The long-term effects of oil spills on fish

More than 210 million gallons of crude oil spilled into the Gulf of Mexico during the spring and summer of 2010 from the Deepwater Horizon oil well. In this segment we go inside the mote marine laboratory in Sarasota, Florida where scientists are studying the long-term effects of the oil spill on fish.

TRANSCRIPT

More than 210 million gallons of crude oil spilled into the Gulf of Mexico during the spring and summer of 2010 from the Deepwater Horizon oil well.

In this segment, we go inside the Mote Marine Laboratory in Sarasota, Florida, where scientists are studying the long-term effects of the oil spill on fish.

Here's the story.

This is the Mote Aquaculture Research Park just east of Sarasota, Florida.

Scientists here have been studying ways to raise fish for both the dining table and the research lab.

What we're doing here is developing the technology to produce marine species in sustainable manners.

And we use our systems and the biological advances that we make with these different fish to try to advance the development of aquaculture in the United States and also to help restore declining fisheries.

I came here to meet with Dr. Kevan Main and the researchers looking at the effect of oil on fish.

A unique project that we've been working on for the last couple of years has been to look at the use of cultured fish in order to examine what the impacts are from environmental assaults that might happen in nature.

One such assault was the Deepwater Horizon oil spill.

We all sat mesmerized for months during the summer of 2010, wondering when they would ever cap the well 1 mile deep at the bottom of the Gulf.

As this drama played out on our TVs at home, scientists immediately began studying the impact on the environment.

What we're trying to do here is gain a better understanding of what happened to those animals in a controlled environment.

And so we do everything, from spawning the fish to produce the test animals that are going to be used in the experiments, to raising them clear up to adult size.

And then, throughout the research trials that are done by the Ecotoxicology group, we then keep those animals alive.

Dr. Dana Wetzel heads up the toxicology research at Mote Marine Laboratories.

Oil -- if it doesn't kill an animal, it certainly could then ultimately compromise it in a number of different ways.

It could compromise its immune system.

It could compromise its ability to reproduce, its behavior.

There are a number of facets to the impacts on an organism's health.

Could you give us a brief overview of the process by which you guys take this large oil spill and then emulate that in the lab on a smaller scale?

What we're trying to do is evaluate different habitats within the ocean, different niches.

So we're looking at fish that live in the water column.

We're also looking at fish that live coastally, that are used to being in the near-shore environment.

And then we're also looking at fish that are burrowing in the sediment.

They're benthic fish.

We have pompano that represent living in the water column, and we're exposing them to an oil-and-water test solution.

We have red drum, who live, coastally, near-shore, and we're exposing them to an oil-contaminated food.

And then we have flounder, which are benthic organisms, and those are exposed to oil-contaminated sediments.

So we're trying to emulate three different types of exposures with three different species of fish.

The research here is focused on long-term effects that go far beyond the initial fish kill at the Deepwater Horizon spill.

A lot of times, what we have a tendency to do is to count the number of dead animals from a spill and count the number of live animals and use that as a benchmark for understanding the impact from an oil spill.

But, in actuality, oil -- if it doesn't kill an animal, it certainly could then ultimately compromise it in a number of different ways.

It could compromise its immune system.

It could compromise its ability to reproduce, its behavior.

There are a number of facets to the impacts on an organism's health, rather than just, is it dead?

I also sat down with microbiologist Andrea Tarnecki, who's looking at bacteria in and on the fish.

So, fish have some bacteria that will cause disease, and they have a much larger percentage of bacteria that are beneficial.

And they're doing all the same good things in fish that they're doing in people.

So they help with digestion.

They produce vitamins and amino acids that the fish can use directly.

They boost the immune system of the fish.

And they also help fight off potential pathogens, as well.

So, I'm looking at the changes in the bacterial communities of the fish as they're exposed to oil and the dispersants, versus fish that aren't exposed, looking at things like differences in bacterial diversity, which is the total number of species of bacteria.

Alongside that, I'm looking at comparing those changes with what's happening inside the fish itself.

These scientists have collected massive amounts of data, which will take several months to evaluate.

The process is complex, but a few initial pieces of the puzzle are beginning to form.

And what we found is that the fish that were exposed to oil were significantly impacted, both in the amount of the sperm motility, and viability was far less in the oil-exposed fish than it was in the control fish.

And then the egg production was far less.

When we're all done, we're going to have, you know, hundreds of thousands of data points that we're going to have to strategically piece together and understand what's going on in the big picture.

Right now, you know, we have little pieces that have been answered like, how much have they accumulated?

Are they responding with gene expression?

Are there some genes that are being elevated and some that are being suppressed?

Are they exhibiting oxidative stress?

Is there any evidence of DNA damage?

So, the answer is 'yes.'

We're finding little pieces and parts of all of those.

When we are able to put it all together, I think we'll have a very compelling story to tell.

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