Threats to fish and fish habitat in Canada

The sustainability and productivity of fisheries today are threatened by multiple and interacting stressors, including:

  • habitat degradation or loss, which may occur as a result of the fragmentation of habitat, infilling of lakes or streams, conversion of wetlands or other activities in a watershed such as logging, urbanization, or the clearing of riparian or aquatic vegetation;
  • flow alteration, which may alter habitat characteristics or cause the death of fish, and may be caused by dams or other impoundments, water diversion, stream crossings or water extraction for uses such as municipal, industrial, or agricultural uses;
  • aquatic invasive species, which may threaten fish through competition, predation or habitat impacts;
  • overexploitation of fish, which may lead to depleted or unsustainable populations; and
  • pollution of many kinds, which may adversely affect water quality and fish health.

All of these stressors take place in the context of a changing environment. While many of these stressors are beyond the control of any single regulatory body or individual, their impacts can be managed collectively to provide for sustainable and productive fisheries.

Although overexploitation, aquatic invasive species and pollution are all threats to the sustainability of fisheries, the Fisheries Protection Program within DFO focuses on the management of impacts to fish resulting from habitat degradation or loss and alterations to fish passage and flow. Other components of the Fisheries Act and various pieces of federal, provincial, and territorial legislation address these other threats.