Shark Depredation and Unwanted Bycatch in Pelagic Longline

Introduction and Methods
1.2. Methods
Information was collected from the following 12 pelagic longline
fisheries from eight countries:
(i) Australia longline tuna (Thunnus spp) and
billfish (Istiorphoridae spp) fishery,
(ii) Chile artisanal mahi mahi (dolphinfish) (Coryphaena spp)
and shark fishery,
(iii) Chile swordfish (Xiphias gladius) fishery,
(iv) Fiji longline tuna fishery,
(v) Italy Mediterranean industrial longline swordfish fishery,
(vi) Japan distant water longline fishery,
(vii) Japan offshore longline fishery,
(viii) Japan nearshore longline fishery,
(ix) Peru artisanal mahi mahi and shark fishery,
(x) South Africa longline tuna and swordfish fishery,
(xi) US Hawaii longline tuna fishery, and
(xii) US Hawaii longline swordfish fishery.
Information from the U.S. Atlantic, Caribbean and Gulf of Mexico
longline swordfish and tuna fisheries are also included in this
assessment, however, no interviews with fishers from these fisheries
were conducted as part of this study. From January - December 2006,
149 vessel captains, fishing masters, crew, vessel and company owners,
fishing cooperative staff and port officials from these 12 fisheries
were interviewed at 24 fishing seaports (nine seaports in Australia,
including the main port of Mooloolabah; Arica, Iquique and
Valparaiso, Chile; Suva, Fiji; Sicily, Italy; Kesennuma, Kii-Katsuura,
Yaizu and Misaki, Japan; Ilo, Paita and Salaverry, Peru; Cape Town
Harbour, Hout Bay Harbour and Richards Bay Harbour, South
Africa; and Honolulu, U.S.A.). Table 1.1 summarizes the breakdown
of who was interviewed for each fleet included in the study.
Information from the interviews; analyses of available logbook
and observer data; and a review of the literature was collected and
analyzed to:
• Determine shark catch rates, disposition of caught sharks and
costs and benefits from shark interactions to better understand
longline industry interest in reducing shark interactions;
• Describe the range of longline industry attitudes towards shark
capture and depredation to understand the degree of interest in
shark avoidance;
• Identify practices employed by longline fishers in response to
shark interactions;
• Identify promising concepts not currently practiced to reduce
shark capture, reduce depredation and gear damage, improve
discard methods, and determine what obstacles must be
overcome to implement these concepts;
• Identify priority research and development, monitoring and
management measures; and
• Identify economic, social and ecological effects of legislation
affecting shark practices, assess if the legislation has resulted in
reduced interest in capturing and retaining sharks, and discuss
how these laws may have affected shark fishing mortality levels.