Amanda Ash

The Goldfish (Carassius auratus) is arguably the most popular and well known ornamental fish species and this popularity has been responsible for feral populations of Goldfish being recorded from almost every Australian state and indeed throughout much of the world. While generally regarded as a freshwater fish, a preliminary study of the fish faunas of the Vasse-Wonnerup by the authors recorded Goldfish in the system during a time when the estuary was salty (~17 ppt, i.e. half full strength seawater). A population of Goldfish has been known to occur in the Vasse River since the early 1990s, however, it was incorrectly thought that the Goldfish could not penetrate into the Ramsar listed Vasse-Wonnerup wetland, as, at certain parts of the year, the system became salty. Worringly, in Europe, research has shown that several introduced freshwater fish (e.g. the Zander; Stizostedion lucioperca) have been able to survive in estuarine waters for long enough to use these systems as a ‘salt bridge’ to invade other, previously uncolonised, freshwater environments. As Goldfish are known to resuspend nutrients and increase turbidity during their foraging, exacerbate algal blooms, decrease aquatic vegetation and predate on and compete with native species, they could pose a major threat to health of the Vasse-Wonnerup wetland and its other tributaries. This poster and presentation document (i) the abundance of goldfish in seven regions of the Vasse-Wonnerup wetland and in each of its four tributary rivers, including the Vasse River, which has an abundant Goldfish population, seasonally over 18 months; (ii) the results of a set of laboratory experiments to test the acute and gradual salinity tolerances of Goldfish from the Vasse River and (iii) a comparison of these tolerances with those obtained from Goldfish bought from a pet store. The management implications of these findings are then discussed.

Due to the endangered status of African painted dogs (Lycaon pictus) it is important to understand what parasitic diseases they are exposed to and what effect these are having on the rapidly declining wild populations. Conversely, zoo collections of these animals are under different pressures due to their captive lifestyle such as stress, nutrition, inbreeding and intensive housing. Faecal samples were collected from captive populations housed at Perth Zoo, Monarto and Adelaide Zoos and DeWildt Wildlife Trust in South Africa. Wild populations have been sampled from Zambia and Namibia with further sampling to be undertaken Zimbabwe and South Africa. Samples have been analysed via microscopy and parasites observed identified to genus. Giardia cysts and Spirometra sp. were detected in captive populations while parasite eggs of Taeniidae, Ancylostomatidae and Sarcocystis were detected in the wild populations. Molecular characterisation was then conducted in order to characterise those parasites found. Of particular interest is the zoonotic potential of the Giardia sp. detected in captive animals and the determination of Echinococcus sp. from the Taeniid ova found. Further sampling will add statistical rigour in order to quantify faunal structure.