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Latest Research Finds Serious Heart Troubles When Oil and Young Tuna Mix

This story was first published on March 26, 2014. It was updated April 9, 2015 to reflect additional research.

Atlantic bluefin tuna prepares to eat a smaller fish.

Atlantic bluefin tuna are a very ecologically and economically valuable species. However, populations in the Gulf of Mexico are at historically low levels. (Copyright: Gilbert Van Ryckevorsel/TAG A Giant)

In May of 2010, when the Deepwater Horizon rig was drilling for oil in the open waters of the Gulf of Mexico, schools of tuna and other large fish would have been moving into the northern Gulf. This is where, each spring and summer, they lay delicate, transparent eggs that float and hatch near the ocean surface. After the oil well suffered a catastrophic blowout and released 3.19 million barrels of oil into the Gulf, these fish eggs may have been exposed to the huge slicks of oil floating up through the same warm waters.

An international team of researchers from NOAA, Stanford University, the University of Miami, and Australia recently published a study in the journal Proceedings of the National Academy of Sciences exploring what happens when tuna mix with oil early in life.

“What we’re interested in is how the Deepwater Horizon accident in the Gulf of Mexico would have impacted open-ocean fishes that spawn in this region, such as tunas, marlins, and swordfishes,” said Stanford University scientist Barbara Block.

This study is part of ongoing research to determine how the waters, lands, and life of the Gulf of Mexico were harmed by the Deepwater Horizon oil spill and response. It also builds on decades of research examining the impacts of crude oil on fish, which began after the 1989 Exxon Valdez oil spill in Alaska. Based on those studies, NOAA and the rest of the research team knew that crude oil—including oil from the Deepwater Horizon oil spill (Incardona et al. 2013)—was toxic to young fish and taught them to look carefully at their developing hearts.

“One of the most important findings was the discovery that the developing fish heart is very sensitive to certain chemicals derived from crude oil,” said Nat Scholz of NOAA’s Northwest Fisheries Science Center.

This is why in this latest study they examined oil’s impacts on young bluefin tuna, yellowfin tuna, and amberjack, all large fish that hunt at the top of the food chain and reproduce in the warm waters of the open ocean. The researchers exposed fertilized fish eggs to small droplets of crude oil collected from the surface and the wellhead from the Deepwater Horizon spill, using concentrations comparable to those during the spill. Next, they put the transparent eggs and young fish under the microscope to observe the oil’s impacts at different stages of development. Using a technology similar to doing ultrasounds on humans, the researchers were able create a digital record of the fishes’ beating hearts.

All three species of fish showed dramatic effects from the oil, regardless of how weathered (broken down) it was. Severely malformed and malfunctioning hearts was the most severe impact. Depending on the oil concentration, the developing fish had slow and irregular heartbeats and excess fluid around the heart. Other serious effects, including spine, eye, and jaw deformities, were a result of this heart failure. (Incardona et al. 2014 [PDF])

Top: A normal young yellowfin tuna. Bottom: A deformed yellowfin tuna exposed to oil during development.

A normal yellowfin tuna larva not long after hatching (top), and a larva exposed to Deepwater Horizon crude oil as it developed in the egg (bottom). The oil-exposed larva shows a suite of abnormalities including excess fluid building up around the heart due to heart failure and poor growth of fins and eyes. (NOAA)

“Crude oil shuts down key cellular processes in fish heart cells that regulate beat-to-beat function,” noted Block, referencing another study by this team, (Brette et al. 2014).

As the oil concentration, particularly the levels of polycyclic aromatic hydrocarbons (PAHs), went up, so did the severity of the effects on the fish. Severely affected fish with heart defects are unlikely to survive. Others looked normal on the outside but had underlying issues like irregular heartbeats. This could mean that while some fish survived directly swimming through oil, heart conditions could follow them through life, impairing their (very important) swimming ability and perhaps leading to an earlier-than-natural death.

“The heart is one of the first organs to appear, and it starts beating before it’s completely built,” said NOAA Fisheries biologist John Incardona. “Anything that alters heart rhythm during embryonic development will likely impact the final shape of the heart and the ability of the adult fish to survive in the wild.”

Even at low levels, oil can have severe effects on young fish, not only in the short-term but throughout the course of their lives. This is why the research team, composed of scientists from NOAA, Stanford University, and the University of Miami, is studying fish exposed to low levels of crude oil as embryos that subsequently grow into juveniles and adults in clean water. Initial research has shown that subtle disruptions of the embryonic heartbeat can produce permanent changes in heart shape that negatively affect swimming performance and other behaviors critical for fish survival. The team has shown similar underlying effects on juvenile mahi mahi (Mager et al. 2014), and studies are ongoing using zebrafish.

These subtle but serious impacts are a lesson still obvious in the recovery of marine animals and habitats still happening 25 years after the Exxon Valdez oil spill.

Find the most up-to-date summary of NOAA-funded research on crude oil’s potential effects on fish in the Gulf Mexico.


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Japan Confirms Dock on Washington Coast Is Tsunami Marine Debris

A worker uses a 30% bleach spray to decontaminate the Japanese dock which made landfall on Washington’s Olympic Peninsula in December 2012.

