Evaluating potential biodegradable twines for use in the snow crab fishery off Newfoundland and Labrador

Retrieval Operations of Derelict Fishing Gears Give Insight on the Impact on Marine Life

“…In case the king crab pot is lost, the degradation of the cotton string creates a permanent opening, allowing captured crabs to escape. The estimated time to failure for a 96-thread cotton string (5 mm, 115.2 kg initial breaking strength) is 182 days (Winger et al, 2015). Twisted cotton strings (2.5-5.0 mm thickness, 16.6 kg -39.3 kg initial breaking strength) demonstrated a degradation time ranging from 68 to 234 days, while braided cotton strings (2.0-5.2 mm thickness, 11.8 kg -42.4 kg initial breaking strength) exhibited a span of 108 to 205 days (Araya Schmidt and Queirolo, 2019).…”

“…On the other hand, when abandoned snow crab pots were recovered after spending approximately 1.5 years at sea, none of the 5 mm diameter cotton strings used had deteriorated, maintaining a mean breaking strength of 17 kg (Humborstad et al, 2021). Thereby, the effectiveness of this mechanism highly varies depending on cotton thread count, diameter, presence of a core, manufacturing processes, cotton quality / blends, braiding method, usage / storage before the pot is lost, pot type and environmental conditions (Winger et al, 2015). During this ALDFG retrieval operation, the escape mechanism was found to be open in 16 out of the 21 observed king crab pots with an average residence time of 196 days.…”