Interactions between water temperature and contaminant toxicity to freshwater fish.

Warming of freshwaters as a result of climate change is expected to have complex interactions with the toxicity of contaminants to aquatic organisms. The present study evaluated the effects of temperature on the acute toxicity of endosulfan, chlorpyrifos, and phenol to 3 warm water species of fish-silver perch, rainbowfish, and western carp gudgeon-and 1 cold water species, rainbow trout. Endosulfan was more toxic to silver perch at 30 °C and 35 °C than at 15 °C, 20 °C and 25 °C during short exposures of 24 h, but at 96 h, temperature had no effect on toxicity.

Effects of temperature on ventilatory behavior of fish exposed to sublethal concentrations of endosulfan and chlorpyrifos.

The ventilation amplitude and frequency of silver perch Bidyanus bidyanus, and the ventilation frequency of rainbow fish Melanotaenia duboulayi and rainbow trout Oncorhynchus mykiss, were determined at different temperatures upon exposure to endosulfan and chlorpyrifos, respectively. Silver perch and rainbow fish were tested at 15, 20, 25, 30, and 35 degrees C, while rainbow trout was tested at 10, 15, 20, and 25 degrees C. Although some trend of increasing amplitudes with increasing temperature was evident; there was no significant temperature response of ventilation frequency rates over time in silver perch pre-exposed to 10 microg L(-1) endosulfan for 18 h.

Distribution of frogs in rice bays within an irrigated agricultural area: links to pesticide usage and farm practices.

In the Coleambally irrigation area (NSW, Australia), the occurrence of four tadpole and frog species in rice bays on farms growing either rice only or both rice and corn was studied over two seasons. In addition to analysis of species occurrence, both gonadal histology and assessment of Batrachochytrium dendrobatidis infection rates were performed. The rice acreage available as potential tadpole habitat was extensively distributed throughout the irrigation area, but more corn was grown in the northern region compared with the southern region.

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

The upper temperature tolerance limits of four freshwater fish species, silver perch Bidyanus bidyanus, eastern rainbowfish Melanotaenia duboulayi, western carp gudgeon Hypseleotris klunzingeri, and rainbow trout Oncorhynchus mykiss, were determined using the critical thermal maximum (CTMaximum) method. The CTMaximum tests were carried out with unexposed fish and fish exposed to sublethal concentrations of endosulfan, chlorpyrifos, and phenol to determine whether or not the CTMaximum was affected. The CTMaximum temperature of B.