Misleading Mammal

Well, they fooled me. There’s a seal named Lobodon carcinophaga, which means “lobe-toothed crab eater”: the crabeater seal.

possible culprit of crab predation, or is it???

But you know what, these seals DON’T eat crabs. Crabs aren’t even on their radar (these seals live in Antarctica, where crabs do not roam). They eat krill with their specialized teeth.

crabeater seal skull on display at the Crary Labs Museum in Antarctica

tastey krill

And their teeth must be pretty special, because they eat 80 million tons of krill a year! Then leopard seals eat them.

AHHHHHHHH!

So now I know, and knowing is half the battle.

Note: there aren't polar bears in Antarctica either. Just so you know.

Merry Christmas!

How fitting is it that the most wonderful time of the year has its own island (Christmas Island) and that island is also called “the kingdom of the crabs” and “the crabbiest place in the world”? Two happier things couldn’t be combined!

Coconut crab (Birgus latro)

(photos from ag.gov.au)

Christmas Island red crabs (Gecarcoidea natalis)

heading to sea

Christmas Island is home to 20 terrestrial and intertidal crabs, including coconut crabs (a personal favorite: I’ve seen these guys in the Solomon Islands) and red crabs. The latter are famous for their massive march to the sea from their jungle home:

(I strongly encourage you to watch all the National Geographic videos on the red crab migration [millions of crab babies!!], but I’ll warn you now: you will come to hate yellow crazy ants!)

SO MANY BABIES!

Red crabs undergo an incredible physiological change when embarking on their journey: they have to get their muscles from couch-potato to marathon-runner, which involves changes in their gene expression (rather than an 18 week training program. Lucky!). Scientists from the University of Bristol just published an article on red crab leg muscles, and it is covered quite splendidly here.

I’ll leave you with my take on a Christmas Island Christmas tree:

HAPPY HOLIDAYS!

Red crab reading:

Postel, U., F. Thompson, G. Barker, M. Viney, and S. Morris. 2010. Migration-related changes in gene expression in leg muscle of the Christmas Island red crab Gecarcoidea natalis: seasonal preparation for long-distance walking. Journal of Experimental Biology 213: 1740-1750.

Interagency Crab Meeting 2010

Another year, another fun get-together of all the Alaskan crab researchers! There's nothing like hanging out with a room full of crab lovers (I was trying to write that phrase in latin, but it would come out as cancerphiles or something, and that just didn't express the right message).

This year the meeting highlighted Crustacean Enhancement and Genetics,

with these presentations:

Developing genetic fingerprinting techniques for lobster seeding trials in New England - Rick Wahle (University of Maine) [I love lobsters and got to work with them on Long Island!]

Some population genetic considerations for red king crab management in Alaska - Dave Tallmon

Update on genetic studies of snow and king crabs at ADF&G - Stew Grant

three crab girls enjoying the sights:

Courtney Lyons, Miranda Westphal, and me

Student presentations included:

Evidence of predator-induced behavioral plasticity of juvenile red king crab (Paralithodes camtschaticus) - Ben Daly

Qualitative modeling of the Pribilof Island blue king crab fishery - Courtney Lyons

Growth of juvenile red king crab, Paralithodes camtschaticus, in Alaska - Miranda Westphal

Interannual variability in pre-hatch fecundity of eastern Bering Sea snow crab, Chionoecetes opilio - Matt Catterson

Defining population structure of snow crab (Chionoecetes opilio) - Greg Albrecht

Gonadosomatic index in male snow crab, Chionoecetes opilio, from the eastern Bering Sea: another look - Molly Zaleski (me)

Variability in reproductive potential of eastern Bering Sea snow crab with environment and stock demography - Joel Webb (the host with the most)

# Effects of ocean acidification on larval development in Alaska Tanner crabs (Chionoecetes bairdi) – Raphaelle Descoteaux

# Ecosystem-based fisheries management and population dynamics of the collapsed, Yakutat Bay Dungeness crab (Cancer magister) stocks in Southeast Alaska: A proposal – Jared Weems

# poster presentation

Ask A Grad Student: Greg Albrecht

Don't let the fish throw you off; Greg is a true crab lover all the way! While not studying snow crab genetics, he's playing dress-up with decorator crabs. He's a model for the rest of us!

