Annie Brook - Upper Annie Brook

Basin : Busselton Coast

Catchment : Mary Brook - Station Gully

River condition at the Upper Annie Brook site (site code: MB15ANNI2, site reference: 6104078) on Annie Brook has been assessed as part of the Healthy Rivers program using standard methods from the South West Index of River Condition (SWIRC). The SWIRC incorporates field and desktop data from the site and from the broader catchment. Field data collected include 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)

The Upper Annie Brook site was first assessed under Healthy Rivers in October 2017. The site was not able to be assessed in March 2022 as part of routine assessments across the Busselton Coast region as the site was dry. All known assessments are listed below:

2022 – summer (March 14–15): Healthy Rivers ‒ dry
2017 – spring (October 11–12): Healthy Rivers

Other data:
There are currently no monitored gauging stations on Annie Brook.

Search the site code or site reference in the Department of Water and Environmental Regulation’s (the department) 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.

Condition summary

This site is in the upper catchment of the Annie Brook. Annie Brook is a small, seasonally flowing brook which discharges into Geographe Bay via Station Gully Drain.

It should be noted that considerable effort is underway to improve health in the system and wider catchment under the Revitalising Geographe Waterways program, run by the multi-agency Vasse Taskforce.

The 2017 condition assessment was carried out within the Noongar season of Kambarang, which is the beginning of longer dry periods, where many of the plants and animals undergo transformations with the change in warmer weather. The site was dry during the Noongar season of (March) in 2022, which is generally the driest and hottest part of the year with little to no rain. The below image shows flow during Kambarang (October) in 2017.

UPPER ANNIE BROOK SITE – ANNIE BROOK, KAMBARANG (OCTOBER) 2017

Species found in subcatchment

This includes all species found within the subcatchment of the assessment site, from this and previous studies in the area. The photos are linked to more information about each species, including maps of where they are expected across the south-west.

Native Species

Species found at the site

Fish and crayfish

The species captured at the Upper Annie Brook site during the 2017 sampling period are provided in Table 1. The table includes a list of all species previously reported in the subcatchment, which provides an indication of species that may occur at the assessment site. As differences in habitat within a subcatchment naturally influence species distributions, and variability in methods between sampling programs can affect the species caught, this list is only indicative.

Below are some of the notable findings from the assessments.

Two species of fish and one crayfish were found at this site in October 2017. This comprised two native freshwater fish (nightfish and western minnow) and one native crayfish (gilgie).

Gilgie was the most dominant species with more than 100 individuals recorded, comprising of 85 per cent of the catch. About one-third of the catch recorded were juveniles. The ability for gilgie to burrow to maintain contact with the water table during dry periods explains their dominance at the site. As was demonstrated in 2022, this section of the Annie Brook is known to dry during the summer months.

Although nightfish and western minnow were found in lower abundance at this site (two and fourteen individuals, respectively), a range of size classes including juveniles were recorded during the 2017 for both species.

These results show that this section of Annie Brook provides suitable permanent habitat for gilgie, as well as providing seasonal habitat for native fish. This also demonstrates that the wider system is providing the habitat conditions to support successful recruitment. The presence of permanent water fish species during spring, including the relatively slower-moving nightfish and juvenile life stages, suggests that a permanent water refuge exists close by.

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.