Ghost fishing, the continued catch of fishes and invertebrates by lost fishing gear, represents an animal welfare issue as well as a waste of both potential food and ecosystem resources. Fishing gear is lost by both commercial and recreational fishers, and management authorities often lack an overview of gear loss and subsequently potential impact on coastal populations. To investigate the hazard and catch composition of lost fishing gear along the Norwegian coast, recreational divers in collaboration with scientists conducted systematic reporting of retrieved lost fishing gear. Through this citizen science project, a total of 12,101 gear items were retrieved and reported, including traps, gillnets and fyke nets. Combining both data on the catch ratio of the gear and its relative quantity, we identified the five most hazardous gear types to be parlor traps, gillnets, fyke nets, wrasse traps and square collapsible traps. The parlour trap was the most hazardous trap, due to high catchability and quantity. The correct classification of gear type could not be confirmed in 2.8 – 6.1 % of the pictures taken by divers, depending on reporting format, and divers reported the wrong gear type in 1.4 % of the reports. Brown crab (Cancer pagurus) was the species most often found in retrieved gear. Furthermore, the vulnerable species European lobster (Homarus gammarus) and Atlantic cod (Gadus morhua) were also common. These results can inform future clean up-initiatives and management responses to ghost fishing, including preventive measures against gear loss and gear restrictions and customization.

Data was collected by recreational divers when retrieving lost fishing gear along the Norwegian coast between June 2015 – June 2020. All diver reports included a photograph of the retrieved gear, and all photos and forms were quality checked by the authors to check if the three different gear types (traps, gillnets and fyke nets) were correctly identified. All photos of traps were checked and classified into nine different trap-types: parlour trap, round collapsible trap, square collapsible trap, wooden trap, large square trap, circular kelp forest trap, crayfish trap, wrasse trap and other traps. “Other traps” include traps that could not be categorized into the eight trap types, for example, because they were homemade. Data were reported in two different ways within the period. From June 2015 to December 2018, paper forms with pictures were sent to the Norwegian Diving Association and then to the Institute of Marine Research either by mail or e-mail. These reports included depth and GPS coordinates for the retrieved gear. From September 2017, a mobile app report system, “Fritidsfiske” (“Recreational fishing”), was launched by the Norwegian Directorate of Fisheries. Data reported through the app until June 2020 is included. Within the app, divers could deliver reports connected to their diving club. After an app update in March 2019 divers that were associated with a diving club supplied more detailed reports than other participants. All diver reports included GPS coordinates for the retrieved gear. However, detailed reports also included information on depth, bottom conditions, slope, presence of rope and buoy, and whether there were alive or dead animals found in the equipment. Catch was reported as number of live and dead individuals separately within five categories: brown crab (Cancer pagurus), European lobster (Homarus gammarus), wrasse family (Labridae), Atlantic cod (Gadus morhua) and other fish.

All data files are text files.

• Gear and trap type, time, depth, coordinates
  • This dataset contains data on all gear retrieved by divers where the gear type could be verified. The coordinates are given in decimal degrees. They have been reported in different formats and transformed.
• Rope, buoy, bottom conditions and slope
  • This dataset contains data on presence of rope, buoy, bottom conditions and slope by gear type. The data is from all gear retrieved by divers and reported in the app after the app update that allowed divers to supply more detailed reports.
• Catch data
  • This dataset contains data on all reported catches (alive and dead) by gear or trap type. Data herein is retrieved by divers and reported in the app after the app update that allowed divers to supply more detailed reports.