Age: 27

Degree: MS Marine Biology

Current City: Fairbanks

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

My project focuses on defining the genetic population structure of snow crab within the Bering, Chukchi and Beaufort Seas. I'm using 7 microsatellite markers and have 613 samples collected from 13 locations. The hypothesis I'm testing is that due to their long distance larval dispersal abilities the entire stock will have low genetic differentiation. This is an important question for management of the current fishery and figuring out what's going on in the arctic.

a lovely C. opilio

2. Have you come across any opilio-bairdi hybrids, and if so, have you included them in your genetic analysis? In your opinion, are they truly 2 separate species (C. opilio and C. bairdi) , or simply subspecies of one another? Let’s fuel the debate!

To my knowledge, none of the crabs sampled were hybrids; however, that's hard to tell since identifying them can be difficult especially if they aren't first generation. Genetic techniques can be used to distinguish the two, or at least what portion of each species they are; however, we didn't conduct any of those tests or collect any Tanners, which would have been necessary.

So yeah... a species: they are typically defined by two animals that can interbreed and produce fertile offspring; however, that means that opies and bairdis would be the same. There are other examples of this like the cutthroat and rainbow trout that make a cutbow hybrid. So, to the best of my knowledge (which is just basically Wikipedia and asking the grad student in the office next to me) often times genetics and the ecological niche that they fill are used to define the species. Opilio and Tanner crab have different habitat limitations (mostly based on temperature) and although they overlap, I don't think a Tanner would stand a chance in the Arctic. So with that and the significant differences we see in their DNA (at least at this point... given that hybrids don't rule the Oceans... yet) we can say they are still different species.

Now as to "subspecies" well that's kind of a fuzzy line in my opinion. I think that technically subspecies can interbreed, but don't very regularly due to behavioral differences and ecological barriers (i.e. dogs and wolves). In my opinion, Tanners are still morphologically differentiated in a number of ways (size being one big one) and at this point are still defined by different habitats (thermal tolerances).

3. You have also been studying decorator crabs and their decoration choices. What led you to this work and what’s the weirdest thing you’ve seen a decorator crab choose?

I have long thought decorator crabs to be cool, but diving in Kachemak Bay this past summer gave me an opportunity to start a small study on their behavior. I have found flagging tape, viable fish eggs and of course lots of algae on crabs; however, the funniest finding was a crab sampled from a location containing a mix of algae and trash (95% and 5% cover, respectively) who had placed a piece of an old windshield wiper on his carapace.

decorator crabs showing off their flair


4. You eventually want to teach high school: why? (What sparked this interest?)

So that I'll have summers off to play with decorator crabs and go fishing... oh yeah, and I guess to "inspire" the next generation.

 oh snap!

I'm inspired!

5. What is your favorite piece of crab paraphernalia?

My crab pot

crab on!

Thanks, Greg! And I have some great crab dip recipes, just in case you don't know what to do with all that king crab. Just saying. 

Glittered holiday crab cards

Taking a page from Martha Stewart, I decided to share a fun card idea with you:

Step 1:

Download this crab cutout and print it on white paper or cardstock (you can also make a template to trace onto your paper each time). Cut along the black lines, leaving the tips of the legs and the sides of the claws connected where the blue dashed line runs. (Don't cut the legs and chelae off though, and try not to eyestalk-ablate them.)

Step 2:

Fold your crab! If you used a template you don’t have to worry about lines showing, but if you just printed directly onto the cardstock, make sure the printed side is face down. Add glitter!! I used glitter paint, but Martha is a fan of the glue-glitter combo.

Step 3:

Glue your crab to a cardstock background (I used yellow, but you could use whichever color you prefer) and delight a loved one with your home-made card!

