More than 130 sea turtles were released into the Gulf Stream off the North Carolina coast on Thursday after recovering from cold-stunning, or hypothermia, brought on by a drastic drop in water temperature.

The crew of US Coast Guard cutter Cushing helped the North Carolina Wildlife Resources Commission to launch a rescue operation after a cold snap in North Carolina sent temperatures below freezing in parts of the state.

Over 100 cold-stunned green sea turtles were found floating or washed ashore.

After spending some time in a rehabilitation facility the turtles were taken 15 to 20 miles offshore to warmer waters where the Coast Guard crew with their family members helped North Carolina Wildlife Resources Commission personnel release the animals.

As with other reptiles, sea turtles rely on their external environment to regulate body temperature and cold-stunning occurs when water temperatures drop below 10 degrees Celsius.

Symptoms include decreased heart rate and lethargy, which renders the turtles virtually paralysed and vulnerable to injury or death by predators and boats.