Publication Abstract

Pathways of ornamental and aquarium fish introductions into ponds of Epping Forest (England): the human vector

G.H. Copp, K. Wesley and L. Vilizzi.

We examined the frequency of occurrence and density of non-native fishes in restored ponds of Epping Forest (Essex, England) to determine whether colonisation of these ponds by fish is driven by Talling’s ‘element of chance’ or by environmental or human factors. We examined ponds that had been drained of water and voided of fish (or treated with rotenone) on a known date and into which no piscivorous or non-native fishes had been subsequently stocked. We measured the period of time since pond restoration, pond area, distance to nearest residential housing, distance to nearest footpath, distance to nearest water body or stream, and the proportion of pond vegetated. Talling’s ‘element of chance’ as a natural phenomenon appears to play a minor role, as both fish variety richness (number of ornamental varieties) and density (fish per 10 min. electrofishing) increased as distance from the nearest road decreased. Variety richness was also weakly, negatively correlated with the proportion of pond occupied by aquatic and marginal vegetation. The rate of non-native fish introductions (adjusted variety richness per year) could also be estimated reliably from pond distance to the nearest road, being about 3.5 ornamental varieties introduced per year in ponds adjacent to roads, but the rate appears to be much greater in ponds that had recently (< 1.5 years) undergone restoration. Societal issues and the implications for conservation and management are discussed.

Reference:

G.H. Copp, K. Wesley and L. Vilizzi (2005) Pathways of ornamental and aquarium fish introductions into ponds of Epping Forest (England): the human vector. Journal of Applied Ichthyology, 21(4): 263-274.