Assessment Of Red Swamp Crayfish Presence, Distribution And Abundance Within The Fidden Valley System.
Abstract
The presence of invasive red swamp crayfish (Procambarus clarkii) was determined at the Wied il-Fiddien to Wied il-Ghasel valley system in Malta. A proportion of this valley was restored between 2015-2021, funded via the European Regional Development Fund. Restoration involved mechanically excavating silt from the valley bed. It was shown that invasive crayfish were actively present from Wied il-Fiddien to the dam beneath the Mosta Roundabout (approximately 4.05 km downstream). In total, 656 crayfish were caught and culled, with an estimated biomass of 20-25 kg. All documented crayfish were speculated to be P. clarkii. Crayfish were present in sites at a higher elevation level than Wied il-Fiddien. The environmental characteristics of the study site and the opinions of local hikers and visitors regarding the ecological impact crayfish invasion during fieldwork are also included.