Download Tuna Fisheries in the NZ EEZ and adjacent waters with special reference to stock status and swordfish bycatch : Volume 3

(1999) This report summarises available information on the tuna fisheries for albacore (Thunnus alaluga), bigeye tuna (T. obesus), skipjack tuna (Katsuwonus pelanus), and southern bluefin tuna (T. maccoyii) operating within the New Zealand EEZ. Information on yellowfin tuna (T. albacares) and swordfish (Xiphius gladius), which are bycatch in these fisheries, is also discussed. Each species is treated as a major section beginning with a synopsis designed to place information from the New Zealand EEZ in the context of the stock as a whole, the fisheries in the Pacific Ocean and global catches. Subsequent sub-sections treat the distribution, domestic landings, foreign licenced catches, fishing effort for each fleet, frequency of each fishing method, and catch efforts and trends for each species within the EEZ. Relative abundance indices are also derived for bigeye and southern bluefin tunas using standard CPUE models. Observer data collected onboard New Zealand and Japanese tuna longliners are used where possible to summarise information on sex, size comparison, and to derive length-weight relationships for these species. In addition to the main fishing methods used to catch tuna in the EEZ (i.e. surface longlining, trolling, and purse seining), discard practices and the data used in the various analyses are also reviewed in the report.