A California blue whale, 65-feet-long, swims off the coast of Baja, Calif. (Gilpatrick/Lynn/NOAA)

Good news! According to a study published in the journal Marine Mammal Science, the endangered California blue whale population has probably returned to near pre-whaling levels. Bad news: They're the first set of blue whales to do so, and we still keep hitting them with ships.

The blue whale is a magnificent beast in the truest sense of the word. At close to 100 feet in length and weighing in at around 200 tons, they're the largest known animals on the planet. And they weigh two to three times as much as the heaviest known dinosaurs. A casual exhalation can send water shooting 30 feet high from out of a blue whale's blowhole, and their hearts weigh as much as a car. Despite that massive size, they can swim gracefully and (sort of) quickly: When agitated, they achieve speeds of more than 20 miles an hour.

But commercial whaling -- the hunting of whales for meat and oil -- hit worldwide populations hard. The hunting of blue whales for commercial purposes was banned by the International Whaling Commission in 1966, and since then only illegal whaling (and incidental deaths related to other fishing, shipping, and pollution) have threatened the species. We know that the blue whale population in the North Pacific (most often spotted in California, as the whales migrate there during the summer) has now reached about 2,200, the largest known on earth. Researchers previously assumed that the pre-whaling population must have been much higher than that, but the authors of Friday's paper disagree.

The researchers used historical data to estimate the number of whales caught from each population between 1905 and 1971. They now estimate, based on the relative number of whales that were caught in the North Pacific, that the current population is actually at 97 percent of the historical one.

If California has always had a relatively small blue whale population, it explains why the area's population growth has slowed in recent years: It may be almost back to normal. The researchers believe that our nasty habit of running into whales with our ships (at least 11 were struck along the west coast last year) isn't actually a major concern. They believe that the population can maintain its stability regardless. "It's a conservation success story," lead author and University of Washington doctoral student Cole Monnahan said in a statement.

Still, the researchers said, it would be really, really great if we could stop ramming into endangered whales with our ships. California may have reached its capacity for healthy and happy blue whales, but we don't want to backtrack. As for the rest of the world's blue whale populations, there's still a long way to go.