I linked up to this blog:

I wonder if they get hot flashes too

A recent paper has shown that female snow crabs experience menopause. OK, you’re right, they’re not calling it that, but the title says it all: "Histological studies on the spent ovaries of aged snow crabs Chionoecetes opilio caught in the Sea of Japan"!

Kon et al. (2010) sampled very old-shell female opies for GSI, ovarian color, and embryonic development. The purpose of this project was to estimate the fecundity of a population in the western Sea of Japan that has experienced a perceived increase in female average age due to artificial reefs and reserves.

Sea of Japan and Fukui Prefecture (starred) where the crabs were offloaded

With females getting older, the researchers wanted to determine if they were reproductively contributing as much as their younger sisters. Long story short: they were not.

The very old-shell females’ ovaries had dozens of nodules, which were darker tinted areas, indicating degeneration of unspawned eggs. Most of the ovarian eggs were strongly deteriorated, either through oosorption or oolysis, and none had the potential for ovulation.

red and black discolorations = nodules

The neat thing that this project discovered was how old one of their very old-shell girls was: one female was found with an 8 year 1 month old tag. She had been tagged directly after her terminal molt, which occurs at least at age 1½, so this female was more than 9½ years old!

Grandma opilio!

Previous estimates in the Sea of Japan had been 8½ years old based on tagging studies, while Bering Sea females may get up to 8½ years also (6 to 7 years after their terminal molt). Atlantic female snow crabs survive 4 to 5 years after their terminal molt.

This gal was OLD! I’m glad I aged a little better, at least when I was 9½.

Nerding it up, even in 1993

(photo courtesy of my dad, Jay Fox)

Read more and check out the histology slides:
Kon, T., M. Ono, and Y. Honma. 2010. Histological studies on the spent ovaries of aged snow crabs Chionoecetes opilio caught in the Sea of Japan. Fish Sci 76: 227–233.

Welcome Allacanthos yawi!

A new crab species has been discovered, and not from some deep-sea, hard-to-find chasm, but from a river in Costa Rica! Allacanthos yawi is a decapod crustacean in the family Pseudothelphusidae, and was discovered 1,000 meters above sea level in the Río Volcán drainage (Buenos Aires County, Puntarenas Province, Costa Rica)!

A. yawi showing off his lovely green carapace (scale bar = 10 mm)

The crab was found by Luis Rólier Lara while he was scouting for the Costa Rican Electricity Institute (they want to build a hydroelectric plant), identified by Ingo Wehrtmann from the Museum of Zoology and the School of Biology at the University of Costa Rica, and described by Célio Magalhães from the National Institute of Amazonian Research. Melania Pérez, a Costa Rican archeologist, gave the crab its species name yawi, which means “crab” in the indigenous language Cabécar (or more fully “river crab that lives under rocks”, as reported by Tico Times).

the pretty mottled female A. yawi (scale bar = 10 mm)

Let’s wish this newly-discovered crab luck! With battles against expanding pineapple farms, hydroelectric projects, and pollution, this endemic little species may need it!

Pineapple attack!!

(A. yawi is a preserved male from Magalhães et al., 2010)

Read about it:
Magalhães, C., L. R. Lara, I. S. Wehrtmann. 2010. A new species of freshwater crab of the genus Allacanthos Smalley, 1964 (Crustacea, Decapoda, Pseudothelphusidae) from southern Costa Rica, Central America. Zootaxa 2604: 52–60.

Shanghai hairy crabs revisited

After posting my last blog, I thought more about crab vending machines, and tried to look at it with an open mind. I found this AP video that explains the vending machine better than most of the ones I was watching in Chinese or Japanese (go figure):



I also, admittedly, like to read comments on YouTube videos, and some of them made me think:

"The only difference between these cold-but-living crabs and the ones in restaurant supply rooms is that the public can see them." --  I personally have eaten freshly killed and cooked lobsters, Dungeness crabs, and red king crabs, so I shouldn't be so squeamish, should I? The difference would be that I’ve never held them in tiny boxes and forced them into a hypothermic state before eating them. Food for thought. (Ha!)

