News

Time to catch up on a few items on the fish front.

Sharks may be worth more alive
than dead

A shark in the bush (so to speak) may be significantly more valuable than a shark in the hand.  A study published recently in Oryx - The International Journal of Conservation and using data from 70 sites in 45 countries estimates that shark-related ecotourism brings in over $300 million dollars annually, and that the value of the industry may more than double over the next two decades.  Contrast that to $630 million, the estimated value of global shark fisheries - and throw in the fact that value of those fisheries steadily declining. The takehome - leave those sharks alone.  Shark-related tourism in the Caribbean alone leads to over 5,000 jobs and produces over $100 million in revenue.

The lookdown, Selene vomer

In the new Proceedings of the National Academy of Sciences, we hear about new ideas related to fish camouflage in the open ocean.  Traditionally, it has been believed that a fish's best strategy in open water has been to make itself less visible by using a mirror effect, reflecting sunlight to allow the prospective predator or prey to blend into the background.  New research suggests that this strategy, while effective in some circumstances, does not work well in others.  This is particularly true when light penetrating the surface is polarized.  Turns out that many fish species are sensitive to polarization, and the the nature of polarized light is constantly changing.  This means that a mirror strategy won't always be the most effective camouflage.

The authors of the PNAS paper observed lookdowns (Selene vomer), and found that the fish were able to change the way in which light reflected from their bodies in a manner that approached the optimum with regard to camouflaging themselves.  In some light situations, that meant acting like a simple manner.  At other times, the reflected light was altered so as to make the fish less visible in a polarized environment.  It's unclear if the process is passive, with the skin of the fish responding to the available light, or if the fish or somehow activity changing the way light is reflected.

In the Prehistoric Fish o'the Day category, a paper appearing in Geodiversitas describes a new species of acanthodian which lived during the Devonian some 408 mya.  The fossils, discovered in Eastern Spain, are mainly from juveniles with none from fish larger than a meter in length.

Acanthodian

The acanthodians, sometimes referred to as "spiny sharks", were among the first of the jawed vertebrates.  They were characterized by a series of stout spines in front of all the fins.  Many of the early acanthodians had two rows of paired ventral fins.  This makes them particulary interesting to students of vertebrate evolution, as the rows of fins have been suggested (through the fin-fold theory) to have paved the way for the evolution of paired fins and, ultimately, limbs.

There are lots of different things that we call "fish", and they belong to lots of different taxonomic groups.  I mean, hagFISH aren't even considered vertebrates any longer.  Still, all of the 28,000 or so species that we refer to as fish all have some basic similarities, likely due to the unforgiving nature of the aquatic realm.  You can't be evolutionarily sloppy and function well in the water.  However, within the basic fish template, there's still room for a lot of diversity.  This week in Fish Biology, we'll be discussing body forms, the many ways that the basic fish design has been molded to better function in a specific role. Regardless, here's a teaser. Scientific binomials, so as not to give anything away in the common names.

What drives the...

...odd mouth of Nemichthys scolopaceus,

....the spectacular dorsal fin of Istiophorus platypterus,

...or the misshapen fins of Histrio histrio?

Is there adaptive value in the magnificent rostrum of Pristis pectinata,

...or of Polyodon spathula?















What about the greatly elongated pectoral fins of Cheilopogon melanurus,

...or pretty much anything about Ogcocephalus darwini?

Why does Chaenocephalus have yellow blood?












And, finally, what in blue blazes is going on with Macropinna microstoma?

Fish - eries

There's been a lot written in recent years about the plight of the world's fisheries.  Many of them are in real trouble as the result of overfishing.  One result has been a shift toward reliance on invertebrates like prawns, lobsters, and mollusks.  New research from the Environment Department at York suggests that these new, shellfish-dependent fisheries, may be subject to collapse with increasing stress from climate change.  The authors, in a paper appearing in Fish and Fisheries, suggest that it's imperative that we continue to work toward restoring the health of finfish based fisheries, and stress the need to marine protected areas to allow the restoration of diversity and productivity.

River monsters

A big-river specialist

OK, that was just to catch my students' eyes.  They're addicted, and we do hope to do some big fish work on the Tombigbee this summer.  What I want to talk about here though is not the size of the fish, but the size of the rivers.  A new study published in Frontiers in Ecology and the Environment looks at the prospects for saving big-river specialist fish, those guys that are dependent on big waters like the Mississippi.  The authors looked at distribution patterns of big-river specialists in the Mississippi basin, and found that moderately sized tributaries, those with 166 cubic meters per second, support 80% or more of the basin's 68 big water lovers.

