Barriers to fish passage

Impact

In order to maintain populations, fish and many other aquatic organisms need to move between habitat areas within waterways.  Some can migrate very long distances between particular locations in a waterway and the open ocean.  Regulation of waterways, e.g. dams and weirs and periods of very low or no flow that result in physical obstruction and/or pooling that may inhibit fish passage.  These barriers can have serious implications for the viability of some aquatic species (e.g. reduced breeding potential or death) and subsequently negative impacts on biodiversity.

Suggested indicator: In-stream habitat⁺

Barriers to fish passage may be associated with:

Potential associated impacts	Suggested indicators+
Habitat and fish population fragmentation	In-stream habitat Fish Aquactic macro-invertebrates
Reduced access to spawning areas leading to: reduced breeding opportunities and genetic diversity of many native species	Fish
Reduced access to feeding areas	Fish
Reduced food supplies for dependant terrestrial and aquatic species leading to reduced numbers	River & wetland fauna Native land fauna Exotic pest fauna Fauna behaviour

⁺ Descriptions of indicators (PDF, 76K)* provides a brief description of each indicator including techniques and purpose.

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Last updated 7 September 2010

Land Manager's Monitoring Guide

• Monitoring overview
• Selecting indicators
• - Enterprise or production systems
• - Land practices
• - Management activity
• - Impact
• Indicators