"I'm a brit living in Nanjing and saw this machine the first time the other week. To be honest it didn't surprise me. And by China standards, it's quite humane. The crabs are kept cold so they sort of hibernate then they wake up when you get them out of the machine. Compared to the conditions that other live produce are kept in (i.e. fish and frogs and terrapins sitting in dirty water, sometimes with other dead animals in the same tank), this seems to be a step forward for China." -- Interesting point. My friend Kat has been touring Asia and witnessed a lot of different conditions for other live animals. Maybe these crabs are lucky.

"Finally a way to defeat the GIANT ENEMY CRAB!" -- NO! WRONG! Thumbs down on your opinion, buddy!!

An Alaskan opinion found here.

There's still the question of management, but I like taking a fresh look at difficult topics! What do you think?

Snickers, Tato Skins, and Crabs

You've probably already seen this, but just in case you missed it:

Yes, that’s a vending machine, selling live crabs.

WHAT?????

Live crabs!?! Because nothing says snack-on-the-go like a slightly hypothermic crustacean. Oh, and don’t forget the crab vinegar, sold conveniently on the bottom row!

cold and cramped crab

So who are these unlucky little crabs, forced into tiny “edible plastic” boxes and sold in a Nanjing (China) subway vending machine? No one really used scientific names in their articles/blogs (my nerdiness was quite offended by this), but they were commonly referred to as either “hairy crabs” or “dazhaxie”. As far as I can tell, that makes them Eriocheir sinensis, also known as the Shanghai hairy crab or the Chinese mitten crab.

Chinese mitten crab

If you’re a blue crab fisherman out of Maryland, you may have instinctively screamed and ran away from your computer. Why? The Chinese mitten crab is being quite the pesky invasive species up in American waters. It thrives in estuarine environments, making the hairy crab a great candidate for aquaculture cultivation.

However, the hairy crab is having trouble in China, potentially being affected by overfishing in the Yangtze River. (Does anyone know their management plan? Let me know!)

N = Nanjing, S = Shanghai, and the (seemingly) beautiful waterway is the Yangtze River

Really? Overfishing? No, not a crab that’s so plentiful it’s being packaged and sold live in a vending machine. And if you get a dead one, the vendor will give you three free crabs. The hairy crab is also favored for the female roe, which means that this potentially-overharvested animal is targeted specifically for their future stock (the crab embryos). Yikes.

the tastey tradition of Da Zha Xie

You know, I’ll just stick with the Tato Skins. Thanks.

Hairy crab leisurely reading material:

Anger, K. 1991. Effects of temperature and salinity on the larval development of the Chinese mitten crab Ericheir sinensis (Decapoda: Grapsidae). Marine Ecology Progress Series 72: 103-110.

Lee, T.-H., and F. Yamazaki. 1989. Cytological observations on fertilization in the Chinese fresh-water crab, Eriocheir sinensis, by artificial insemination (in vitro) and incubation. Aquaculture 76: 347-360.

Yes, Tina Turner, you had a question?

"What’s methyl farnesoate got to do, got to do with it?

What’s methyl farnesoate, but a sesquiterpenoid?

What’s methyl farnesoate got to do, got to do with it?

Who needs a heart when you’ve got mandibular organs?"

Wow, that's a good question Tina (or three, really). I'm surprised you're so familiar with crustacean hormones, but I guess I should never underestimate Ms. Turner.

mm-hmm!

Well, now that I've been set straight, let me answer your big question: what does methyl farnesoate (MF) have to do with crab love? That is the big question in my graduate thesis, and I'm afraid I don't have all the answers... YET. But here's what I do know:

You'll remember that MF is synthesized in the mandibular organs (MO):

methyl farnesoate leaving the mandibular organs and heading for the gonads

When the MF leaves the MOs (ah, science and acronyms), it binds to specific receptor sites that can change the physiological activity of the target (such as the gonads). What results is increased gonad development, so far recorded in these crustaceans:

monsoon river prawn Macrobrachium malcolmsonii (pictured is a congener)

and red swamp crayfish Procambarus clarkii

green crab Carcinus maenas,

Indian field crab Oziotelphusa senex senex (another congener picture),

and spider crab Libinia emarginata

In the red swamp crayfish, green crab, spider crab, and Tanner crab (you remember Chionoecetes bairdi), higher MF also correlates with more reproductive behavior. And, since MF stimulates secretion of ecdysteroids by the Y-organs (which in turn stimulates the production of a new shell and shedding of the old one), mating and molting are hormonally linked!

