This week: Eastern Fish Health Workshop

There's a special conference every year that's one of the best kept secrets in the fish world; its the Eastern Fish Health Workshop and this year its in sunny Shepherdstown WV, home of the National Fish Health Research Laboratories, which (as a quirk of history) are part of the USGS's Leetown Science Center.  I've been going ever since I came to America in 2000 and I just love it.  Why?  Well, its a combination of things.  Its small, usually around 100 people, which means you can spend some quality time with your colleagues. There's no concurrent sessions, so you aren't forced to miss anything, and there's also no poster sessions, which I consider to be largely a waste of time.  It covers a great diversity of topics - fish health in aquaculture, wild fisheries, coral health on reefs, aquarium animal health, crustacean health and mollusc sessions, as well as thematic sessions like immunology and chemotherapy.  There's no more diverse such conference annually, probably because its not affiliated with a scientific society that would limit scope.  The only meeting that comes close is the ISAAH, in Tampa later this year, and that only runs every 4th year.  But the best thing about the meeting is the people.  Perhaps as a result of its breadth of subject, it attracts folks of broad vision and diverse interests and I just love that.  I always leave energised by the people I meet and topics we discuss.  Indeed, one of my biggest current projects - metabolomics of whale sharks (more on that in future posts) - was inspired by an EFHW talk by Andrew Dacanay a few years back.

This year's conference is especially important because its the 35th anniversary!

So, I'll be in WV this week and will try to blog some about the talks as they happen.  This will mean writing from the Droid, so forgive me if things come across a little stilted.  Its an a amazing device, but its no substitute for a real computer.  It also means I might not do any blogging on peer reviewed research this week.  I'd like to think I'll be studious and go back to my room for that stuff, but there's more to be gained by picking someone elses brain.  Perhaps I'll post some interviews instead.

The Travel Bug bites hard, but it hurts so good

Just once in life I did the totally reckless thing of looking at a photo (in a Lonely Planet guide, if I remember) and saying "Thats it, I am going there, now" and then doing exactly that.  The place was Leh, which is in region called Ladakh, in the province of Jammu & Kashmir in Northern India.  Not once did I ever regret that decision; Leh was one of the most magical places I ever visited, probably made moreso because of the liberating decision to go half way round the world to see it and the good buddies I shared the experience with.

Well, I feel the same bite about Saba in the Netherlands Antilles.  Every time I look at a photo of that little volcanic speck and imagine the hair-raising landing at the airport, followed by the equally follicle-lifting drive through a myriad switchbacks clinging to the side of that impossibly steep volcanic plug, I can barely resist the urge to just walk out the door, head for Hartsfield-Jackson and jump on a plane.  I have assiduously suppressed these feelings for years in favour of pedestrian realism, but now PLoS One has published a series of papers about the diversity of critters on the bank reef adjacent to Saba.  How am I supposed to resist that?  Thanks a lot PLoS...

Somebody help a travel junkie out; either convince me to go, or talk me down!  Ever been there?  Whats it like?

Picture from Throwingpoo.com (I kid you not)

12,081ft - The oceans, by the numbers

I was inspired by recent articles highlighting a revised calculation of the ocean’s average depth as 12,081ft, to consider the seas in a numerical light today. To that end, here’s a few random, sourced numbers and back-of-the-envelope calculations that might be food for thought:

0.87% = Amount we can see by diving from the surface (about 100ft) over the average depth
0.28% = Amount we can see by diving over the deepest part (Challenger Deep, Marianas Trench off the Philippines)
2.9 = Number of times deeper the deepest part is, compared to the average.
5,400 = Number of mammal species in the world
25,000 = Number of fish species in the world
Millions? = Number of marine invertebrates species in the world (no-one really knows)
2.3 Million = The number of US citizens directly dependent on ocean industries (source: NOAA)
$117 Billion = Value of ocean products and services to the US economy (yr 2000, source: NOAA)
50% = US population living in coastal zones
48% = The proportion of all human-produced CO2 absorbed by the oceans in the Industrial era (NatGeo)
0.1 = The pH drop in the surface oceans since 1900
0.35 = Expected pH drop by 2100 (source)
18 = The number of times more heat absorbed by the oceans than the atmosphere since 1950 (source - TAMU). Global warming is an ocean process far more than an atmospheric one.
3.5 Million = Estimated tons of plastic pollution circling in the Great Pacific Garbage Patch, and growing.

