Intraspecific variability: an important consideration in forming generalisations about toxigenic algal species

Intraspecific variability (strain differences) in key characteristics such as life-history traits, behaviour, nutrition, genetics and toxicity, has been experimentally documented for many toxigenic microalgae, including species of cyanobacteria, dinoflagellates, haptophytes, raphidophytes and diatoms. This paper summarises findings from published studies on intraspecific variability in toxicity. The data show that different, often opposite, interpretations at the species level would have resulted from consideration of individual strains. A survey of recent literature on harmful algae revealed that intraspecific variation is still commonly overlooked in characterisations of these species and generalisations about their roles in foodwebs. The available data underscore the importance of including multiple strains in research to advance understanding about toxigenic algal species and the importance of tempering conclusions to consider the potential for differences beyond the strains studied.