Time-tension line cutters offer a potential tool to mitigate whale entanglements in deepwater fisheries

Abstract Entanglement in vertical buoy lines from fixed-gear fisheries remains a primary threat to the critically endangered North Atlantic right whale (Eubalaena glacialis, NARW). Low breaking strength (LBS) components are used in some fisheries to reduce entanglement severity, but routine hauling forces in deepwater fisheries often exceed their safe working limits. Time-tension line cutters (TTLCs) offer an alternative for deepwater fisheries that do not weaken the vertical buoy line. We conducted 400 tests to quantify TTLC performance under laboratory conditions, including an assessment of repeated use, tension, and water temperature on time to cut (TTC). Our results showed that the baseline TTC varied among units, but when this was taken into account, we found that a) 70% of the units exhibited no statistically significant change in TTC across repeated use, b) higher tensions and repeated activation shortened TTC, and c) water temperature had a strong inverse relationship, with colder temperatures significantly increasing the TTC for all units. These findings provide critical guidance for tuning TTLC design and evaluating their suitability for safe, effective deployment in deepwater fixed-gear fisheries.