Water quality parameters and population characteristics for the Flinders Ranges Gudgeon

ABSTRACT The Flinders Ranges Gudgeon (Mogurnda clivicola) in South Australia, is restricted to permanent spring-fed pools of two creeks in the Northern Flinders Ranges. Consequently, the fish is classified as critically endangered. Regular monitoring of selected water chemistry and fish population characteristics has been conducted since 2018 by a “Friends of Parks” group in an ongoing project contributing to the conservation management for this endangered species. Mogurnda clivicola were abundant and healthy in Weetootla and Nepouie springs, with six or fewer fish displaying any skin lesions on each of the four sampling occasions of May and August 2019 and June and August 2020. Hence the fish populations were not adversely affected by the exceptionally low rainfall years of 2018 and 2019. Fish of less than 2 cm total length were present at each sampling time point, indicating that breeding can occur on an opportunistic basis rather than during a breeding season. Following a substantial flood during February 2020, a substantial breeding event resulted in large numbers of small fish and at Nepouie Spring. For pools that contained fish, the water quality parameters measured and their ranges were: conductivity 1141–13 800 µS/cm; dissolved oxygen concentration 1.9–12.0 mg/L; temperature 11.4–29°C; pH 7.1–8.8; [Ca++] 36–213 mg/L; [NO3-] 0.2–17.7 mg/L.