Sunday, March 20, 2011

Big Country Comes to Town

(This is a cross-posting from our Tag A Giant blog, courtesy of TAG Scientist Robbie Schallert)

The TAG team was back on the water Friday in search of more bluefin. After a long run past The Point in some sporty seas, Captain Dale put us on the fish fact we had a tuna hit the flat line as it was being let out! Anglers Daragh Brown and Erin Wright, having been trained by living legend Peter Wright, brought the fish in with ease. Once to the back of the boat, Alan "Big Country" Scibal took charge of the leader and wired the fish to the transom door. Dr. Dre surgically implanted the tags, and with a couple of quick stiches, the fish were ready to head out the door to show the school their new hardwear. By the end of the day, we had 4 fish tagged, all in the 220-260 pound size range. It was a long ride home as we battled a head sea the whole way but no one seemed to mind after a great day on the water. You can see some of the action below...


Thursday, March 17, 2011

Luck of the Irish

Our Tag-A-Giant team is currently off the coast of North Carolina tagging bluefin tuna.  I'm going to be cross-posting their blog entries here, or you can follow them directly at the Tag-A-Giant blog.  This first one is courtesy of TAG Scientist Robbie Schallert.  Go TAG Team!

TAG-A-Giant 2011 got underway with four bluefin tagged on a gorgeous North Carolina day. The Sensation, captained by Dale Britt and Mate Alan Scibal, hooked a double header to kick off St. Patty's Day with Irish scientist Daragh Browne in the chair. Duke grad student Caitlin Hammer fought the next two fish under guest captain Peter B. Wright's tutelage. The ocean was filled with life on the other side of the Gulf Stream with schools of hammerhead sharks, mantas and tuna exciting the crew. There were literally hundreds of tuna surfing down swell...a site to behold! It is great to get the season started...hopefully the weather will hold through the weekend!

Wednesday, March 9, 2011

White Shark Team Take Census of Northern California Population

The white shark research team has published two papers in the past few days, documenting the ability to recognize individual sharks year after year by the distinctive shapes and markings on their dorsal fins; and then using this information to estimate the total size of the white shark population in this region.

The first study, which was published March 1 in the journal Marine Biology (Anderson et. al., 2011) shows that it is possible to positively identify the same shark year after year - even over time periods as long as 15-22 years!

Figures a and b show the fin of a single shark in 2007 and 2008;
Figure c shows a different shark in 2008 - illustrating how
distinctive the fin edge shape can be.

  The second study, published today in the journal Biology Letters (Chapple et. al., 2011), uses fin photographs like those above to calculate the total size of the white shark population that returns to northern California each year - and the estimate was just 219 individuals.

Because this marks the first census of this population, we have no way of knowing whether this number is typical, or if it is unusually low (or even unusually high).  What it provides, however, is a baseline that can be used in the years ahead to monitor changes in the adult white shark population - which will be a key step in managing and, if needed, protecting these animals in the wild.

As one might expect, we've had a lot of media interest in the story.  You can check out the latest news coverage at the GTOPP website.

Monday, March 7, 2011

GTOPP data to be integrated into Ocean Observing System

Back in the early days of TOPP, one of our goals was to see if it might be possible to one day use the data we get from tagged animals to help us understand the ocean itself. This concept, which we dubbed "Animals as Ocean Sensors," came a giant step closer to reality last week, with the birth of a new partnership between GTOPP and the national Integrated Ocean Observing System (IOOS).

The concept behind the partnership is simple: electronic tags often carry a variety of environmental sensors to detect light, temperature, pressure and sometimes even salinity or other ocean chemistry. When we attach these tags to an animal - especially one like an elephant seal that dives continuously throughout its journeys - it provides an exceptionally rich dataset, profiling regions of the ocean that would be expensive and logistically difficult to access by human oceanographers.

In a series of meetings held March 2-3, 2011 at the NOAA Fisheries Service lab in Santa Cruz, California, biologging scientists worked directly with the IOOS team to discuss how best to begin the process of integrating animal tagging data into the Ocean Observing System. On Friday, March 4, we were joined here at the Hopkins Marine Station by the IOOS Director Zdenka Willis, to share the results of the meeting with the media and the public. You can see highlights of these discussions at the links below:

Monterey County Herald:  Agencies Join Forces to Track Marine Animals in Monterey Bay