MF stimulating the secretion of 20-hydroxyecdysone (20-HE) from the Y-organs

My research will look at the mating/molting relationship in snow crabs: will MF be lower in post-molt males? Will it correlate with lower gonads (GSI)? I can't wait to find out!

So you see, Tina, MF has a lot to do, lot to do with it!

Ask A Grad Student: Ben Daly

Ben Daly lives in Seward, AK, working with the Alutiiq Pride Shellfish Hatchery raising baby king crabs from fertilized females collected in the field. He will also soon be raising a baby of his own! Congratulations!!

Age: 29

Degree: pursuing PhD in Fisheries

Current City: Newport, OR

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

My project explores the feasibility of king crab stock enhancement in Alaska. Specifically, I am looking at ways to optimize hatchery production of juvenile crabs. I am also developing release strategies for juvenile crabs.



2. Your lab is in Seward but you are currently working in Newport, Oregon. What is a challenge you’ve had to overcome with this location change (and how)?

The biggest challenge in working in other labs is learning how the seawater systems work in terms of supply, filtration, temperature control, etc. For example, at the Newport Lab, the seawater temperature is controlled by adjusting heat exchangers, which is impacted by the flow rates into the various tanks containing crabs, fish, etc. Changing the flow in one tank can affect the temperature in other tanks. To adjust for this, I have had to be very careful in maintaining flow conditions in my experimental tanks.

3. You take all of your classes through video-conferencing. What would be your top 2 tips for other distance students?

1. Try to participate in class (ask questions, make comments) as much as possible. This keeps you feeling involved with the other students and the professor. It also reminds them that you are a real person and not just a face on a TV screen.

2. Bring coffee to stay alert. It can be easy to become distracted or to lose focus.

4. Has raising baby king crabs prepared you for raising baby humans?

Ben: Yes, raising baby king crabs is preparing me for raising humans. The crabs require daily care, especially as larvae. The larvae are very sensitive to temperature fluctuations and an inadequate food supply, just like baby humans. One nice thing about baby crabs: they don’t cry.

Beate (wife): No, not unless the baby crabs need to be nursed or have their diapers changed!

"Feed me!!"

5. What is your favorite piece of crab paraphernalia?

We try to limit our crab paraphernalia as it can get out of hand due to gifts from relatives. Right now our favorite piece is our crab “welcome mat”, which has a big picture of a blue crab. Sometimes it can feel good to stomp on the mat with my boots to get out any built-up animosity towards the crabs……..just joking……..I love the crabs.

Thanks Ben!

"Sea-Fever" tribute to Legoless

Well friends, Legoless has finally succumbed to his injuries, may he rest in peace. Please know that his last moments were eating herring with one of the female crabs.

I know he wasn't really a sailor, but the last stanza of "Sea-Fever" kind of made me think of all my past crabs (I had to memorize this poem when I was living on a schooner).

Sea-Fever

I must down to the seas again, to the lonely sea and the sky,
And all I ask is a tall ship and a star to steer her by,
And the wheel's kick and the wind's song and the white sail's shaking,
And a grey mist on the sea's face, and a grey dawn breaking.

I must down to the seas again, for the call of the running tide
Is a wild call and a clear call that may not be denied;
And all I ask is a windy day with the white clouds flying,
And the flung spray and the blown spume, and the sea-gulls crying.

I must down to the seas again, to the vagrant gypsy life,
To the gull's way and the whale's way where the wind's like a whetted knife;
And all I ask is a merry yarn from a laughing fellow-rover
And quiet sleep and a sweet dream when the long trick's over.

