Wednesday, August 31, 2011

The Color Purple

When Jake Marzucco was fishing for blue crab (Callinectes sapidus), he never thought he would land a purple one! But land one he did in Chesapeake Bay. 

this blue crab is clearly having an identity crisis

This purple blue crab isn't as uncommon as you'd think, and may owe its purple hue to a genetic mutation. (BONUS: what sex is the above crab?) Another purple blue crab was caught a few years ago and said to be a Baltimore Ravens fan, but that's just ridiculous. All blue crabs are Chicago Bears fans, regardless of their pigmentation. I know this as fact.

See? This is an actual photograph from National Geographic showing the
blue crab's Bears preference. (Well, maybe the Bears logo is from here.)

Anyway, we've seen other odd-colored crustaceans with an albino blue crab here and a blue lobster and half-and-half lobster here. What you may not know is this blue crab was just trying to fill out the rainbow:

Friday, August 26, 2011

Happy Crab-iversary!

nothing says romance like crabs! (from here)

This week was a bit slow in the blogging sense because my husband and I celebrated our 2 year wedding anniversary with a 3-day camping trip on lovely Douglas (across the bridge from Juneau). It was rainy and beautiful! 

But now back to work!

Friday, August 19, 2011

Orange Goo Update

Last week I reported on the orange goo that had unexpectedly appeared in Kivalina, Alaska here. Original analysis of the unknown substance led scientists to believe it was a mass of some sort of crustacean eggs or embryos. However, they've now come to discover the ooze is:


"Spores!?! Is this bad, guys? Is this bad??"

Closer analysis of the orange substance revealed the goo to be rust spores. The spores come from fungal infections on plants before being released into the air.

samples of the orange spores from Kivalina

fungal rust spores  (Order: Uredinales)

So, while crabs are off the hook, the people of Kivalina may still be affected by this not-yet-identified fungal spore: respiratory infections, possible effects on their fresh water stores, and an apparent fish kill the night the spores first appeared.

It's my crab in a box!

Guess what day it is: Crabday!

And guess who we're featuring today (I'll give you a hint):

That's right, it's the Box Crab! Specifically, we'll be learning about the

Brown Box Crab
Lopholithodes foraminatus

During my first semester working in the wet lab at UAS (Juneau), two fishermen came in and handed me a bag with what they originally thought had been a rock. Turns out it was a female brown box crab, doing what she does best:

sadly I didn't take a picture of her, but this is what she looked like ^^
(the brown box crab pictured is housed at the Ucluelet Aquarium, BC)

Pretty tight, right? Box crabs, as you may have noticed, can package themselves up, protecting their legs from curious passersby. But how do they respirate while they're all squared away? Brown box crabs have two circular openings that form when they tuck themselves in called foramen through which water can circulate.

you can see the curvature on the legs and
the purplish hue where the foramin will form

tah-dah! one box crab, complete with the ability to get water to its gills!

Brown box crabs range from Kodiak, AK to Sand Diego, CA. They are clammers (like Billy Joel, for all you Long Islanders out there. True story, I totally saw Billy clamming outside his house once in Oyster Bay. But back to the crabs.) using their chelae to dig through the sediment and crush their prey. They also eat brittle stars and urchins, and they are preyed upon mainly by octopus. Another animal using (and abusing) the brown box crab is the blacktail snailfish, who apparently likes to lay its eggs IN the brown box crab gills!?! I'm not sure how this happens (read more here), but I guess that, while the eggs may collapse some of their gill filaments, the crabs are able to survive the intrusion.

a golden king crab with its gills exposed to show snailfish eggs. ouch!

Now these box crabs aren't to be confused with the Calappa sp. box crabs; brown box crabs are lithodids, related to king crabs! You can kind of see the resemblence in their rostrums (noses), which might also explain why the brown box crab's other common name is the Oregon queen crab.

an "Oregon queen crab" aka brown box crab in Kodiak, AK

All hail the Queen!

