Soak duration is the length of time that pelagic longlines remain in the water, between line setting and line hauling. Average soak time varies among fisheries and is dependent on factors such as the target species, number of hooks deployed and the time required to bring them aboard.
In their meta-analysis, Swimmer et al (2021) found that reducing soak duration has the potential to reduce shark bycatch. Their conclusions are as follows:
Some research has investigated whether limiting soak time can reduce shark catches (Watson et al. 2005, Carruthers et al. 2011). Given that soak time is essentially increased effort, the real question is how soak time influences shark survival, which varies dependent upon shark species. Some species have been found to have high onhook survival (e.g. blue shark, other large shark species) (Ward et al. 2004, Diaz & Serafy 2005, Campana et al. 2009), which is likely a function of branchline length and the ability to swim and effectively respire while hooked (Heberer et al. 2010). Shark species’ vulnerability to survival of fishing gear has been previously reviewed, with clear differences among species’ blood chemistry, fight time, and survival (Gallagher et al. 2014, see Reinhardt et al. 2018).