Land Use Concerns
The way we use the land has direct impacts on the nearby stream habitat.
Fertilizers and pesticides are contaminants that can harm the health of fish and aquatic habitat. Poor livestock management and increasing urbanization can both result in habitat degradation.
Fertilizers/Pesticides
Fertilizers and pesticides can be toxic to fish if they enter the water. Metals contained in fertilizers and pesticides are also contaminants. Zinc, copper, lead, and aluminum can accumulate in the sediment where insects thrive. Fish feeding upon these insects are affected resulting in abnormal development and reproduction.
Phosphorus and nitrogen, which come from fertilizers, can cause algal blooms which reduces the oxygen in the water, decreasing fish survival. Organophosphorus, a type of pesticide, used in agriculture, gardens, and on pests, causes dark-red discoloration, hemorraging, tremors, convulsions, and spinal abnormalities in fish. Also, the delivery agent in spruce bud worm spray is thought to impact salmon smoltification.
Livestock
The way livestock is managed can impact streams and fish habitat. When livestock are permitted to graze along the edge of the stream, they increase sedimentation in the river. The stream banks are weakened when vegetation is overgrazed, resulting in erosion. When the vegetative cover is lost, runoff increases. Coupled with manure, this runoff can be a source of contamination for the nearby stream, harming resident fish and aquatic insects which need clean, cool, well-oxygenated water to thrive.
CSOs
Combined sewage overflow (CSO), is the result of aging and inadequately sized sewer pipes. Old pipes can not hold both storm drainage and sewage, so overflow ends up in local rivers. Even well-managed sewage treatment effluent may present a challenge to fish since some contaminants, like estrogen, are not cleaned out of the water before the effluent is dumped back into the river. Exposure to hormones has been shown to have an impact on fish physiology, growth and development. Storm drainage can also carry contaminants from roads and parking lots.
Urbanization
During rain storms, pollutants from dirty streets including pet waste, herbicides, vehicle waste, and household chemicals wash into local streams. Urban areas with riverbank development increase erosion because of the loss of vegetation, decreased flood plains, and river channelization.
About Us | Recreational Fishing | Work With Us | Fisheries Management
Habitat Restoration | Fish Production | Invasive Species
Data | Education | Contacts | Links | Site Map | Home
U.S. Fish and Wildlife Service