First record of a non-native crayfish in Ethiopia: morphological and molecular evidence

Abstract

Freshwater habitats are particularly vulnerable to biological invasions due to increasing introduction pathways, such as aquaculture, trade, and infrastructure development. Among aquatic invaders, freshwater crayfish are considered highly impactful thanks to their ecological versatility, omnivorous feeding habits, and capacity to modify habitats. In Africa, introduced crayfish have already caused ecological disruptions, including biodiversity loss and ecosystem alteration in systems such as Lake Naivasha in Kenya (Gherardi et al. 2011), and have proven difficult to eradicate once established (Nunes et al. 2017, Madzivanzira et al. 2020). In December 2025, a crayfish population was detected in the North Shoa Zone, around the Sheno area (central Ethiopia), representing the first documented record of this taxon in the country. The population was found in a series of artificial water bodies formed by excavation during road construction activities. These depressions, filled by groundwater, form a network of small pools, with the largest (~8500 m²) acting as the main habitat. The site is located at approximately 2500 m a.s.l. and is seasonally connected to nearby temporary streams, providing potential routes for dispersal. Crayfish individuals were observed both within the reservoir and in adjacent stream channels, suggesting dispersal beyond the initial introduction site has begun. Specimens were collected and transferred to the National Fishery and Aquatic Life Research Center (NFALRC), and tissue samples were later obtained for molecular identification. Preliminary morphological observations indicate affinity with cambarid crayfish (possibly Procambarus sp.), while molecular analyses using mitochondrial markers (COI and 16S rRNA) are ongoing. Interviews with local residents suggest a likely anthropogenic introduction linked to infrastructure development activities. Foreign workers involved in road construction are suspected to have introduced the species, and local individuals were reportedly trained in harvesting techniques. Informal exploitation is already occurring, with crayfish being collected and sold, indicating rapid integration into a small-scale economic activity. Although ecological impacts have not yet been documented, the presence of an established population, suitable environmental conditions, and hydrological connectivity indicate a high potential for further spread. Invasive crayfish are known to affect freshwater ecosystems through predation, competition, and habitat modification (Twardochleb et al. 2013). The global expansion of crayfish aquaculture, particularly of Procambarus clarkii , has been identified as a major driver of introductions outside native ranges (Chen et al. 2024). This study provides the first evidence of crayfish introduction in Ethiopia and highlights the importance of early detection in data-poor regions. The apparent recent introduction suggests that management actions, including monitoring, containment, and awareness initiatives, may be effective in limiting further spread.