, but this one was worth the wait. Raphaelle is on the cutting edge of ocean acidification work, which we learned a little bit about here and here, and won for best student poster presentation at this year's Alaska Marine Science Symposium. Oh yeah, and she can speak English and French!

Age: 24

Degree: M.S. Marine Biology

Current City: Fairbanks, AK

1. Describe your project, in 4 sentences or less.

My project looks at the effects of ocean acidification on the development of crab larvae (Tanner, Dungeness, and black-clawed cancer crabs). Part of the carbon dioxide we emit in the atmosphere gets dissolved in the oceans and reacts with water molecules to form an acid, causing the oceans to become more and more acidic. So I performed experiments in the lab in which I placed newly-hatched crab larvae into waters of different pH, or acidity. I am now at the stage of measuring things like body length, weight, and shell composition to assess whether the different pH conditions in which the young crabs were raised affected their development.

And in French…

Le but de mon projet est de déterminer si l’acidification des océans aura un impact sur le développement des crabes an Alaska. Une bonne partie du dioxide de carbone que nous produisons se dissous dans les océans et réagit avec les molécules d’eau, formant un acide. Ainsi, plus nous émettons du dioxide de carbone, plus nos océans deviennent acides. J’ai effectué une expérience dans laquelle j’ai placé des larves de crabes dans des eaux de différent pH et je suis présentement au stade de mesurer différents paramètres comme la longueur, le poids et la composition de la carapace de mes jeunes crabes. En comparant ces paramètres parmi les crabes qui ont grandit dans les eaux de différents pH je pourrai déterminer si l’acidification des eaux aura un impact sur le développement des crabes dans le futur.

closely-monitored flow-through systems

2. What has been your biggest challenge with this project so far and how have you overcome it?

One of the big challenges so far has been dealing with logistical difficulties of working with such small animals. The crab larvae I am looking at are very small. They are about 1-2 mm long and weigh a fraction of a milligram. Measuring, weighing, and analyzing their shell chemistry at this scale has required a lot of team work, patience, and imagination!

can you believe how cute these little
Tanner crabs (Chionoecetes bairdi) are!?!

3. Why Alaska? Are you from here, or did the project lure you here, or was there something else about AK that brought you here?

I am originally from Quebec, Canada and came to Fairbanks as an exchange student for the senior year of my undergraduate degree. I was studying at McGill University in Montreal and felt like I needed to experience something different. Wow! Fairbanks was definitely different and I just fell in love with it. I knew I had to stay! I met my current advisors, Katrin Iken and Sarah Hardy, and we came up with this great ocean acidification project for my Master’s degree.

4. Which was harder: finishing the Equinox marathon or keeping larval crabs alive?

I actually walked the Equinox marathon once and ran the relay last year. The goal is to run the whole thing this year. I’m sure training for it will be difficult but I would still expect keeping larval crabs alive to be harder! This year has been a great learning experience for me in terms of raising larval crabs but I still have lots more to learn!

the Eqinox Marathon profile - yes, that does say a gain of 3,285 feet!

5. What is your favorite piece of crab paraphernalia?

I don’t own much crab paraphernalia frankly but I do LOVE my brand new “I love snow crabs” mug!

woo-hoo! the Snow Crab Love mug in action!

Thanks, Raphaelle, and good luck with the Equinox!