Fish community responses to metal pollution Original Research Article

The effect of metal pollution on fish communities was assessed at 47 sites, including a Cd and Zn gradient. Fish community structure was assessed by applying diversity indices, index of biotic integrity and the abundance/biomass comparison method (ABC-index). To relate the community responses to metal pollution, toxic unit values for dissolved metals (TUw) and for metals in fish liver (TUt) were calculated. If all sites were considered only a good relationship was found between the IBI and the TUw, with 56% of the variation in IBI being described. Within the pollution gradient (sites 1–12) the described variation increased up to 85%. Relating the community structure to TUt, the described variation in IBI further increased to 87%. Our results indicate that besides water quality other factors influenced diversity and ABC-index. The IBI proved a suitable index for the assessment of metal pollution, provided that other water quality characteristics meet the water quality criteria. The IBI can be used to assess the effect of metals on fish community structure.