A 15-year-old boy was found alive after spending nearly three days clinging to an overturned boat in the freezing Bering Sea.

But when rescuers finally reached him, his first words revealed the devastating price of his survival.

Derek Parker Aghnaanga had gone halibut fishing near Alaska’s St. Lawrence Island with his older brother and cousin when their small skiff capsized and drifted into open water on September 4.

For roughly 62 hours, the teenager held onto the overturned vessel.

He had no food.

No drinking water.

And by the time rescuers found him, he was alone.

His brother and cousin were dead.

“Through the teeth chattering, he had mentioned that his brother was still under the skiff,” Northwest Explorer captain Adam White recalled.

Then came another horrifying detail.

“He said that in the previous night before our rescue that his cousin had slipped away off the top of the skiff.”

The Coast Guard located Aghnaanga Monday morning after Alaska State Troopers reported that the fishing party had failed to return home.

A Coast Guard aircraft spotted what appeared to be a person on top of the overturned skiff at around 10:30 a.m.

The fishing vessel Northwest Explorer was nearby.

Its captain and 13-member crew were asked to help.

At first, White said, the object on the horizon was difficult to identify.

“We saw the unusual object on the horizon,” he said.

The crew sounded the ship’s horn.

As they approached, the impossible became clear.

Someone was alive.

Dramatic footage from the rescue shows the vessel closing in on the overturned boat before the teenager becomes visible on top.

“It’s unbelievable,” White said.

“It’s remarkable.”

The conditions made his survival even more extraordinary.

The water temperature was about 10 degrees Celsius — roughly 50 degrees Fahrenheit — cold enough for prolonged exposure to become life-threatening.

Aghnaanga was already showing signs of hypothermia when the crew pulled him aboard.

They wrapped him in blankets.

They tried to warm him.

And they kept him talking as the vessel headed toward Nome, where he would finally be reunited with family.

Only then did rescuers begin to understand everything he had endured.

Aghnaanga had been fishing with his older brother, 35-year-old Sidney Kulowiyi, and his cousin, 34-year-old Barton Rookok.

According to relatives, Kulowiyi was captaining the skiff when disaster struck.

After the boat overturned, he became trapped underneath it.

Aghnaanga survived above the hull while his brother remained beneath the vessel.

His cousin initially managed to stay on top of the overturned boat with him.

But during the ordeal, Rookok slipped into the sea and disappeared.

The teenager was left alone.

His mother later said he remained on the skiff for days after watching both men die.

He had virtually nothing to sustain him.

No food.

No water.

No shelter beyond the overturned vessel beneath him.

And no certainty that anyone would ever find him.

Still, he held on.

Hour after hour.

Through the cold.

Through the wind.

Through darkness.

Through the knowledge that his brother and cousin were gone.

White said the teenager’s endurance was difficult to comprehend.

“That kid was on top of that skiff,” he said.

“I mean, that’s one tough kid.”

The rescue has stunned people across Alaska.

Surviving that long in exposed maritime conditions is dangerous for anyone, let alone a teenager.

Hypothermia can impair judgment, coordination and consciousness as the body loses heat.

Dehydration and exhaustion would have added to the danger.

Yet Aghnaanga stayed with the boat.

That decision may have saved his life.

An overturned vessel is significantly easier for search crews to spot than a person alone in open water.

When rescuers finally reached him, he had survived long enough for help to arrive.

But the relief of finding him alive was immediately mixed with grief.

His family was not getting everyone back.

A GoFundMe created to support the family and help pay funeral expenses quickly approached its $40,000 goal.

The campaign reflects the extraordinary emotional collision surrounding the rescue.

One family member survived what seemed almost impossible.

Two others did not.

And a 15-year-old boy now has to live with memories few people could imagine enduring.

For nearly three days, the overturned skiff was the only thing separating him from the Bering Sea.

It was where he watched his family members disappear.

It was where he waited without knowing whether anyone was coming.

And it was where rescuers finally found him.

Alone.

Freezing.

Exhausted.

But alive.