The olive ridley sea turtle Lepidochelys olivacea is the most abundant marine turtle species in Guatemala, representing > 99% of all nests. Along with other marine turtles, they are important both culturally and ecologically. Conservation efforts rely almost exclusively on an informal system whereby local residents can harvest olive ridley sea turtle nests on the condition they donate 20% of each nest to a hatchery, where the eggs are incubated and hatchlings later released. This system was initiated in the 1970s and, until recently, no effort has been made to determine its sustainability. In a 2020 publication based on tracks on a single beach in Guatemala and 15 years of egg incubation data from Guatemalan hatcheries, it was concluded that the population had increased. Several weaknesses were detected in this research. To verify the validity of the conclusion, we analysed data from 22 years (2 years are missing) and 11 beaches using several statistical models. We used an intraseasonal model of nesting phenology to fill in missing data for monitored periods during a nesting season, and a new method of spatial and temporal aggregation of nesting seasons. Based on our findings, we reject the hypothesis that olive ridley sea turtle nesting activity is increasing. The total nesting activity for these 12 beaches was stable over the 22-year period. Because of inconsistent hatchery management and the financial dependency of local communities on the sale of turtle eggs, the number of incubated eggs cannot be used as an indicator of the population trend of olive ridley sea turtles in Guatemala.

Knowledge of the abundance and distribution of species is important for designing and prioritizing conservation and management activities. Despite numerous existing studies on the distribution and status of sea turtles, we still lack knowledge about certain populations, especially in Angola, which is considered to be the southernmost range of nesting sea turtles in the eastern Atlantic. This study provides an overview of the status, size and distribution of the olive ridley sea turtle Lepidochelys olivacea population nesting along the coast of Angola, and its relevance in the context of other olive ridley turtle nesting populations in the Atlantic. Aerial and ground surveys were conducted along 1,410 km of Angolan coastline and daily beach monitoring over 53.9 km of seven permanent study sites at a range of latitudes during 2011–2020. Angola hosts the largest olive ridley turtle nesting population in the Atlantic, and the largest non-arribada population globally. Although the population appeared relatively stable, the pressures from various threats on land (e.g. consumption of turtles and eggs) and at sea (captures in fishing gear) necessitate the development of a comprehensive management plan, improved and strengthened legislation and law enforcement, and a cohesive approach to conserving all sea turtle species in Angola.