The Winjan Bindareb Boodja Rangers have come together with Murdoch University’s Harry Butler Institute, Fisheries and Aquaculture team for the first time to learn from each other whilst doing Fish Community Index Sampling in the Waangaamaap Bilya (Serpentine River), Bilya Maadjit (Murray River) and Bindjareb Djilba (Peel-Harvey Estuary).

Fish communities provide important ‘signals’ about the ecosystem health of estuaries. Their component species typically occupy habitats from the top to bottom of the water column, feed across most levels of the food web, and encompass varied behavioural traits and estuarine use patterns. Taking a community-wide view of the fish fauna can reveal many clues about the cumulative and complex impacts of the estuarine environment on higher ecological health.

The Peel Fish Community Index (Peel FCI), was developed by Hallett et al. (2019) specifically for the Peel-Harvey Estuary. This index uses the same principles as that for Swan-Canning FCI, which has run on an annual basis since 2012.  The Peel FCI has been used to measure and track the ecological health of the Peel-Harvey Estuary over a 40-year period from 1978 to 2018. It synthesises complex information from a range of structural and functional metrics of the fish community into a simple ‘report card’, with grades; A, very good, to E, very poor.

In 2020/21 Peel-Harvey Catchment Council contracted Murdoch University to undertake sampling during Summer and Autumn using the methods developed by Hallett et al. (2019). The nearshore waters of the Waangaamaap Bilya (Serpentine River) and lower reaches of the Bilya Maadjit (Murray River) received poor scores in Summer. Moreover, in deeper, offshore waters with Upper Murray received a Fair/Poor grade in Summer and a Very Poor grade and score of only 9 out of 100 in Autumn, due to extensive hypoxia (reduced oxygen). Regular FCI sampling provides a means to assess how fish communities are responding the wide array of stressors that are affecting the river and estuarine ecosystem.

PHCC has again contracted the Murdoch University Harry Butler Institute, Fisheries and Aquaculture team led by Dr James Tweedley to repeat the methods developed by Hallett et al. (2019) and used in Tweedley et al. (2022) to conduct the Peel FCI in the Summer and Autumn of 2023. PHCC has engaged the Winjan Bindareb Boodja Rangers to work alongside the Murdoch University team in some of the sampling sessions this season. It is a step towards facilitating cross-cultural sharing, providing new training opportunities and working towards developing a noongar-led fish monitoring program.

Fishing is embedded in traditional and continuing Bindjareb Noongar culture and our Elders have shared their concerns about reduced numbers of Yellow-tail and Bream in particular. Unlike Mullet and Herring which breed in the ocean, these species breed in the estuary and are therefore reliant on a healthy estuary system sustain a healthy population. Future monitoring that focusses on specific species of significance to the Noongar community will complement the FCI assessments that considers the fish community as a whole in relation to ecosystem pressures.

PHCC is looking forward to continuing to work with our Bindjareb community and the Murdoch University Harry Butler Institute to better understand our fish populations, the health of our waterways and focus management actions in response to this.

The project is supported by Peel-Harvey Catchment Council through funding from the Australian Government’s National Landcare Program and Alcoa Foundation’s ‘Three Rivers, One Estuary’ initiative.

References

Hallett C, Valesini F, Yeoh D (2019) Assessing the health of the Peel-Harvey Estuary through its fish communities. Final Report ARC Linkage Project LP150100451.

Tweedley, J.R., Krispyn, K., Maus C. & Cottingham, A. (2022). Peel-Harvey Estuary condition assessment based on fish communities – 2020/21. Report for the Peel Harvey Catchment Council. Murdoch University, Perth, Western Australia. 46 pp.

We acknowledge the Noongar people as Traditional Custodians of this land and pay our respects to all Elders past and present