Posted on April 2, 2025
The Fraser River Estuary is one of the most ecologically significant places in British Columbia, containing intertidal marsh and mudflat habitats that support Pacific salmon, migratory birds, and many other species. However, over a century of development has reduced these habitats to an estimated 70 per cent of their historical extent. Remaining habitats face several threats, including climate change, invasive species, and altered natural processes.
Though efforts to build new tidal marsh habitats in the estuary have been occurring for over four decades, a recent study led by Ducks Unlimited Canada identified the challenges these projects face and observed that many no longer function as they were originally intended. The authors of this study proposed that new, innovative approaches are needed to build healthier and more resilient tidal marshes in the Fraser Estuary, like designing and experimenting with approaches that leverage natural processes, and developing targeted invasive species management techniques.
With funding from the Government of Canada and the Province of British Columbia through the BC Salmon Restoration and Innovation Fund, an initiative called Restoring Fraser River Estuary Salmon Habitat (ReFRESH) leans into the identified knowledge gaps that past research has revealed. ReFRESH has many goals, including applying innovative solutions to coastal marsh restoration through pilot projects like the Sturgeon Bank Sediment Enhancement Pilot Project, and studying and monitoring local sites to further understand the effectiveness of certain interventions, and is in its early stages of bridging the gaps in our understanding of marsh creation and ecological function in the Fraser River Estuary. Led by Ducks Unlimited Canada, Raincoast Conservation Foundation, Asarum Ecological Consulting, and the Lower Fraser Fisheries Alliance, ReFRESH aims, in part, to ensure that future restoration efforts are guided by both scientific insights and local Indigenous knowledge.
An aerial view of the Fraser River before it meets the Pacific Ocean.
Re-telling the story of marsh creation
Marsh creation in the Fraser River Estuary is not a new concept. From early dredge spoil islands to modern restoration projects, human influence on these landscapes has intensified over the past century. However, much of this history has gone undocumented. Many biologists involved in early restoration work are retiring, and with them, valuable lessons risk being lost. Even more importantly, the role of Indigenous communities in stewarding these ecosystems for millennia has largely been overlooked.
ReFRESH is working to change this by assembling a comprehensive history of marsh creation in the estuary. By weaving together scientific records, historical accounts, and Indigenous perspectives, this project will create a foundational resource for future restoration work.
Biologists and field staff catalogue fish and intertebrate species as part of a monitoring program.
Do created marshes work?
Over the years, more than 100 marsh creation projects have been undertaken in the estuary, yet there has been little long-term monitoring to determine whether these habitats function as intended—especially for species like salmon that rely on estuarine environments for survival. By assessing fish and invertebrate communities in both created and natural marshes, this research will provide insights into what design elements enhance ecological function. Understanding how these habitats support biodiversity will help ensure future projects are more effective.
Where should we focus conservation efforts?
One of the biggest challenges in restoration is deciding where to allocate resources. With so many competing priorities—salmon, migratory birds, culturally significant species, carbon sequestration—how do we determine the best places to restore? These research components of ReFRESH will develop a prioritization framework to guide conservation decisions, ensuring that future efforts are strategic, impactful, and aligned with the needs of Indigenous communities and conservation organizations alike.
By bringing together history, science, and Indigenous knowledge, this research has the potential to reshape the way we approach marsh restoration in the Fraser River Estuary. The lessons learned will not only help restore vital habitats but also ensure that the voices of those who have stewarded these lands for millennia are at the heart of conservation efforts.
Biologists and field staff take readings at a monitoring station along the Fraser River Estuary