And yet:

30 = Number of times thicker the atmosphere is (out to the “edge of space” about 60 miles) than the average ocean. That would be the atmosphere that astronauts describe as a “thin veneer” on the planet…
0.06% = Thickness of the average ocean, compared to the radius of the earth. I think we can argue that the water is the veneer, not the air
$4.48 Billion = NOAA’s 2010 budget, including the National Ocean Service, Weather Service and Fisheries Services. (source NOAA)
$18.7 Billion = NASA’s 2010 budget, i.e. 4 times the size of the agency that looks after our own planet (source NASA)
$664 Billion = Department of Defense base budget 2010, not counting special allocations (source DoD)
0.6% = The amount you would need to cut Defense in order to double the NOAA budget

Some sources:
http://www.corporateservices.noaa.gov/~nbo/FY10_BlueBook/NOAAwide_One_Pager051109.pdf
http://www.corporateservices.noaa.gov/~nbo/10bluebook_highlights.html http://news.nationalgeographic.com/news/2004/07/0715_040715_oceancarbon_2.html  
http://oceanworld.tamu.edu/resources/oceanography-book/oceansandclimate.htm
http://web.archive.org/web/20080625100559/http://www.ipsl.jussieu.fr/~jomce/acidification/paper/Orr_OnlineNature04095.pdf  

Play Bit-o-critter, round 18

This one's a little harder; but I think you guys are up to the challenge...

The solution to Bit-o-Critter round 17

Juliebug nutted out that the critter in round 17 was a hyperiid amphipod.  Hyperiids are freaky looking things, like the sort of thing H.R. Giger might have used for inspiration for the creature from Alien.  Julie also uncovered some stories about swarming hyperiids, predatory hyperiids and parasitic hyperiids.  Check it out

Just like cows, fish chew their cod

Baddum-tish!  OK, they don't chew their cud, but I can never resist a good pun (although I was seriously considering "Ruminations on the way fish eat" - better?).  I just love this new paper by Gintof et al. about how fish chew, mostly because its an idea that I never would have ever considered.  Basically, they explored whether fish just bolt their food, like lizards and snakes, or whether they engage in "intra-oral prey processing" (= chewing, sometimes sicnetific jargon cracks me up).  After looking at several model fish species, they conclude that yes, fish chew, and they chew about as many times as mammals do.  Its not like mammal chewing (especially herbivores) in that there is little side-to-side motion, but its rhythmic, and thats the most important thing.  This means that the bolting of food by lizards and snakes represents evolutionary loss of chewing, or that the model fish and all mammals both evolved chewing separately (they call this convergent evolution). 

They looked mostly at "basal" fishes like pikes, salmons and arowanas, that is, fish that show the most in common with the ancestors of all fish - I hate to use the term "primitive".  Its significant because it shows that chewing showed up early on in fish evolution.  One theory they put forth for the early appearance of chewing is that the rhythmic pumping of the jaws was necessary to keep fluid moving through the mouth and gills while eating.  Under that view, breathing water through the mouth and gills preadapted all who came after for processing food in their mouth, as opposed to, say, lobsters, whose teeth are in their stomachs.  I would dearly have loved it if they had included a more derived fish like a perch, pufferfish, or the sheepshead (with creepy human-like teeth, shown hereabouts) to show that chewing persisted in other branches of fish evolution, but you can't have everything.

Its a fun paper, you can read it here:

Gintof C, Konow N, Ross CF, and Sanford CP (2010). Rhythmic chewing with oral jaws in teleost fishes: a comparison with amniotes. The Journal of experimental biology, 213 (Pt 11), 1868-75 PMID: 20472774

Q: What do Sam Waterston and Sigourney Weaver have in common?

A: They are both actively drawing public and legislative attention to the issue of ocean acidification.   That is, the decrease in the pH of the sea as a result of its absorbing increasing amounts of atmospheric CO2, that most pernicious of greenhouse gases.  Waterston, who is on the board of Oceana, was just testifying in DC about it, as Weaver was recently.

Oh, and if you thought this post was going another direction, here you go:

Sam Waterston was in 1976's Sweet Revenge with Norman Matlock who was in 1984's Ghostbusters with Sigourney Weaver.

