Does this taste a little toxic to you?

You can't taste all contaminants in your food, so how do you know the crab you're eating is safe? The following question was asked during the last crab chat:

Is crab meat tested for contaminants before going to market?

The short answer: yes, somewhat. Alaskan seafood is generally free of contaminants (as is seafood from the rest of the country, according to "government tests") and the Alaska Seafood company follows FDA's Hazard Analysis Critical Control Points (HACCP) regulation program. Hooray for Alaskan crabs!

enjoying fresh contaminant-free Alaskan Dungeness crab

HOWEVER, when it comes to imported seafood, we can't be too sure how safe it is. We import a lot (which is surprising to me with all the 'merican seafood we have here), but only about 2% of it is tested by the FDA. Of that seafood tested, 8% of imports from China and 16% of imports from Taiwan were contaminated in 2010. Does that mean you shouldn't eat imported seafood? No. But I would choose wisely about what kind of fish, shrimp, or crab I buy with the help of Blue Ocean Institute's seafood guide.

screenshot of the Blue Ocean Institute online guide

All the focus shouldn't only be overseas. Like I said, domestic fisheries are pretty clean, but the FDA does routine inspections that sometimes result in processing plant clean-ups and food recalls. Those inspections include testing the meat but also looking at facility cleanliness, meat handling, and processing techniques.

inspecting some king crab legs!

So, the longer answer: yes, domestic crab meat and a small percentage of imported crab meat is tested before going to market.

Found you!

If you follow Snow Crab Love on facebook, you may remember that I started keeping track of the non-crab related keyword searches that bring people to my blog:

this was just the beginning - it's gotten even weirder, I promise!

I'll share the final results at the end of the year, but in the mean time I was curious what other websites thought of Snow Crab Love and the search phrases that draws its way. I saw The Bloggess check her stats using Alexa, so I figured I'd check it out too. Here are the results:

TOP QUERIES DRIVING TRAFFIC TO SCL FROM SEARCH ENGINES

Totally weird, right? But when I google "the bullet crab", sure enough a link to this post comes up (currently it is the 7th link in the list).

a mantis shrimp's fist accelerates faster than a speeding bullet

(If you watch Arrested Development, you might get this photo reference)

The one that really confused me was "hat is fecundity". After pondering what it could mean and picturing things like this:

the hat had babies

I realized it was probably a commonly misspelled question of, "What is fecundity?" And what is it? Fecundity refers to how many babies something can produce (what their reproductive capacity is). For example, a female snow crab's fecundity can be measured in how many eggs she holds in her clutch (if you click on the link, check out slides 14 - 16). Or the fecundity of my hat (inspired by Princess Beatrice at the wedding of Prince William and Kate Middleton, and worn during a midnight 5K race) could be measured by how many little hats spring forth from it's bow-y goodness.

(this was a few years ago, but a good hat [joke] never goes out of fashion)

So now you know. I wonder if this is going to change my search analytics...

Giving a whole new meaning to "shrimp"

Last week I shared some microscope photos of a megalopae hermit crab, which I was pretty excited about (there was high-fiving involved). But that reminded me of these little cuties that one of my bosses snapped:

almost-babies!

They're shrimp embryos! I had the fun opportunity to dissect several shrimp from Prince William Sound and Mark Carls took advantage of the presence of gravid females to get some sweet shots. The picture above is of spot shrimp embryos, but we also saw coonstripe and pink shrimp.

coonstripe shrimp embryos

a closer view on those coonstripe babies

pink shrimp embryos still attached to their mother's pleopod

Their eyes are developed, but what I found especially neat was all of their little markings! (Remember seeing shrimp chromatophores from this post?) Once they grow up, each shrimp would have looked like this:

spot shrimp (Pandalus platyceros)

note the white spots on its first and fifth abdominal segments

(and try to ignore the white stripes on their carapace...)

coonstripe shrimp (Pandalus hypsinotis)

these guys have dark strips on their abdomen and

a bigger, arched carapace compared to the other shrimp 

pink shrimp (Pandalus borealis)

pink pink pink!

Those embryos were definitely the shrimpiest tiniest little shrimp I've ever seen!

"meep!" - spot shrimp embyros

Micro Awesomeness

Hey y'all! I've been working all week pulling stomach contents out of baby Pacific cod (Gadus macrocephalus) and walleye pollock (Theragra chalcogramma). I know, I know. They're not crabs. They're not even crustaceans. BUT they eat crustaceans!

Boom! Euphausiid in the house!

It's not surprising to find one hundreds of these bad boys in a fish stomach. Euphausiids, or krill, are pretty ubiquitous and are the go-to prey item for a lot of animals, even the crabeater seal. The excitement in the lab this morning came from this guy:

"oof"

He's obviously different from the krill we'd been seeing all week. What sparked fellow Southampton College and University of Alaska Fairbanks alum (holla!) Casey Debenham's curiosity was that large claw.

that's a legit chela

Right off the bat we could tell this was a crab!! But what kind of crab? On further inspection, with the help of Emily Fergusson, stomach content pro, we saw that the left claw was quite a bit smaller than the right. This was the tipping point!

Do you know what it is? I'll wait while you guess.

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It's a hermit crab!

can you see it?

It's a Pagurid in the megalopae stage! Pretty cool right? I guess he hadn't settled yet to find a protective shell and was just chilling up in the water column. Had he not been eaten, he might have grown to look like this:

although he'd probably be rockin' a gastropod shell

Oh well. Circle of life, amirite?