This could be significant for conservation efforts.  There's little that can be done to restore natural conditions to the nation's major rivers.  Perhaps we would be better served to aim some conservation dollars toward these all-important tributaries.

FYI, that 166 cubic meter per second threshold is slightly in excess of 5,000 cubic feet per second (unfortunately, those are the default units on NOAA's hydrologic data reports, like those here).  If I've done the math right, the Tombigbee at Dempolis has a flow rate, at the moment, in the area of 8,000 cfs - that's about 225 cubic meters per second.

A new semester...

...starts tomorrow, and with it we'll try once again to be a bit more active here.  This semester brings Biology of Fish, as well as an online Evolution class - a couple of topics that should lend themselves well to blogging.  Even if it means not collapsing on the couch at the end of the day.

We'll start with this an interesting study examining the evolution of disease.  That's a topic that my evolution students will look at in depth later in the semester.  This one's in birds, house finches to be specific.

Pathogenic organisms can find themselves in a bit of a quandary.  They're dependent on their host organisms for survival, reproduction, and dispersal.  But they run the risk of overdoing it.  As they reproduce, the host may become sick.  If the numbers are too exorbitant, the host may even die.  If a pathogen reproduces in such numbers that it kills or disables its host prior to spreading to new ones, it'll soon be out of the parasite business.  However, coevolution of parasite and host can result in just the right balance of "sickness".

Virginia Tech's Dana Hawley and her coauthors, in a paper published in PLOS Biology, explore the evolution of house finch eye disease, a form of conjunctivitis in the invasive house finch caused by the Mycoplasma gallisepticum.  The researchers expected to see the disease become milder with passing time, all the better to expedite its spread.  They were surprised to see it actually become more virulent. In two different locations.

The house finch, Haemorhous mexicanus,
carrier of house finch eye disease 

What is particularly interesting in this case involves the two regions that were examined.  The study focused on birds from two different areas, California and the Eastern Seaboard.  Samples taken from sick birds in each area from 1994 through 2010 showed increasing virulence.  However, the bacterial strain the spread from east to west across the continent was less virulent.

Apparently, to spread, the bacteria needed healthier birds.  Birds that could fly a little further and live a little longer.  Once established in a location, though, more virulent strains could evolve - sicker birds may not disperse as well, but they produce lots of bacteria.

This relates to a number of other studies that have revealed some truisms about human disease.  For example, a pathogen that can be transmitted through the air or by an insect vector can afford to be more virulent than one that requires the host to be actively eating or drinking.  More to come on that.

Even more remarkable...

...also from New Scientist, this video from the Cetacean Research Institute in South Korea. It shows a group of long-beaked common dolphins (Delphinus capensis) apparently attempting to save an injured dolphin by using their bodies to keep their companion afloat. This went on for over a half hour, until the injured animal died and was allowed to sink.

Great video...

...from the New Scientist web site.

Elephant seals are known to dive to depths of over a mile, remaining submerged for more than an hour, in search of food.  We haven't been able to watch the process, at least at the depths, until this.  A teenager watching a live video feed for a camera at a depth of almost 900 meters in the North Pacific saw this elephant seal making a snack of a lamprey.

Back to work

Seems like it might be time to crank up the old starfish.  I'll be teaching evolution and vertebrate zoology this semester, along with an online offering in biogeography.  This makes for a nice way to share some ideas outside the classroom.  The main problem is overcoming inertia, which gets harder and harder with passing time.  If the posts seem a little forced, especially early on, bear with me.  We'll get there. 

As always, I'll focus here on the things I teach, and the things that fascinate interest my students and me.  That's fish, all things evolutionary, and assorted other items.  Sometimes we get distracted.



Mary Lee being tagged.

