Identifying and Conserving Tilapiine Cichlid Species in the Twenty-First Century

Abstract

The use of species as the unit of organismal identification has implications for policies that support conservation and management. For most fish, including tilapiine cichlids, identification in the last century supported by alpha taxonomy produced keys and descriptions of diagnostic features and designation of correct species names. The rapid increase in species discoveries in the twenty-first century has resulted in large turnover of names and descriptions. However, these updates have had little impact on conservation of tilapiine cichlids, mostly because the wide distribution of cichlid species provides the false impression of resilience to habitat disturbance. There is a need to provide clarity on intraspecific variations, in order to conserve cichlid populations threatened by species introductions and habitat loss. Here, we review some powerful tools that assess differences in morphology, trophic ecology, and genomics and enable definition of units of conservation of tilapiine cichlids. We discuss advances in geometric morphometrics in morphological characterization of tilapiine cichlids. Similarly, we show how sequencing technology has influenced the definition of units of conservation, namely evolutionary significant units, which take into account gene flow between populations, and recognize demography and migrations. We also highlight next generation sequencing technology that is revolutionizing biomonitoring using environmental DNA.