Tuesday, August 16, 2011

Cats love crabs too

We celebrated the cats birthday last weekend (it's late, and yes, we're those people), and boy do they love their crab toy! (The catnip probably helped.)

Scout delighting in crab-shaped joy

Boo checkin' it out

sweet little crocheted crab, slightly worse for the wear love

it can sense the danger nearby

Does anyone else have crab-shaped cat toys or knit/crochet crabs? If you do, I'm sure you'll find some cats that will happily get in on some Snow Crab Love!

Friday, August 12, 2011

Hermit Crabday!

My friend Gretchen (harbor seal chick!) sent me this cartoon and I thought it was so funny and perfect as an opener to show just how cute hermit crabs can be. So here you go, crab lovers, it's hermit Crabday!!

There are SO MANY hermit crab species out there, it's kind of hard to know where to start. But you've already met one beautiful hermit crab from our first Crabday: the coconut crab! Remember, coconut crabs (Birgus latro) give up the extra protection around their abdomen after adolescence. Then they just rock out with their... soft abdomen out. Yes.

You see, most hermit crabs you know and love need shells because of this feature:

The hermit crab's soft abdomen spirals perfectly to fit inside a
snail shell, as you can see with this guy in the glass shell.
Guess he won't be throwing rocks any time soon, you know what I mean?

If you're like me, you're probably wondering how they mate with all that shell in the way. Male and female hermit crab anatomy is pretty similar to snow crabs, but for males to successfully copulate with female hermit crabs, all they have to do is give a little knock-knock (who's there?) and rock the shell, literally, to convince the female to come out of her protective home. Then BAM!

So, with all that out of the way, here are the cuties I promised:

here's a little Alaskan guy I found in my rocky intertidal backyard - Pagurus sp.
(read about hermit crabs in Alaskan seabird diets here)

"EEEE, I'm a tiny hermit crab!"

I love how comically large the shell is for this beautiful blue hermit crab

hermit crab: "Need a lift?"
anemone: "I got your back, bro."

TGIC, am I right?

Monday, August 8, 2011

The secret of the ooze


Orange goo has been washing up on the Alaskan shore of Kivalina. It's also been spotted floating in the harbor, in Buckland River (150 miles away!), and in rainwater. RAINWATER?? Yes, you read that correctly. People put out buckets overnight and found this orange goo had been collected with the rain the next day.

the floating orange mystery off Kivalina, AK

People from Kivalina, an Inupiat Eskimo village 625 miles northwest of Anchorage, were baffled; none of their 374 residents had ever seen anything like the orange goo before.

Kivalina, Alaska (marked as the orange blob) and Buckland River (orange pin);
you can see Anchorage in the map on the right, labelled and marked by a small blue dot

What's the answer to this quandary? Juneau scientists are saying this orange goo is in fact crustacean eggs/embryos (remember learning about the different colors of crab clutches throughout embryo development here?). Jeep Rice from NOAA's Auke Bay Lab confirmed (here) that the substance, "... is natural. It is not chemical pollution; it is not a man-made substance." Great!

Yum! a sample at the AK DEC, Anchorage

But wait, what kind of crustacean is it? And more importantly, HOW DID THEY GET INTO THE RAIN!?!?!? Seriously, people, should I expect to get crab cakes with my Juneau rain from now on? (Maybe a little remoulade too?) As long as bears aren't suddenly awesome at karate, I'm pretty OK with that.

"We just got back from a fishing trip in Alaska!"

Follow-up: see what scientists are saying the ooze is now in the blog post "Orange Goo Update"

Friday, August 5, 2011

The name’s Lightfoot. Sally Lightfoot.

No, she’s not a Bond girl. She’s not a talk-show host either. She’s the next crab featured for Crabday!!

Sally Lightfoot Crab
Grapsus grapsus or Percnon gibbesi
(the two species most commonly referred to as SLC)

First we’ll look at Grapsus grapsus, because, let’s be honest, that’s a pretty rockin’ species name! I’ll call her Sally G.

How beautiful is this crab!? Grapsus grapsus in the Galapagos.

