Are Mayflies Disappearing?

Anglers Alliance Tasmania is concerned

Howard Jones

Anglers Alliance Tasmania (AAT), the overarching body for freshwater Tasmanian angling, is working for your fishery and is receiving numerous reports from respected fishers of longstanding who have grave concerns for the sustainability of our cherished highland waters. Many anglers have observed marked changes in the frequency and abundance of mayfly hatches and the exciting visual flyfishing it brings, on diverse highland waters across Tasmania. Why mayfly? According to our scientific advisors (Entomologists), mayflies are a reliable indicator of water quality and biodiversity. In response, AAT is seeking to shed light on this issue and has initiated a “Collaborative study into environmental and angler impacts on shallow highland waters.”

The intent is to collect information and investigate multiple factors contributing to changes observed by anglers. Targeting our efforts and resources the current emphasis is Penstock Lagoon. An increasingly popular and pressured shallow highland water, with very limited flow through, having existing data available and highlighted by numerous anglers for declining dun numbers, Penstock is seen as an appropriate focus for the study. Hydro Tasmania has made available extensive data from historical water sampling in a suite of highland lakes. The data will be examined for potential relationships between environmental inputs and angler observations.

Hydro has undertaken preliminary scientific analysis by way of water and sediment sampling at Penstock and will undertake enhanced sampling of shallow highland waters as part of routine testing of waters it oversees. To determine angler visitation information traffic monitoring equipment has been installed at the entrance to the Penstock ramp to gain an accurate picture of peaks and troughs of seasonal boat angling effort.

In collaboration with renowned entomologist John Gooderham from Waterbug Blitz and Ron Thresher who has sampled mayflies from Penstock over many years, AAT coordinated an inaugural citizen science bug sampling at Penstock Lagoon in November. The two experts mentored anglers as they sampled six individual sites around the lagoon and then worked alongside them to identify and collate the macro-invertebrates collected. It is intended to establish ongoing macroinvertebrate sampling days to be conducted by interested anglers. Their findings will be authenticated using Waterbug Blitz protocols available through a phone app, cataloguing the diversity and make-up of the insects at designated sites around the lagoon.

AAT is seeking greater input from anglers who have diaries and historical records of their fishing experiences in our highland waters and are willing to add to the breadth of understanding in this collaborative project. It is hoped to publish a survey to formalise and collate such angler observations.

If you’re keen to share your experience, please send your information to: anglersalliance@gmail.com with ‘Shallow Water Study’ in the subject, or, post to GPO Box 963, Hobart, 7001.