Seth Muir is stepping down after seven years at the helm of Salish Sea Expeditions, the nonprofit has announced.

Muir’s last day as executive director was Jan. 16. He is leaving to become the executive director with Sail Sand Point.

“Seth has been a great advocate for supporting science education and the health of Puget Sound, a great representative of Salish, and a great leader who has built and strengthened the organization,” said Trina Wellman, Salish’s board president.

“I love the work that Salish does, and there has never been a more important time for organizations like Salish to inspire middle school and high school students with confidence, critical thinking and scientific curiosity,” Muir said. “Salish is well-positioned for growth.”

The board for Salish Sea Expeditions has appointed Matt Eldridge as interim executive director while the organization conducts a national search for a new director. Previously, Eldridge served on Salish’s board and separately as its interim executive director. He also chaired the search committee that hired Muir in early 2012.

“While we will miss Seth, we are pleased that someone from Salish will be helping a fellow Northwest maritime organization to further its mission,” Wellman added. “We are excited to have Matt manage Salish while helping to recruit its next executive director.”

Eldridge has held multiple interim leadership roles in the greater Seattle area over the past eight years as interim executive director at the Kirkland-based Wave Aquatics, as interim executive director at Bainbridge Island’s Helpline House, and in two transitional senior vice president roles at IslandWood. He is also a co-founder of the impact investing network investorflow.org.

Eldridge holds a bachelor’s degree from Stanford, a master’s from the University of Cape Town, and a MBA from Yale. A graduate of Gig Harbor High School, he grew up sailing on the waters of Puget Sound.

Salish officials said that under Muir’s leadership since 2012, Salish has reached a total of 17,000 students since formation, increased program offerings to expand participation, and solidified significant funding relationships with area foundations and federal and state agencies (including being among the first organizations to be awarded a No Child Left Inside grant from Washington State Recreation and Conservation Office).

Additionally, during Muir’s tenure Salish acquired the 85-foot ship M/V Elettra III and received a Jones Act Waiver from the U.S. Congress to operate the vessel. He also won first prize in Social Venture Partners’ 2015 Fast Pitch competition where he shared the organization’s vision for expanding its reach and impact aboard the Elettra.

At Sail Sand Point’s Magnuson Park office in Seattle, Muir will lead expansion of the nonprofit organization’s programs which are designed to bring the joy and life-enhancing benefits of sailing and small boats to people of all ages, abilities and backgrounds.