Short-Lived Fishes: Annual And Multivoltine Strategies

The diversity of life histories across the animal kingdom is enormous, with direct consequences for the evolution of lifespans. Very short lifespans (maximum shorter than 1 year in their natural environment) have evolved in several vertebrate lineages. We review short-lived fish species which complete either single (annual/univoltine) or multiple (multivoltine) generations within a year. We summarize the commonalities and particulars of their biology. Apart from annual killifishes (with >350 species), we detected 60 species with validated lifespan shorter than 1 year in their natural environment. Considering the low number of reports on fish lifespan (<5% of 30,000+ fish species; 1,543 species), the total number of short-lived fish species may be relatively high (>1,200 species). Short-lived fish species are scattered across 12 orders, indicating that short lifespan is not a phylogenetically conserved trait but rather evolves under specific ecological conditions. In general, short-lived fish species are small (typically 55 +/- 35 mm), experience high predation (making them important part of ecosystem trophodynamics) and live in shallow warm waters with high productivity and stable abiotic conditions (e.g. Gobiidae, Clupeidae). Others utilize temporally constrained environments, where they survive unfavourable conditions as dormant stages (annual killifishes). They also utilize less productive environments; in this case, they migrate between productive and un-productive environments (e.g. Myctophidae, Salangidae). These species include the putatively shortest-lived (Schindleria pietschmanni: Schindleriidae) and earliest maturing (Nothobranchius furzeri: Nothobranchiidae) vertebrates and represent the lower limit of vertebrate longevity. Their examination may provide important insights into the evolutionary and mechanistic understanding of ageing.