When there’s a lot of hype around anything — a movie, restaurant, landmark — it’s hard not to be let down by reality. Ever seen Plymouth Rock?

But Mother Nature has surprised me lately, exceeding my expectations with her natural phenomena: First, there was last year’s total eclipse, then the Northern Lights and now, the alewives, which, if you hurry, you can still see making their way up Maine’s rivers and streams.

I’ve been trying to get a glimpse of these fish for years, as they migrate over the span of a few weeks each spring from the ocean to lakes and ponds where they spawn. But the timing and duration of their run varies, depending on the weather and water flow, and either I’ve missed it altogether or I haven’t known quite where to look, until now.

I almost overlooked them this year, too, when — upon hearing that the migration had gotten started early (thanks to higher air temperatures and rainfall earlier this spring) — I headed out to Mill Brook Preserve in Westbrook the first chance I got. If it wasn’t for a woman standing atop a rock jutting out into the water from the trail, smiling as she filmed the stream with her phone, I might not have realized that was the spot.

It takes a minute, too, for your eyes to adjust to seeing what’s below the surface (though polarized sunglasses help), but once they do, it’s dramatic. In an eddy, an impossible number of fish were seemingly treading water as they built up the strength to try to make it over the ledge of rocks upstream. Meanwhile, a smaller but determined group attempted to swim up the waterfall, continually getting swept back down and whipped around by the whitewater.

It was both hard to watch and hard to look away, like when a Kardashian cuts a cucumber.

But I was heartened to find out that, no matter how many times it takes, alewives will keep trying to make it over any obstacles in the river until they succeed, according to Zach Whitener, senior research associate at the Gulf of Maine Research Institute in Portland. That is, if they don’t get eaten trying, a common occurrence and part of why they’re so important to the ecosystem.

Full of ocean grub, these fish are calorie bombs akin to cheeseburgers for any animal that gets its beak or paws on them, Whitener said. In fact, their round bellies, said to resemble the stereotype of a female tavern owner, are where the species gets its name.

But before we go canceling this fish, let’s consider what it’s accomplished. Dams, pollution and other impediments in Maine’s rivers led to the species’ disappearance from some bodies of water for as many as hundreds of years (including Highland Lake, where the alewives in Mill Brook were headed).

Recent recovery efforts — such as removing dams, installing fish passageways and stocking lakes — have worked so well, however, that they can now be fished in greater numbers, with bodies of water in Arrowsic, Penobscot and Pembroke coming on board this spring as sites for the commercial harvesting of alewives, often used as lobster bait. Its predators, like eagles and osprey, also have rebounded as a result, Whitener said.

That’s a pretty powerful fish and, I think, worth appreciating up close. Because of high river flows and unusually cold weather, people should be able to see the alewives in the Sebasticook, Damariscotta and Androscoggin rivers, as well as most smaller streams, through Memorial Day, said Mike Brown, head of Fisheries Management and Monitoring for Municipal Harvest at the Maine Department of Marine Resources.

So, if you can, make a point to get to your nearest alewife viewing site or make a plan to do it next spring. The perseverance of this fish, in the face of both physical and ecological hurdles, is something to behold.