January 3, 2013 — A worker uses a 30% bleach spray to decontaminate and reduce the spread of possible marine invasive species on the Japanese dock which made landfall on Washington’s Olympic Peninsula in December 2012. (Washington Department of Fish and Wildlife/Allen Pleus)

The Japanese Consulate has confirmed that a 65-foot, concrete-and-foam dock that washed ashore in Washington’s Olympic National Park in late December 2012 is in fact one of three* docks from the fishing port of Misawa, Japan. These docks were swept out to sea during the earthquake and tsunami off of Japan in March 2011, and this is the second dock to be located. The first dock appeared on Agate Beach near Newport, Ore., in June 2012.

Using our trajectory forecast model, NOAA’s Office of Response and Restoration helped predict the approximate location of the dock after an initial sighting reported it to be floating somewhere off of Washington’s Olympic Peninsula. When the dock finally came aground, it ended up both inside the bounds of NOAA’s Olympic Coast National Marine Sanctuary and a designated wilderness portion of Olympic National Park.

Japanese tsunami dock located on beach within Olympic National Park and National Marine Sanctuary.

In order to minimize damage to the coastline and marine habitat, federal agencies are moving forward with plans to remove the dock. In addition to being located within a designated wilderness portion of Olympic National Park, the dock is also within NOAA’s Olympic Coast National Marine Sanctuary and adjacent to the Washington Islands National Wildlife Refuge Complex. (National Park Service)

According to the Washington State Department of Ecology, representatives from Olympic National Park, Washington State Department of Fish and Wildlife, and Washington Sea Grant Program have ventured out to the dock by land several times to examine, take samples, and clean the large structure.

Initial results from laboratory testing have identified 30-50 plant and animal species on the dock that are native to Japan but not the United States, including species of algae, seaweed, mussels, and barnacles.

In addition to scraping more than 400 pounds of organic material from the dock, the team washed its heavy side bumpers and the entire exterior structure with a diluted bleach solution to further decontaminate it, a method approved by the National Park Service and Olympic Coast National Marine Sanctuary.

Government representatives are examining possible options for removing the 185-ton dock from this remote and ecologically diverse coastal area.

Look for more information and updates on Japan tsunami marine debris at http://marinedebris.noaa.gov/tsunamidebris/.

*[UPDATE 4/5/2013: This story originally stated that four docks were missing from Misawa, Japan and that “the first dock was recovered shortly afterward on a nearby Japanese island.” We now know only three docks were swept from Misawa in the 2011 tsunami and none of them were found on a Japanese island. This dock has now been removed from the Washington coast.]


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Abandoned Vessels: Drifting Across the Pacific Ocean Since 1617

Adrift Japanese fishing vessel.

The derelict Japanese fishing vessel RYOU-UN MARU drifts more than 125 miles from Forrester Island in southeast Alaska. The fishing vessel has been drifting unmanned at sea since the 2011 Japanese earthquake and subsequent tsunami more than a year ago (U.S. Coast Guard, Air Station Kodiak).

You might have already heard about the rusted-out, abandoned fishing vessel adrift off British Columbia, Canada. The 170 foot (53 meter) long vessel is the Ryou-Un Maru, a squid boat that broke free from a dock in Hokkaido, Japan, after the March 11, 2011 tsunami. Fortunately, no one was on board when the tsunami happened.

Over the past year it has drifted across the Pacific Ocean and was first observed in Canadian waters. The U.S. Coast Guard is now tracking the drift of the vessel, which entered U.S. waters March 31, 2012, and currently it is about 155 nautical miles away from Baranof Island in southeast Alaska.

The drift of the vessel confirms what generations of beach combers have known for a long time. The Pacific Ocean currents form a giant conveyor belt that carries flotsam (floating items) across the Pacific. Over the years I’ve found glass fish floats, glass bottles, and other Japanese items that have washed up along the coast of Washington state where I live.

But a big fishing vessel—that must be something really unusual—or is it?

In 2003, the 97-foot ship Genei Maru #7 caught fire and was abandoned at sea about halfway between Japan and the United States. This “ghost ship” ran aground on Kodiak, Alaska, after drifting at sea, crewless, for five months. And in 2006, the U.S. Coast Guard found an abandoned coal barge adrift off the Kenai Peninsula of Alaska, which had wandered across the Pacific from Russia.

Cover page of historical record of drifting Japanese vessels.

The document, “Record of Japanese Vessels Driven Upon the North-West Coast of America and its Outlying Islands,” was originally published in 1872.

But there is evidence that vessels have been drifting across the Pacific for a long time. Check out this old document from 1872, “Record of Japanese Vessels Driven Upon the North-West Coast of America and its Outlying Islands.”

Some archaeologists think that Indigenous cultures of the Pacific Northwest Coast have been strongly influenced by the effects of foreign shipwrecks. Artifacts from shipwrecks, including metals and other technologies, may have been used by these tribes (Quimby, G. I. 1985. Japanese Wrecks, Iron Tools, and Prehistoric Indians of the Northwest Coast. Arctic Anthropology 22(2): 7–15.).

And the blog A Blast From the Past has a lengthy discussion on historical and more recent cases of vessels washing across the Pacific.

The oldest record is from 1617, when an abandoned Japanese ship was found near Acapulco, Mexico, but there are likely many other wrecks that went unrecorded because the vessels probably stranded in areas then inhabited only by native tribes.

The March 2011 tsunami certainly added to the amount of debris floating across the Pacific. If you find items you think might be from the tsunami, you can report them to DisasterDebris@noaa.gov.