Study

TurtleWatch: a tool to aid in the bycatch reduction of loggerhead turtles Caretta caretta in the Hawaii-based pelagic longline fishery

  • Published source details Howell E.A., Kobayashi D.R., Parker D.M., Balazs G.H. & Polovina J.J. (2008) TurtleWatch: a tool to aid in the bycatch reduction of loggerhead turtles Caretta caretta in the Hawaii-based pelagic longline fishery. Endangered Species Research, 5, 267-278.

Actions

This study is summarised as evidence for the following.

Action Category

Set unwanted catch quotas

Action Link
Reptile Conservation

Promote knowledge exchange between fishers to improve good practice

Action Link
Reptile Conservation

Establish temporary fishery closures

Action Link
Reptile Conservation
  1. Set unwanted catch quotas

    A study in 2005–2007 in pelagic waters north of Hawaii, USA (Howell et al. 2008) found that after an annual unwanted catch quota was established for loggerhead turtles Caretta caretta in a swordfish Xiphias gladius shallow-set longline fishery, turtle catch reached the limit in the second year after the fishery re-opened with catch limits, but was lower in the first and third year. Results were not statistically tested. In the first year after the fishery re-opened with a turtle catch limit, nine loggerhead turtles (0.004–0.049 turtles/1,000 hooks) were caught, but in the second year the catch limit of 17 turtles (0.013–0.044 turtles/1000 hooks) was reached and the fishery was closed for the rest of the year. In the third year, 12 turtles were caught (0.0–0.028 turtles/1,000 hooks). In late 2004, the fishery re-opened after a two-year shut down due the high number of loggerhead turtle catch levels. After re-opening, a catch limit of 17 turtles/year was established, after which the fishery would close for the rest of the year. In January–March 2005–2007, line deployments (2005: 520; 2006: 842; 2007: 797), hooks put out (2005: 429,580; 2006: 670,914; 2007: 689,486), and loggerhead turtle interactions were monitored. In January–March 2007, fishers were also provided daily information in electronic and paper format from a ‘TurtleWatch’ tool that recommended areas to avoid to reduce turtle interactions (see original paper).

    (Summarised by: Katie Sainsbury)

  2. Promote knowledge exchange between fishers to improve good practice

    A before-and-after study in 2005–2007 in pelagic waters north of Hawaii, USA (Howell et al. 2008) found that a tool (‘TurtleWatch’) created to facilitate knowledge exchange and the avoidance of loggerhead turtle Caretta caretta interactions with a swordfish Xiphias gladius shallow-set longline fishery, did not reduce turtle catch, and fishers did not spend less time fishing in areas recommended for avoidance by the tool. Results were not statistically tested. After the tool was deployed, 0–0.03 loggerhead turtles/1000 hooks (12 total turtles) were caught compared to 0.01–0.04 loggerhead turtles/1000 hooks (17 total turtles) in the previous year and 0–0.05 turtles/1000 hooks (9 total turtles) two years earlier. Fishers did not remain south of the fishing boundary line recommended by the tool, instead the whole fishery moved further north than previously and remained north for a longer time than in the two preceding years (see paper for details). ‘TurtleWatch’ combined historical fishing, environmental and turtle behavioural data to recommend areas to avoid fishing. In January–March 2007, information from the tool was disseminated daily in electronic and paper format to industry professionals and fishers. The fishery also had a legal catch limit of 17 turtles/year, after which fishery closures were imposed. In January–March 2005–2007, line deployments (2005: 520 deployments; 2006: 842; 2007: 797), number of hooks put out (2005: 429,580 hooks; 2006: 670,914; 2007: 689,486), and loggerhead turtle interactions were monitored.

    (Summarised by: Katie Sainsbury)

  3. Establish temporary fishery closures

    A study in 2005–2007 in pelagic waters north of Hawaii, USA (Howell et al. 2008) found that after annual catch limits were established for loggerhead turtles Caretta caretta in a swordfish Xiphias gladius shallow-set longline fishery, turtle catch reached the limit in the second year after the fishery re-opened with catch limits but was lower in the first and third year. Results were not statistically tested. In the first year after the fishery re-opened with a turtle catch limit, nine loggerhead turtles (0.004–0.049 turtles/1,000 hooks) were caught, but in the second year the catch limit of 17 turtles (0.013–0.044 turtles/1000 hooks) was reached and the fishery was closed for the rest of the year. In the third year, 12 turtles were caught (0.0–0.028 turtles/1,000 hooks). In late 2004, the fishery re-opened after a two-year shut down due the high number of loggerhead turtle catch levels. After re-opening, a catch limit of 17 turtles/year was established, after which the fishery would close for the rest of the year. In January–March 2005–2007, line deployments (2005: 520; 2006: 842; 2007: 797), hooks put out (2005: 429,580; 2006: 670,914; 2007: 689,486), and loggerhead turtle interactions were monitored. In January–March 2007, fishers were also provided daily information in electronic and paper format from a ‘TurtleWatch’ tool that recommended areas to avoid to reduce turtle interactions (see original paper).

    (Summarised by: Katie Sainsbury)

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