One of the kayakers, Chris Denehy, tried to get as close as possible to the stricken animal to nudge it out with his oar while the others helped make a channel for it to pass through.
According to news.stv.tv, the kayakers were told about the trapped animal by a local postman.
Speaking to the Metro, Chris said: "He was literally drowning because the weed was pulling him under.
"He did seem quite distressed and must have been in there a while."
But after making his way back to his friends, the dolphin put on a little show to say thank you.
Chris uploaded the footage to YouTube, with the caption: "Three juvenile dolphins in Northbay on the Isle of Barra. One of the dolphins was completely trapped in seaweed and shallow water. After a successful rescue the dolphin joined the other two for a fine display of thanks!"
One happy user wrote: "Good to see there are still some caring people in the world!"
Dolphin trapped in seaweed 'thanks' kayakers after rescue
Pig Beach, or Pig Island, is an uninhabited island in Exuma, the Bahamas, famed for its many swimming pigs. They are said to have been dropped off on the island by sailors who wanted to return to cook and eat them, but never returned. Others say the pigs survived a shipwreck and managed to swim to the island. Today, the pigs are fed by tourists who visit the island to meet its unexpected residents.
Okunoshima Island, in Japan, attracts tourists to witness its huge rabbit population that has taken over the island, with many people visiting to feed the animals. The island, often called Usagi Jima or Rabbit Island, was used as a poison gas facility in World War II. The rabbits were intentionally set loose after the war when the island was developed as a park.
The jungles of Guam have up to 40 times more spiders than the forested areas of the nearby Pacific Islands thanks to the invasive brown snakes that wiped out 10 of the 12 spider-eating bird species. Because the birds ate some of the insects that spiders eat, there is also now more food for the spiders to eat. One of the most common types of spider in the jungle is the yellow and black Banana Spider.
The wild horses on the Assateague Island in Maryland are actually feral but tough enough to survive the scorching heat, stormy weather and poor quality food found on the remote barrier island. Local folklore says they are survivors of a shipwreck off the coast of Virginia. Assateague is one of the few places in America where you can view wild horses and visitors are advised to admire the animals from a distance.
Located just a few kilometres off the northern beaches of False Bay, near Cape Town, Seal Island is home to approximately 65,000 Cape Fur Seals. The island is a popular feeding ground for the great white shark and lucky visitors may see the fish breaching in pursuit of its prey. Seal Island is like a sea of brown bodies stretching and hauling themselves along the rocks. It is too rocky to disembark but well worth observing from a boat.
The rhesus macaques on Cayo Santiago, also known as Monkey Island, off the eastern coast of Puerto Rico, were introduced in 1938 for scientific research. Around 1,200 free-roaming monkeys can be found on the small island and while it is not open to tourists, you can get an up close view of the animals from the water.
The island of Tashirojima, or Cat Island, off the coast of Ishinomaki in Japan has a larger cat population than it has humans. The people who live on the island are those who take care of the cats. To the locals the cats represent luck and fortune, and there is even a cat shrine at the centre of the island, along with cat-shaped cottages. Cat-loving tourists are welcome to visit the island, but dogs are not allowed.
Every year during the wet season (October to December), Christmas Island's adult red crabs begin their migration from the forest to the Indian Ocean where they breed and spawn. With tens of millions of red crabs living on the island it is possible to witness them pour out of the jungle and take over Christmas Island. The phenomenon lasts several weeks, forcing roads to close for the crabs to cross.
Norway's famous bird island, Runde, is teeming with birds - more than 500,000 that visit from February to August during the nesting season. Bird mountain, with its cliff formations towards the ocean, is dominated by Atlantic puffins. Their nesting season is between April and August, when 100,000 pairs of puffins can be found on the western side of Runde. Outside puffin season, they stay at sea along the coast.
The tiny uninhabited island of Ilha da Queimada Grande, off the coast of Brazil, is definitely one to avoid as it is teeming with one of the most venomous snakes on the planet, the Golden Lancehead Viper. Every three feet, one of the snakes is lurking, terrifying generations of fisherman. Currently, the Brazilian Navy has banned people from visiting the island but occasionally scientists are granted access.
There are approximately 3,000 polar bears and just 2,642 people in the Svalbard archipelago. A large number of polar bears are found on the surrounding islands east of Spitsbergen, yet you should be prepared to encounter one anywhere in Svalbard. As the world's largest land carnivores they are beautiful but dangerous and human encounters often have a fatal outcome. There are polar bear watching cruises which allow you to see the animals from a distance.
