Blue marlin blues: Loss of dissolved oxygen in oceans squeezes billfish habitat

December 15, 2011

The science behind counting fish in the ocean to measure their abundance has never been simple. A new scientific paper in Nature Climate Change shows that expanding 'ocean dead zones' (areas of low oxygen) driven in part by climate change makes that science even more complex.

Blue marlin, other billfish and tropical tuna are high energy fish that need large amounts of dissolved oxygen. Scientists from the disciplines of oceanography and fisheries biology are sounding an alarm that the expansion of dead zones is shrinking the useable habitat for these highly valuable pelagic fish in the tropical northeast Atlantic Ocean. And as dead zones shrink habitat by depriving fish of areas with enough dissolved oxygen for them to thrive, they squeeze these species into surface waters where they are more vulnerable to fishing.

"The shrinking of habitat due to expanding hypoxic zones needs to be taken into account in scientific stock assessments and management decisions for tropical pelagic billfish and tuna," said Dr. Eric Prince, fisheries scientist and principal investigator representing NOAA's Southeast Fisheries Science Center on the project. "Without taking it into account, stock assessments could be providing false signals that stocks are healthy, when in fact they are not, thus allowing overfishing that further depletes these fish stocks and threatens the sustainability of these fisheries."

The data on blue marlin, one of the most valuable and storied fish on the planet, were collected using pop up satellite tracking devices. These devices recorded the horizontal and vertical movement of these fish. The information on fish movement was then compared to detailed oceanographic maps of the same ocean areas showing the location of low-dissolved oxygen zones. By comparing the movement of the blue marlins and the location of low-oxygen areas, the study shows that blue marlin ventured deeper when dissolved oxygen levels are higher and remain in shallower surface waters when low dissolved oxygen areas encroach on their habitat from below, squeezing them into surface waters.

"We found that the blue marlin's habitat is being compressed, while the threats from human activity are increasing. In human terms, you might describe it as if you were in a house on fire with all of the doors and windows were locked, leaving only one exit, then discovering you have a robber inside the house at the same time," said Dr. Jiangang Luo, scientist at the University of Miami's Rosenstiel School of Marine & Atmospheric Science, who processed and analyzed the popup satellite tagging data for the research team.

"Working closely with oceanographers, we are getting a much clearer picture of how climate-driven dead zones are shrinking the habitat for some of the world's most valuable fish. The alarming picture painted by this study will hopefully inform our management decisions, improving the long-term health of blue marlin and other billfish and tropical tuna fisheries in the central Atlantic," said Luo.

The oceanographic data were collected and analyzed by co-author Lothar Stramma and colleagues at the Leibniz Institute of Marine Science in Kiel, Germany.

While the new paper focuses on the tropical northeast Atlantic Ocean in the waters off West Africa, the expansion of low-oxygen zones is occurring in all tropical ocean basins and throughout the subarctic Pacific, making the compression of habitat a global issue. The problem for pelagic fishes in the tropical Atlantic is particularly acute, the authors note, because many of these fish species and the unintended catch, called bycatch, are already fully exploited or overfished.

