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Aquatic fauna passage (biopassage)

Many Australian native fish species and other water-based fauna need a range of habitats to complete their life cycle and rely on specific seasonal and life stage habitats.

Fauna often need passage between different habitats, e.g. to move upstream and downstream, for several critical reasons, such as to:

  • return to and from spawning grounds
  • find waterholes for drought refuge
  • repopulate areas after drought
  • critical movements after flooding
  • move in response to changing water quality or oxygen levels
  • access food in different habitats, and
  • evade predators.

This page and following pages provide general information about aquatic fauna passage, types of movement and ways to facilitate improved aquatic fauna passage.

Claude Wharton Weir Fishway Photo by Andrew Berghuis

Quick facts

Many fish are stimulated to move during flood conditions.
This is due to many Queensland waterways being ephemeral or episodic and only flowing after rainfall (i.e. intermittently or during the wet season).[2]

Disclaimer: In addition to the standard disclaimer located at the bottom of the page, please note the content presented is based on current knowledge of biopassage designs. Many of the biopassage systems described have not been trialled in all regions in Queensland. Please note that biopassage systems (fishways) built prior to 2014 were built differently to current standards. Information on these pages may be updated when possible as new trials are conducted, effectiveness is monitored and research is undertaken. To submit further information on biopassage designs or suggestions for additional technologies, please contact us using the feedback link at the bottom of this page.

A range of legislation and approvals may be required for construction, particularly under the Fisheries Act 1994 and Planning Act 2016. Many of the tools and much of the knowledge and information about fishway types were sourced from, and developed within, Queensland Fisheries. Contact local and State government at the beginning of any project before any construction or planning is undertaken to ensure appropriate requirements are incorporated into the project.


Aquatic fauna passage (biopassage) is the process where fish and other water based fauna move naturally around their environment (modified from Obstructions to fish passage in New South Wales South Coast streams[3]). Biopassage is critical to the survival of many native species. Species of both fresh and saltwater fish, for example, need to move freely within waters at different times to access food and shelter, to avoid predators, and to seek out mates to breed and reproduce. Examples of the various types and reasons movement are included in movement types below.

Biopassage may be maintained or improved via the retention or restoration of waterway and aquatic connectivity and conditions, to facilitate the passage of all mobile aquatic species throughout their life cycle[5].

Aquatic fauna migration is defined as 'movements resulting in an alternation between two or more separate habitats'[4]. Migration movements are regular, repeated, and large-scale between different sites of the home range for different life history events of a species[1].

Biopassage, including fish passage and turtle passage, can be improved through structures such as fishways, fish ladders, fish-friendly culverts, elver passes or eel passes and through turtleways[4]. Turtleways, elver/eel and other aquatic fauna passes are considered emerging technologies. For the purposes of these webpages, fish, aquatic fauna and aquatic species are used interchangeably.

Aquatic fauna can rely on access to a wide range of habitats for survival during their life cycle. Appropriate connectivity between habitats facilitates these life history events and supports populations of aquatic fauna to thrive, and drives migration.

Movement types

Aquatic species move through waterways during times of flow to repopulate areas after dry periods or drought, resulting in genetic variability between streams. In dryland river systems, where flow ceases for extended periods, aquatic species become reliant on deeper pools or waterholes as refuges. Access to these refuge areas is critical for the survival of aquatic species through dry periods. After dry events, biopassage is critical for repopulation of the system.

Aquatic species move in many ways, such as:

    Conceptual model of fish movement in Australian tropical coastal streams, highlighting the return of small and juvenile fish through the tidal interface. Source: Tim Marsden.
  • local movement - access food, avoid predators, shelter during daylight
  • daily movement - access habitat, food and shelter, defend territory, avoid predators
  • seasonal movement - breeding cycle in response to rising water levels or temperatures
  • upstream movement - access to new habitats or established spawning areas
  • downstream movement - post-spawning movement, avoid predators
  • lateral movement - access food, breeding cycle and juvenile recruitment to habitat areas
  • migration movement.

Some aquatic species migrate between fresh and salt water to complete their life cycle[1]. This migration is termed diadromy and there are three categories of diadromous species - catadromous, anadromous, and amphidromous.

Catadromous species are spawned in marine habitats and migrate to freshwater areas for the majority of their adult life, but return to marine environments to reproduce. Examples in Queensland include barramundi (Lates calcarifer), Australian bass (Macquaria novemaculeata), sea mullet (Mugil cephalus), freshwater eels (Anguilla spp.), jungle perch (Kuhlia rupestri) and tarpon (Megalops cyprinoides)[1].

Anadromous species are spawned in freshwater habitats, and spend their juvenile lives in freshwater, but migrate to marine environments to spend their adult life. These species migrate back to the freshwater environment (upstream migration) to reproduce[1].

The time spent in either habitat varies between species, and the distance travelled also varies from short distances to hundreds of kilometres. In addition to having access to these habitats, aquatic species must also undertake physiological adjustments when moving from freshwater to salty (marine) waters.

Amphidromous species are spawned in fresh, brackish or marine waters and move between water types after hatching for reasons other than reproduction. Examples of amphidromous Queensland fish species include freshwater amphidromous cling gobies (e.g. Stiphodon spp.), which are spawned in freshwater but young larvae are washed downstream to the sea and return to freshwater as juveniles, and marine amphidromous mangrove jack (Lutjanus argentimaculatus), which spawn in marine waters but juveniles often inhabit the lower freshwater reaches of rivers[1].

Most native fish species that complete their lifecycle wholly in freshwater also have a requirement for movement within river systems. This type of migration is termed potamodromous and in Queensland is undertaken by fish such as golden perch (Macquaria ambigua) and silver perch (Bidyanus bidyanus).

Potamodromous species often spawn in upstream freshwater habitats and drift downstream (while remaining in freshwater) as larvae but return to upstream freshwater habitats to spawn[1].

Oceanodromous fish remain in marine environments. They spawn in particular areas, drift on ocean currents as larvae, and settle as juveniles to grow into adults. They migrate back to the spawning grounds to spawn. Tailor (Pomatomus saltatrix) are a well-known Queensland oceanodromous species.

Additional information

Pages under this section


  1. ^ a b c d e f Allaby, M (2020), A Dictionary of Zoology. [online], Oxford University Press. Available at: [Accessed 4 March 2021].
  2. ^ Kennard, MJ, Pusey, BJ, Olden, JD, MacKay, SJ, Stein, JL & Marsh, N (2010), 'Classification of natural flow regimes in Australia to support environmental flow management', Freshwater Biology. [online], vol. 55, no. 1, pp. 171-193. Available at: Scopus.
  3. ^ Obstructions to fish passage in New South Wales South Coast streams | NSW Department of Primary Industries. [online] Available at: [Accessed 3 May 2021].
  4. ^ a b Stern, SJ & Friedlaender, AS (2018), 'Migration and Movement', in Encyclopedia of Marine Mammals. [online], Elsevier, pp. 602-606. Available at: [Accessed 1 March 2021].
  5. ^ Stockwell, B, Fennesy, R, Berghuis, A, Johnston, B & Hutchison, M (2008), Burnett Mary regional biopass strategy. [online], Department of Primary Industries & Fisheries. Available at:

Last updated: 10 May 2021

This page should be cited as:

Department of Environment, Science and Innovation, Queensland (2021) Aquatic fauna passage (biopassage), WetlandInfo website, accessed 18 March 2024. Available at:

Queensland Government
WetlandInfo   —   Department of Environment, Science and Innovation