Sawfishes are considered one of the most endangered families of fishes globally. Their diadromous ecology and vulnerability to fishing nets have brought most populations to the brink of collapse. Conservation of surviving populations is hindered by limited knowledge of historic and contemporary distribution. Colombia and Panamá are 2 of 22 countries considered as high priority for the development of species-specific national legal protection of the Critically Endangered largetooth sawfish Pristis pristis. To construct a baseline for the temporal and spatial distribution of the largetooth sawfish in Colombia and Panamá, we collected historical records from museum databases and literature over the past century, analysed available small-scale fisheries landings databases, and conducted interviews with fishers in 38 locations. We found 248 records of sawfish occurrences across both countries between 1896 and 2015, with 69% of the records from before 2000. The declining frequency of observations was corroborated by fishers, who reported fewer sawfish sightings and catches over the last 20 yr. Results from a regression model of total length and observed date suggest that the maximum size of observed sawfish individuals has also declined over time. We use location data from sawfish records to identify potential ‘bright spots’ that may foster remaining populations of sawfish. The locations of sawfish records were broadly characterised as remote areas with high mangrove forest cover. Given the length and cultural diversity of the Pacific coastlines of Colombia and Panamá, our findings provide important guidance to implement rapid conservation and fisheries interventions in these priority areas and highlight geographical gaps in knowledge for further work.

Birgus latro, the largest terrestrial arthropod in the world, has undergone a substantial decline globally over the last decades, with only a few healthy populations remaining where they are actively protected. We aimed to quantify demographic and spatio-temporal dynamics of a protected population of B. latro on Aldabra Atoll (Seychelles). Based on results along 2 transects on the atoll from 2007 to 2016, we calculated an average (±SE) density of 23.7 ± 1.1 ind. ha-1. This suggests a population of around 5000 B. latro in the coastal area of Picard Island, which is likely to be an underestimate due to the cryptic nature of the species. The average density within the study area was stable over the study period, and over the yearly cycle, the population exhibited high spatial and temporal variability in count, size and sex ratio and in association with the lunar cycle. Aldabra’s B. latro population is male-biased (3:1 male:female) and sexually dimorphic, with males being larger than females. Males and females moult at different times of the year, and the breeding season overlaps with the region’s wet season (December-March) and was in synchrony with the lunar phase. B. latro on Aldabra present colour polymorphism in a 4:1:1 ratio of orange:blue:intermediate (mixture of orange and blue). Results confirm that Aldabra is an important refuge for B. latro and potentially a natural source population for other areas in the region. Similar long-term studies on B. latro are encouraged to improve knowledge on the species and to support conservation actions to halt the species’ decline.