Gulf Oil Spill Disaster: The Animals Most at Risk With time running out, here are the animals most at risk in the disaster.

June 24, 2010 -- As oil continues to gush into the Gulf of Mexico after the explosion on BP's Deepwater Horizon rig, cleanup crews and animal welfare experts are working tirelessly to prevent massive ecological damage on the coast.

But several animal species are in the crosshairs of the giant oil slick spreading across the gulf. With time running out, here are the animals most at risk in the disaster, and what you can do to help.

1. Atlantic Bluefin Tuna

Already one of the most threatened species of fish on the planet, Bluefin tuna could suffer huge losses in the wake of the spill.

The reason? Bluefin tuna only breed in two places on earth: the Mediterranean Sea and the Gulf of Mexico. And the Deepwater Horizon spill is impacting the very area of the gulf where the bluefin spawn. And they only spawn once a year. The time? You guessed it: right now. According Ellycia Harrould-Kolieb, a marine biologist interviewed by Newsweek, "This could spell the end to bluefin."

Before the spill, it was predicted that man's hunger for sushi might spell the end of the bluefin. Bluefin is especially prized in Japan, and overfishing has already devastated worldwide bluefin stocks; the population has dropped by more than 70 percent in the past 30 years.

2. Sea Turtles

For millions of years, sea turtles have lumbered onto the beaches of what is now Gulf Shores, Alabama, to lay eggs and continue their lineage. The annual ritual is carried out like clockwork each summer.

But now, more than 350 dead turtles have been discovered in the gulf since the Deepwater Horizon explosion, and experts are worried that the spill could disrupt their mating and breeding cycle for good.

Sea turtles are thought to be especially at risk since they spend most of their time on the water's surface, putting them at high exposure for inhaling and ingesting the oil floating in the gulf. The animals also are known to "mouth or chew on anything," according to Michele Kelley, standing coordinator of the Louisiana Marine Mammal and Sea Turtle Rescue Program, in an interview with National Geographic. That means they'll likely munch the oil to see what's going on.

There are only seven species of sea turtle in the entire world, and five of them rely on the Gulf of Mexico to serve as a critical habitat. And each of those five species is endangered.

3. Dolphins

Dolphins are among the many sea creatures surfacing closer and closer to Florida beaches in the weeks since the explosion on the Deepwater Horizon, a phenomenon that some marine experts think is tied to the spread of the oil slick.

As many as 5,000 bottlenose dolphins could be calving at the moment—right in the oil's path. Earlier this week, a team from Greenpeace spotted dozens of the mammals frolicking in the oil sheen off the coast of Louisiana.

Like sea turtles, dolphins are at risk from inhaling and ingesting the oil since they must surface to breathe. Dolphin carcasses have already been found in three states since the beginning of the crisis. Scientists are attempting to determine whether the animals died due to exposure to the oil.

4. Brown Pelicans

The Brown Pelican—the State Bird of Louisiana—uses the delicate wetlands of the Delta region to spawn and raise new generations. But state officials fear that decades of rebuilding the state's pelican population (they started in the 1960s with virtually none of the birds in the Pelican State) could be negated by the BP oil spill.

The first time around, pesticides like DDT had destroyed pelican populations. Now, the chemical ooze seeping in from the gulf could devastate the population once more.

Wildlife experts in Louisiana estimate that as many as 10,000 pairs of pelicans could be breeding at the moment in the affected area. Oil could continue to wash up near nesting areas for months and months to come. And since young pelicans like to wander around the affected marshland as they get their bearings, the oil contamination could spell disaster.

Pelicans spend much of their time floating on the surface of the water—the same place as the oil. Wildlife experts fear that their feathers could become coated in oil, causing them to lose buoyancy.

5. Oysters

Oysters have long been associated with Gulf Coast cuisine, but oyster houses that have been open for generations are closing in the French Quarter as oystermen are forced to stay home.

Due to oil contamination, many oyster beds have already been shut down. And oystermen fear that proposed plans to pump freshwater into the Delta to help push back encroaching oil could throw off the precise balance of seawater and freshwater that allows oysters to grow.

And as the water warms, oyster larvae could be born right into the oil, poisoning another generation of oysters.