An estimated 250,000 turtles are caught each year in set net fisheries globally. Bycatch of turtles in small-scale set net fisheries is considered the single greatest threat for some sea turtle populations. Six of the seven marine turtle species are categorized as Vulnerable, Endangered or Critically Endangered globally. Capture of turtles also leads to net damage, time required to disentangle the animal and reputational damage for the fishery.
Recent research from the Pacific coast of Ecuador, Peru and Chile reveals that these coastal fisheries catch more than 46,000 turtles annually, with more than 16,000 killed in the process. Species affected include leatherbacks and hawksbills which are critically endangered worldwide.
NetLight is a device that illuminates fishing gear, increasing its visibility to turtles, seabirds and cetaceans. It is a small, long-lasting and robust device that is easily attached to the top rope of fishing nets and trawls. The use of net lights in drift gill nets and bottom-set gillnets has led to reductions of between 40% and 100% in the number of turtles caught in nets.
Research in Cyprus suggests that NetLight reduces sea turtle bycatch per vessel by an average of 62% – potentially 57 turtles saved per typical vessel per annum. Other studies have taken place in locations across the Mediterranean, Adriatic, South and Central America using various models of netlights. These studies all show significant turtle bycatch reduction in gillnet fisheries.
|
Paper |
Location | Product/model used | Effect | Species |
Gear Type |
| Trialling net illumination as a bycatch mitigation measure for sea turtles in a small-scale gillnet fishery in Ecuador. (Darquea et al., 2020) |
Ecuador |
Light – constant green | 93% bycatch reduction.
No effect
|
Green Turtle (chelonia mydas)
olive ridley turtle (lepidochelys olivacea) |
Artisanal gillnet |
| Gillnet illumination as an effective measure to reduce sea turtle bycatch.(Allman et al., 2020) |
Mankoadze and Winneba, Ghana |
Light – constant green | 74% bycatch reduction
82% bycatch reduction 91% bycatch reduction |
Leatherback Turtle (Dermochelys coriacea)
olive ridley turtle (lepidochelys olivacea) Green Turtle (chelonia mydas) |
Drift gillnet |
| An illuminating idea to reduce bycatch in the Peruvian small-scale gillnet fishery. (Bielli et al., 2020) |
Peru |
Light – constant green | 70 – 74% bycatch reduction | Loggerhead Turtle (Caretta caretta)
olive ridley turtle (lepidochelys olivacea) Green Turtle (chelonia mydas) |
Surface drift & bottom-set gillnet |
| Reducing Sea Turtle Bycatch in the Mediterranean Mixed Demersal Fisheries. (Lucchetti et al., 2019) |
Mediterranean |
Light – constant UV | 100% bycatch reduction | Loggerhead Turtle (Caretta caretta) | bottom-set gillnet |
| Can ultraviolet illumination reduce sea turtle bycatch in Mediterranean set net fisheries? (Virgili et al., 2018) | North Adriatic Sea, central Mediterranean | Light – constant UV | 100% bycatch reduction | Loggerhead Turtle (Caretta caretta) |
bottom-set gillnet |
| Reducing green turtle bycatch in small-scale fisheries using illuminated gillnets: the cost of saving a sea turtle. (Ortiz et al., 2016) |
Sechura Bay, northern Peru |
Light – constant green | 64% bycatch reduction | Green Turtle (chelonia mydas) | Artisanal gillnet |
| Developing ultraviolet illumination of gillnets as a method to reduce sea turtle bycatch. (Wang et al., 2013) | Baja California Sur, Mexico | Light – constant UV | 40% bycatch reduction | Green Turtle (chelonia mydas) |
Coastal & pelagic gillnets |
| Developing visual deterrents to reduce sea turtle bycatch in gill net fisheries. (Wang et al., 2010) | California Sur, Mexico |
Light – constant green |
40% bycatch reduction |
Green Turtle (chelonia mydas) |
Artisanal gillnet |