Big Trouble in Little Bering Sea

Oh man, you guys. This is a doozy.

I posted a brief Tanner crab (Chionoecetes bairdi) update from Alaska Department of Fish and Game yesterday on Facebook. TL;DR - the Bering Sea fishery for bairdis is closed for the 2016/2017 season.

The bairdi fishery in the Bering Sea has had a rocky past with openings and closures fluctuating throughout the years, but it was starting to look good again even as recently as 2015! The fishery was closed from 1997 - 2004, open fully 2006 - 2009, closed again from 2010 - 2013, then open fully until 2015 with high catches and high vessel participation (112 vessels in the 2015/2016 season compared to 32 in 2013/2014).

from the 2016 crab SAFE data

You can read all about the fishery in the latest Bering Sea/Aleutian Islands stock assessment and fishery management report (in nerd lingo - the crab SAFE), which is put out by the North Pacific Fishery Management Council. Here's a link to the Crab Plan Team with all their fun reports, and this link will send you to the current Council meeting (happening now) where you can find the 2016 crab SAFE in the Agenda. It's listed under "C. Major Issues/Final Action Items" as the first item.

OK, so that's bairdi, but you all know I really love me some opies. How are they doing?

Not good. ADF&G announced that Bering Sea snow crab will be open this year (October 15th, as usual) but with the lowest total allowable catch (TAC) in 45 years. The low TAC, at 21.57 million pounds, is  nearly HALF of what it was last year (40.57 million pounds)! Why? Because surveys of the crabs have shown a decline in the number of mature males out there (who we like to eat) AND mature females out there (who make the babies).

from the 2016 crab SAFE data

This low baby-makin' biomass means potentially fewer adults in the future. That's why management has to be so conservative to allow for the crabs to do their business and replenish the stock. But for the moment it also means low catches and A LOT less money for our crab fishermen, processors, and on down the line. The other thing fishermen have to worry about is any accidental retention of bairdis since that fishery is closed, making these crab-cousins prohibited.

opilio up top, bairdi on bottom

Good luck, crabs!

Anchorage Crab Extravaganza!

Last week 2 weeks ago (time flies!) I attended the 2014 Alaska Marine Science Symposium, and boy was it crab-tastic! I went to present a couple posters on my work with the Gulf of Alaska Project (my portion is studying baby fish body condition), but you better believe I stopped at all the crab posters I could find!

Here's a run-down of some of the neat crabby things I learned:

Snow crabs are loving detritus up in the arctic! Lauren Divine looked at Chionoecetes opilio stomach contents from crabs collected in the Chukchi and Beaufort Seas. Along with detritus, crabs were eating polychaetes, bivalves, brittle stars (you can see a pile of them from this post), and other crabs including opies!

Lauren showing off her poster and special friend

that's a larger-than-life snow crab ready to show you...

...its stomach contents!

Alaska Department of Fish and Game is mapping Tanner crab (Chionoecetes bairdi) habitat to better understand their distribution off of Kodiak. The fun part of this: underwater pictures of crabs in action!

(download the abstracts here)

Ocean acidification will affect larval Tanner crabs as the ocean's pH drops. Here's Chris Long presenting his work where they exposed brooding females to different levels of pH (the lower the pH, the more "acidified" the water is). The greatest effect was toward larval survival. He also gave a talk on how a similar experiment affected the embryos of Tanner crabs (there's a difference... I can explain further if you'd like) and they weren't doing too well either.

over-achiever: giving a poster presentation AND a talk!

Remember how I said aging crabs was near-impossible? Alexei Pinchuk, Ginny Eckert, and Rodger Harvey are out to prove me wrong!

