Effects of river red gum, Eucalyptus camaldulensis, litter on golden perch, Macquaria ambigua

Abstract

Aquaria with added river red gum, Eucalyptus camaldulensis, litter became hypoxic, with decreased pH and contained up to 30 mg 1−1 tannin and lignin. Survival of golden perch, Macquaria ambigua, larvae in aquaria treated with a simulated annual litter density of 450 g m−2 for 72 h was 14·9% for 15‐day‐old larvae and 0% for 8‐day‐old larvae. A litter density of 1223 g m−2 resulted in total mortality for both age groups of larvae. Aeration increased survival of larvae to a minimum of 68·8% in 1223 g m−2 litter treatments compared to 89·8% in aerated controls and 86·8% in non‐aerated controls. A kinetic behavioural assay was used to detect alarm responses in golden perch larvae and juveniles exposed to leachates from river red gum bark, leaves and wood. Eight‐day‐old larvae exposed to bark and wood leachates (0·001–10 g 1−1) exhibited an initial period of hyperactivity, followed by a concentration‐dependent decrease in spontaneous activity. Larvae exposed to leaf leachates displayed only a decrease in spontaneous activity. Four‐month‐old juveniles exposed to wood leachates were also initially hyperactive, then progressively developed mild hypoactivity at increasing leachate concentrations. Juveniles exposed to wood leachates at 20g 1−1 for 30min suffered 97·5% mortality in 96 h. Wood leachates induced dose‐dependent lamellar fusion, epithelial dissociation and necrosis in the gills. The presence of toxic leachates and low oxygen availability in flooded river red gum forests may make these habitats unsuitable as nursery areas for native fish.

The effects of three organic chemicals on the upper thermal tolerances of four freshwater fishes

“…Endosulfan, chlorpyrifos, and phenol were supplied by Hoechst Australia, Dow Elanco Australia, and Rhone Pouline Laboratory Products, Australia, respectively. Endosulfan and chlorpyrifos are widely used agricultural pesticides, and phenol is a naturally found component in urban and country rainwater in Australia as a result of leachate from vegetation [22]. Fish maintenance, acclimatization, and CTM tests were carried out in dechlorinated bore water, passed through two sets of filters including an activated carbon filter prior to use.…”

Short-term effects of a prolonged blackwater event on aquatic fauna in the Murray River, Australia: considerations for future events

“…Fish kills caused by hypoxic blackwater have been recorded several times in different aquatic habitats across Australia, including in the Murray Valley (see for example Gehrke et al 1993;McKinnon and Shepheard 1995;Baldwin et al 2001;Townsend and Edwards 2003;Baldwin and Whitworth 2009). Although relatively few fish were actually reported dead during this event (Allan Lugg, pers.…”

“…Hypoxic blackwater events have been attributed to several fish kills in Australia (e.g. Gehrke et al 1993;McKinnon and Shepheard 1995;Baldwin et al 2001;Townsend and Edwards 2003;Baldwin and Whitworth 2009) and emergence (and sometimes mortality) of large crustaceans, such as the Murray crayfish (Euastacus armatus) (McKinnon 1995). However, McNeil and Closs (2007) also demonstrated that several fish in floodplain wetlands have high tolerances to hypoxia, and are able to avoid or tolerate hypoxic conditions by surface respiration.…”

“…golden perch (Macquaria ambigua), mountain galaxias (Galaxias olidus), carp gudgeon (Hypseleotris spp.) and southern pygmy perch (Nannoperca australis)) (Gehrke et al 1993;McMaster and Bond 2008) and potentially affect reproductive outputs (e.g. Morrongiello 2011; Morrongiello et al 2011).…”

Behavioural responses of a south‐east Australian floodplain fish community to gradual hypoxia

“…During extended droughts, hypoxic episodes may occur frequently in isolated floodplain lentic waterbodies (billabongs), particularly where water temperature is high (Gehrke, 1991;Lake, 2003). For the majority of the Australian inland fish fauna very little is known about their distribution in hypoxic habitats and even less about the mechanisms and adaptations used for surviving hypoxic episodes (Gehrke, 1991;Townsend, Boland & Wrigley, 1992;Gehrke, Revell & Philby, 1993;Closs & Lake, 1996;King, Humphries & Lake, 2003).…”