This supplement to a 2002 compendium of NOAA large whale entanglement prevention research has newer studies, including investigation of SAM gillnet gear, gillnet weak links and anchoring systems, evaluation of gillnet weak links, and a pilot study of options for reducing vertical line entanglements.

This is a compendium of various studies evaluating potential deterrents to large whale entanglements.

Pingers have been used on shark nets set along Queensland's beaches since 1992. Due to an increase in whale entanglements in 2009, new pingers (Fumunda F3 whale pingers and F10 dolphin pingers) were deployed between July and August 2010. Subsequently updated research on the use of these pingers was needed. For this study, the acoustic characteristics of pingers used on shark nets in Queensland Australia were measured and used to model sound propagation, estimate over what range marine mammals could detect the pingers, monitor ambient noise and to make recommendations on pinger deployment to the Queensland Shark Control Program (QSCP). The results of the sound propagation study indicate that the tones were a few hundred Hz less (2.6-2.8 Hz for F3 and 9.4-9.6 Hz for F10) than indicated. All pingers emitted multiple harmonics and fundamental tones. The power spectrum density levels varied up to 20 dB from angle to angle and pinger to pinger. The 1st harmonic of F3s was audible to all marine mammals over the longest ranges. Only 2 of the 6 tested pingers reached the manufacturer's listed audible range of 1-5 km. During testing, the ranges depended on the individual pinger and angle of the pinger toward the mammal. When animals travel alongside the net, a number of pingers should be set in a series. Based on the current configuration of 3-4 pingers per net of 200 m, humpback whales would hear all of the pingers at any location along the net but dolphins would hear only 1-2 pingers. When animals swim straight at the net, maximum pinger spacing would need to be based on the animals swim speed. The current net/pinger configuration is adequate for humpback whales, dugongs and dolphins swimming at normal travelling speeds. The current pinger spacing is insufficient for dolphins swimming straight at the net at high speeds.

The authors investigated several data sources and conducted surveys to identify potential mitigation measures that could be used to reduce humpback whale entanglements in Western Australia (WA). The Cetacean Stranding Database (CSD) and Commercial Whale Watching Database (CWWD), managed by the Western Australia Department of Parks and Wildlife, were both investigated. High occurrences of whale entanglements off the central coast of WA were identified in the CSD.  Commercial fishing records combined with entanglement records indicated that entangled whales mostly move contrary to movement patterns of the general population. Suggesting the high entanglement rates off the central coast may be reflective of southern and eastern movements of entangled whales during their northward migration. The CWWD database indicated changes in the timing of whale migrations. Updates to logbooks were also made during this study. Paper based logbooks were updated to smart-phone applications. Spatial models indicated that depth ranges of 4-40 ma nd distance from the coast (5-21 m) are useful in predicting the occurrence of humpback whales. An industry lead workshop identified potential whale entanglement mitigation measures, all of which were trialed by fishers after the workshop. All mitigation measures tested, except for remote releases, showed a trade off between price and practicality. Based on these results, rope type, rope length and number of floats used were tested industry wide during trials. This project examined the use of acoustic pingers and found their use made no difference to the behavior of humpback whales. An assessment of their effectiveness was not conducted during this study. Other results from this study indicated, preliminarily, that whales are more likely to become entangled in thinner ropes, and mainlines that are yellow or orange.