Hawaiian island Kauai is famed for its lush vegetation, pristine beaches and… chickens. Roosters, hens and little chicks are found roaming the island and are believed to be descendants of former fighting cocks unleashed during a devastating hurricane which hit over a decade ago. The birds are found in outdoor food courts, ruining sugar cane and corn crops, and even waking tourists at the crack of dawn.
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National Geographic Traveller Photo Contest 2015 - more entries
Dolphin trapped in seaweed 'thanks' kayakers after rescue
"The little tarsier, nicely nestled in a leaf, suddenly opens its eyes! They are nocturnal so what a surprise. These tiny primates (3 to 6 inches) are found only in the Philippines and most of them are in sanctuaries. This one was in a sanctuary in Bohol Island."
"The famous hall "Halle der Circe" is located at the end of the highest-lying touristic cave in the world (2100 m alt.), which can be reached only by experienced cavers. With proper lighting the permanent ice in the hall shines in beautiful blue tones, which add enchantment atmosphere to the frozen hall."
"The Moeraki Boulders are unusually large and spherical boulders lying along a stretch of Koekohe Beach. These boulders are grey-colored septarian concretions, which have been exhumed from the mudstone enclosing them and concentrated on the beach by coastal erosion."
"The island of Borneo, which is split between the countries of Malaysia, Indonesia, and Brunei, was once covered with a lush tropical rainforest, but in the wake of ongoing deforestation and the expansion of plantation farming, the habitats of the island's endemic and endangered species are being destroyed rapidly. Relentless deforestation has precipitated the loss of 90 per cent of the orangutan population in 100 years. At this rate, some expect this species to become extinct within the next 20 years."
"While foraging for food, sometimes Greater Flamingos get into mild altercation with their neighbours. This is one such moment when these two big guys bumped into each other. And when this happens, they both stand tall and bite each other's beak and continue to do what they were doing. While this is clearly a fight, the way they do this appears to be a romantic moment."
"On a summer night, in the colonial town of Santa Clara, Cuba, people hurry to get home before the storm."
"I visited Deadvlei in 2008. The personal emotional and spiritual connection I felt with "The Beginning" I know I had to return someday. That time came in May 2015. I knew I had to make a photograph that reflected how I felt during my first visit and on this visit. I did capture it. I fell it was not just a sense of place but a sense of time."
"This disorienting photo was taken from a cliff overlooking Lake Louise in Banff national park. The two people are enjoying a canoe ride on Lake Louise's turquoise waters."
'I was working at my family farm some 150 km from the Calbuco Volcano when a friend called me and told me what was happening. I took my camera and tripod and drove to Puerto Varas where a quiet chaos was ensuing and decided to keep on driving to a darker area. Upon arrival the volcano was quiet again, not even vapour was coming out, so, a little disappointed, I went to rest. Two hours later all hell broke loose and I could take some of the pictures I've been dreaming about ever since the Chaiten eruption in 2008.
"Every year, humpback whales come to Kingdom of Tonga during July to September. The mothers raise their babies and when they are enough strong they go far away to the cold water. During whale watching activity, you can live some incredible experiences by interaction with this fabulous mammal. This young calf played with me during 30 minutes under the control of his mother, a great memory!"
"This is taken at the volcanic beach at Stokksnes in south-eastern Iceland in February 2015. I used a 2-second exposure to capture the water trails as the waves receded over rocks at the edge of the beach, just as the sun was setting behind me, illuminating the mighty Vesturhorn mountain and some peaks in the far distance."
"There's nothing quite like being able to stand at the base of Niagara Falls as you feel and hear the thundering roar of the water as it falls over the edge and plunges 170' down to the Niagara River."
"Villarrica volcano, located more than 700 kilometers south of Santiago de Chile, has been erupting since 2003 is in eruption process. This photograph was taken last May 11 in the city of Pucon."
"While touring the waterways along the Antarctic Peninsula, we saw two Adelie Penguins watching their surroundings from the top of an Iceberg."
"The Rock restaurant is just off shore in Zanzibar. As the sun set, I was taking photos of The Rock before going out there to have dinner. As the light levels dropped, the light came on in the restaurant and I knew I had my shot."