"Development of Biochemical Measures of Age in the Alaskan Red King Crab:

Towards Quantifying Thermal Effect on Aging"

Last but not least, I learned about ZOMBIE CRABS!!! (No, not these zombie crabs.) Leah Sloan, a UAF grad student, is looking at the distribution of that nasty parasite, the rhizocephalan, and how it may be affected by temperature. The infected king crabs she's studying are referred to as 'zombie crabs' because their bodies have basically been hijacked by the parasite to be a walking, eating, parasite-brooding machine! She's answering her temperature question by exposing larval rhizocephalans (aka parasitic barnacles) to different temperatures and tracking their survival. I'll interview her soon for an "Ask a Grad Student" post so we can all learn more.

she had me at "Zombie"!

I took so many other crab notes, so we'll see if I can share them all with you over the next... year!?!? By then I'll be ready for another round of Marine Science Symposium fun!

What's goin' on

It's almost snow, Tanner, and red king crab season! The opening is October 15th! The limit for Bristol Bay red king crab is 8.6 million pounds and the reopened Tanner crab fishery is 3.1 million pounds. The snow crab quota almost 54 million pounds (down a but from last year's 66.3 million pounds) - they're kind of a big deal!

Are you ready? More importantly, are the fishermen?

(Turn off the closed captioning by hitting the "CC" icon for easier viewing.)

Mark Begich commented on the importance of the fishing permits: “These permits take hours to process. The paperwork trail is important so we know it’s not illegal crab caught by fish pirates on the other side of the Bering Sea. The paperwork trail helps Americans know the crab we’re eating is safe."

it's a tough job, but someone's got to do it!

Special Note: This is currently happening in Alaska. This post takes no political sides. This post is only to share information regarding the Alaskan crab fisheries. Please, no negative comments!

Friday Fun at NOAA

Last Friday (July 26th) was the Ted Stevens Marine Research Institute open house, and man was it fun! The lab hosted tours, an interactive touch tank, NOAA partners in research and management, and had yummy refreshments courtesy of the Ted Stevens Foundation. I was on aquarium duty, so I got to meet people right as they came in and answer any questions they had about the fish, crabs, and other animals in the facility's aquaria. If you didn't have a chance to make it out, don't worry: I took notes!

The TSMRI (that's our little acronym for this lab... scientists and their abbreviations, amirite?) entrance has these lovely metal "walls" that line the sidewalk leading to the front doors. They make me smile with their shiny rockfish and herring, but what really catches my eye is the little metal Dungeness crab.

see it?

oh, why thank you, welcome crab!

What can I say, I love metal dungies! Even nerdy Lord-of-the-Rings-referencing ones. Moving in to the building you are greeted with our largest aquarium (there are three more around the back). It holds several species of rockfish, some sculpins, sablefish, dolly vardin, kelp greenlings, and a lingcod.

lots of things to ooh and aah over

It also currently holds some snazzy red king crabs (Paralithodes camtschaticus) and some cheeky Dungeness crabs (Metacarcinus magister)!

Hi, gorgeous!

SFOS student Jennifer Stoutamore took time to say "Hi"

to her fellow king crabs on her way to the UAF table

this Dungy was photobombed by a greenling

Aside from the aquarium and the great tours through the lab, the touch tank was a huge crowd pleaser! It was stocked with sea stars, sea cucumbers, hermit crabs, lyre crabs, Tanner crabs, urchins... the list goes on and on!

holding a hermit crab - outreach in action

a Tanner crab (Chionoecetes bairdi) showing off

his perfect M-shaped mouth and bright red eyes

Check out KTOO's coverage of the event here to see more photos and hear the open house in action. Thanks for stopping by!

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!!!

On your marks, get set, Tanner crab fish!

A Tanner crab (Chionoecetes bairdi) fishery is opening tomorrow off of Kodiak. Where, you might ask? Right here:

beautiful Kiliuda Bay

But wait, what's all that racket going on in Kiliuda Bay, home of the upcoming Tanner crab fishery?

Oh, this old thing?

