American Museum of Natural History

Wildlife Forensic SeminarFebruary 2011

Steve Oszust

…but you can’t tuna fish.Steven Oszust

When you think of tuna, what comes to mind?

When you think of tuna, what comes to mind?

What is tuna?What kind do we eat? How have humans affected tuna populations? What policy changes should we make?

There are over 48 different tuna species.The Thunnus genus includes 9 species:Albacore, Thunnus alalunga Yellowfin tuna, Thunnus albacares Blackfin tuna, Thunnus atlanticus Southern bluefin tuna, Thunnus maccoyii Bigeye tuna, Thunnus obesus Pacific bluefin tuna, Thunnus orientalis Northern bluefin tuna, Thunnus thynnus Longtail tuna, Thunnus tonggol Karasick tuna, Thunnus karasicus

Maximum sizes of Thunnus tuna species (centimeters).

The most important of these for commercial and recreational fisheries are:• yellowfin (Thunnus albacares)• bigeye (T. obesus)• bluefin (T. thynnus, T. orientalis, and T. macoyii)• albacore (T. alalunga)•skipjack (Katsuwonus pelamis)

In 2007, 4 million metric tons of tuna were harvested from the world’s oceans. Specifically, (FAO data) lists:

69% from the Pacific21.7% from the Indian Ocean9.5% from the Atlantic and Mediterranean Sea

Bluefin Tuna in the Atlantic

Purse seines are large nets that can measure over 2 km long and 200 meters deep.

Longline gear involves the use of a main line of up to 150 km in length from which as many as 3,000 shorter branch lines.

Fishing Aggregating Devices, better known as FADs, are floating objects put intentionally in the ocean to attract marine life.

Regulatory Policies:Fishing methods to reduce “bycatch” Quotas-

2006 ICCAT reduced the Bluefin tuna quota in the Mediterranean Sea from 32,000 metric tons in 2006 to 25,500 metric tons in 2010.  

2008 ICCAT set the annual quota at 22,000 metric tons, gradually reducing it to 18,500 tons by 2011.  

2009 ICCAT agreed to shorten the fishing period to one month and reduce the quotas to 13,500 metric tons annually.  

Wildlife ForensicsDNA sequencing of known tuna speciesCreation of a barcode for mtDNA for

diagnostic purposesMonitoring of tuna products and cross-

referencing against established barcodes

UNKNOWLINGLY CONSUMING ENDANGERED TUNA

A GENETIC TOOL UNCOVERS THE SPECIES OF TUNA PLATED IN SUSHI RESTAURANTSWhile most of us would never willingly consume a highly endangered species, doing so might be as easy as plucking sushi from a bento box. New genetic detective work from the Sackler Institute for Comparative Genomics at the American Museum of Natural History shows that bluefin tuna is routinely plated in sushi bars sampled in New York and Colorado. A quarter of what was labeled as tuna on sushi menus was bluefin, and some was even escolar, a waxy, buttery fish often labeled "white tuna" that is banned for sale in Japan and Italy because it can cause gastrointestinal distress. The new research is published in PLoS ONE.

Sergios-Orestis Kolokotronis, the coordinator of the DNA Barcoding Initiative for Conservation at the Museum