As a motivation to get going, I'll share this item on Ocearch.  It was brought to my attention by my daughter, currently residing in Jacksonville, FL.  Ocearch describe themselves as a "non-profit organization with a global reach for unprecedented research on the ocean's giants."  One of their preoccupations happens to be great white sharks, which they tag and track across the world.  One of their tagged great whites is Mary Lee, pictured at right.  Mary Lee, 16 feet long weighing almost 3500 pounds, was tagged last September off Cape Cod.  She spent the fall moving down the Atlantic Coast.  What caught my daughter's eye was the fact that, as of midnight on January 8th, Mary Lee was swimming in the surf zone off Jacksonville Beach.  She's moved a bit offshore over the last couple of days.  You can see where she is now if you follow the links on the Ocearch page, as well as follow a number of other tagged fish.  Pretty amazing stuff. 

About now, my guys should have descended on Key West, and I've probably sought refuge at Captain Tony's.  The captain's gone now, but he's not gone far.

Getting in the mood...

That time again

Approaching Thanksgiving week.  In even-numbered years, that means the Subtropical Ecology field trip is on tap.  We depart tomorrow.  Two vans, two utility trailers, 16 students, and two faculty headed for Paynes Prairie, Lake Okeechobee, Fakahatchee Strand, and points beyond.  The goal tomorrow is reach St. Marks, which was the ultimate destination of our September trip.  This time, it's a stopover on our way to Gainesville.  Friday morning at the Florida Museum of Natural History, then on to Paynes Prairie that afternoon. 

I'll be posting some updates and photos.  If all goes well, my graduate students will be posting to a blog of their own, located at Pines, Palms, and Panthers.  They're still figuring things out, so expect a few sideways images.

Wish us luck.

It's a new day...

...and I'm loading up a (mostly) new batch of students to take part in the Renew our Rivers cleanup on the Tombigbee.  The Corps of Engineers office in Demopolis (and some former students) do a great job of organizing the event.  Photos later.

More Alabama news...

You hate to keep piling on, but this is actually zoology-related.  Kind of.  The supposed sighting of a gorilla in Hale County last weekend led to a quick check with nearby zoos, who reported that all of their big apes were exactly where they should be.  So, of course, that leads to only one logical conclusion.

That's right, Bigfoot.

The most valuable item in this article is the news that the existence of Bigfoot was confirmed in 1902.  Actually, if you follow their link to this truly fascinating Bigfoot article by the Alabama Free Press (apparently some sort of paranormal-obsessed blog) , you can ascertain where this little piece of info originated.  You'll also find out that there have been 60 Bigfoot sightings in Alabama since 1980.  Given that there have been considerably fewer gorilla sightings in that period, I'd say the case is solved.

More good news!!!

Terry England is a state representative from GEORGIA.  NOT ALABAMA.  I repeat, Terry England is NOT from Alabama.


Rep. Terry England compares women to cows, pigs and chickens. from Bryan Long on Vimeo.

Caution - scientist approaching!

The students in our lab don't defend their posters.  They go on the offensive.

"So, you got a question?  Didn't think so."

By the way, the poster may not look like anything special right now, but it's coming together.  Tells an interesting story.  Should be ready for Association of Southeastern Biologists in April.  And a huge shoutout to the undergraduate researchers from Small Southern who really showed out at the symposium today.  They represented well.

A little Tuesday night music...

Alabama Shakes.  If you don't know them, get ready.  You will soon.

The first cut...

Earlier this semester, my vertebrate zoology class discussed the conodonts, the jawless vertebrates that arose in the Cambrian and own the distinction of being the first toothed vertebrates.  New research published in the Proceedings of the Royal Society B and summarized here at Nature News reveals that these first teeth were also among the sharpest.  The  extreme sharpness may have allowed the small, jawless conodonts to produce significant forces with the side to side action their teeth.  In addition, there's evidence that the animals had mechanisms allowing them to sharpen and condition their super-sharp teeth as they were worn down or broken. 
Fossil  conodont teeth were known from Cambrian rocks long before the animals that bore them were identified.  Now, it looks like these relatively little-known vertebrates were solving some evolutionary puzzles before the jawed counterparts that followed them, and in a dramatically different way.

Good news, bad news....

...on the evolution front.  According to Forbes, the percentage of young adults in the U.S. that "believe in" evolution is significantly higher than the percentage among older adults.  The bad news is that it's still only 49%.  Still, the arrows point up.

Wobbegong snacking

Remarkable photo by Daniela Ceccarelli with the ARC Centre of Excellence for Coral Reef Studies, who caught this image of a tasselled wobbegong lunching on another shark.  Here's the story at New Scientist.