PORT ANGELES — Smelt, a tiny fish with big importance, is the latest species to show rapid recovery after the fall of the Elwha River dams.

The marine waters near the Elwha’s mouth have experienced a 20-fold increase in surf smelt abundance since the dams were removed two years ago, according to a study led by the National Oceanic and Atmospheric Administration.

“We’re seeing a big rebound,” said Anna Kagley, a NOAA fishery biologist.

Surf smelt are a schooling fish that grow a bit bigger than sardines. They and other forage fish, such as herring and sand lance, are key food sources for seabirds, marine mammals and salmon.

“They’re the meat and potatoes of the marine food system,” Kagley said. “So it’s nice to see them recover.”

Several other species are rebounding where the Elwha meets salt water at the Strait of Juan de Fuca, including Dungeness crab, flounder and sand lance.

Candlefish, a forage fish listed as threatened under the Endangered Species Act, began appearing in the river’s mouth shortly after the dams came down. The fat-rich fish hadn’t been seen in the Elwha’s estuary in at least 60 years.

Many Puget Sound forage fish stocks have experienced sharp declines in recent years. To the surprise of scientists, the strait may be experiencing a bit of a population boom. The revived Elwha can’t take full credit, but it can claim credit for the substantially bigger boom at its mouth.

The 20-fold increase in smelt is thanks to the tons of pent-up sediment that flowed downriver after the concrete dams were blasted out. The wave of sand rebuilt the estuary and turned rocky beaches into prime smelt spawning habitat. Smelt spawn in the tidal zone, usually near sandy bluffs or river mouths, which provide fine sand granules that match smelt’s millimeter-sized eggs.

“Herring and other forage fish spawn in larger gains of sand, but smelt prefer small sand like the kind we’re now seeing at the Elwha,” Kagley said.