That's right. Sitting in Kiliuda Bay is the Kulluk, Shell's oil rig that had run aground off Kodiak January 1st. The Kulluk is using Kiliuda Bay as safe harbor, but as such, any boats that will be participating in tomorrow's fishery will need to get special permission from the Coast Guard to do the same if the fishermen want to sleep in the bay. As for the fishery itself, the Kulluk should be out of the way as it is anchored in a nursery area for juvenile Tanner crabs and is therefore closed to the fishery.

Kiliuda Bay is enlarged showing the grey area closed to fishing

As long as the Kulluk stays "intact and upright" it shouldn't pose a threat to the crabs. And we can totally trust that nothing like that would happen, right? I mean, it was built in 1982 (and is older than me) but survived a season in the Arctic and didn't spill any oil during the grounding, so...

(waves crashing over the Kulluk when it was first grounded)

Sorry, all that craziness aside, the Tanner crab fishery is opening and you can place orders for pick up in Kodiak, Homer, or Anchorage! The Bering Sea Tanner fishery is closed for 2013 so this Kodiak fishery is a great opportunity for Alaskans (or at least those not privy to Southeast Tanners) to get some fresh C. bairdi meat and support local fishermen.

 a good Kodiak catch

Are you involved in the Tanner crab fishery or from Kodiak? Let me know how the fishery goes and what, if anything, you had to change to accommodate the Kulluk!

a sweet victory for bitter crabs

I recently visited family in Illinois and, while flying there, talked with a fellow passenger about bitter crab disease and the prevalence of it in southeast Alaskan Tanner crabs (Chionoecetes bairdi). In one area, the parasitic dinoflagellate affected 95% of the crabs, and that was back in 1987! Lately some southeast Alaskan populations had 100% of their primiparous females infected (Sherry Tamone talked about that at the Alaska Marine Science Symposium in 2011). Bitter crab is a problem in Alaska, but it is also affecting fisheries off Virginia and along the eastern coastal US, as well as in crab hatcheries in China and lobster populations in Scotland! What is causing this, and how is it spreading? What can fishermen do to quell the infection rate? And how can processors assist the fishermen in this effort?

 an infected Tanner crab (top) with milky hemolymph

and a healthy Tanner (bottom) with translucent hemolymph

Lots of questions, I know. Scientists have been feverishly researching Hematodinium sp, the dinoflagellate that is wreaking havoc on commercial crab species. A group of crab scientists at VIMS were able to trace the life history of Hematodinium sp. "[W]e can now really start picking the life cycle apart to learn what the organism does and how it functions," said Jeff Shields.

(Jeff Shields, VIMS)

The researchers noticed a pattern of development time in the dinoflagellate that correlates with cycles of infection in the field and molting of blue crabs (Callinectes sapidus). This knowledge enables them to make suggestions, at least in the realm of aquaculture, on how to avoid the spread of bitter crab by minimizing any effects the parasite could have on crabs during certain periods of both host and parasite life cycles. It seems small, but it's an important victory 15 years in the making in the battle against bitter crab disease!

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!

O is for opilio

I was recently asked how to distinguish between snow crabs (Chionoecetes opilio) and Tanner crabs (Chionoecetes bairdi). The person knew the difference in eye color thanks to this post: snow crabs have beautiful green eyes while Tanners have blood red eyes. Another way to tell the difference is to read their lips epistome margins. Opies have flat epistomal plates while bairdis have M-shaped plates:

snow crab on top, Tanner crab on bottom

I like to picture the snow crabs making an "O" sound when I look at their faces as if they were saying "OOOOO-pilio"!

Um, so let's say "meatballs" represent the red eyes? Yes.
(Sorry, I couldn't think of a good "M" word.)

There are a couple other differences: generally adult Tanners seem to be larger than adult snow crabs (at least in my experience) and their bodies are shaped a bit differently. Snow crabs have rounder bodies (their carapace length-to-width ratio is about 1) while Tanners are packing wide loads (their length:width is less than 0.945).

carapace shape and epistome margin from left to right:

pure Tanner crabs, three variations on hybrids, and then pure snow crabs

That may seem like a small difference, but if you're on a boat measuring hundreds upon hundreds of crabs, you start to know who is who before you even check their eye color and epistomal plates. You can also get a feel for something awry, like if you have a wide guy but with green eyes. Then you check his epistome margin and it looks like this:

not quite flat, but not quite M-shaped...