Kodiak Crab Festival 2013

I have yet to make it to the Crab Festival in Kodiak (next year? fingers crossed!) but this year my dear friend and fellow crab enthusiast, Miranda Westphal, was on the scene with her family to catch some crabby fun!

poster design by Adina Preston

While the Crab Festival celebrates crabs, it is also a celebration of Kodiak itself and life on an island. Miranda shared some festival moments dedicated to the people who make Kodiak home:

horses horses horses horses!

(any Sleepless in Seattle fans out there?)

Kodiak dancers

beat boys taking it up a notch

the marimba band (with back-up maraca players)

 

who's that there but our very own Laura Stichert,

snow crab biologist extraordinaire!!

But don't worry, crab lovers. There were also crabs:

Crab Fest Bed Race...

so many jokes, so little time

I'll have to make sure I get there some day! Did you go? What was your favorite part? Leg? Tail? (Har-dee-har-har!) Thanks, Miranda!

(logo by Sean Lawler)

How low can they go?

You didn't think I forgot about answering the questions from our crab chat did you? Nope! The next question to answer is:

Just how deep in the ocean do king crabs and snow crabs live?

To answer this I looked at the crab survey data from 2012. This is only looking at Bering Sea crabs in summer, so it's a little limited, but I figured it was a great place to start. Here's what I learned:

King crabs really stay out of each others' way! Every sampling location that found red king crabs was absent of blue king crabs. Also, on average, blue kings were found deeper in the Bering Sea than red kings; the average blue king crab depth was 87.6 meters (287.5 feet) and the average red king crab depth was 51.7 meters (169.7 feet). This was interesting to me because the bycatch of blue king crabs in red king crab fisheries has closed down red king fisheries in the past (due to low blue king crab abundance), but it would seem that for the summer of 2012 that might not have been a concern.

Heading deeper into the Bering Sea, I found the Chionoecetes crabs! Both Chionoecetes bairdi and Chionoecetes opilio liked an average depth around 91 meters (91.5 m and 91.4 m, respectively), which is close to 300 feet. Unlike the king crabs, these Chionoecetes cousins hung out together quite a bit, which isn't too shocking since they're known to hybridize.

gross

The thing that caught my eye with hybrid Tanner crabs was that their average depth was slightly shallower than the two "pure blooded" crabs (88.1 meters). If I didn't have a real job, I would look into the sex distribution of male and female bairdi and opilio crabs and compare that to the distribution of hybrids to finally answer who's mating with whom. Anyone else want to check it out!?!? Let me know. (Seriously. I'm totally interested.)

average depths (in meters) for the locations where red king crab,

blue king crab, Chionoecetes bairdi, C. opilio, or their hybrids were present

The other thing that caught my eye is that hybrid crab presence was NOT dependent on both "pure" crabs being there (during the survey, that is). Of the 157 sites that had hybrids, 25 sites were missing on of the original species. Plus, there were 70 sites that had both bairdi and opilio crabs but no hybrids. (Fun fact: those sites had a deeper average at 107.4 meters.)

So, that's how low king crabs and snow crabs can go! For perspective, if the Bering Sea's depth was in line with a football field, red kings would make it just past the 50 yard line while blue kings and hybrid Tanners would be in the red zone. But bairdis and opilios would go ALL. THE. WAY!!!

Cold Crabs Conquer Puberty!

Cold crabs terminally molt at smaller sizes than warm crabs!

What?

OK, let's start over. You know how snow crabs have a final, or terminal molt? Instead of molting every year and growing, snow crabs will molt up to a certain (as yet undetermined) point, then stop molting. The terminal molt is marked by their claws growing larger than the rest of their body's growth, meaning that, if they were humans, all of a sudden you'd see this guy:

He's never going to get any bigger. He's terminally molted.

The tricky thing with snow crabs is that they'll terminally molt at all sorts of different sizes, so while some may max out at 2 inches carapace width, others can grow to over 4 inches (and beyond). Because of their terminal molt, some snow crabs will never grow large enough to be legally harvested for the commercial fishery (the size limit is 78 mm or ~3 inches). For example, below is a plot of snow crabs surveyed in the Bering Sea last summer (2012), with a bright orange line marking the legal size limit.

 you can tell the large clawed, terminally molted males

from the small clawed (still have at least one more in 'em) males

based on the proportion of their claw ("chela") height to their carapace width

For the males that are designated "small clawed", they're not worried being to the left of that orange line: they will molt at least once more and potentially grow larger than 78 mm, thus grow into the fishery! But the "large clawed" males aren't getting any bigger than what you see, so all those dark circles to the left of the orange line are snow crabs that can mate with the ladies but won't be on your dinner plate any time soon ever. So what's the worry? We've discussed this idea before that the smaller terminally molted males may end up reproducing more than the larger guys simply because they won't be picked up by the fishery and will have more time to sow their crabby oats on the Bering Sea floor. If size at terminal molt is a heritable trait, this could lead to more snow crabs at small sizes, which would obviously be bad for the fishery.

But where does temperature come in?!?!? Keep your pants on, I'm getting there! The colder the temperature, the smaller the males seem to be when they have their final molt (see Dawe et al., 2012). In higher latitudes, like the North Atlantic and North Pacific, this means a greater proportion of males that won't enter the fishery. That's definitely bad for fishermen.

HOWEVER, (picture Marisa Tomei saying that)

... if ocean temperatures continue to warm as they are already, more males will terminally molt at larger sizes! We just don't know how the increased temperatures will affect other aspects of their metabolism, so it's up in the air about whether or not global climate change is a bonus for male snow crab size. I guess we'll find out!

Read more from this post and from this paper:
Dawe, E. G., D. Mullowney, M. Moriyasu, and E. Wade. 2012. Effect of temperature on size-at-terminal molt and molting frequency in snow crab Chionoecetes opilio from two Canadian Atlantic ecosystems. Marine Ecology Progress Series 469: 279–296.