Sally G roams along the west coast of Central and South America. However, she is most well known as the beautiful red rock crab inhabiting the Galapagos Islands, as recorded by Charles Darwin! There, the Sally G’s munch on algae and different dead animals like fish, birds, and even seals! That may seem pretty viscious, but it’s a tough environment for these little crabs, being preyed on by the likes of feral house cats.

something tells me this iguana isn't as into snuggling as the Sally Lighfoot crab

G. grapsus does have supporters though: John Steinbeck wrote about Sally G crabs in his Log from the Sea of Cortez (a great read!), and, while we’re dropping names, Martha Stewart is an admirer, having printed Sally G on fun towels for her Galapagos collection.

What about Sally P, aka Percnon gibbesi? This crab has been called “the most invasive species in the Mediterranean”! (And that’s saying something, as it’s one of 13 invasive decapods crustaceans recorded there.) But that just means Sally P is one hearty crab. She ranges from California to Chile and Florida to Brazil, not to mention from Madeira, Portugal (off the Moroccan coast) to the Gulf of Guinea along the west coast of Africa!

Percnon gibbesi nestled into some nice coral

Sally P has beautiful coloration and stripes on her walking legs, which I thought might explain another nickname of P. gibbesi: the urchin crab. I was wrong. Sally P can be found most often in the company of long-spined urchins, using their spines as protection from predators. And the urchins don’t have to worry, because unlike Sally G, Sally P is a vegetarian, eating primarily algae and detritus.

Sally P and its urchin guardian

Now that you know Sally Lightfoot, feel free to introduce them to your friends at parties. Consider yourself on a first name basis.

Tuesday, August 2, 2011

Crab nerds united!

It's here! The 25th Lowell Wakefield Fisheries Symposium publication is out! The book detailing a meeting of so many crab nerds under one roof! And for 4 days, no less! Many participants have already gotten theirs, including my lab mate Miranda, but I'm still waiting on mine. That doesn't mean that I haven't hijacked her copy of Biology and Management of Exploited Crab Populations under Climate Change to get my crab-learnin' on!

I've referenced the knowledge I gained/people I met from the symposium here, here, and here, for a start. Today I'd like to highlight a paper from the book itself:

Preliminary analysis of spermathecal load of primiparous snow crab (Chionoecetes opilio) from the eastern Bering Sea, 2005-2008
Laura M. Slater, Kirsten A. MacTavish, and Douglas Pengilly

(What can I say? They had me at 'spermathecal load'.)

Their project was a monitoring program measuring spermathecal loads in primiparous female snow crabs from the eastern Bering Sea. They wanted to monitor the loads because a 2005 paper showed this group of females had low sperm reserves, which can mean that they won't have enough sperm stores to fertilize subsequent clutches after their first batch. (And remember, mating can be a dicey thing for female snow crabs!) The goal of the program was to see if large-scale interannual variability exists for female snow crab sperm reserves in the Bering Sea.

So what did they find out? First, clutches were mostly either 3/4 full or full, with healthy, viable eggs. Spermathecal loads in primiparous females had quite the range: from 0.001 g to 0.180 g! These loads are actually pretty low compared to crab stocks on the east coast, but since so many clutches were full of viable eggs it might not be an issue for these ladies.

The eastern Bering Sea was divided into three regions: northwest NW (area closest to Russia), central C (including St. Paul), and southeast SE (an area including St. George and Nunivak Island). Females were smallest in carapace width and had the lowest spermathecal loads in the NW region. There were also variations in loads over the different years of the study (as seen in the graph below), but only region and carapace width had any significant effects on the log-transformed spermathecal loads (ANCOVA, p < 0.05).

average spermathecal loads from the three regions of
the eastern Bering Sea during 2005, 2007, and 2008 

What does this mean? Sperm reserves in primiparous females are size-dependent (on the female's carapace width) and show spatial variation (between the different regions of the eastern Bering Sea). Using these differences, sperm reserves may end up being a helpful tool for predicting the presence and fitness of reproductively active males, which, as you know, is my #1 interest!