Epic Tagging

Dr. Steve Wilson and Robbie Schallert tag a giant bluefin

in Port Hood, Nova Scotia

The TAG team is up in Canada where we’ve had an epic 5 days of nonstop bluefin tagging.  I’m Ethan Estess from the Monterey Bay Aquarium and Stanford University’s Tuna Research and Conservation Center, here with TAG scientists Robbie Schallert and Dr. Steve Wilson of Stanford University. We came to Port Hood, Nova Scotia on September 27th to work with Mike Stokesbury’s team from Acadia University to study giant bluefin in the Gulf of Saint Lawrence. 

TAG team Dr. Steve Wilson, Robbie Schallert (center), and Cpt. Dennis Cameron (at head irrigating the gills)

We awoke on the 28^th to flat calm seas and sunny skies. The Tag-A-Giant team headed out with Captain Dennis Cameron and Craig of the Bay Queen IV and Bernie and Steve of the Carrie Anne.  The bait had barely hit the water when we hooked up on a giant bluefin tuna.  An hour later the 270cm fish was on the tagging mat and a minute later it was back out the door, outfitted with an acoustic and pop-up archival tag (PAT).  These tags will help unlock the mysteries of bluefin migratory patterns and spawning cycles, providing critical information for their management and conservation.   To date most of these Canadian giants have been tracked to the Gulf of Mexico spawning grounds, but a few (less then 2%) make their way to the Mediterranean Sea.

A giant bluefin being reeled in by the crew of the Bay Queen IV

The bluefin were there in force to feed on the large schools of herring in the region.  We double tagged 6 fish with acoustics and pop-ups, and many of these fish were the largest I've seen.  All of Sunday’s fish were over 260cm, easily weighing 800 pounds or more.  These fish were extremely well fed and very big around!

Measuring the length of a giant bluefin

Over the next 3 days we deployed 14 more electronic tags in perfect fishing conditions.  Cape Breton is one of the most beautiful places I’ve ever been and we were surrounded by spectacular wildlife.  Hundreds of pilot whales, or “blackfish” as our captain called them, circled our boat throughout.  They were there for the same reason the bluefin were- to feed on the massive schools of herring spawning along the island.   Gannets dive-bombed and grey seals bobbed along with curious glances towards our bait.  One of the highlights of the trip was placing a tag in the largest giant bluefin TAG has ever tagged- a 313cm bluefin we tagged and released.  This behemoth barely fit on the deck of the Day Queen IV.  This fish is surely a spawner, and hopefully its PAT tag will teach us about bluefin spawning locations and behaviors in the Gulf of Mexico.


-Ethan Estess

Surrounded by hungry pilot whales with our other fishing vessel

the Carrie Anne in the background

Cape Breton sunset

Stay tuned for some great tagging news!

The Fifth HIBT Great Marlin Race Gets Under Way

The boats leave the starting line on the "Start fishing!" call

On Monday, August 5, 38 angling teams from around the world gathered just off the Kona Coast, awaiting the radio call to, “Start fishing, start fishing, start fishing!” in the 54^th annual Hawaiian International Billfish Tournament. This year’s HIBT also marked the fifth year of the Great Marlin Race, which was born there as part of their 50^th Anniversary celebrations. Now run in a unique collaboration among the HIBT tournament, Stanford University researchers and the International Game Fish Association, the IGFA Great Marlin Race (IGMR)  has grown into a program spanning the globe.

As the 2013 HIBT IGMR began, seven of the ten satellite tags had been sponsored or partially sponsored. For this year’s race, the IGMR organizers decided to pilot the use of Wildlife Computers’ new “miniPAT” pop-up satellite archival tags. Somewhat smaller than their predecessors, these tags offer more sophisticated data handling features in addition to creating less drag in the water.

Stanford University marine biologist Randy Kochevar said, “In bluefin tuna, we’ve found the miniPATs to stay attached longer, giving us more data and better tracks than we got using the older tags. We hope this will also be true with marlin.”

The first day of the tournament was full of action, with more than two dozen marlin tagged and released. One satellite tag, sponsored by the Whangaroa Sport Fishing Club #1 out of New Zealand, was deployed by Ihu Nui Captain McGrew Rice on a 200 lb. blue marlin caught by Janice Allan.

