Experiment 1: DNA Degradation
An DNA degradation experiment was conducted using C. sivickisi to determine how quickly eDNA may degrade once the jellyfish is removed. Decay to < 1% of the original eDNA concentration has been found in some studies to take anywhere from 48 hr to 10 days (Thomsenet al. 2012; Pilliod et al. 2014); however, there have been no such determinations for cubozoans. In this trial, C. sivickisi medusae were collected at night off the coast of Magnetic Island, North Queensland (24/09/2019). Once collected, a single adult jellyfish (inter-pedalia distance 2-3 cm; n = 16) was placed in a 10 L bucket (n = 16) filled with 7 L of artificial saltwater. After 12 h the medusa was removed. Each bucket (n = 4) was sampled once so that all samples were independent with the full 7 L of water being filtered through 5 um nylon filters. The filtering of water (n = 4 buckets per time) was undertaken on day 0, 3, 6 and 9 post the removal of jellyfish to determine the concentration of eDNA remaining in the water column. Filter papers were placed in sterilised 2 mL tubes containing 1 mL of Longmire solution (Renshaw et al. 2015; Williams et al.2016) and stored at 4 oC for future extraction and analysis.