Tuesday, May 25, 2010

DarWIN, not DarLOSE!

I've always thought the comedic talents of both Dana Carvey and Charles Darwin were highly underrated.

Sunday, May 23, 2010

Thoughts on North Carolina's Gill Net Issues

It's been a hot topic in this state for a while that gill nets are both important to the commercial fishing industry and highly controversial.  I personally know a couple people involved in this debate, and have been following it with some interest, though I haven't had a chance to really post anything on it until now.  Which is timely, because apparently management decisions have been made

Thursday, May 20, 2010

Feeding Habits Analysis: Pizza Toppings

In my last post about the things I'm finding in shark puke, I discussed the presence of menhaden in the diet of spiny dogfish.  These fat, oil-rich fish make quite a nutritious meal, and it usually only takes a handful of them (or chunks of one of them) to fill an average dogfish stomach. 

However, there are times when the optimum meal just isn't available and you've got to go with quantity over quality.  The title of this post is a big hint as to what I'm talking about here.

Tuesday, May 18, 2010

Dogfish Where They're Really Not Supposed to Be

Earlier I posted about spiny dogfish sticking around in parts of North Carolina when the conventional wisdom says they should be heading north (and I'm still looking for more dogfish stories from the Beaufort/Morhead City area).  Well, it seems now that spiny dogfish aren't content with just being in estuaries, now they want to swim up the river itself.

Far from home.  From kfvs12.com.

According to multiple sources, a two-foot female spiny dogfish was found washed up on a boat ramp on the Ohio River in Illinois.  Though initially misidentified as a juvenile bull shark, this was quickly cleared up.  There are a few theories out there as to why this dogfish ended up in the Ohio River, including release from a home aquarium, being left as a prank (I know of an incidence of someone leaving a dead blue shark under the diving board in a public pool as a prank), fisheries discard, or being lost from a shipment headed for biology class dissections.  The fact that the spines have been removed suggests the latter, though it's likely we'll never know what caused this dogfish's extraordinary migration.

Saturday, May 15, 2010

Dogfish Diets and the Influence of Holden

I can never get enough of this picture.  Photo by Andy Murch.

As always, I have spiny dogfish and what they're eating on the brain, and the Menhaden of History post over at Southern Fried Science and Kevin Z's challenge to the marine blogosphere got me thinking about the papers that have helped form my own meager contributions to the field of shark puke analysis.  So today I'm going to try my hand at a little research blogging.

Thursday, May 13, 2010

Feeding Habits Analysis: Tasty Menhaden Morsels

This week I finally got to start diving into my dogfish stomach contents, and the results so far have been nice and gory.  The post up at Southern Fried Science about the Menhaden of History really brought home the importance of these humble oily fish in the diets of just about everything bigger than them.  As the quote from G. Brown Goode states, "their mission is unmistakably to be eaten."

If the mission of menhaden (of which the Atlantic species has the deceptively badass Latin name Brevoortia tyrannus) is to be eaten, then the mission of the spiny dogfish is unmistakably to do the eating.  Though I've only scratched the surface of my samples so far, the gut contents I've analyzed have overwhelmingly included menhaden, either whole or in pieces.  Photographic evidence of the carnage the jaws and teeth of Squalus acanthias can create can be found below the jump.

Monday, May 10, 2010

How the Oil Spill Affects Fisheries

Kevin Z over at Deep Sea News has an interview with fisheries biologist Dave Kersetter that explains how the oil spill in the Gulf may affect (and is already affecting) the area's fisheries.  This should be required reading for anyone following the subject, and be sure to read up on the excellent coverage of the spill going on over at Deep Sea News.

Saturday, May 8, 2010

Spiny Dogfish Where They're Not Supposed to Be

It's been brought to the attention of myself and others in my lab that spiny dogfish have been turning up in North Carolina waters south of Cape Hatteras in the past couple weeks.  According to the conventional wisdom they should all have been heading north to summer off of New England about a month ago.  I was fishing down at Atlantic Beach just a week or so ago and saw no spinies, but plenty of people were pulling up smooth dogfish.  However, call-ins and the fishing reports have been mentioning spiny dogfish showing up in apparently considerable numbers. 

If any intrepid readers happen to catch any spiny dogfish in the Beaufort/Morehead City/Atlantic Beach area please let me know as a comment in this post.  Photographic evidence would be appreciated, and can be sent to cbangley@gmail.com.  Just as a refresher, here's how you identify a spiny dogfish:

Image from Maryland DNR
Spiny dogfish can be easily told from other small sharks by the spines present on both dorsal fins.  Other helpful features include the lack of an anal fin and the generally dusky coloration with scattered white spots.  

Smooth dogfish will be much lighter colored, have an anal fin, and lack dorsal fin spines.  Sharpnose sharks can be very similarly-colored, but again will have an anal fin and lack dorsal spines.  These are really the only species in the area that might get visually confused with spiny dogfish.

It'll be another couple days before I can get back down there and try to catch any dogfish for myself, so any sightings would be appreciated.

Sunday, May 2, 2010

I Live!

Yeah, it's been a while.  I've finally dug my way out from under the end of the semester mess and after exams tomorrow I'll be a free man for the summer (at least until I start teaching).  As I take a break from studying to remind you that I still exist, here are some of the things I've been remiss in writing about: