Monday, November 29, 2010

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?

Wednesday, November 24, 2010

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.


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.

Wednesday, November 17, 2010

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.


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!

Friday, November 12, 2010

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!

Tuesday, November 9, 2010

"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).


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

Tuesday, November 2, 2010

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!