Many of you know I LOVE October. I continually sing, "It's the most wonderful tiiiiime of the yeeeeear!" and I'm not talkin' about Christmas, y'all! Among all the reasons I love October (fall colors, Halloween, crab season openers), I just learned it's also National Seafood Month! Yes, not only should you be celebrating everything pumpkin, but also everything locally harvested from Alaskan waters! And to learn more about local seafood, you can read this Seafood 101 pamphlet. The link will bring you to the layout and you can zoom in to read the different articles. Who knows, it may even inspire your next Halloween costume:
Hey there! I've been working on this for a little bit the last 6 years (grad school + coming to terms with publishing my Master's thesis while starting a 'real' job...) but it's finally almost here:
Relationship of molting, gonadosomatic index, and methyl farnesoate
in male snow crab (Chionoecetes opilio) from the eastern Bering Sea
It's been accepted for publication in the Journal of Crustacean Biology and you can read the abstract from the advanced article here. To say I'm pretty pumped would be an understatement! I've had cod and pollock and humpback whales swimming through my brain so much lately that it's nice to get crabby once more! Not like this:
My friend was out on a crab survey this summer and spotted this guy:
Nothing out of the ordinary, right? EXCEPT FOR THESE:
We've seen extra appendages before (here and here). They most often are a result of some trauma to that leg that the crab's physiology tries to heal through regeneration (remember, crabs can rebuild entire legs!) that goes awry. When my friend posted these photos, someone asked if they were mobile or able to move independently. While I wasn't there, allow me to speculate: these bonus crab bits are just that. Bonus. The crab can't control their movement (you can see that they don't have actual joints, just the impression) and if the leg gets dropped for whatever reason and is regenerated, it likely won't have those mutations the second time around. BUT it would be cool if they could move, because imagine how much more scary that would make this guy:
Remember when we learned that crustaceans actually feel pain here? In short, scientists offered crabs two shelters: one normal and one that delivered a shock. After being exposed to the electric shelter, the crabs had a learned response to avoid that sensation (presumably pain) and only choose the normal shelter.
Well, stemming from that research, scientists are now learning that crustaceans may feel anxiety too! I mean, it's not too shocking (I know...) that electrocuting an animal would stress it out, in our human understanding of the phrase, but scientists are observing behaviors that can be attributed to a stressed response. To test for anxiety in crustaceans, scientists exposed some crayfish to an electric field then put them in the test environment. The environment itself had no secret shocks, but rather had different light treatments: light places and dark places. All animals that weren't shocked before placement wandered around in both the light and dark environments, as if they hadn't a care in the world! All animals who were electrocuted prior to placement chose to stay in
the dark places - in the wild this would be like them finding cover and
hiding. They had experienced something that stressed them, so they were staying away from a threatening, exposed place!
"man, you cray!" - 'stressed' crayfish
This, along with some physiological work the researchers did as well, means that instead of calling them "stressed", I can take away the air quotes that indicate I'm just anthropomorphizing their behavior and call them stressed!
A lot of times when I see advances in robotic technology I usually go into a panic about the impending robot apocalypse that's sure to follow. HAVE WE LEARNED NOTHING!?!?!?!
"I want to dance on your bones!" - every robot, I assume
BUT, when I saw the Crabster CR200, my heart instantly melted!
The Crabster is a creation from the Korean Institute of Ocean Science and Technology designed to, you guessed it, walk on the ocean floor! This little fellow can go where propeller-driven ROVs can't and doesn't kick up as much debris, so the video footage captured by its ELEVEN cameras can be clearer with our little crab-like friend. This link had two videos of the Crabster in action, so check it out!
It's like the large, potentially harmful, but still adorable version of these guys I bought my California nieces, so if Aunt Molly approves, so
I mentioned last year that I was going to keep track of the keyword searches that bring people to Snow Crab Love, because some of them were frankly strange. Here are the top 5 non-crab-related searches that brought people here and, I'm guessing, left them asking, "What am I doing here!?!?" 1. Tina Turner
5. Dead Iguana Pictures I seriously have no idea (a) why anyone would search that and (b) why that search word would bring people to my blog MULTIPLE times! Other fun searches were "Captain Picard", "Baby Beagle Costumes", "If I only had a brain", and "Kelsey Grammar" (what?).
Is anyone else singing Sheryl Crow right now? Just me?
It's Science Fair time up here in Juneau!!! That means data has been collected, numbers have been crunched, and posters are being put together for the big presentation this weekend! This will be my third year judging and I'm so excited to see all the projects the high school students have come up with this year!
Last year I was also a mentor (mentioned here) but sadly my student didn't end up presenting her results. It was sad in two ways: (1) she was pretty pumped about the project, but had double-booked the weekend because she was also super involved in a lot of school activities (go get 'em!), so it was too bad she didn't get to present her work. (2) This experiment involved live animals, so had I known she wouldn't complete the program, I wouldn't have mentored this type of project. I take working with animals very seriously and take it to heart if/when any of the animals in my care die.
That being said, I still want to present the fun little project I had the opportunity to participate in since it hasn't been shared yet! Hermit crabs depend on gastropod shells to protect their soft, delicate abdomens. Because of this need for protection, shell strength is an important variable for them when choosing which shell to inhabit. Given the choice in normal situations, it's been observed that hermit crabs will choose intact shells over damaged ones, since the damaged ones would be easier to break into by their predators. We wondered how their shell choice might differ in differing situations: will they make the same choice under stress? How about if they think there are a bunch of potential shells around - will they be as choosy initially? Will they still worry about shell strength???
To test this question, we took hairy hermit crabs, Pagarus hirsutiusculus, that were being housed at the University of Alaska Southeast wet lab and offered them two shells: one intact, one with a tiny hole. When giving the crabs an opportunity to make this choice, we took advantage of their use of chemical cues and exposed them to different "smelling" water. We exposed some of the hermit crabs to water that smelled like a known predator, the Dungeness crab, to act as the stress treatment. We exposed others to water that smelled like dead snails to mimic a gastropod predation event, or a time when several snails are being eaten and therefore leaving their shells up for grabs. We finally had a control treatment where the hermit crabs made their choice in the same water that had been pumping through their holding tanks.
In order to encourage shell selection, we had to gently remove the hermits from their original shells (crazy easy to do without any harm to the crabs!). We saved their original shell so that they could move back into it when the trial was finished. We also measured their original shell's weight so that we could offer them test shells of similar size/weight (we didn't want to give a big crab a small shell!).
science! collecting naked crab weights!
We measured the time it took for them to approach a shell, the time it took for them to enter a shell, and their shell selection. We took note if they changed which shell they chose too, just in case any of them had buyer's remorse.
choices choices: the two shells offered are from the same species of snail,
but one is damaged goods and one seems shiny and new
(the small white thing in the leftmost part of the tank is a bit of gravel)
What did we find? For all treatments, the hermit crabs chose the intact shells over the damaged shells. This wasn't too shocking, but it was still interesting to see that, even under stress (Dungeness-scent) or at leisure (dead snail-scent), they still made the same basic decision.
more hermit crabs chose intact shells than damaged shells
and rarely changed their minds, although one crab switched from
an intact shell to damaged one in the predator treatment...
The time it took for the crabs to approach a shell and enter it were very similar. It seemed like some of the crabs would just wander around the tank for the most part and sense the shells by touch rather than sight. Once they touched a shell, they would hurry their little tushes into it! The time it took for them to find the shells was roughly the same across all treatments (ie "there was no significant difference in average time for first approach or shell entry across treatments (ANOVA, p > 0.05)").