There you go Kevin Bacon, you're not so special after all, anyone can do it...

Seaweeds and corals go through the media meat-grinder

“If it bleeds it leads” is a common meme in the journalism field, but when it becomes the mantra of science reporting, sometimes the real message gets lost in translation. Unfortunately, so it is with a new paper from Doug Rasher and Mark Hay down the road at Georgia Tech. In their work, published in PNAS this week, they show that algae from coral reefs can have toxic effects on adjacent corals including bleaching (expulsion of the symbiotic algae that are responsible for much of the corals success) and even death. They provide evidence that these effects are mediated by lipid soluble compounds and that they are much reduced on reefs that have healthy herbivorous fish populations to keep the algae in check. There, I summarized their work in 2 sentences. It’s disappointing, then, that the NSF (NSF for goodness sake!) turned that into “Killer Seaweed: Scientists Find First Proof that Chemicals from Seaweeds Damage Coral on Contact”. Unfortunately, that kind of catch-phrase gets picked up all over, so that MSNBC ran with “Killer seaweed threatens corals: Innocent-looking species turns into an assassin of nearby reefs” (assassin? Really?!). The Georgia Tech website went with “Research shows that chemicals from seaweed kills corals on contact”. Not as dramatic perhaps, but more reasonable. Ed Yong at Discover Blogs chose to emphasise the fish side of the story: “Overfishing gives toxic seaweeds an edge in their competition with corals”; both these seem fine to me, but honestly, I don’t know what’s wrong with using the title of the paper “Chemically rich seaweeds poison corals when not controlled by herbivores”. I think Rasher and Hay did a good job distilling the essence of the paper into a punchy and information-dense title. In any case, its frustrating to see crux of a paper lost in attempts to sensationalise the story, as did all the outlets who went with the “killer seaweed” theme.

Putting aside the press treatment, I think there’s an important part of the story missing from this paper. In it, Rasher and Hay report that in the absence of herbivores, 40-70% of common seaweeds cause bleaching of a model coral species (Porites), depending on where you are. If you average that – 55% - then roughly half of seaweeds were toxic to their model coral. On this proportion and their comparison of overfished and non-overfished reefs, they base the conclusion that these algae are bad for corals, that herbivores suppress the algae and, therefore, that overfishing will increase coral declines by allowing toxic algae to proliferate. All of these seem reasonable ideas, but I kept asking myself: what about the reciprocal effect? What percentage of corals are antagonistic to algae? If, say, half of all corals can damage adjacent algae, then the net effect of all this antagonism at the largest scale is zero. If half of algae kill corals and half of corals kill algae, it could be zero sum. This seems important to me, because it would undermine the conclusion that overfishing of herbivores will necessarily lead to declines in reef corals. Indeed, I could make the reverse argument that overfishing of corallivores (fish that eat corals) might lead to proliferation of corals and therefore the decline of reef algae. We just don't know because that work hasnt been done. 

Of course, you can’t include everything in a single paper and I would expect the authors to respond to my point by saying that the experiments I describe were beyond the scope of their project. But I think it could have been a better paper if they acknowledged that there’s another possibility that cannot be excluded, based on work that’s yet to be done.

Rasher, D., & Hay, M. (2010). Chemically rich seaweeds poison corals when not controlled by herbivores Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0912095107

Play Bit-o-Critter round 17

A family will do fine today

Calling the corals home

Ed Yong at Discover Blogs has a great post up about a PLoS One paper describing how coral larvae find their way back to the reef from the plankton, using sound.  This is a remarkable ability for a tiny ciliated ball of cells, demonstrated through a nifty experiment where the scientists played sound from different directions into a dish of tubes containing coral larvae and showed that they moved towards the speaker playing sounds from a reef.

Putting aside the remarkable little larvae, maybe we shouldn't be surprised. Anyone who has ever put their head underwater on a reef, especially a Pacific reef, can tell you they are noisy places.  I always thought it sounded like frying bacon - a sizzling crackle of clicks, pops, scrapes and cracks, courtesy of snapping shrimps, parrotfish and a myriad other beasts.  The first time I heard that sound I remember being startled, and then amazed.  Serene underwater scenes?  Serene, my butt!

