Featured Research

from universities, journals, and other organizations

Comprehensive view of the status of Atlantic bluefin tuna

Date:
December 9, 2011
Source:
Tag-A-Giant Foundation (The Ocean Foundation)
Summary:
Bluefin populations on both sides of the Atlantic Ocean have declined precipitously since 1950, according to a new study. The model estimates the number of Atlantic bluefin tuna remaining in the ocean and projects future population sizes based on alternative management scenarios. The new model is revolutionary in its ability to account for population overlap (mixing) of this highly migratory animal on the North Atlantic foraging grounds.

A new model built around biological data from electronic tags, ear bone microchemistry and fisheries catch data for Atlantic bluefin tuna indicates fishing on one side of the Atlantic influences the other side. Bluefin populations on both sides of the Atlantic Ocean have declined precipitously since 1950, according to a study recently published in the peer‐reviewed online journal PLoS ONE.

Related Articles


The model estimates the number of Atlantic bluefin tuna remaining in the ocean and projects future population sizes based on alternative management scenarios. The new model is revolutionary in its ability to account for population overlap (mixing) of this highly migratory animal on the North Atlantic foraging grounds.

Two or more Atlantic bluefin populations are currently recognized by ICCAT, the international commission charged with conserving highly migratory fishes like bluefin in the Atlantic. A western population spawns in the Gulf of Mexico and is primarily fished by North Americans, and an eastern population spawns in the Mediterranean Sea and is fished by European and North African fishers, along with high seas longliners from multiple nations. The PLoS ONE study indicates that since 1950 adult bluefin tuna numbers have declined by as much as 83% in the Gulf of Mexico spawned western Atlantic population, and 67% in the Mediterranean spawned eastern Atlantic population.

This innovative model incorporates new biological data such as the extensive migrations recorded on electronic tags and the information on natal origin lodged like a birth certificate in the minerals of ear bones, in order to account for the intricate movements on a seasonal scale. Bluefin can live up to 35 years of age, and reach 1500 lbs in size. Tag tracking data indicate that individual bluefin can rapidly move between western and eastern management regions but then separate and return to distinct spawning areas. The Mediterranean population was modeled with a significantly lower age to first reproduction or maturity than the Gulf of Mexico population, increasing the resilience of the former population. The combination of biological and mathematical inputs has shown a significant subsidy exists when the larger Mediterranean population moves into western waters to feed.

"Current population models assume that a fish caught in the West Atlantic was born in the west, and a fish caught in the east was born in the east," said senior author Dr. Murdoch McAllister of the University of British Columbia. "We now know that upwards of 50% of bluefin caught in some western fisheries were spawned in the Mediterranean, and incorrect assignment of these fish biases assessments and may compromise recovery efforts of this valuable species." High levels of fishing in the Mediterranean Sea, including pirate fishing, resulted in the highest fishing mortality on record for the species between 1998 and 2007. Importantly, the model shows that this egregious overfishing in the East depleted not just the eastern population but the western one as well. The eastern catch of bluefin tuna has been cut by approximately half since 2007 so this trend may reverse in the coming years.

The model estimates that eastern bluefin tuna can recover relatively quickly with perfect adherence to current regulations. However, significant illegal overfishing continues to be documented and threatens the recovery of fish in both the eastern and western Atlantic. Recovery of the depleted western Atlantic bluefin tuna population will take more than 15 years under current fishery regulations.

"This model presents a challenge to the global community responsible for the management of Atlantic bluefin tuna, both from a regulatory and scientific perspective," said senior author Dr. Barbara Block of Stanford University. "If regulations are not enforced, population recovery will stall. If we don't account for population overlap in assessments, the estimates upon which we base management will be flawed."

Funding for this study was provided by the Lenfest Ocean Program, Tag‐A‐Giant Foundation, the Canadian Fisheries and Oceans International Governance Strategies Fund, the Monterey Bay Aquarium Foundation, and the National Oceanographic and Atmospheric Administration.


Story Source:

The above story is based on materials provided by Tag-A-Giant Foundation (The Ocean Foundation). Note: Materials may be edited for content and length.


Journal Reference:

  1. Nathan G. Taylor, Murdoch K. McAllister, Gareth L. Lawson, Tom Carruthers, Barbara A. Block. Atlantic Bluefin Tuna: A Novel Multistock Spatial Model for Assessing Population Biomass. PLoS ONE, 2011; 6 (12): e27693 DOI: 10.1371/journal.pone.0027693

Cite This Page:

Tag-A-Giant Foundation (The Ocean Foundation). "Comprehensive view of the status of Atlantic bluefin tuna." ScienceDaily. ScienceDaily, 9 December 2011. <www.sciencedaily.com/releases/2011/12/111209171946.htm>.
Tag-A-Giant Foundation (The Ocean Foundation). (2011, December 9). Comprehensive view of the status of Atlantic bluefin tuna. ScienceDaily. Retrieved December 21, 2014 from www.sciencedaily.com/releases/2011/12/111209171946.htm
Tag-A-Giant Foundation (The Ocean Foundation). "Comprehensive view of the status of Atlantic bluefin tuna." ScienceDaily. www.sciencedaily.com/releases/2011/12/111209171946.htm (accessed December 21, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Sunday, December 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Reuters - Light News Video Online (Dec. 19, 2014) Millions of monarch butterflies begin to descend onto Mexico as part of their annual migration south. Rough Cut (no reporter narration) Video provided by Reuters
Powered by NewsLook.com
The Best Protein-Filled Foods to Energize You for the New Year

The Best Protein-Filled Foods to Energize You for the New Year

Buzz60 (Dec. 19, 2014) The new year is coming and nothing will energize you more for 2015 than protein-filled foods. Fitness and nutrition expert John Basedow (@JohnBasedow) gives his favorite high protein foods that will help you build muscle, lose fat and have endless energy. Video provided by Buzz60
Powered by NewsLook.com
Birds Might Be Better Meteorologists Than Us

Birds Might Be Better Meteorologists Than Us

Newsy (Dec. 19, 2014) A new study suggests a certain type of bird was able to sense a tornado outbreak that moved through the U.S. a day before it hit. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins