Richard Drew / AP

An injured dolphin surfaces in the Gowanus Canal in the Brooklyn borough of New York, on Jan. 25.

An injured dolphin that became stranded in Brooklyn's Gowanus Canal died Friday, a marine foundation said.

The Riverhead Foundation confirmed to NBC News the dolphin passed away Friday evening. No other details about the mammal's death were immediately available.

Earlier Friday, live helicopter video from NBCNewYork.com showed the sea mammal bobbing up and down in the canal's murky water — which the U.S. Environmental Protection Agency declared a Superfund site in 2010 because it contained a "century's worth" of pollutants.

The dolphin appeared to be stuck in one section of the canal, coming up occasionally for air as a New York Police Department crew worked to figure out a rescue plan. It was unclear how the creature got into the predicament. The NYPD told NBC News the dolphin was stuck in the vicinity of Union Street, between Bond Street and Nevins Street, which is at least a mile into the canal and away from the Gowanus Bay.

Authorities were hoping the dolphin would be able to escape by itself during the Friday evening high tide, but if not, were planning on helping it out on Saturday, police told The Associated Press.

A senior biologist at the Riverhead Foundation told NBCNewYork.com rescuers were waiting to see if the dolphin would leave on its own: "The best course of action is to see if that when the tide comes back in the animal will move back out," Robert DiGiovanni told NBCNewYork.com. "It’s giving the animal time to work the problem out before you introduce stress by intervention."

The Northeast Regional Office of the NOAA Fisheries Service confirmed to NBCNewYork.com this mammal was a short-beaked common dolphin, which is known for a dark gray cape on its back.

Witnesses had said the animal appeared to be bleeding from its dorsal fin, the New York Daily News reported.

"He keeps going up and down and going from side to side and people are saying we don’t know what’s taking so long to go in there and save him," Brooklyn resident Cathy Ryan told the Daily News. "He’s in bad shape. You can tell. A dolphin is gray, but he's black right now. He was starting to swim toward the middle of the canal. But it doesn't look good."

Michael Heiman / Getty Images

Officials stand on the side of the Gowanus Canal as the dolphin comes up for air after getting stuck on Jan. 25, in the Brooklyn.

Eight-year-old Anabell Blaine told NBCNewYork.com she had hoped they got the dolphin out: "Dolphins are so beautiful."

The Gowanus Canal is in Brooklyn, flanked by the Park Slope, Cobble Hill, Carroll Gardens and Red Hook neighborhoods, according to NBCNewYork.com. It empties into New York Harbor.

The Environmental Protection Agency says storm water runoff, sewer outflows and industrial pollutants have made it one of the most extensively contaminated water bodies in the U.S.

Manufactured gas plants, mills, tanneries and chemical plants are among the many facilities that operated along the canal, according to the EPA.

The EPA said the contamination in the canal poses a threat to the nearby residents who use the canal for fishing and recreation.

Bystander Vinny Internicola told the Daily News on Friday he can smell the water from his vantage point: "I can’t imagine being in there."

A day earlier, a WNBC news helicopter spotted a minke whale swimming in Gowanus Bay.

NBCNewYork.com's Gus Rosendale contributed to this story.

When a dolphin needed help off the coast of Hawaii, he was determined to let a scuba instructor know.

Keller Laros was leading a group of divers on a tour of the waters off of Kona, Hawaii, on Jan. 11. He often goes on his dives with professional underwater videographers and this night was no exception.

But as Laros, his camerawoman and the rest of the group began their dive, nothing seemed out of the ordinary. 

"All of a sudden I heard a loud squeak, and I turned around, and the dolphin was literally three feet behind me," Laros said. "He swam right up to me."

The bottlenose dolphin slowly swam around Laros, the other divers, and manta rays -- which were what the divers had been gone down to see in the first place -- when they heard the squeak.

What struck Laros immediately about the dolphin was that he was alone.

"We've seen five of those dolphins at this dive site at the night dive before. They're very curious and intelligent animals," he said. "Dolphins are really social animals. In the past we've seen at least two [at this site]."

Laros, who has done more than 10,000 dives, quickly knew something was wrong. When the dolphin circled by him again, Laros noticed he had a fishing line hooked onto his fin.

As camerawoman Martina Wing's underwater video rolled, Laros gestured with his hand for the dolphin to come close.

"I said, 'come here,' and he swam right up to me," he said. "I put my hand out and I was able to get the fishing hook out of his left pectoral fin. The fishing line came from his mouth down through the hook in the left pectoral fin, and then was wrapped all the way around the pectoral fin and it trailed off down the side of the animal."

