2005 Grand Prize Winner - Implementing the Winning Idea

Deep-Setting Technique for Reducing Longline Bycatch of Sea Turtles

Steve Beverly, fisheries development officer, Secretariat of the Pacific Community (SPC), New Caledonia

Mr. Beverly's winning idea was tested on a large scale in Hawaii during 2006. A project was designed and subsequently funded by the University of Hawaii’s Joint Institute for Marine and Atmospheric Research (JIMAR) and was carried out by the Secretariat of the Pacific Community and JIMAR with assistance from the National Oceanic and Atmospheric Administration’s Fisheries Service Observer Program.

Mr. Beverly supervised experimental sets and collected data on the first two trips, while Hawaii scientists and observers supervised experimental sets and collected data during the next five trips. Ninety sets were made during seven tuna longline trips from a Hawaii-based longline boat, F/V Caroleigh. Fishing took place from June to December.

A total of 45 experimental sets used Mr. Beverly's winning deep setting technique while 45 control sets used the boat’s normal setting configuration. 2000 hooks were set each fishing day and the two set types were alternated from one day to the next. No other setting parameters were changed. Temperature depth recorders (TDRs) were attached to both gear types to monitor actual depths fished. TDRs confirmed that the experimental deep sets had all hooks fishing below 100 meters (328 feet) while control sets had a high percentage of hooks fishing shallower than 100 meters.

Preliminary results are very promising, indicating that the technique not only reduces catch of bycatch species but that it also increases catch of the main target species. For example, data from trips one through six showed that the deep sets caught 1.27 times more of the main target species, bigeye tuna, than the control sets – while the control sets caught 3.14 times as many striped marlin (one of the main bycatch species) than the deep sets.

One of the concerns of the Hawaii fishermen was that the technique would result in loss of revenue if fewer byproduct (bycatch that is marketed) species were caught. However, bigeye tuna has a higher market value than all of the byproduct species so the increase in bigeye catches would most likely offset any revenue losses due to reduction in byproduct catch.

The captain and crew of F/V Caroleigh adapted to the new setting technique quickly. By the second fishing trip they were able to set the gear using the deep setting technique as a matter of routine. Once all data from this project are analyzed a formal manuscript will be written and hopefully published.

With the kind support of WWF, Mr. Beverly has produced a brochure titled "Set Your Longline Deep: Catch more target species and avoid bycatch using a new gear design". This brochure can be downloaded from this page (see top- right) and www.spc.int/coastfish/publications in English, French, and Spanish.