Does non-native pumpkinseed Lepomis gibbosus affect endemic algae-scraping Capoeta aydinensis in case of introduction to a small stream? An ex situ growth experiment

Abstract

The survival and establishment of alien fishes in novel environments can result in resource partitioning with native fishes. This can cause ecological impact and suppression of native populations. However, quantifying the impact of novel interactions between alien and native species remains highly challenging in the wild. Consequently, to determine the ecological risk of Lepomis gibbosus in case of introduction to a small stream, experimental approach was used to predict its competitive interaction with a poorly studied endemic fish, Capoeta aydinensis. The aim was to test whether L. gibbosus has an adverse effect on native species using an experimental design under allopatric and sympatric context with temperature regimes of 15 and 24ºC. The results indicated that temperature and fish proportion had effects on the growth of C. aydinensis while these factors were not important for L. gibbosus. These results provided little evidence of L. gibbosus presence being detrimental for endemic C. aydinensis, but nevertheless steps should be taken to avoid their further co-habitation in the wild.