World Fish Migration Day brought a curious parade at Amoskeag Fishways

May 29—On World Fish Migration Day Saturday, in the underwater viewing room at Manchester's Amoskeag Fishways, curious minds age 4 and older were transfixed by a riverside show.

Merrimack River travelers including river herring, shad, smallmouth bass and sea lampreys were on parade during the peak of fish migration season in New Hampshire.

Spectators pressed themselves to the glass, waiting for the next species to make a cameo appearance.

"There goes another one!" squealed 7-year-old Arya Antinoro of Derry, spotting a pink and brown lamprey — which looks like a smiling eel decorated with confetti and not what it really is: a prehistoric cousin of sharks. Another lamprey — a fish barely changed from the Earth's Cretaceous period — latched onto the viewing room glass to rest on its way upriver to spawn. It flashed a double row of teeth in its ring-shaped mouth, perfect for hitching onto passing travelers.

What's to like about all these creatures?

"They swim," said Aria's 4-year-old brother Anthony, demonstrating with his arms, as river herring whizzed by like racehorses neck and neck. "It's a school!" Anthony exclaimed.

World Fish Migration Day isn't a holiday, an event on a Google calendar, or an occasion many people know about. It's been celebrated worldwide every two years since 2014 as a way to remember the importance of healthy, clean, free-flowing rivers — which support the fish that swim upstream to lay their eggs, as well as other freshwater critters, including the microscopic ones.

With warmer water temperatures, "We are seeing different fish migration patterns in the Merrimack," said Patrick Kuklinski, Fishways' operator, an environmental scientist who delves into what's happening in the river.

Rising temperatures and combined sewage overflow into the Merrimack, plus rainwater washing pollutants from land into the river, are having an impact on the Merrimack's inhabitants.

World Fish Migration Day's founders, the World Fish Migration Foundation, advocate for ways to restore and protect healthy, free-flowing rivers, and for closely monitoring the fish populations that use them as migratory routes.

Ashley Antinoro first came to Amoskeag Fishways when she was 6 and brought her two children and parents Saturday to experience "just getting up close and personal with the fish."

Fishways was installed in 1989 because the dam in Manchester made the river impassable for fish that swim upstream to spawn, Kuklinski said. Fishways' Atlantic salmon restoration project ended in 2013 because of insufficient numbers of salmon to make it worthwhile. Few if any Atlantic salmon migrate up the Merrimack today, he said.

Max Grammes of Bedford, who is 4 going on 5, was fascinated by Saturday's underwater wonderland that kept changing before his eyes. Two years ago, his family moved to New Hampshire from Florida, where Max first became interested in sharks and animals in general.

He eagerly announced his favorite fish, the one he would pick if he could become any species: "Tuna fish!"

"He loves going to the big sandbox — the beach," said his mother, Alexis.

"I want to be a lamprey. They have spots and they're movin'!" said Jace Gallo, 5, of Pittsfield, as more part-time river dwellers scooted by in a swarm of bubbles.