Wednesday, May 29, 2013

Tagging Moroccan Giants at the Pillars of Hercules

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).

Artisanal 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:  
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)

Wednesday, May 22, 2013

TAG at the ICCAT SCRS Intersessional Meeting in Tenerife, Canary Islands, Spain

Last week I joined the United States Delegation and a group of international researchers, including TAG Researcher, Dr. Andre Boustany, and former TAG Director, Shana Miller, at an intersessional meeting for the International Committee for the Conservation of Atlantic Tuna’s (ICCAT), Standing Committee on Research and Statistics (SCRS).  The focus of the meeting was to review and discuss bluefin tuna biological parameters for stock assessment purposes. The meeting was held from May 7-13, 2013 at the Oceanographic Center of the Spanish Institute of Oceanography in Canary Islands. 

Participants from the ICCAT Standing Committee on Research and Statistics (SCRS) at the 2013 intersessional meeting on Bluefin Tuna Biological Parameters in Tenerife, Canary Islands, Spain.  
Among other objectives, we were tasked with assessing biological information available for the 2015 Atlantic bluefin assessment, reviewing basic biological assumptions and relationships, evaluating the reliability of existing and historical information about bluefin biology and fisheries, and discussing opportunities for incorporating relevant data into ICCAT databases.  We were divided into thematic working groups to discuss bluefin size conversions (e.g. length to weight, curved fork-length to fork-length), age conversions (e.g. growth curve, aging), reproduction (e.g. sex ratio, maturity, fecundity and spawning), natural mortality, and population structure and stock mixing (e.g. genetics, tagging, stock-age key tables).

TAG team and alumni at Volcan El Teide (3718 m) in Tenerife, Canary Islands, Spain.  From left to right: TAG Scientist Dr. Andre Boustany, former TAG Director Shana Miller, and TAG Director Dr. George Shillinger 
The first two days of the meeting involved a series of thematic presentations and discussions intended to provide an update about existing knowledge regarding Atlantic bluefin biological and fisheries research.    The remainder of the meeting was devoted to working group breakout sessions and plenary discussions, during which working groups drafted and presented content for inclusion within a report that will be presented at the ICCAT Bluefin Stock Assessment Methods meeting in Boston during July 2013.  The results from the meeting will also be used to inform the SCRS position at the meeting of the “Working Group of Fisheries Managers and Scientists in support of the Western Bluefin Tuna Stock Assessment” to be held in Montreal, Canada, June 26 to 28, 2013.

Friday, May 3, 2013

TAG North Carolina 2013 – It’s a wrap!

Tag-A-Giant North Carolina 2013 – It’s a wrap!

TAG wrapped up another season in North Carolina on April 3, 2013.  Despite some challenging weather and scrappy fishing conditions, we managed to squeeze in six fishing days on the Sensation, during which we tagged five bluefin tuna (3 fish double-tagged with acoustic and archival tags, one fish double-tagged with a PAT and archival tag, and 1 fish tagged with an acoustic tag). We caught one particularly large tuna (234 cm CFL ~ 550 lbs) but the other fish were all in the 200-250 lb range.

As always, TAG North Carolina delivered on excitement, camaraderie, and adventure --- with some good fishing in the mix too.  I’ve shared a few of these memories below.

Herbert C. Bonner Bridge

A classic North Carolina fishing day out of Oregon Inlet starts early --- with views of dawn bursting over Pamlico Sound.  We punch through the spans of the Herbert C. Bonner Bridge (2.7-mile bridge built in 1963) point towards the Gulf Stream, threading the shoals as we go.

Departing Oregon Inlet through the Herbert C. Bonner Bridge at dawn.
TAG welcomed a team of three ‘Wills’ (Will Graham, Will Herring, and Will Thames) on behalf of the 2012 Reelin’ for Research Tournament winners (lead by Matt Logan).  TAG is proud to sponsor the Reelin’ for Research Tournament through the donation of a Research Charter for tournament winners. The 5th Annual Reelin’ for Research Tournament begins Saturday, May 4th, 2013, with the goal of “fighting” to “land” a cure for the kids!  This year the tournament hopes to raise $500,000!  To learn more about Reelin for Research, please visit:   

The three ‘Wills’ – Will Thames (left), Will Graham (center), and Will Herring (right) join the TAG team on a special TAG Research Charter donated to the Reelin’ for Research Tournament.

Windy weather and sloppy seas were frequent during the 2013 TAG North Carolina deployment
Although we didn't catch any tuna with the Reelin’ for Research team, we enjoyed some excellent wildlife viewing, including pilot whales and breaching humpback whales!

Humpback whale breaching in the Gulf Stream off the Outer Banks, North Carolina.

Humpback whale breaching in the Gulf Stream off the Outer Banks, North Carolina.
On March 31, we were joined by a team from Durham, North Carolina -- Jen Poole, Samir Arora, and Ted O'Hanlan.  Also onboard were three recently rehabilitated turtles (one loggerhead, and two juvenile Kemps Ridleys) , whom we released into the warm waters of the Gulf Stream on behalf of the North Carolina Aquarium on Roanoke Island (NCARI)
TAG Director, Dr. George Shillinger, prepares to release a rehabilitated juvenile Kemp’s Ridley turtle into the Gulf Stream
Alan ‘Big Country’ Scibal and Dr. George Shillinger release a rehabilitated loggerhead turtle into the Gulf Stream.
 During three of our six fishing days, we caught, tagged, and released bluefin tuna.

TAG researchers, Dr. Andre Boustany (left) and Dr. George Shillinger (right) deploy both an archival and acoustic tag on a North Carolina bluefin.
TAG researchers, Dr. Andre Boustany (inserting tag) and Dr. George Shillinger (irrigating fish) tag a North Carolina bluefin
We were joined by several other friends of TAG, including Richard Montana (co-founder of the Reelin’ for Research Tournament), and TAG supporter, John Pazienza, who travelled from Florida to join for two days on the water.

 Alan ‘Big Country’ Scibal waits while Richard Montana fights a bluefin on the Sensation.

Dr. Andre Boustany assesses a tuna while Dr. Shillinger prepares a tag for deployment.

Captain Charles Perry (‘CP’) stands ready as anglers John Pazienza and Alan Sciabal fight a bluefin double-header on the Sensation.

‘Big Country’ takes a wrap as angler John Pazienza fights from the chair and Dr. George Shillinger (with liphook) and Dr. Andre Boustany prepare to deck and tag the fish.

TAG Director, Dr. George Shillinger and TAG scientist Dr. Andre Boustany measure a bluefin. 
In addition to the humpback whale show, we had a close encounter with a big basking shark.

‘Big Country’ watches as a big basking shark swims past the Sensation.
As anglers and scientists, we know that successful fishing is never guaranteed – anytime we travel anywhere to tag fish.  However, one thing is certain for sure with TAG North Carolina – great camaraderie and an awesome opportunity to partake in a globally important research initiative!

From left to right, First Mate Alan ‘Big Country’ Scibal, Captain Dale Britt, TAG Director, Dr. George Shillinger, and TAG Scientist, Dr. Andre Boustany gather for a family-style seafood pasta dinner.

The TAG 2013 North Carolina Team at Oregon Inlet -- From left to right, First Mate Alan ‘Big Country’ Scibal, TAG Director, Dr. George Shillinger, TAG Scientist, Dr. Andre Boustany , Captain Charles (‘CP’) Perry, and Captain Dale Britt, stand in front of the FV Sensation.
We owe a special debt of gratitude to all whom have contributed their time, energy, and passion to furthering the research mission and vision of Tag-A-Giant.  We appreciate your support and look forward to TAG North Carolina 2014!