Laros was able to remove the hook from dolphin's fin, but still needed to get him untangled from the line. As the dolphin patiently floated inches in front of him, Laros took out dive tools that he carries in his suit, including a pair of small scissors.

He was able to clip the line off of the dolphin's mouth and fin, but there was still a little left. The dolphin went up for a breath of air and came back down.

Then Laros and another dive guide removed as much line from under the fin as they could. 

"I guess the dolphin was happy with our work. He swam away and we never saw him again," he said.

During the three minutes that Laros was face-to-face with the dolphin, and the eight minutes in total that he estimated they interacted, he was worried he might scare the animal.

"The dolphin was big -- maybe up to ten feet long," he said. "I was worried when I was removing the fishing line if I hurt him, he could inadvertently be startled and hurt me. I was concerned, but not frightened."

Laros, the founder of the Manta Pacific Research Foundation, has removed many fishing hooks from manta rays and turtles that have swallowed bait, but said he had never helped a dolphin.

"It's a huge thrill to be able to help an animal that clearly knows what's going on," he said. "He made the effort to come to us... The dolphin is really intelligent. It's a relationship. He came to us because he had a problem."

The original eight-minute video of Laros' interaction with the dolphin had gotten over half a million views by Wednesday afternoon. Click below to see Laros' abridged version, with audio.

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SeaWorld is defending the actions of its employees in Orlando, Fla., after an 8-year-old girl from Georgia was injured by a dolphin.

Jillian Thomas of Alpharetta was participating in the feeding at the dolphin facility Nov. 21. When she held a paper fish container up  so the dolphin could grab it, the animal lunged at her and bit her hand. Her father, Jamie Thomas, captured the attack on camera. The video shows the girl’s face contorting in pain as the dolphin briefly grabs her left hand.

Jillian suffered three puncture wounds, but her mother said she didn't think park employees took her injuries seriously.

In a statement, SeaWorld officials said they addressed the incident appropriately.

"Nothing is more important to us than the health and safety of our guests, employees and animals," the statement said.

"Educators and animal care staff were at the attraction when this happened and immediately connected with the family. In addition, a member of our health services team was in the area at Dolphin Cove and quickly responded and treated the young girl.

"The video had not been previously shared with us and we have not had a chance to assess it, but certainly take the situation seriously."

Food for the dolphins comes on small trays. In a video from the exhibit, an announcer warns visitors not to hold them up, as the dolphins will reach for them.

In the video, Jillian can clearly be seen picking up the tray, but her mother claims she never heard the warning.

SeaWorld said guests are given clear instructions on how to feed the dolphins, including specific directions not to pick up the paper trays.

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Paul Bersebach / AP

A dolphin swims in wetlands at the Bolsa Chica Ecological Reserve in Huntington Beach, Calif. Rescue crews tried over the weekend to guide the confused dolphin from the shallow waters of Bolsa Chica.

A lone dolphin that has spent the past five days swimming in the Bolsa Chica wetlands in Southern California may be the victim of bullying, NBCLosAngeles.com reported.  

The dolphin may have been prevented from leaving the Huntington Beach nature preserve by other dolphins, Peter Wallerstein, director of Marine Animal Rescue told the Register. This would be a rare occurrence, as dolphins are social creatures that typically travel in a pod.

NBCLosAngeles.com: Dolphin chooses to stay in Bolsa Chica wetlands

“He was scared, he was intimidated, he was bullied,” Wallerstein told the Los Angeles Times. Dolphins "can be very aggressive toward each other. They’re not the sweet, loving, gentle animals portrayed by the movies and the cartoons. They do have a dark side.”

On Saturday, Wallerstein and officers from the state Department of Fish and Game used paddle boards to shoo the dolphin back to the ocean. When two other dolphins emerged, apparently blocking the lone dolphin's path back to the ocean, it dove under the paddle boards and swam back to the wetlands.

But Dennis Kelly, who has studied dolphins and marine life for 34 years, told the Orange County Register that he doubted the dolphin is being bullied.

“Maybe the others are angry,” Kelly, an instructor of Orange Coast College, said. “‘You’re lagging behind, you moron.’ Maybe they were going whack it. ‘You’re not paying attention. Slap! OK, we’re leaving.’”

On Monday, the 7-foot dolphin stayed put and fed on fish. Observers said the dolphin could figure out on its own how to return to the ocean via the narrow channel.

For now, marine life experts are adopting a hands-off approach while watching the dolphin around the clock.

Meantime, crowds have gathered and are beginning to name the dolphin, even if they don’t know its sex. Contenders are Fred and Bolsa Chica Bob.

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