And...

...the return of night music.  I find myself desperately in need of something a little upbeat.

Gulf whale shark

Remarkable video from the Mobile Press-Register's Ben Raines.  Large whale shark about six miles off Alabama's Orange Beach.

Swimming with a whale shark off the Alabama coast

Unfortunately, these magnificent fish have been observed recently swimming and feeding in heavy oil.  They're unlikely to survive.

Worth knowing

Is BP attempting to buy up Gulf of Mexico marine scientists?  Appears so.

Pallid sturgeon

Here, Fisheries and Wildife officials from Montana discuss conservation efforts designed to increase stocks of the pallid sturgeon, Scaphrhynchus albus.  The pallid is one of some two dozen sturgeon species, most of which face a very uncertain future.  Pallids, natives of the Missouri and Mississippi River drainage systems, are similar to, albeit considerably larger than, the more common shovelnose sturgeon (Scaphirhynchus platorhynchus).  That, in itself, is proving to be a bit of a problem for the big fish.



Researchers at Tennessee Tech University in Cookeville have determined that the similarity of the pallid to the shovelnose may be helping push it toward extinction.  There is a thriving fishery for shovelnose sturgeon in Tennessee, where females are harvested for their eggs which are marketed for caviar.  The pallid sturgeon, which no longer reproduces in nature as a result of habitat alteration, is apparently also suffering from overexploitation through mistaken identity.  The researchers, in their observation of the shovelnose fishery, observed accidental by-catch of pallids.  Young individuals are virtually indistinguishable from the shovelnose, with the pale coloration typical of pallids showing up only in older fish.  Furthermore, pallids are occasionally killed in lost "ghost" nets left behind by shovelnose fishermen.

The USFWS has been asked to invoke the "Similarity of Appearance" provision allowed under the Endangered Species Act, which would shut down the shovelnose sturgeon fishery in Tennessee.  A decision is expected in September.

Sex ratios in reef fish

A new paper appearing in American Naturalist examines the impact of overfishing on reef fish populations, and comes to some interesting and, perhaps, unexpected conclusions.  Australian biologist Stefan Walker and his colleagues observed that, as population sizes declined, many reef fish were producing fewer young per individual.  This in spite of the fact that lower population sizes should mean more available resources.  To get at the cause of this phenomenon, the researchers tagged and followed over 200 cylindrical sandperches (Parapercis cylindrica) on the Great Barrier Reef.  These fish are sequential hermaphrodites, born female with some later changing to males.  Walker and team found that the frequency of sex changes was inversely related to fish density, resulting in a higher percentage of males, and therefore lower egg production, in more heavily impacted populations.  The researchers go on to tout their findings as further evidence that marine protected areas, which do a better job of densities, are a more effective way to conserving populations than fishing quotas.

That which does not kill us

It's been a long, tough, summer.  Seems they always are.  But it's almost over, and it's been life-changing.  Again, seems they always are.  A few more scars, a little more recognition of mortality.  I'm  promising myself that this will be the last one like this - seems I always I do that.

But, it's time to establish the old routine.  Watch this space.

They're here....

Wrote several months ago about the steadily increasing number of sightings of alligators as they continue to spread into their former range.  My field methods class was doing fish community work in a local stream yesterday, and came across this...

That's an alligator track, and not a small one.  The hind foot measures about 11.5" to the tip of the longest digit.  With a little regression and some literature work, we're estimating a total length of 9-10 feet.  The stream is not a big one, some thirty feet across, averaging 1-3 feet in depth.  But there are some deep holes, and it supports (supported?) good populations of gar and bowfin.  Lots of beaver and raccoon in the area as well.  A crocodilian could do worse.

I've been working this stream for 18 years, and this is the first gator sign I've seen.  It won't be the last.  Alligators, in my view, pose of much more significant threat than do sharks, and statistics seem to bear that out.  Let's be careful out there, guys.