University of Miami Rosenstiel School of Marine & Atmospheric Science

---

---

	The Blue Road to Atlantis by JAY NUSSBAUM (Author) In the tradition of The Celestine Prophecy and Jonathan Livingston Seagull, THE BLUE ROAD TO ATLANTIS is an inspirational retelling of Hemingway's TheOld Man and the Sea. This is a gently humorous and ultimately touching story told from the perspective of a remora eel who is travelling with his mentor, a wise and beautiful marlin, to Atlantis in order to save the lives of all the fish in the ocean. En route to Atlantis, the marlin is hooked by a fisherman, who turns out to be Hemingway's character from The Old Man and the Sea. As the marlin struggles for survival, he ponders the meaning of life, the importance of love, friendship and forgiveness, the power of fear and the importance of following one's dreams at all costs. His thoughts encourage readers to 'go with the current' by...
	Narcissist Nation: Reflections of a Blue-State Conservative by George J. Marlin (Author) It’s not easy being Catholic and conservative in secular ‘Blue State’ New York, but that’s what George J. Marlin is, always has been, and always will be. Don’t ask him to change.      Besides, like America, it’s the Empire State that needs to change. Generation after generation of elitists have put in place their plans for making the machineries of state work more efficiently and more equitably, and they’ve succeeded in wrecking what was never broken in the first place. And Mr. Marlin has a name for political types who think they know better than the rest of us: narcissists. Narcissists have been fouling up societies since the beginning of time. As Marlin writes:Throughout history, a subset of people have viewed themselves as superior to the rest of the population due...
	OBSERVATIONS ON THE BODY FORM OF THE BLUE MARLIN (MAKAIRA NIGRICANS AMPLA POEY) by G.M.& La Monte,F. Conrad (Author)
	Hidden Agendas by Marlin Potash (Author), Marlin S., Dr. Potash (Author) This package reveals what's really going on in work, love, and family. Through real-life case studies, Dr. Potash leads us to understand the hidden meanings of others so we can deal with people more effectively.
	Get a piece of the Big Rock. (37th Big Rock Blue Marlin Tournament, North Carolina): An article from: Business North Carolina by Charlie Peek (Author) This digital document is an article from Business North Carolina, published by Business North Carolina on July 1, 1995. The length of the article is 3342 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser. Citation Details Title: Get a piece of the Big Rock. (37th Big Rock Blue Marlin Tournament, North Carolina) Author: Charlie Peek Publication: Business North Carolina (Magazine/Journal) Date: July 1, 1995 Publisher: Business North Carolina Volume: v15 Issue: n7 Page: p10(9) Distributed by Thomson...
	Tragedy brings out the best in Big Rock. (37th Big Rock Blue Marlin Tournament, North Carolina): An article from: Business North Carolina by Business North Carolina (Publisher) This digital document is an article from Business North Carolina, published by Business North Carolina on July 1, 1995. The length of the article is 662 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser. Citation Details Title: Tragedy brings out the best in Big Rock. (37th Big Rock Blue Marlin Tournament, North Carolina) Publication: Business North Carolina (Magazine/Journal) Date: July 1, 1995 Publisher: Business North Carolina Volume: v15 Issue: n7 Page: p14(1) Distributed by Thomson...
	A Fossil Blue Marlin (Makaira nigricans Lacepede) from the Middle Fades of the Trinidad Formation (Upper Miocene to Upper Pliocene), San Jose del Cabo ... (Southern California Academy of Sciences) by Harry L. Fierstine (Author), Shelton P. Applegate (Author), Gerardo Gonzalez-Barba (Author), Tobias Schwennicke (Author), Luis Espinosa-Arrubarrena (Author) This digital document is an article from Bulletin (Southern California Academy of Sciences), published by Southern California Academy of Sciences on August 1, 2001. The length of the article is 5689 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser. Citation Details Title: A Fossil Blue Marlin (Makaira nigricans Lacepede) from the Middle Fades of the Trinidad Formation (Upper Miocene to Upper Pliocene), San Jose del Cabo Basin, Baja California Sur, Mexico. Author: Harry L. Fierstine Publication: Bulletin (Southern California Academy of Sciences) (Refereed) Date: August 1, 2001 Publisher:...
	A fossil skull of the extant blue marlin (Makaira nigricans Lacepede, 1802) from the late Miocene of Orange County, California.(Report): An article ... (Southern California Academy of Sciences) by Harry L. Fierstine (Author) This digital document is an article from Bulletin (Southern California Academy of Sciences), published by Southern California Academy of Sciences on August 1, 2008. The length of the article is 5535 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available immediately after purchase. You can view it with any web browser. Citation Details Title: A fossil skull of the extant blue marlin (Makaira nigricans Lacepede, 1802) from the late Miocene of Orange County, California.(Report) Author: Harry L. Fierstine Publication: Bulletin (Southern California Academy of Sciences) (Magazine/Journal) Date: August 1, 2008 Publisher: Southern California Academy of Sciences Volume: 107 Issue: 2 Page:...
	Bluewater Fly Fishing by Trey Combs (Author) The ultimate guide to attracting the greatest pelagic species to the fly.
	The Last Marlin: The Story of a Father and Son by Fred Waitzkin (Author) Young Fred Waitzkin is a Jewish boy stretched between the divergent values of parents who cannot tolerate one another. Fred's father, Abe, is a brilliantly talented salesman whose relentless will drives him to succeed-he literally brightens American cities with fluorescent lighting fixtures. Abe marries Stella, an abstract artist and daughter of a wealthy industrialist with whom Abe forges an alliance. When his parents' marriage disintegrates, Fred retreats into fishing, learning the trade from the master captains of Bimini. In scenes ranging from Long Island synagogues to evenings with famous painters to the boats of drug smugglers and the once marlin-rich waters of the Gulf Stream, Fred sinks boats and battles thousand-pounders believing that fishing is the only hope. Woven through this...