Reproductive ecology and diet of a persistent Ameiurus melas (Rafinesque, 1820) population in the UK

Abstract

The black bullhead Ameiurus melas was introduced to Europe from North America in the early 20th Century and invasive populations are now present in many European countries (Novomesk a et al., 2013). Their invasion is assisted by their traits of high reproductive output, parental care, omnivory, aggressive behaviour and tolerance to environmental parameters (e.g. Leunda et al., 2008; Novomesk a et al., 2013). In the UK, however, they are not invasive, with only a single, persistent wild population believed to be present (Britton et al., 2010). The lag phase – the time period between the introduction of a species and an invasion developing – can be considerable for non-native fishes. For many species, its cessation requires a change in environmental conditions and/or the provision of a new dispersal opportunity (Fausch, 2007). The aim of this study was to assess the reproductive ecology and diet of A. melas in UK conditions through assessment of this persistent population. As there was only one population available, the plasticity of their traits in UK conditions could not be assessed; however, the study results are compared with their populations elsewhere. An assessment is then made to identify whether these aspects of their ecology are inhibiting their invasion of UK freshwaters. Note that Novomesk a et al. (2013) recently concluded that morphological plasticity was not a factor affecting their invasive ability and so is not considered here.