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Small freshwater fish5/20/2023 ![]() For example, undercut banks are often used by banded kōkopu, shortjaw kōkopu and eels (tuna) while inanga use overhanging vegetation. In-stream cover is important for most native fish but different species prefer different types of cover. river-bottom substrate: spaces between gravels, stones and boulders.overhanging vegetation: grasses and trees that droop into the water.In-stream cover gives fish shelter in rivers and streams. giant kōkopu).īackwaters are often changed or removed as a result of flood protection work and other riparian and in-stream works. In large alpine and braided rivers, backwaters are important places for fish to escape from high flows and floods, and are used by many juvenile native fish.īackwaters provide habitat for several native fish including: Backwaters form when side channels or river meanders are cut off from the main flow as a river moves. Backwatersīackwaters are areas of a river or stream that are open to the river at only one end, usually the downstream end. Most streams and rivers contain runs, but they can be degraded by sedimentation, river widening and a lack of vegetation along and beside the banks. Runs are important habitat for native fish including: Runs are stretches of river with a uniform current, an unbroken surface and moderate depth and water flow. Stream in Ahukawakawa Swamp, Egmont National Park Pools are often missing in waterways that have been straightened or narrowed to drain land or improve the flow of flood water. Pools provide habitat for many native fish including: Pools often form on the outside of bends in a river or stream, and collect sediment and organic matter carried downstream. Pools are deep, slow-flowing stretches of river with a smooth surface. Pool in Rock Burn, Mt Aspiring National Park These include reduced water flows, and fine sediment that smothers the stones and rocks, reducing habitat for algae, invertebrates and fish. Rapids and riffles can be degraded by many pressures. Rapids and riffles provide habitat for many native fish including: Spaces between rocks provide spaces for fish to hide and to spawn. Rocks and large stones in these areas provide a stable base for algae, plants and invertebrates to live on. Rapids and riffles are short, steep sections of river with fast-flowing, shallow water. Types of river habitat Rapids and rifflesīutterfly Creek, East Harbour Regional Park Juvenile galaxiids are often found in the slow flowing areas along a stream edge, while the adults prefer slow flowing wetlands (giant kōkopu) or fast flowing mountain streams (kōaro). Small streams also have more diverse habitats and therefore usually more fish.įor example, kōaro, redfin bully and torrentfish/panoko spawn in freshwater, move downstream as larvae, grow into juvenile fish at sea, then travel back upstream to mature into adults. Some species travel further inland than others, making small headwater streams and rivers just as important as larger waterways. Migratory fish move between freshwater and the sea during their lifecycle. Some non-migratory galaxiid larvae live in slow flowing backwaters while adults often prefer shallow and fast flowing riffles. Non-migratory fish spend their entire lives in freshwater and use different habitats at different life stages. ![]() To be healthy, native fish communities need to have access to a range of good quality habitats. New Zealand’s diverse freshwater fish species use many different river and stream habitats – many require specific habitats to complete their lifecycle.
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