Aquatic fauna passage (biopassage)

 

 

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

Fish and other aquatic species are stimulated to move by a variety of cues, including changes to the season or changes to water flow.

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:

• 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

• Department of Agriculture and Fisheries - Fishways
• Department of Agriculture and Fisheries - Fish Passage
• 'Why do fish need to cross the road?' - Department of Primary Industries NSW
• Fish Barrier Prioritisation (Landscape Scale Coastal, no economic analysis)
• Fish Barrier Prioritisation (Landscape Scale Coastal, with economic analysis)
• Instream Structure Prioritisation (Protected areas)
• Fish Barrier Prioritisation (Wetland/Offstream)

Pages under this section

References

1. ^ a b c d e f Allaby, M (2020), A Dictionary of Zoology. [online], Oxford University Press. Available at: http://www.oxfordreference.com/view/10.1093/acref/9780198845089.001.0001/acref-9780198845089 [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: https://www.dpi.nsw.gov.au/content/research/areas/aquatic-ecosystems/outputs/1998/obstruction-fishpassage [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: https://linkinghub.elsevier.com/retrieve/pii/B9780128043271001734 [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: https://vdocuments.mx/download/burnett-mary-regional-biopass-strategy-burnett-mary-regional-biopass-strategy.

Last updated: 10 May 2021