Stanford University marine biologist and IGMR Post Doc Aaron Carlisle chats with Captain Shane O'Brien of the Strong Persuader

The second satellite tag wasn’t placed until Friday, when tag sponsor Marty Firestein of the Balboa Angling Club from California tagged a 250 lb. blue marlin caught by his son Mitch on board Hooked Up.

By the end of fishing on Friday, a total of eight tags had been sponsored or partially sponsored:

Tag 1 – Whangaroa Sport Fishing Club, New Zealand (deployed)

Tag 2 – Balboa Fishing Club, California, USA (deployed)

Tag 3 – Teams – Olympia Dream Fishing Club, Japan; Kona Game Fishing Club Tayio, Japan; Hilton Grand Vacations Fishing Club Ohana, Japan; Kona Game Fish Club Kusatu, Japan

Tag 4 – Laguna Niguel Billfish Club #1, California, USA; Laguna Niguel Billfish Club #2, California, USA

Tag 5 – Mission Bay Marlin Club, California, USA

Tag 6 – Game Fishing Club of South Australia, Australia

Tag 7 – LAE Fishing Club, Papua New Guinea

Tag 8 – Pajaro Valley Gamefish Club, California USA (half-sponsorship, looking for a partner)

As has happened in the past, the remaining six tags will be deployed over the days and weeks following the tournament, as opportunities arise to tag and release marlin. Both the Mission Bay Marlin Club and the Laguna Niguel Billfish Club #1 are still fishing after the tournament, and we wish them luck in catching marlin and getting satellite tags on them!

On the Eve of the Fifth Annual HIBT Great Marlin Race

Tournament Founder and Director Peter Fithian has briefed all the teams, all of the national anthems have been sung, the taiko drummers have played, the Kona restaurants have feasted the anglers, and the Start Fishing call is just a short night sleep away. I am joined at this year's Hawaiian International Billfish Tournament by Aaron Carlisle - the new IGMR Post Doc, and a long-time member of the Block Lab. This will be Aaron'he s first marlin tournament - and it's almost impossible to believe that it will be my fifth HIBT - making it the Fifth Anniversary of the Great Marlin Race! Who knew, when Peter Fithian and Tournament Coordinator and IGFA Representative Bob Kurz called Dr. Block back in 2009, that the Great Marlin Race would even work once - let alone grow into an international research and conservation effort.

39 teams from 13 different countries attend the pre-tournament briefing

Yet here we are again - having deployed more than 100 tags, for 6,416 days of tracking, over more than 65,000 nautical miles, since we started five years ago. We have enjoyed incredible generosity from the tournament organizers with whom we've worked, as well as the anglers, captains and crews who have made it possible. As we begin our day tomorrow, we already have sponsors for 8 of the 10 tags, and we are grateful for everyone's willingness to get involved.

A local taiko drumming team wows the crowd

Aaron and I will be riding along with Mitch and Marty Firestein from the Balboa Angling Club tomorrow, on board the Humdinger. This will be a new boat for me, but I've heard nothing but good things. Here's hoping that we and all the anglers are successful in this year's event!

Tagging Moroccan Giants at the Pillars of Hercules

(Post from Tag A Giant director Dr. George Shillinger)

On the heels of the ICCAT meeting in Tenerife, I joined Dr. Pablo Cermeño (TAG/Stanford University, WWF, KAI Marine Services), and a team from the Moroccan National Institute of Fisheries Research (INRH) (Noureddine Abid), ICCAT’s Atlantic-wide Research Programme for Bluefin Tuna (GBYP) (Dr. M’Hamed Idrissi), the World Wildlife Fund’s (WWF) Mediterranean Programme (Dr. Gemma Quilez-Badia, Naima Rodríguez López), and the tuna trap "Es-Sahel" (Larache, Morocco), owned by "Société Maromadraba".  

The Morocco 2013 tuna tagging team. From left to right: Dr. Pablo Cermeño, Dr. Gemma  Quilez-Badia, Naima Rodríguez López, Dr. M'Hamed Idrissi, Dr. George Shillinger, and Noureddine Abid.

Geographical location of the El Sahel trap and other Moroccan traps along the Atlantic coast (Abid et al., ICCAT SCRS/2011/081).

