Lagoons of San Juan Island

Jakle's Lagoon

NPS

Coastal lagoons are recognized as being particularly important ecological habitats to many plant and animal species. Old Town, Jakle’s, and Third lagoons, all located in American Camp, are the only temperate marine lagoons on San Juan Island. Lagoons are rare in the Pacific Northwest and many plants growing around the lagoons are regionally unique, including native Virginia peppergrass—a host plant of the endangered island marble butterfly.

Invasive species and strong winter storms threaten the lagoon ecosystem. Park staff monitor changes in the lagoon, remove invasive plants, and survey and document the island marble butterfly and its habitat.

Virginia peppergrass, the only native host plant of the island marble butterfly, likes to grow in between driftwood. Please help protect this endangered butterfly by not removing or stacking driftwood. You may inadvertently crush its host plant and cause harm to eggs and larvae.