COLLEGE STATION, Oct. 2, 2008 The Atlantic bluefin tuna is the largest and most sought-after of all tunas, weighing as much as 1,400 pounds and capable of fetching as much as $50,000 or more in Asian markets where its meat is a prized commodity, one big reason why its numbers have declined precipitously since the 1970s. New research findings reported in Science have critical implications for how bluefin tuna are managed on both sides of the Atlantic Ocean.
A team of international researchers led by Dr. Jay Rooker of Texas A&M University at Galveston adds a new chapter to this emerging story, providing critical insights into the population structure and mixing of North American and Mediterranean populations of bluefin tuna. This comes at an important time as new assessments by international scientists suggest that both western and eastern fisheries are unsustainable at their current levels.
In the current study titled, "Natal Homing and Connectivity in Atlantic Bluefin Tuna Populations," Rooker and fellow researchers examine the chemical composition of the fish's ear bone the otolith to identify individuals from different nurseries. Chemical signatures in the form of stable carbon and oxygen isotope ratios served as a "birth certificate" and were used by the researchers to determine the origin of adolescent and adult bluefin tuna (2-20 years of age or more) on spawning and foraging grounds in the Atlantic Ocean.
The study shows that trans-Atlantic movement and mixing of populations was high with over half of the juveniles collected in North American waters being of Mediterranean origin. "North American fisheries for juvenile bluefin tuna appear to be supported to a large degree by the Mediterranean population, and thus the condition of this population will directly impact recreational fisheries for bluefin tuna in U.S. waters," according to Rooker.
"Our data coupled with archival tagging data clearly show that the
|Contact: Keith Randall|
Texas A&M University