Artisinal fishing boats in the harbor  at Larache.
Image: George Shillinger

Fishing boats in the harbor at Larache, Morocco.
 Image: George Shillinger

View of Larache, Morocco from the harbor.
Image: George Shillinger

Dr. Cermeño initiated this exciting collaboration for TAG during 2012, after working with ICCAT and WWF during 2011 to tag tuna caught within the Moroccan tuna traps. Société Maromadraba had reached its quota in two days and was prepared for us to commence tagging fish remaining in the Es-Sahel trap, as per the research agreement established with ICCAT and partners. The trap was now filled with over 4000 giant tuna, estimated to average over 2.25 meters and weigh over 220 kgs apiece.

 Boats, floats, nets, and anchors comprise the Es-Sahel tuna trap off Larache, Morocco.
Image: George Shillinger

Artesinal fishermen working at the Es-Sahel tuna trap off Larache, Morocco.
Image: George Shillinger

The goal of the tagging expedition was to deploy acoustic tags, mini-PATs tags, and conventional tags on this enigmatic aggregation of Atlantic bluefin tuna.  Fish tagged during the 2012 deployment by the ICCAT-GBYP and WWF at the Es-Sahel trap travelled to putative Mediterranean spawning grounds in the South Balearic Islands and off the coast of Libya, and to Atlantic habitats off the Azores and Madeira.

Tracks of nine Atlantic bluefin tagged off Larache, Morocco during 20012 by ICCAT-GBYP and WWF (Quilez-Badia et al., ICCAT SCRS/2012/143).

This year’s addition of acoustic tags to the tracking effort will potentially allow us to obtain longer-term data about movements and residency patterns within Mediterranean and Atlantic foraging habitats that are equipped with receiver arrays.  It is anticipated that a line of acoustic receivers deployed by the Ocean Tracking Network (OTN) will eventually span the Strait of Gibraltar (“Gibraltar Curtain”), between Spain and Morocco, enabling us to record the passage and seasonal movements of the tagged fish between the Atlantic and Mediterranean.

Bluefin tuna are linked to all the ancient civilization inhabiting the Mediterranean. Aristotle (384 BC – 322 BC) in his “History of Animals” described not only the species but also migration along the Mediterranean. Bluefin tuna have been a source of food for millennia; Phoenicians started fishing tuna in the Mediterranean c. 3000 year ago with a net that evolved into modern day tuna traps. Similarly Romans, Greeks and Middle age Dukes exploited this resource, and the fishing continues today.


Tuna traps use a passive net system anchored near shore to capture migratory bluefin tuna. A wall net coming from land to off-shore tries to direct the tuna to a labyrinth of nets during its spawning migration to the Mediterranean and in some areas when leaving the Med after spawning. Once the tuna reach the final chamber the fishermen bring up the tuna capturing them with the help of hand-hooks.

Schematics of ancient Mediterranean tuna traps (source unknown).

Image depicting fishermen at a Mediterranean tuna trap (origin and site unknown -- possibly Zahara, Spain). Source:http://www.zaharaenlaweb.com/es/paginas/almadrabas-de-zahara-de-los-atunes  

La pêche du thon (La pesca del tonno), acquaforte di Jean-Pierre Houël, 1782.
Source: Voyage pittoresque des Isles de Sicile, de Malte et de Lipari. Paris, 1782. 

The Atlantic Moroccan tuna trap fishery contributes on average up to 70% of Morocco’s total bluefin catch (~ 1450 metric tons), and comprises approximately 5% of the total bluefin catch within the Eastern Atlantic and Mediterranean (Abid et al., SCRS/2011/081).  The first Moroccan traps were established nearly a century ago.  Today the traps occur along the north Atlantic coast of Morocco to the Strait of Gibraltar. They are typically situated around 3 nautical miles offshore, extending to depths of around 60 m. Since the trap fishery is primarily directed at the spawning fraction of the Eastern Atlantic bluefin stock, it provides a unique opportunity for generating abundance indices to monitor stock status and inform stock assessments.  Relatively easy access to the trapped fish also provides researchers with a unique opportunity to deploy electronic tags on fish that would be otherwise inaccessible or extremely challenging to encounter through conventional (e.g. recreational sportfishing) tag deployment methodologies.

