-cleavage reaction in a single tube. The entire process is operated at a constant temperature, avoiding thermal cycling. Low-template replicate experiments conservatively redefined the OORC limit of detection as 6 copies/reaction. To support near-field application, we further integrated the assay with a portable handheld fluorescence detector capable of 365 nm photoactivation and fluorescence readout. This portable and highly sensitive workflow extends the potential of eDNA monitoring, offering a practical tool for the conservation of endangered species.