Reduced Soak Time
WHAT IS REDUCED SOAK TIME?
‘Soak time’ is the length of time during which fishing gear is in the water. In fisheries that use static gear (lines, nets, pots and traps, for example) reducing soak time in turn reduces the period in which sensitive species may encounter and interact with fishing gear, reducing the chance of them becoming entangled and/or bycaught.
CURRENT RESEARCH
A study of small cetacean interactions with turbot gillnets in the Black Sea found that duration of soaking time does not seem to have any effect on bycatch rates. However, a study of a small-scale Greenland halibut fishery in Canada found that shorter soak times resulted in significantly lower rates of Greenland shark bycatch, without affecting catch rates of halibut.
Most existing research has focused on the impacts of increased soak time rather than the potential of reducing soak time to reduce bycatch. A study in Irish fisheries found that increasing the soak time increased the rate of seal depredation (where predators take fish from gear in the water) in the pollack fishery, by around 5% per hour of gear deployment. This same effect has been observed in Cape Cod’s fixed gear fishery. This may be because seals are attracted to the noise or vibrations caused by caught target fish, which increase as more fish are caught. Furthermore, the longer that gear is left to soak, the higher the chance a seal will encounter it. This phenomenon was also observed in a study of dolphin interactions with bottom-set net fisheries off Southern Iberian Atlantic waters, where longer nets require a longer soaking time and as a result are at more risk of dolphin depredation – even though these longer nets do not necessarily yield higher daily catches for fishermen.
Bycatch of loggerhead turtles in Atlantic longline fisheries has been shown to increase with increased soak time. The implications for target catch were negligible for some species (swordfish) although significant for others (bigeye tuna). Longer soak time (in combination with longer hauling time) may also reduce the survival rates of small- and medium-sized individuals of deep-sea skate species brought abroad and then released, based on a study of demersal longline fisheries targeting Patagonian toothfish in the Southern Ocean.
These findings suggest that reducing soak time could reduce the incidence of wildlife bycatch. However, this operational change would need to be balanced with the potential for reduced target catch.
Interested in how this and other measures could mitigate bycatch in your fishery? Get in touch with us to collaborate or take part in a study.
This page was last updated on 04.12.24.