The solution to Bit-o-Critter round 16

Miriam from DeepSeaNews correctly identified Glaucus atlanticus, a spectacular pelagic nudibranch.  Like a lot of neustonic animals, they are bright blue, which relates to the intense sunlight exposure they get in the top inches of the ocean.  The same blue coloration is seen in calanoid copepods, jellies and other things that live right at the surface. 

This pic of Glaucus from Wikimedia Commons.

The solution to Bit-o-critter round 15

As Akira so succinctly put it - Euthynnus alletteratus.  To the rest of us, that's the little tunny.  In his follow-up, Aki pointed out that the spots below the pectoral fin were the give away - no other tuna has them.

Play Bit-o-critter, round 16

The fish people have had it way too easy lately, so here's one of "the other 95%"

Remember - if you get it right, you have to follow up with some details so the rest of us learn something

Whale sharks start to give up their secrets

Whale sharks are the largest fish in the oceans; they can grow to 20m in length and weigh many tons, although 7-9m is closer to the common average these days.  Despite their tremendous size, scientists don't know that much about them.  We know that they eat plankton and that they live in the tropical oceans throughout the world and there have been quite a few papers reporting their presence in different waters, but these represent only the most basic foray into the biology of a species.  More recently, there's been a few more including one that explores genetics (Castro et al., see below) and some that have started to explore behaviour (see Brunnschweiler et al.).  Up to this point, the focus has all been external; that is, only the biology that can be observed from the outside.  That's no surprise really; its a logical place to start and there are some huge logistic challenges to working with whale sharks, as you can probably imagine.

There are 4 whale sharks in the collection at Georgia Aquarium in Atlanta and I have been lucky enough to work with these amazing animals since 2006.  Part of that work has involved veterinary examinations, which has allowed us, for the first time, to look at aspects of the internal biology of whale sharks. The first part of that work is now in print: a paper I co-authored with the aquarium's principal clinical vet, Dr. Tonya Clauss, and a colleague from National Aquarium in Baltimore, Jill Arnold (Jill is an expert in medical techniques, especially blood work), which is in the latest issue of Aquatic Biology.  Our paper is a discovery-based one (i.e. not testing a specific hypothesis) about the nature of the blood of whale sharks, both the cells and the chemistry of the blood serum.  Its open access, so you can get it at the journal web page here

In it, we show that whale sharks have blood that is fundamentally similar to that of some other sharks, specifically the bottom dwelling ones like nurse sharks and wobbegongs, but pretty different from the toothy predatory sharks like great whites.  They have very large red cells, actually white cells too, but this is something they share with the bottom dwellers, so it appears to be a feature of the group rather than a function of the size of the whale shark as such.  Whale sharks are the only pelagic members of that group, the order Orectolobiformes.  Why such large cells, then?  Our study didn't answer that question, but my best guess is that they have relatively low metabolism compared to the carcharhinids, which may need the high relative surface area of smaller red cells to improve the movement of oxygen in and out of cells.  This is the first of several hypotheses that we can only begin to pose because of these first discovery-based efforts.

I can't tell you how excited I am that we can begin to share what we've been learning at the Aquarium.  The chance to work with whale sharks is a real gift for a fish nerd like me, and the opportunity afforded by having access to them in the more controlled environment of an aquarium makes it possible to do safely and effectively research that has been prohibitively difficult with free-ranging whale sharks up to this point.  Of course, the ultimate goal is to extend that work to compliment the field research, and I look forward to telling you more about that in future posts.

Brunnschweiler, J., Baensch, H., Pierce, S., & Sims, D. (2009). Deep-diving behaviour of a whale shark during long-distance movement in the western Indian Ocean. Journal of Fish Biology, 74 (3), 706-714 DOI: 10.1111/j.1095-8649.2008.02155.x 

Castro, A., et al. (2007). Population genetic structure of Earth's largest fish, the whale shark ( )
Molecular Ecology, 16 (24), 5183-5192 DOI: 10.1111/j.1365-294X.2007.03597.x 

Dove, A., Arnold, J., & Clauss, T. (2010). Blood cells and serum chemistry in the world’s largest fish: the whale shark Rhincodon typus Aquatic Biology, 9 (2), 177-183 DOI: 10.3354/ab00252