FIELD NOTES: TIDELINE TO ALPINE

Test Pilot Sean Jansen doesn’t approach adventure as spectacle. His work lives in the space between endurance and awareness, using long, self-supported journeys as a way to understand place and bring attention to what’s at risk of being lost. A conservation-driven adventurer, writer, and fly fisherman, Sean is drawn to routes that demand patience and humility.

As a fly fisherman, steelhead trout once moved through the waters he grew up around, San Mateo Creek, home to Lower Trestles. Today, every remaining population is on the verge of extinction. “I wanted to do a trip where my arena wasn’t in constant motion,” Sean told us. One that gave back to his native Southern California. 

Tideline to Alpine became a way to connect those dots. On foot, Sean traced the coastline to where rivers meet the sea, then followed those systems inland. The early miles along the coast were sobering. “Homes, concrete, and development,” he said. The channels where freshwater once flowed freely were often constrained or erased altogether.

Snow, overgrowth, bears, mountain lions, rattlesnakes, and deep solitude replaced pavement and seawalls. “That’s when I realized how much hope was still left,” Sean said. Not only for the fish, but for how wild Southern California remains, often hidden in plain sight within an hour of Los Angeles. By December 2025 when Sean concluded the expedition, he had walked 1,200 miles over 86 days, taking 2.6 million steps

Sean primarily relied on the Airtex Hooded Long Sleeve for protection from sun, branches, insects, and exposure. An essential piece for the journey that mattered just as much as his water filtration system. Breathable layers that could handle constant movement, long days, and harsh conditions

And through it all, the steelhead remained the point.

The trip delivered a blunt field lesson: across many river systems in the range, the headwaters are still pristine, but only a small handful of waters flow freely to the sea. Over nearly 1,200 miles, he recorded only one potential steelhead sighting, a stark reminder that this is an edge-of-existence story.

 “Despite our backgrounds, we all still have tools that can inspire change,” Sean said. If we want these fish back, we have to give them passage to what still works: reconnect the pathways so they can reach cold, intact headwaters and rebuild from there, an approach he aligns with ongoing barrier-removal work led by CalTrout and partners. 

From tideline to alpine, Sean’s path is a reminder that conservation doesn’t require perfection or credentials. It requires attention, effort, and a willingness to move through the world with purpose. Sometimes, the most important work begins simply by walking it out. 🚩

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