Featured Research

from universities, journals, and other organizations

Spawning habitat of bluefin tuna in Gulf of Mexico: Critical area intersects Deepwater Horizon oil spill

Date:
May 31, 2010
Source:
Stanford University - Hopkins Marine Station
Summary:
Electronic tagging and fisheries catch data have revealed pronounced differences in preferred habitat of Atlantic bluefin tuna and yellowfin tuna in the Gulf of Mexico, despite their close ancestry, according to a new study. Bluefin tuna return to the same regions of the Gulf of Mexico during spring months to spawn. Yellowfin tuna are more widely distributed throughout the warm Gulf waters and occupy the region throughout the year.

This shows the track (yellow line) and daily positions (dots) of a giant bluefin tuna electronically tagged off Canada on October 25, 2008 -- which spent the period from March 23-May 24, 2009, in the Gulf of Mexico. The track is overlaid on the area of the Deepwater Horizon oil spill as of May 24, 2010 (black). Peak spawning of bluefin tuna occurs in this area during April and May.
Credit: Tag-A-Giant Foundation and Stanford University

Electronic tagging and fisheries catch data have revealed pronounced differences in preferred habitat of Atlantic bluefin tuna and yellowfin tuna in the Gulf of Mexico, despite their close ancestry, according to a new study published today in the peer-reviewed journal PLoS ONE. Bluefin tuna return to the same regions of the Gulf of Mexico during spring months to spawn. The bluefin are selecting a particular habitat along the slope waters of the Gulf of Mexico, which has unique oceanographic properties that are predictable and can be seen from satellites. Yellowfin tuna are more widely distributed throughout the warm Gulf waters and occupy the region throughout the year.

Related Articles


"The bluefins' habitat requirements are relatively exact so we can predict with reasonable accuracy where bluefin tuna are likely to be spawning at any given time based on oceanographic data continually being gathered by satellites and weather buoys," said lead author Steven Teo of the University of California at Davis. "This is in stark contrast to yellowfin tuna, which exhibit much more generalized environmental preferences." The fidelity to breeding areas over time detected in this study is reminiscent of salmon returning to their natal stream to spawn.

Bluefin tuna are among the most valuable fish in global markets. The International Commission for the Conservation of Atlantic Tunas (ICCAT, http://www.iccat.int) currently manages the Atlantic bluefin tuna as two distinct populations, with western Atlantic spawners of the Gulf of Mexico forming a distinct population genetically from the eastern spawners of the Mediterranean Sea. The western Atlantic stock has suffered a significant decline in spawning stock biomass since 1950, and a 20-year rebuilding plan has failed to revive the population or the North American fishery. The failure of the Gulf of Mexico spawning population to rebuild, as well as the scope of illegal and under-reported catches -- particularly in the Mediterranean Sea -- are of such major concern that the species was recently considered by the United Nations for endangered species listing in March of 2010.

Targeted bluefin fishing has been banned in the Gulf for over twenty years, but bluefin continue to be captured accidentally on pelagic longlines, often resulting in mortality. The study shows that bluefin tuna are captured in the Gulf of Mexico from January through June each year, and the highest pelagic longline catch rates are in April and May, during the bluefin spawning season.

The authors compared environmental preferences and spatio-temporal distributions of bluefin and yellowfin tuna as revealed by pelagic longline catch rates and scientific tagging cruise conducted by the Stanford University and Monterey Bay Aquarium team coupled with oceanographic data sets. Drawing on these data, a model was developed to determine the relative probability of catching bluefin and yellowfin tuna at a given place and time. This model showed that there are two major hotspot regions within the Gulf where bycatch occurs -- one in the eastern Gulf of Mexico to the north of the Loop Current, and the other in the western Gulf of Mexico. Both regions are along the slope where the shallow continental shelf depth changes rapidly to the deep sea. It is within these hotspots that bluefin tuna prefer to spawn in circular, swirling water masses called "cyclonic eddies." These eddies are more productive and slightly cooler than surrounding warm Gulf ocean currents. Yellowfin tuna, however, are much more widely dispersed throughout the Gulf of Mexico throughout the year.

These findings indicate that it would be possible to utilize spatial management techniques to protect western Atlantic bluefin tuna on their breeding grounds in the Gulf of Mexico without compromising the yellowfin tuna fishery, which could be carried out in other areas during the critical bluefin tuna breeding times.

Unfortunately, these findings also give cause for concern in light of the recent Deepwater Horizon oil spill. "Both catch data and electronic tags indicate the Gulf of Mexico along the continental shelf is the preferred habitat of this majestic fish. I think it is amazing how precisely we can predict where the bluefin are. Unfortunately their spawning habitat overlaps the Deepwater Horizon oil accident site, and the timing of the spill coincides with the time when we expect them to be there spawning" said senior author Dr. Barbara Block of Stanford University.

Funding for this study was provided by the Lenfest Ocean Program, the Tag-A-Giant Foundation, the David and Lucile Packard Foundation, the Monterey Bay Aquarium Foundation, the National Oceanographic and Atmospheric Administration and the Disney Foundation.

For more information, visit www.tagagiant.org.


Story Source:

The above story is based on materials provided by Stanford University - Hopkins Marine Station. Note: Materials may be edited for content and length.


Journal Reference:

  1. Steven L. H. Teo, Barbara A. Block, Sharyn Jane Goldstien. Comparative Influence of Ocean Conditions on Yellowfin and Atlantic Bluefin Tuna Catch from Longlines in the Gulf of Mexico. PLoS ONE, 2010; 5 (5): e10756 DOI: 10.1371/journal.pone.0010756

Cite This Page:

Stanford University - Hopkins Marine Station. "Spawning habitat of bluefin tuna in Gulf of Mexico: Critical area intersects Deepwater Horizon oil spill." ScienceDaily. ScienceDaily, 31 May 2010. <www.sciencedaily.com/releases/2010/05/100528210726.htm>.
Stanford University - Hopkins Marine Station. (2010, May 31). Spawning habitat of bluefin tuna in Gulf of Mexico: Critical area intersects Deepwater Horizon oil spill. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2010/05/100528210726.htm
Stanford University - Hopkins Marine Station. "Spawning habitat of bluefin tuna in Gulf of Mexico: Critical area intersects Deepwater Horizon oil spill." ScienceDaily. www.sciencedaily.com/releases/2010/05/100528210726.htm (accessed October 25, 2014).

Share This



More Earth & Climate News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

EU Gets Climate Deal, UK PM Gets Knock

EU Gets Climate Deal, UK PM Gets Knock

Reuters - Business Video Online (Oct. 24, 2014) EU leaders achieve a show of unity by striking a compromise deal on carbon emissions. But David Cameron's bid to push back EU budget contributions gets a slap in the face as the European Commission demands an extra 2bn euros. David Pollard reports. Video provided by Reuters
Powered by NewsLook.com
Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Raw: Tornado Rips Roofs in Washington State

Raw: Tornado Rips Roofs in Washington State

AP (Oct. 24, 2014) A rare tornado ripped roofs off buildings, uprooted trees and shattered windows Thursday afternoon in the southwest Washington city of Longview, but there were no reports of injuries. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Fast-Moving Lava Headed For Town On Hawaii's Big Island

Fast-Moving Lava Headed For Town On Hawaii's Big Island

Newsy (Oct. 24, 2014) Lava from the Kilauea volcano on Hawaii's Big Island has accelerated as it travels toward a town called Pahoa. 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