Steelhead activists confront surfers over “standing waves” at Carmel Lagoon.

After a February storm, Carmel River Steelhead Association President Brian LaNeve headed to the rising lagoon at Carmel River State Beach. That’s when he saw four surfers trying to cut a manual breach, digging first with their hands, then using bodyboard fins as shovels.

LaNeve says he convinced them to stop and fill in the trench. “Legally I can’t condone it,” he recalls telling them. “As a kid, I probably would have done it.”

When water flows over a shallow spot in a river, the current breaks, creating a standing wave steep enough to surf. At Carmel Lagoon, surfers sometimes make one by digging into the mouth of the lagoon, allowing gravity to pull water into the ocean.

“It’s a novelty,” says local surfer Ron Triplett. “It’s something to do when the waves aren’t good.”

But a manual breach at the wrong time, LaNeve says, can be catastrophic for native Carmel River steelhead. If surfers carve a breach when no water is coming down the river, it can drain the lagoon before summer, leaving juvenile fish without critical habitat until the winter rains.

Young local surfers apparently started breaching the lagoon in the past few years, LaNeve says.

The potential risks to steelhead don’t seem to have caught up with the Monterey Bay chapter of Surfrider, a nonprofit organization for environmentalist surfers.

Triplett, the chapter’s board chair, has heard of surfers arguing with beachwalkers over lagoon breaching. (The police were called in an altercation last month, he says.) But he hadn’t known it could endanger steelhead.

“No comment, and that’s because I’m ignorant of the issue,” he says. “That’s not ever been discussed at our meetings.”

Ximena Waissbluth, a Surfrider board member and environmental activist, echoes his surprise. “That’s not something that’s been flagged for us,” she says. “It’s certainly something that we wouldn’t support, now that I know.”