Soft plastic fishing lures and fishing nets significantly influence the decomposition of Ecklonia radiata

Discarded or lost fishing gear from recreational or commercial fishers significantly contributes to global marine pollution. This debris accumulates with organic detritus on the seafloor, potentially impacting detrital dynamics. We used an outdoor mesocosm experiment to test hypotheses that soft plastic lures with nylon lines and commercial-grade fish netting influence the decomposition of Ecklonia radiata detritus in current and future ocean temperatures. Commercial-grade fish netting had no significant impact on the decomposition of E. radiata detritus but did increase the change in nitrogen content of detritus over time. Soft plastic fishing lures significantly decreased the decomposition of E. radiata detritus by 14.4 % and decreased its C/N ratio over time. At 26 °C, detritus decomposition and its C/N ratio significantly increased but did not affect carbon or nitrogen. We highlight that the type of fishing gear can determine the effect on detrital decomposition and the associated detrital dynamics. •The first study to observe the effect of fishing gearon the decomposition of Ecklonia radiata.•Soft plastic fishing lures reduced the decomposition of Ecklonia radiata detritus by 14.4% and decreased its C/N ratio over time.•Commercial netting had no effect on the decomposition of E. radiata detritus but increased the change in nitrogen over time.•At 26°C, E. radiata detritus decomposition and its C/N increased. However, carbon and nitrogen were unaffected.