TurtleWatch: A Tool for Reducing Loggerhead Turtle Bycatch

Content Type
User Story
Photo of a Loggerhead Turtle
Data Applications
Fisheries & Aquaculture

Fisheries bycatch has been implicated as a contributing factor in the population decline of endangered Pacific loggerhead turtles. In order to reduce interactions between longline fishing vessels based in Hawaii and loggerhead sea turtles, the NOAA Pacific Islands Fisheries Science Center created an experimental information product called TurtleWatch.

Photo of a Loggerhead Turtle
A loggerhead turtle encountered by NOAA's Longline Observer Program. Image courtesy of NOAA Fisheries Pacific Islands Regional Office.


TurtleWatch provides fishers with information on the predicted location of water in the turtles' preferred temperature range (water cooler than 65.5°F and warmer than 63.5°F). Predicted temperatures for the product are calculated using sea surface temperature data and derived ocean current vectors from the OceanWatch Central Pacific node.

TurtleWatch experimental product example
The TurtleWatch product is a map showing the predicted location of the loggerhead sea turtle's preferred temperature habitat. Fishers are advised to fish in areas either warmer 65.5°F or cooler than 63.5°F. Grey arrows indicate the direction and strength of the average ocean currents over the most recent week of available data. Solid black lines mark the 63.5°F and 65.5°F temperature contours. The red area between these lines represents the region where more than 50% of loggerhead turtle interactions have occurred during the first quarter of the year.​


References and Related Reading

  • Hatase, H., K. Goto, K. Sato, T. Bando, and Y. Matsuzawa. 2002. Using annual body size fluctuations to explore potential causes for the decline in a nesting population of the loggerhead turtle Caretta caretta at Senri Beach, Japan. Marine Ecology Progress Series 245:299-304.
  • Hays, G.C., A.C. Broderick, B.J. Godley, P. Luschi, and W.J. Nichols. 2003. Satellite telemetry suggests high levels of fishing induced mortality in marine turtles. Marine Ecology Progress Series 262:305-309.
  • Howell, E.A., A. Hooever, S.R. Benson, H. Bailey, J.J. Polovina, J.A. Seminoff, and P.H. Dutton. 2015. Enhancing the TurtleWatch product for leatherback sea turtles, a dynamic habitat model for ecosystem-based management. Fisheries Oceanography 24(1): 57-68.
  • Howell, E.A., D.R. Kobayashi, D.M. Parker, G.H. Balazs, and J.J. Polovina. 2008. TurtleWatch: a tool to aid the bycatch reduction of loggerhead turtles Caretta caretta in the Hawaii-based pelagic longline fishery. Endangered Species Research 5: 267-278.
  • Peckham, S., D. Diaz, A. Walli, G. Ruiz, L. Crowder, and W. Nicholas. 2007. Small-scale fisheries bycatch jeopardizes endangered Pacific loggerhead turtles. PLoS One 10:e1401.