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  • Physical and biological effects of fish-friendly tide gates


Northwest Fisheries Science Center (NWFSC) Fish Ecology FE - Watershed


Tide gates
Physical and biological effects of fish-friendly tide gates
The purpose of this one-time stand-alone study is to evaluate how effective "fish-friendly" or self-regulating tide gates (SRTs) are at increasing connectivity for fish rearing in estuaries. The work was carried out in North Puget Sound, Washington Coast, and Columbia River estuaries by Correigh Greene, Jason Hall, and Eric Beamer (Skagit River System Cooperative), and compared SRTs with traditional flap gates and reference sites that were not blocked by any tide gate. Thus far, the study has produced a report for ESRP (Estuary Salmon Restoration Program), the organization that funded it. Up to two peer-reviewed papers are planned. The audience for this work includes federal and state managers, local planners, Watershed Councils, and applied ecologists.

Research Themes

Habitats to support sustainable fisheries and recovered populations
Healthy oceans, coastal waters, and riverine habitats provide the foundation for aquatic resources used by a diversity of species and society. Protecting marine, estuarine and freshwater ecosystems that support these species relies on science to link habitat condition/processes and the biological effects of restoration actions. The NWFSC provides the habitat science behind many management actions taken by NOAA Fisheries and other natural resource agencies to protect and recover aquatic ecosystems and living marine resources. The NWFSC also maintains a longstanding focus on toxic chemical contaminants, as a foundation for regional and national research on pollution threats to fisheries and protected resources.
Recovery and rebuilding of marine and coastal species
The Pacific Northwest is home to several iconic endangered species, including Pacific salmon and killer whales, and several rockfish species. Mandates such as the Endangered Species Act, MagnusonStevens Act, and the Marine Mammal Protection Act, grant NOAA Fisheries the authority to manage the recovery of depleted species and stocks. The NWFSC contributes to species recovery through research, monitoring and analysis, providing NOAA managers and regional stakeholders the tools and information they need to craft effective regulations and develop sustainable plans for recovery.

Research Foci

Characterize the interaction of human use and habitat distribution, quantity and quality
The ability to define the state of an ecosystem requires insight into the natural processes within habitats, and how anthropogenic interactions with these processes can alter ecosystems and marine organisms. A wide diversity of human activities -- land use and water withdrawals, industrialization and dredging, fishing practices and climate change (e.g., ocean acidification) -- directly and indirectly impact critical freshwater, estuarine, and marine habitats. To best manage west coast marine, estuarine and freshwater habitats in a sustainable fashion, it is necessary to map the spatial and temporal footprint of human impacts and review their potential biological impact on each species of interest. Measurement parameters will be developed to determine the full range of human impacts using spatial data and improved habitat classification.
Describe the relationships between human activities and species recovery, rebuilding and sustainability
Human activities play a major role in determining the status of species and stocks. Rebuilding and recovery therefore need to address how these activities affect their status. At the NWFSC, biophysical modeling is used to link specific human activities such as land use and pollution to habitat conditions, and then to link these conditions and other activities to particular life stages. These models can be used to quantitatively assess how human activities influence species abundance, productivity, distribution and diversity. Not surprisingly, altering human activities in some way is often necessary for species or stock recovery and rebuilding. It is therefore important to understand the socio-economic effects of alternative management structures. Gathering data on their economic costs and social impacts helps identify actions that are cost-effective. These actions will need to be resilient to potential changes in climate throughout the region. Research on how humans react to management strategies helps policy makers avoid those that lead to unintended consequences that can hinder rather than help recovery.
Develop effective and efficient habitat restoration and conservation techniques
Maintaining and re-establishing viability and sustainability of living marine resources requires conservation and rehabilitation or restoration of habitats upon which species depend. Common habitat restoration approaches and tech-niques often presume that habitats are static features of the environment, and that creation of stable habitats is a desirable restoration strategy. However, riverine, nearshore, and marine habitats are created and sustained by dynamic landscape, climatic, and oceanographic processes and biota are adapted to changing habitats that are within the range of natural variability. Hence, current restoration strategies often have limited success, in part because they fail to recognize larger scale processes that drive habitat change, and in part because they fail to recognize intrinsic habitat potential of individual restoration sites. The main goals of this research focus are to: improve understanding of how large-scale processes create diverse and dynamic habitats that support marine and anadromous species, better understand how human activities alter habitat-forming processes and habitats, develop new restoration techniques that are compatible with sustainable habitat-forming processes, and understand the variety of actions needed to adequately conserve intact critical habitats. In addition, NWFSC’s research will improve understanding of how new and existing habitat restoration and protection techniques affect fish and habitat at multiple scales (i.e., reach, watershed, Evolutionarily Significant Unit).


physical linkages between areas
habitat use
how animals use their environment (e.g., foraging)
tide gates
gates used to mute or eliminate tidal inundation


Biological and Physical Effects of Fish-Friendly Tide Gates


Class Actinopterygii
ray-finned fishes
Species Oncorhynchus clarkii
cutthroat trout
Species Oncorhynchus keta
chum salmon, dog salmon, Keta salmon
Species Oncorhynchus kisutch
Coho salmon, silver salmon
Species Oncorhynchus mykiss
rainbow trout, steelhead trout, syeelhead trout
Species Oncorhynchus tshawytscha
Chinook salmon, king salmon, spring salmon


Correigh Greene
Principal Investigator
Jason Hall
Internal Collaborator
Joshua Chamberlin