Collie River South Branch - Cardiff Town Pool

River condition at the Cardiff Town Pool site on the Collie River (site code: CR217COLL1, site reference: 6124031 ‒ previously reported as site code: CR21, site reference: 6121264) has been assessed on several occasions as part of the Healthy Rivers program. The most recent survey was undertaken in March 2022.

Healthy Rivers assessments are conducted using standard methods from the South West Index of River Condition (SWIRC), which incorporates field and desktop data from the site and from the broader catchment. Field data collected included the following indicators, assessed over about a 100m length of stream:

• Aquatic biota: fish and crayfish community information (abundance of native and exotic species across size classes, general reproductive and physical condition)
• Water quality: dissolved oxygen, temperature, specific conductivity, and pH (logged in situ over 24 hours), as well as laboratory samples for colour, alkalinity, turbidity, and nutrients
• Aquatic habitat: e.g. water depth, substrate type, presence of woody debris and detritus, type and cover of macrophytes and draping vegetation
• Physical form: channel morphology, bank slope and shape, bioconnectivity (barriers to migration of aquatic species), erosion and sedimentation
• Fringing zone: width and length of vegetation cover within the river corridor and lands immediately adjacent, structural intactness of riparian and streamside vegetation
• Hydrology: measures of flow (velocity) at representative locations (compared against data from stream gauging stations within the system)
• Local land use: descriptions of local land use types and activities (compared against land use mapping information for the catchment)

All the Healthy Rivers assessments are listed below.

• 2022 – summer (March 2–3): Healthy Rivers
• 2018 – summer (February 21–22): Healthy Rivers
• 2015 – spring (October 19–20): Healthy Rivers ‒ fish and crayfish only
• 2015 – winter (August 10–11): Healthy Rivers ‒ fish and crayfish only
• 2015 – autumn (May 7–8): Healthy Rivers ‒ fish and crayfish only
• 2015 – summer (February 4–5): Healthy Rivers

Note: a long-term logger was deployed during the 2015 sampling; however, the equipment was stolen before data could be retrieved.

Other departmental data: The Collie River - South Branch Gauging Station (site reference: 612034) is about 8 km downstream of the Cardiff Town Pool site. The gauging station is owned by the Department of Water and Environmental Regulation (the department) and has been in operation since 1952.

Search the site code or site reference in the department’s Water Information Reporting (WIR) system to find data for this site and nearby sampling points (flows, surface water quality, groundwater monitoring, department’s meteorological data). See also the Bureau of Meteorology website for additional meteorological data for the area.

The species captured during each of the sampling events are provided in Table 1. The table includes a list of all species previously reported in the subcatchment, which indicates species that may occur at the assessment site. This list is only indicative as differences in habitat within a subcatchment naturally influence species distributions, and variability in methods between sampling programs can affect the species caught.

Six species of fish and crayfish were captured in the March 2022 sampling event. These were two endemic freshwater fish (nightfish and western pygmy perch), two non-native freshwater fish (eastern gambusia and redfin perch) and two endemic freshwater crustaceans (smooth marron and south-west glass shrimp).

The native western minnow and freshwater cobbler have been absent from the last three sampling events, and gilgie were only recorded once across six sampling events. The absence of these species during these periods is not considered to be of immediate concern. The lack of detection is expected to be related to habitat preference and/or low sampling effort (i.e. species are present but were not captured in traps, or species had migrated away from the site temporarily). Further investigation may be required if they remain absent from future assessments.

Cardiff Town Pool typically retains permanent water, providing important aquatic refuge habitat across the dry season; however, the pool dried completely in November 2015 following a particularly dry winter (see images below). Pool water levels and seasonal variability are important considerations when comparing presence and absence of species.

The photos of fauna provided are linked to more information about each species, including maps of where each species is expected across the South West.

Note: collection of fauna from inland aquatic ecosystems across Western Australia requires a licence from the Department of Primary Industries and Regional Development (DPIRD) and the Department of Biodiversity, Conservation and Attractions (DBCA). All species collected must be reported to these agencies as part of licence conditions.

Only fish and freshwater crustaceans (crayfish and shrimp) that typically inhabit river channels are targeted by the standards SWIRC sampling methods; however, other species are periodically captured in traps and/or observed (e.g. turtles, rakali native water rats, tadpoles). The following non-target species were identified on the motion sensor camera at this site in March 2022:

• native bush rat (Rattus fuscipes)
• native kangaroos (Macropus spp.)
• native white-faced heron (Egretta novaehollandiae)
• invasive European Red Fox (Vulpes vulpes) – a declared pest under the Biosecurity and Agriculture Management Act 2007.

For more information on other aquatic species please see the River Sciences fauna page.

Kangaroos at Cardiff Town Pool, March 2022.