~John Masefield

Crabs are taking over AFS

It's that time of year again: the American Fisheries Society Alaska Chapter meeting! This year it's being held in our very own Juneau (yay! No flights for me!!). What's that you say, will there be any crab talks? Yes, oh yes.

Highlights of the meeting:

Crustaceans Are Cooler: Fisheries and Biology

of Crabs and Shrimps in Alaska

Chair: Ginny Eckert, UAF School of Fisheries and Ocean Sciences

Wednesday 9:45 – 11:25 am and 1:00 - 2:40 pm

Defining Genetic Population Structure of Snow Crab (Chionoecetes opilio) in the Bering, Chukchi and Beaufort Seas - Greg Albrecht

Variability in Reproductive Potential of Eastern Bering Sea Snow Crab, Chionoecetes opilio, in Relation to Spawning Stock Demography -  Joel Webb

Reproductive Indices of Male Snow Crab Chionoecetes opilio from the Eastern Bering Sea - Marilyn Zaleski (me)

Alaskan Crab Fisheries: An Historical Perspective - Courtney Lyons

Factors Influencing Snow Crab Recruitment: A Comparison Across Ecosystems - Laurinda Marcello

Red King Crab Paralithodes camtschaticus Larval Supply, Settlement Timing, and Benthic Habitat Structure - Jodi Pirtle

Growth Physiology of Juvenile Red King Crab Paralithodes camtschaticus Reared Under Laboratory Conditions - Miranda Westphal

Recruitment Mechanisms of Eastern Bering Sea Tanner Crab, Chionoecetes bairdi - Jon Richar

Crabs Are Not so Cool When it Comes to Management - Shareef Siddeek *

Should Some Minimum Size Limits be Amended? – Pribilof Islands Tanner Crab - Bill Bechtol *

* heavy hitters! (all the rest are student presenters)

Evolutionary/ Genetics Perspectives on Alaska Fisheries

Chair: Megan McPhee, UAF School of Fisheries and Ocean Sciences

Thursday 8:40 – 9:00 am

Alaskan red king crab (Paralithodes camtschaticus) population genetic structure - Scott Vulstek

Dynamics of Marine Ecosystems

Chair: Gordon Kruse, UAF School of Fisheries and Ocean Sciences

Thursday 10:35 - 10:55 am

Recolonization, Prey Selection and Resource Competition by Sea Otters, Enhydra lutris, in Southern Southeast Alaska - Zac Hoyt (This one doesn't sound crabby, but Zac is looking at sea otter predation on commercially valuable inverts including Dungeness crabs and Tanner crabs.)

Poster Session

Thursday from 11:55 am – 1:45 pm

Populations of ocean shrimp Pandalus jordani in the Gulf of Alaska - Aaren Ellsworth

The decorator dilemma: How Oregonia gracilis chooses what to wear - Greg Albrecht (student); Brenda Konar

Effects of larval rearing temperature on large-scale production of red king crab (Paralithodes camtschaticus) - James Swingle; Benjamin Daly (student); Jeff Hetrick; Ginny Eckert

Blue Genes: Population structure and paternity in blue king crabs (Paralithodes platypus) - Jennifer Stoutamore (student)

Long-term intra-cohort distributional shifts in the eastern Bering Sea population of Tanner crab, Chionoecetes bairdi - Jon Richar (student); Gordon Kruse

Seasonal gonad development of Parastichopus californicus in Southeast Alaska--Jessica Davila (student) (I know this isn’t crabby, but it speaks to me.)

I hope to see you there!

Congratulations (soon to be) Dr. Jodi!

Jodi Pirtle defended her thesis! Hooray! Hopefully I'll have an interview with her about her project on red king crab, but until then let's congratulate her on her upcoming PhD!

juvenile red king crab in the lab

For the occasion I made her red king crab cards. Here's how:

I made stamps out of foam board with cardboard bases.

Fancy, I know:

home-made stamps

Next I stamped them onto cardstock, using shiny gold for a king's crown
and bright red for the crab:

ruh-roh: some practice cards

a finished card

wrapped and ready to go!

Congratulations Jodi!