Alternative Bait
WHAT IS ALTERNATIVE BAIT?
Alternative bait simply refers to switching bait-type/species, aiming to deter non-target animals that are attracted to a certain type of bait. For example, squid bait can be replaced by mackerel bait in longline fisheries to reduce the incidence of sea turtle bycatch.
Importantly, the use of alternative bait must consider the bait preferences of target catch so as to maintain the efficiency of the fishery. Similarly, the attractiveness of alternative bait to other previously non-bycatch species must be considered, as they may become more interested in the new alternative.
CURRENT RESEARCH & USE
Considerable research has been conducted specifically on the replacement of squid bait with mackerel bait to reduce sea turtle bycatch. The trials have suggested that the switch can be effective, reducing turtle bycatch by 75% in a North Pacific pelagic longline fishery and by 56% in an Equatorial Atlantic swordfish longline fishery. These results are backed up by a 2024 study of the Portuguese shallow pelagic longline fishery in the Atlantic which found that use of squid bait versus mackerel bait significantly increased the likelihood of deep-hooking of turtles and some bony fish, which could be due to the observed habit of turtles to swallow squid bait whole as opposed to fish bait which tends to be eaten in multiple bites.
For sharks, the effects of bait-switching lesser known. A 2016 review suggests that the same switch that reduces bycatch in turtles (squid to fish) in fact increases bycatch of sharks, although a more recent review found that both turtles and blue sharks are less likely to be captured on forage fish versus squid. However, additional research is required.
Other research has investigated the use of a combination of both an alternative bait and circle hooks. These trials were conducted in an Atlantic swordfish longline fishery and found the use of an alternative bait to be more effective at reducing turtle bycatch.
Given the contrasting evidence for which alternative bait will be best for reducing bycatch, it is crucial that fishery-specific assessments continue, with recommendations incorporating bait preferences of both target catch and vulnerable bycatch species. Trade-offs may be required where bycatch interactions with different types of wildlife occur.
This page was last updated on 04.12.24.
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