The Critically Endangered green sawfish (Pristis zijsron): current knowledge and future directions

Abstract The sawfishes (Pristidae) are a group of large-bodied, shark-like rays that are among the most threatened marine fishes, having experienced substantial population declines over the past century, primarily due to overfishing and habitat loss. The green sawfish ( Pristis zijsron ) was once among the most understudied pristids; however, following an increase in scientific investigations conducted in recent years, it is currently one of the most thoroughly researched sawfish species. The purpose of this targeted literature review was to determine the current knowledge of P . zijsron and identify critical knowledge gaps in our understanding of this species. Compiled literature corresponded with the following categories: taxonomy and phylogeny; distribution, including possible extirpations and areas of uncertainty; morphology and physiology; ecology; population demography, dynamics and genetics; threats, conservation listings and protection; catch records; wildlife trade; and symbionts and pathogens. Northwestern Australia corresponded with the greatest output of contemporary P . zijsron research, likely due to the presence of viable populations in the region. Critical knowledge gaps include information on global population size and trends, area/s of occupancy, the number of subpopulations present in the wild, effective bycatch mitigation technologies, the spatial ecology of mature individuals and trophic dynamics. Furthermore, the life history, population genetics and symbionts of P . zijsron outside of Australian waters have received little attention. Successful conservation of P . zijsron will almost certainly depend on the extent to which the primary threats to this species (e.g., overfishing and habitat loss) can be effectively mitigated.