DSC_8794 Water abstraction is the removal of water from a waterway for irrigation, electricity generation, stock watering, and industrial or urban use. It reduces the flow of a river. The reduction of water in the main river channels reduces habitat variation in a waterway. Over-allocation of water abstraction rights, is now a major problem in Canterbury, Otago, Marlborough and Hawke’s Bay, it can lead to rivers running dry in summer, which is a serious impediment for migratory fishes. Hurunui *
DSC_9458 Most culverts are built with little concern for fish passage. The worst type is a ‘perched’ culvert such as this one – where water drops freely from a pipe into the waterway. Some of the native fishes are impressive climbers but they cannot climb upside down or jump to get into these pipes. Many of our fish are highly migratory – with lifecycles involving movements between the sea and freshwater, or between rivers and lakes. However, artificial barriers to migration such as this, frequently halt their journeys. Shenandoah Saddle *
DSC_9449 During major earthworks such as this, eroded soil settles out of the water as sediment between the stones of the substrate. Native fishes spend their inactive periods hiding amongst these stones, many lay their eggs under them and some burrow down deep amongst them to seek refuge from floods or droughts. Once these gaps become clogged with sediment there is less habitat for native fish. Maruia *
