Food color and marine turtle feeding behavior: can blue bait reduce turtle bycatch in commercial fisheries?

Published source details Swimmer Y., Arauz R., Higgins B., McNaughton L., McCracken M., Ballestero J. & Brill R. (2005) Food color and marine turtle feeding behavior: can blue bait reduce turtle bycatch in commercial fisheries?. Marine Ecology Progress Series, 295, 273-278.
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This study is summarised as evidence for the following.

	Action	Category
	Use dyed bait Action Link

Use dyed bait

A randomized, paired, controlled study in 2001–2003 in pelagic waters in the Gulf of Papagayo, Costa Rica (Swimmer et al. 2005) found that using blue-dyed bait in a longline fishery did not reduce unwanted catch of olive ridley turtles Lepidochelys olivacea and green turtles Chelonia mydas agassizi, and in separate captive trials found that preference for dyed or non-dyed bait varied depending on the turtle species. Turtle catch rates were similar for blue bait (8 turtles/1,000 hooks, 13 individuals) and non-dyed bait (8 turtles/1,000 hooks, 9 individuals). In separate captive trials, loggerhead turtles Caretta caretta preferred non-dyed bait to blue or red bait and Kemp’s ridley turtles Lepidochelys kempii preferred non-dyed bait to blue bait but red bait to non-dyed bait (see original paper for details). Field trials were carried out simultaneously on two commercial longline fishing vessels in December 2013. In total, 22 lines were deployed using circle hooks (size: 12/0, 560–606 average hooks/deployment, each deployment lasted 8 hours) and baited with blue-dyed (9 deployments) or non-dyed (13 deployments) bait, which was either squid Loligo spp. (12 deployments) or sailfish Istiophorus platypterus (10 deployments). Captive trials tested preferences of two-year-old, captive reared loggerhead (four trials in October 2001–March 2002, 49 individuals) and olive ridley turtles (one trial in July-August 2002, 42 individuals) for dyed (red or blue) compared to non-dyed squid pieces placed in pools (see original paper for details).

(Summarised by: Katie Sainsbury)