That's right, you've got a hybrid! So now you know, and knowing is half the battle.

Hybrid crabs

You may remember me mentioning snow crabs (Chionoecetes opilio) and their congener Tanner crabs (C. bairdi) are makin' babies in the eastern Bering Sea, resulting in hybrid crabs!

hybrid: "I'm a monster!!"

Well, it's getting worse. Or more prevalent? Or just more closely looked for and then accurately identified. Something like that. Anyway, when I was at the Interagency Crab Meeting this year, Dan Urban from NMFS Kodiak updated us on the Chionoecetes hybrid situation:

Chionoecetes hybrids (#/square nautical mile) encountered

during the 2011 NMFS summer trawl survey (draft report here)

And just as I had suspected, Dan said the participants are bairdi males and opie females. Which leads me to this horrifying conclusion: the Tanners are trying to take down the snow crabs! Think about it: it's just like the English vs. the Scots:

"If we can't get them out, we'll breed them out."

It's hard to stomach, I know. And that makes our opie men kinda like these guys:

totally historically accurate.

Maybe some of you out there are romantics and are thinking, "No wait. Maybe the opies and bairdis are actually in love, even though it's forbidden!" Yeah, OK. Like maybe the opie females are from the Capulets and the bairdi males are from the Montagues and it's all very enchanting?

"My only love sprung from my only hate!" - Juliet opie female

That would be sweet, except the crabs in the eastern Bering Sea don't have a major failure in communication that leads to their untimely demise (aka heartbroken suicide). They reproduce! They make hybrid babies! And those hybrids reproduce too, albeit at lower rates (the females tend to have less clutch-fullness). So no. I'm sticking with the Braveheart analogy.

So bitter!

What makes a crab bitter? Is it the lack of contact with its parents after hatching? Is it the constant diet of polychaete worms (I mean, really, who would enjoy that?)? Oh no, it’s something much worse:

Hematodinium sp.

aka the parasitic dinoflagellate that causes bitter crab disease (BCD).

Hematodinium perezi in blue crab (Callinectes sapidus) hemolymph

This nasty phytoplankton infects crabs, destroying the hemocytes (blood cells) in the host's hemolymph which leads to respiratory and organ failure, and finally death. You can tell if you have a bitter crab by their cooked appearance: Chionoecetes bairdi look bright red and C. opilio look milky whitish yellow. The name “bitter crab” (referred to as both disease and syndrome) comes from the bitter flavor of the infected crab’s meat (Taylor and Khan, 1995). The mechanism behind the spread of BCD is unknown, but may happen during molting, cannibalism, or even just physical contact with other diseased hosts.

comparing C. bairdi:

top was infected with BCD (note the milky-colored hemolymph)

while the bottom was healthy

Recently, Mullowney et al. (2011) investigated possible factors of what may be regulating BCD transmission in Newfoundland and Labrador opies. What they found is that BCD may be density-regulated for snow crabs, meaning that the number of crabs in a given area correlated with the prevalence of BCD in that population. In this study’s case, the density-dependence was influenced by small to medium new-shell (recently molted) crabs. Does the newly molted status mean infection happens during molting? They didn’t say. We’ll have to stay tuned on that one.

comparing C. opilio:

the top crab was healthy while

the bottom was infected with BCD (note the opaque color)

Mullowney et al. (2011) did note that the idea of measuring prevalence of BCD in a population is a tricky thing. It is possible to underestimate prevalence due to inefficient fishing techniques and the ability to only diagnose chronic cases of infection. Overestimation of prevalence can occur through those infected crabs seeking out pots (and the accompanying bait) more so than healthy crabs due to the extra nutritional demands the infection is putting on their little crab bodies.

