Collie River South Branch - McAlinden Road

River condition at the McAlinden Road site on the Collie River (site code: CR253COLL1, site reference: 6120015, previously reported as site code: CR-11, site reference: 6121245) 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 the broader catchment. Field data collected included the following indicators, assessed over about a 100 m 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:

Water quality was also logged continuously between December 2014 and September 2015 to assess change in conditions over time.

Other departmental data: The Collie River - South Branch Gauging Station (site reference: 612034) is about 24 km downstream of the McAlinden Road site. This gauging station is owned by the Department of Water and Environmental Regulation (the department) and has been in operation since 1952.

Search on 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.

This site had healthy intact streamside vegetation and exibited good bank stability with minimal erosion.

A sap-sucking insect, known as a psyllid or lerp (related to aphids), was observed on tree leaves and have been observed at other sites in the catchment. They have little effect on trees when population levels are low; however, heavy infestations of nymphs can cause significant leaf-drop, defoliating trees, and is often seen in trees that are already under stress.

McAlinden Road with good streamside vegetation, March 2022.

Psyllid (sap sucking insect) with lerp protective casing on tree leaf at McAlinden Road site, March 2022.

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. This includes three endemic freshwater fish (nightfish, western minnow and western pygmy perch), one non-native freshwater fish (eastern gambusia) and two endemic freshwater crayfish (smooth marron and south-west glass shrimp).

Freshwater cobbler and gilgie were absent; however, this is not considered to be of immediate concern as healthy populations of other endemic freshwater species were present (i.e., the site retains good water and habitat quality). The lack of detection of these species could be related to low sampling effort (i.e. species are present but were not detected, or species had migrated away from the site at the time ‒ which is particularly likely for the migratory cobbler).

The photos of fauna provided are linked to more information about the 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 at this site during March 2022 fieldwork:

• south-western snake-necked turtle (Chelodina oblonga)
• bush rat (Rattus fuscipes)
• rakali water rat (Hydromys chrysogaster) – a Priority 4 under the 2016 Biodiversity Conservation Act, meaning it is a rare or near-threatened species is need of monitoring.

For more information on this and other aquatic species please see the River Science fauna page.

Native bush rat at McAlinden Road, March 2022.