W9 AM Biomonitoring
Wednesday, 16 November 2005: 8:00 AM - 11:40 AM in 339-340

(TRE-1117-837980) The use of two New Zealand native species as biomonitors to evaluate the effects of pollution on fishes.

Tremblay, Louis¹, Trought, Katherine¹, Lowe, Cara ¹, van den Heuvel, Mike ², ¹ Landcare Research, Lincoln, New Zealand² Scion, Rotorua, New Zealand

ABSTRACT- The New Zealand economy is highly based on the 'clean and green' image that attracts tourism and ensures a reputation of sustainability for agricultural products. New Zealand is also a developed country with growing industry (particularly agricultural), and increasing urbanisation. Therefore, monitoring and characterising pollution is a priority to ensure that the consequences of these activities on the receiving environment are minimum and sustainable. The methods used in this project to determine the impact of pollution on fish are effects-based. The two main methods used were the monitoring of population-level variables of a wild fish species the common bully (Gobiomorphus cotadianus) and examining biochemical responses in the shortfin eel (Anguilla australis) that were caged directly in areas of concern. Eel caging studies and wild common bully sampling were conducted at two sites on the South Island, the Cam and Styx Rivers. These catchments receive multiple stressors from a variety of agricultural, industrial and municipal sources. Both Rivers are highly valued by the community and Maori. The results showed that the sources of pollution present in both river systems did not lead to acute toxicity, as none of the caged fish died or showed physical damage such as the presence of fin rot or skin tumour. Of all the parameters measured following the 3-week exposure, the induction of the hepatic EROD was the most significant. Both fish species showed increased level activities of that enzyme. However, eel showed highest levels of hepatic EROD activity in the Cam River downstream from a sewage outfall while the common bully sampled in the Styx River showed the highest activities. Further investigations are warranted to identify the sources of contaminants responsible and determine the long-term effects on the health of the exposed fauna as very little is known on the biology of these species.

Key words: Biomarkers, caging studies, wild fish survey