an eyestalk-ablated C. bairdi from the Tamone lab

potentially infected with BCD (from this article)

BCD is on the rise (remember the velvet swimming crab deaths in France, mentioned here?), and the infection’s resulting mortality is affecting commercial stocks’ reproductive potentiontial. Siddeek et al. (2010) observed BCD and the way it may alter harvest strategies for C. bairdi in Alaska (Sherry Tamone presented on the proportion of BCD in Tanners from southeast Alaska here). Hopefully biologists can learn more about how this disease is transmitted and how it’s affecting populations to better manage our crab stocks!

Read more:
Mullowney, D. R., E. G. Dawe, J. F. Morado, and R. J. Cawthorn. 2011. Sources of variability in prevalence and distribution of bitter crab disease in snow crab (Chionoecetes opilio) along the northeast coast of Newfoundland. ICES Journal of Marine Science 68: 463-471.

also:
Siddeek, M. S. M., J. Zheng, J. F. Morado, G. H. Kruse, and W. R. Bechtol. 2010. Effect of bitter crab disease on rebuilding in Alaska Tanner crab stocks. ICES Journal of Marine Science 67: 2027-2032.

Taylor, D. M., and R. A. Khan. 1995. Observations on the occurence of Hematodinium sp. (Dinoflagellata: Syndinidae), the causative agent of bitter crab disease in Newfoundland snow crab (Chionoecetes opilio). Journal of Invertebrate Pathology 65: 283-288.

15th AFS Juneau Student Symposium

The Juneau student sub-unit of the Alaska Chapter of the American Fisheries Society (I'm laughing at this sentence! Yikes!) put on their 15th Annual Symposium! It had a wide range of talks, so you better believe there were some crab tidbits!

I won best talk last year (yes, that's me, tooting my own horn. Honk-honk!) and since I'm still in the process of processing (ha!) my hemolymph samples for methyl farnesoate I decided to sit this one out.

Yup, my talk was Fight Club-themed.

This year's crab highlights:

Blue king crab (BKC) Paralithodes platypus were heavily represented today with a talk on their genetics by Jennifer Stoutamore (are BKC from St Matthew and the Pribilof Islands genetically distinct populations??) and a talk on their socioecological impact to the people from the Pribs by Courtney Lyons (how does management of BKC bycatch in other fisheries affect the livelihoods of local fishermen??). Both projects are in the beginning stages, but it was exciting to learn more about BKC in general and see what's being researched.

blue kings from St Paul

Chionoecetes were well covered as well: those two heavy-hitters were Joel Webb looking at snow crab C. opilio fecundity and egg production with respect to stock demography and temperature (females shift from an annual to a biennial cycle of embryo incubation in waters < 0° C! Literally cool, I know!) and Jonathan Richar discussing C. bairdi recruitment in the eastern Bering Sea with respect to predator and parental abundances, and then some environmental variables to boot. And Alexis Hall gave a talk about the relationships between trawlers, crabs, and groundfish, where she'll be looking at whether or not groundfish are profiting from discarded crab bycatch from trawling fisheries; I'm pretty sure this includes Chionoecetes crabs, but she's including lots of crabs prevalent in the eastern Bering Sea, just to, you know, be thorough.

Finally, there were the otter talks. What? What do otters have to do with crabs?

Oh, oh, I see. Zac Hoyt is looking at the recoloniztion of sea otters in southern Southeast Alaska after they'd been overharvested in the 1800's fur trade, asking how this new population is affecting both macroinvertebrates (crabs, urchins, clams, etc) and the fishermen who target them after becoming used to a sea otter-free Southeast. Sean Larson is also looking at new sea otter predation with Zac, focusing on sea cucumbers, which are one of my favorite inverts!

Woo-hoo! As it turns out, the Crab Lab cleaned up at this student symposium: Joel Webb and Sean Larson tied for first place and Courtney Lyons won third place for their presentations! Congratulations!