(CNN) The fate of the increasingly rare North Atlantic right whale has always been left up to humans.

Once hunted nearly to extinction, their population is sharply declining again. Any hope for their survival, researchers say, demands immediate action.

A new report from Oceana, a non-profit ocean advocacy group, says unless protections are put in place, the North Atlantic right whale will die out.

"At some point, if trends continue, recovery will simply become impossible," researchers wrote.

There are only 400 of them left, and less than 25% of them are breeding females responsible for the species' survival. At least 28 have died in the past two years, Oceana campaign director Whitney Webber told CNN.

It's a sharp decline driven by fishing, boating and climate change that impacts their food supply, according to the report.

"We're really not seeing the whales die of natural causes anymore," she said. "They're dying at our hands."

The decline is driven by human activity

They're called the right whale not because it's their dominant side, but because they were once the "right whale" to hunt -- they swim close to shore and float when they're killed.

By the time whaling was banned in 1935, they were hunted nearly to extinction. Then, in recent decades, the whale found new enemies.

At least 100 right whales become entangled in vertical fishing lines every year, the report said. Fisheries use traps and pots on the bottom of the ocean with vertical lines attached to buoys so they can pull them up.

North Atlantic right whales like this one struggle to free themselves from fishing gear. Entanglement is one of their leading causes of death.

More than 1 million of the lines cut through whale migration paths in the US and Canada, Webber said. "It's a minefield out there," she said.

They lines are extremely strong to carry the weight of the pots and traps, so when whales get caught in them, they often drag them for months, which slows them down and makes it harder to eat, reproduce and swim. The line cuts into their flesh, too, causing an infection that could kill them.

But those have challenged whales for years. Things have gotten much more dire in the past two years, Webber said.

Since 2017, 8% of their population -- 28 whales -- have died in what the National Oceanic and Atmospheric Administration has dubbed an "unusual mortality event."

It's likely because their food source, a tiny plankton called copepods, are fleeing for cooler waters further north, Webber said. In Canada, the whales face more fishing lines in the water and heavier ship traffic, not to mention hundreds of additional miles in travel.

This means a search for a meal could be fatal.

These problems compound the whale's low birth rate. The mammal doesn't reach sexual maturity until it's 10, and females typically give birth to only one calf every three to five years. Stress from fishing gear entanglement, though, has stretched the period between births to 10 years, the report said.

The whales had names and families. Researchers are crushed

Because there are so few whales, researchers keep a catalog of them. All have numbers, but some, like Punctuation, had names.

The team that's studied them for years know their lineage and have watched children become parents, and in some cases, grandparents.

Punctuation, a grandmother whale named for the comma- and hyphen-shaped marks on her back, was killed in June after a vessel struck her, the report said.

Researchers investigate the death of Punctuation, a grandmother right whale who'd been studied for nearly 40 years. She was killed in a boat collision.

She'd survived two earlier vessel collisions and had been caught in fishing lines five times, but these injuries were too severe to survive: Her organs began to creep out of a 6-foot cut on her back.

She'd had eight calves between 1986 and 2016, and two of them bore their own calves. Many of her calves died under similar circumstances.

Researchers followed the matriarch for 38 years. Her death was a crushing blow, Webber said.

"They knew these whales," she said. "They're very personal."

There are ways to save them

"Functional extinction" is likely in the the next few decades if things don't change. Oceana advocates are working on a proposal for removing vertical fishing lines from the Atlantic, but that process could take years to move through the US government, if it goes anywhere.

In the meantime, the report outlines several recommendations that could improve the North Atlantic right whale's numbers. Two are essential: Discontinuing the use of vertical fishing line, and enforcing speed restrictions in the ocean.

Trading the manual vertical lines for something more high-tech, such as an automated system, is still a ways away, Webber said. In the meantime, fisheries can temporarily close the areas where lines are drawn while whales are in them.

In the United States, many zones with slower speed recommendations are just that -- recommendations, not mandatory restrictions. If speed limits on the ocean are enforced, whale collisions could drop 86%, she said.

Their lives impact the life of the ocean

Seeing the whales go extinct would be "horrific, embarrassing, every bad word there is," Webber said.

"Every creature has a role to play in the ecosystem," she said.

A healthy ocean ecosystem translates to healthy coastal economies. Fisheries rely on the abundance of their crop, and when a link in the food chain disappears, the loss upsets the ecosystem's balance, disrupting population sizes and the presence of natural predators and prey.

If they're gone, the Atlantic Ocean would lose one of its largest and rarest whales.