Proportion of East Atlantic and Mediterranean tuna traps catches by area and by flag. (Abid et al., ICCAT SCRS/2011/081)

the Chagos Archipelago

The mission to the Chagos Archipelago has begun...we finally arrived in the Maldives after two days of traveling...crossing 13 time zones. The Bertarelli Foundation has joined forces with TRCC/TAG/GTOPP to tag apex predators in one of the most remote and protected reef systems in the world. In 2010, the Chagos became the largest marine protected area in the world at 644,000 square kilometers. We have 65 tags (15 miniPAT and 50 acoustic) to deploy on various species...from tuna to sharks to rays. And a 10 receiver acoustic array to set-up.

This morning we will fly across the equator to meet our hosts aboard the Vava II...the 314 foot ship is docked in Gan Island on the southernmost atoll in the Maldives. From there we head due south 500 kilometers.

-Robbie Schallert

Sea Surfing “Wave Glider” to Search for Bluefin Tuna and Striped Bass off the North Carolina Coast

The Wave Glider Carey begins her latest mission

A mobile robot called a Wave Glider outfitted with acoustic receivers to detect free-swimming tagged fish was put in the ocean off the coast of Beaufort, North Carolina today. The glider was launched from the Duke ship R/V Susan Hudson outside the Beaufort Inlet by Drs. Dick Barber and Joe Bonaventura of Duke University.  The Glider is part of a collaborative experiment to test the capacity of the unmanned robot designed for biological ocean observation, to detect where animals are in relationship to ocean conditions. For this first test off the North Carolina seaboard, scientists from Stanford, Duke and Eastern Carolina University are working together to listen for tagged bluefin tuna, striped bass and sturgeon that overwinter in North Carolina waters.

Monitoring marine species is valuable not only for the data about their whereabouts but also to better understand our changing oceans and climate. These species can act as roving reporters providing knowledge of their presence or absence in relationship to ocean conditions.  Bluefins and striped bass overwinter in the coastal waters of North Carolina to feed on Menhaden an oily forage fish that is a coastal favorite of both species.

“I am really enthusiastic about the role of the Wave Glider, this new ocean robot, to help us detect where fish are” said Dr. Barbara Block a professor from Stanford University. “We’ve been tagging bluefin tuna for years, through the Tag-A-Giant program, off the Carolina coast and we’re now moving into the phase of developing techniques to long-term monitor their presence or absence along the eastern Seaboard. The glider provides an opportunity to experiment with how to do this in the rough winter conditions of the Hatteras coastline.”

The Stanford team tags a giant bluefin

The bluefin tunas Block is searching for were tagged with long-term acoustic tags in Canada this past summer and fall. Block estimates there are over 50 bluefin with tags roaming the Atlantic seas, and is hoping that the hot spot region off Carolina will attract the tagged fish into the region. She and her team have studied bluefin tuna for years determined previously this foraging hot spot is like a favorite restaurant where the tunas tend to gather from several populations roaming in the North Atlantic. By deploying the Wave Glider in this region, they hope to hear the tags’ acoustic pings, which allow them to detect and identify individual tunas.

In addition, ECU professor Roger Rulifson is leading a team on the R/V Cape Hatteras, an NSF ship managed by Duke University, which will be out tagging stripped bass acoustic tags.  “We hope that the Glider can pick up some of the new animals we’re releasing in the next few weeks and help monitor the presence of a variety of fish and sharks we’ve been tagging in the region the past few years,” said Rulifson.  Like Barbara, he is investigating how mobile receivers can aid in the teams capacity to monitor where fish are in the rough winter conditions off the Carolina coast.

Duke University Professor Dick Barber stands with the Carey glider

The glider is was deployed by two of Block’s mentors, Drs. Joe Bonaventura and  Dick Barber from Duke University, where Block got her Ph.D. in 1986. “Ocean Observation is critically important, and I am pleased to see the next steps in biological observation being tested here off North Carolina,” says Professor Dick Barber. “I was fortunate to know Frank Carey, the pioneering tuna scientists from Woods Hole Oceanographic, and a Duke Post-doc, after whom the Carey Glider was named, and he would be very pleased to know of the experimental importance of this mission- chasing Atlantic bluefin and striped bass off our coast”. 

The Wave Glider is manufactured by Liquid Robotics of Sunnyvale California. The project is funded by a Rolex award to Block, The Tag A Giant Fund, Duke University, Stanford University and Liquid Robotics.