Navigation Links
Atlantic tuna return thousands of miles to birthplace to spawn

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 migratory patterns of bluefin tuna are more complex than previously assumed and information on mixing must be included in future assessments to ensure that rebuilding efforts are successful."

Despite the high level of mixing, the team also observed that over 95 percent of adult bluefin tuna returned to their place of origin in either the Gulf of Mexico or Mediterranean Sea to spawn.

"Rates of homing reported here are extremely high and comparable to Pacific salmon, which are known to return to the streams in which they were initially spawned, with very high frequency," according to co-author Barbara Block from Stanford University.

"The new otolith chemistry findings fit perfectly with previous electronic tagging and recent genetic data, which show that distinct bluefin tuna populations mix across the foraging zones of the North Atlantic but separate into distinct spawning areas. This has important implications for the assessment of the western Atlantic bluefin tuna population. To know exactly how many of this smaller population remain, we have to account for this mixing."

Commercially harvested bluefin tuna (commonly called "giants" and weighing over 300 pounds) in New England and Canada were found to be nearly entirely of Gulf of Mexico origin. Results demonstrate that Northern Canadian waters may represent critical foraging habitat of the smaller, more vulnerable population that spawns in the Gulf of Mexico.


Contact: Keith Randall
Texas A&M University

Related biology news :

1. New continent and species discovered in Atlantic study
2. To save or savor? Its decision time for Atlantic bluefin tuna
3. Isotope analysis reveals foraging area dichotomy for Atlantic leatherback turtles
4. UD nets NOAA funding for Mid-Atlantic ocean observing
5. Pacific shellfish ready to invade Atlantic
6. Signals from the Atlantic salmon highway
7. Aware, Inc. Announces Richard Moberg to Return as CFO
8. Unfavorable ocean conditions likely cause of low 2007 salmon returns along West Coast
9. A switch that controls whether cells pass point of no return
10. Thousands of starving children could be restored to health with peanut butter program
11. How mother of thousands makes plantlets
Post Your Comments:
(Date:11/12/2015)... , Nov. 11, 2015   Growing need ... analytical tools has been paving the way for ... determination of discrete analytes in clinical, agricultural, environmental, ... being predominantly used in medical applications, however, their ... sectors due to continuous emphasis on improving product ...
(Date:11/9/2015)... Nov. 9, 2015  Synaptics Inc. (NASDAQ: SYNA ... announced broader entry into the automotive market with a ... the pace of consumer electronics human interface innovation. Synaptics, ... ideal for the automotive industry and will be implemented ... Europe , Japan , ...
(Date:10/29/2015)... 29, 2015 Daon, a global leader in ... released a new version of its IdentityX Platform ... North America have already installed IdentityX v4.0 ... a FIDO UAF certified server component as ... activate FIDO features. These customers include some of the ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... , Nov. 25, 2015 /PRNewswire/ - Aeterna Zentaris Inc. ... its business and prospects remain fundamentally strong and ... (zoptarelin doxorubicin) recently received DSMB recommendation to continue ... following review of the final interim efficacy and ... Primary Endpoint in men with heavily pretreated castration- ...
(Date:11/24/2015)... Malaysia , Nov. 24, 2015  Asia-Pacific ... contract research organisation (CRO) market. The trend of ... in lower margins but higher volume share for ... capacity and scale, however, margins in the CRO ... Organisation (CRO) Market ( ), finds ...
(Date:11/24/2015)... ... 2015 , ... Copper is an essential micronutrient that all ... copper is also toxic to cells. With a $1.3 million award from the ... a systematic study of copper in the bacteria Pseudomonas aeruginosa (P. aeruginosa), a ...
(Date:11/24/2015)... , ... November 24, 2015 , ... This fall, global ... competitive events in five states to develop and pitch their BIG ideas to improve ... each state are competing for votes to win the title of SAP's Teen Innovator, ...
Breaking Biology Technology: