As SFist noted earlier this week — and as I myself witnessed first-hand from a sailboat on Sunday — there have been a bunch of whale sightings inside the Golden Gate recently. Not being whale experts, both I and the photographer who shot the above photos of a breaching whale on Tuesday believed we were probably seeing gray whales, as gray whale mothers and calves are known to take pit stops in bays like ours to nurse or rest on their trips north to Alaska. But, those are indeed humpback whales, and their appearances in the Bay in large numbers are actually alarming biologists, as the Chronicle reports, because this is not typical behavior for them at all.

So on the one hand, we're having some very special whale watching moments right here, even within view from land in many cases. But on the other, scientists are worried about all the bad things can happen when animals this big get too close to unwitting boats and vice versa, not to mention several other concerns.

But, then, the same thing seems to have happened with humpbacks — perhaps even the same family, or some relatives — last year.

Mary Jane Schramm, spokesperson for the Greater Farallones National Marine Sanctuary, has an office at Crissy Field and last year she told SFGate that a sighting of a family of three humpbacks inside the Golden Gate was "really special." The spate of humpback whale sightings that continued just outside the Gate through July 2015 was reportedly due to larger numbers of anchovies and krill where they haven't typically existed before.

This year, almost a year to the day, the Chron returned to Schramm for another quote, and this time it's because of even greater numbers. "I’ve been in this game for a lot of decades, and this is the first time I’ve heard of this many humpbacks coming in this far," she said. She points out that humpbacks' food sources tend to be farther offshore, and they could become disoriented the farther they come into the Bay. "The deeper they get into the Bay, the more acoustically confusing it becomes," she says.

Humpbacks are rare sightings in the Bay because they tend to avoid narrow channels like the Golden Gate, and it's curious why they're here in such numbers over the last two weeks. The video below was shot by Lauri Duke, a volunteer at the Marine Mammal Center who said she'd never even seen a humpback in person before.

The other danger is whales breaching right next to boats or kayakers, which can result in this, as seen below, from Monterey Bay last September.

Luckily, those kayakers survived unscathed, but that actually is super dangerous when humpbacks can weigh up to 40 tons.

It's also unclear just how many whales there are, or if people just keep seeing the same pod hanging out in various places near Alcatraz and the Golden Gate. My group saw what we believe was a pod of four on Sunday, but it got confusing when they separated into two pairs at one point.

And this spate of sightings is of course making locals bring up the tale of Humphrey, a humpback who more than once tried swimming upriver into the Delta and became stuck there in 1985, making national headlines. Another pair of humpbacks, a mother and calf nicknamed Delta and Dawn, swam 90 miles upriver in 2007 after being in distress from being hit with a boat propeller — speaking of reasons why scientists are concerned.

Below, CBS 5's Chopper 5 footage of two humpback whales near Crissy Field on Monday.

Previously: Video: Pod Of Whales Frolics Near Crissy Field
Video: Rare Footage Of Gray Whale Mother And Two Calves Caught By Drone