Fish Habitat Restoration
CARP undertakes a variety of complimentary projects that contribute to the conservation of native fish populations and the restoration of fish habitat. These projects typically include some combination of research, monitoring, restoration, and local ecological knowledge.
In order to make informed decisions we need information. In terms of fish and fish habitat conservation there is a wide variety of types of information that may be required, based on a project’s specific objectives. These types of information includes:
Water quality: the chemical, physical and biological properties of water
Fish community structure: what species of fish are found in a given area
Barriers to fish migration (e.g. culverts)
Habitat suitability: how well can a given area support a species vital life life functions
Fish age & growth: this can be determined by examining scale samples
Monitoring is a critical component in long term projects because it allows us to identify changes over time.
Without monitoring we would not be able to tell, with any certainty, whether our actions are having the desired effects. By evaluating the data obtained through monitoring programs we can also identify areas for improvement or other issues that need to be addressed.
Restoration work involves making physical changes to the landscape, in order to return it to a more natural state, or to bring back natural functions that have been altered by human activities.
The installation of culverts or dams is a common action that leads to the alteration of fish habitat. Improper installation can cause a barrier to fish migration, cutting them off from upstream habitat. Clearing blocked culverts and installing fishways are two types of restoration work used to address this issue.
De-vegetation of streamside habitat is another common issue on the Annapolis River. Trees and shrubs provide shade, which helps regulate water temperature, which fish such as brook trout are very sensitive to. By re-vegetating rivers and streams we can create suitable fish habitat. Plants will also help in preventing soil erosion, and aid in filtering water.
Local Ecological Knowledge
Local anglers and other recreational users hold a wealth of knowledge about the rivers and species they fish. Anglers are often the people who interact most with fish and the habitats that support them. We are currently seeking anglers who are interested in sharing their knowledge with us. This knowledge might include where species were caught in the past and at present, where certain species are no longer found, and how river conditions have changed over time.
Community members also have many great ideas about how to approach projects and the areas where work is needed is most. We want to establish a dialogue with community members so that we can exchange information, and work cooperatively to accomplish projects that are of mutual benefit.
Fragmentation of fish habitat is a prolific issue in the Annapolis River watershed and throughout Nova Scotia. Native fish species, such as brook trout and Atlantic salmon, require access to a variety of habitats in order to spawn, forage for food, and find cool water during warm summer months.
One of the predominant causes of aquatic habitat fragmentation is from watercourse crossings (such as culverts) that create barriers which restrict movement of fish through a river system, cutting off their access to important habitat.
Over 70 % of the culverts that Clean Annapolis River Project has assessed since 2007 are barriers to fish passage. In order to address this issue, CARP has begun implementing a variety of restoration actions.
Commonly Encountered Issues
Accumulation of debris can block the inflow, outflow or inside of a culvert. Debris removals are conducted to restore water flow and maintain fish passage at such sites.
Large outflow drops
The outflow drop of a culvert refers to the vertical distance between the bottom of a culvert and the pool directly downstream (called the tailwater). Outflow drops create a barrier to fish movement when the elevation between the water level in a stream and the water level in a culvert is too great for fish to
High water velocity
When culverts are installed on too steep of a slope, the velocity of water passing through the culvert can exceed a fish’s swimming ability. In some cases, channel roughening can be used to slow water velocity
through a culvert, or in more extreme cases, baffles can be installed.
Native salmonids of Nova Scotia
Barrier culvert assessment
Barrier culvert remediation
Subwatershed management planning
Habitat restoration and enhancement
Training and capacity building for NGOs and community organizations