How Oil Is Breaking Tuna’s Heart

The effects of the 2010 oil spill in the Gulf of Mexico are still being felt, and two animal populations are really feeling the pain: tuna and dolphins. Fish and marine mammals, it turns out, are highly sensitive to the chemicals found in petroleum products, and it’s an especially big problem for longer-lived species. Recent research has examined what happened to both dolphins and tuna after the Deepwater Horizon spill, and the image is grim — especially for tuna, who almost literally experienced broken hearts as a result of the uncontrolled release of nearly five million barrels of oil into the Gulf.

In the case of tuna, exposure to compounds found in crude oil can cause heart abnormalities and arrhythmias, causing cardiac arrest in extreme cases. These chemicals effectively slow individual heart cells, which is not desirable in the body’s hardest working and most active organ — especially for athletic organisms like tuna. One of the problems in the case of tuna is that the Gulf is a major spawning area, and the spill occurred at precisely the same moment many fish were gathering to spawn, creating a chain effect through multiple generations as exposure to the harmful chemicals created developmental abnormalities.

Several other fish species have been affected, and many of them are commercially valuable, illustrating that the economic impact of the spill is still a concern. Severe damage to gulf fisheries poses serious problems to struggling local economies that are still trying to recover from the spill. After losing out on tourism revenue and having to reestablish fisheries, some communities are facing a reduction in fish populations that will require careful fisheries management, including, likely, more catch limits to allow the population to recover, even though such limits may create problems for fishermen.

The problem is serious enough that Atlantic bluefin tuna, which base their lives in the Gulf, are being seriously evaluated to determine if they should be listed on threatened and endangered species lists, because their populations have declined so radically. That’s bad news for fish, not just fisheries — shrinking biodiversity can reach a tipping point of no return past which a species cannot recover. The loss of an entire species is always a tragedy, but bluefin tuna in particular are long-lived, and an important part of their environments. If they become threatened or extinct, their shrinking numbers could cause ecological disturbance in their own waters, and that might create a cascade of negative environmental factors.

For dolphins, researchers have long observed that unusually large numbers of the marine mammals washed ashore during the Gulf spill, and they could be linked back to the site. Further research indicates that they had clear signs of lung and adrenal disease linked with chemicals in petroleum, conclusively connecting them with the spill. One of the key components of the research was a rigorous evaluation of the possible causes, as scientists didn’t initially consider the oil spill as a factor; only later did review of samples and the history of dolphin strandings and deaths reveal the oil-dolphin connection.

With another large spill off the coast of Santa Barbara and numerous oil spills on a smaller scale happening on a routine basis, findings like these are a concern. While researchers already understand that spilled oil represents an environmental hazard, this research illustrates the scope of the problem and highlights the fact that it’s a grim picture.

Photo credit: Roderick Eime

72 comments

Siyus Copetallus
Siyus Copetallus3 years ago

Thank you for sharing.

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Nikki Davey
Nikki Davey4 years ago

Sad news

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Paulinha Russell
Paulinha Russell4 years ago

Thank you

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Gisela Gama
Gisela Gama4 years ago

Noted with a very heavy heart ... senseless ....

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Anneke Swanepoel

There is no more respect for any living thing. Look at the cruel world around us. Please do something to save the fish as well.

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Dave C.
David C4 years ago

the time is now to stop using petrol poison

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Shirley S.
Shirley S4 years ago

Humans "progress" always leads to environmental destruction.

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Fred L.
Fred L4 years ago

No wildlife is safe until humans become extinct.

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Sherri S.
Sherri S4 years ago

You would think humans would have found a better fuel source by now. How many animals must be killed until we try to find a real solution to this problem?

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Val D.
Val D4 years ago

Waiting for the day for Big Oil to go away, so we and the other animals can be free someday.

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