Project number: 2003-060
Project Status:
Budget expenditure: $83,841.00
Principal Investigator: James Findlay
Organisation: Department of Agriculture; Water and the Environment (ABARES)
Project start/end date: 29 Jun 2003 - 21 Dec 2005


At present, the target catch within pelagic longline fisheries is only a handful of the more than 70 species of fish taken during these operations. However, a considerable number of non-target species are marketed in Australia and elsewhere as a byproduct. While considerable attention has been focussed on target species and, in recent years, on bycatch species, assessment of the threats to, and opportunities for, the sustainable development of the harvest of byproduct species in Australia's tuna and billfish fisheries is long overdue. In particular, these species may represent significant opportunities for increased production from Australia's commercial fisheries including supply to export markets.

One of the key aims of the Commonwealth's Bycatch Action Plan (BAP) for Australia's tuna and billfish fisheries is the development of mechanisms to convert bycatch into byproduct where appropriate. One of the key impacts on the sustainable utilisation of these species are the current suite of Offshore Constituional Settlement (OCS) agreements that describe catch limits for many species taken in Australia's tuna and billfish fisheries. Analysis of spatial and temporal trends in catch and effort data for byproduct species would greatly assist future actions under the BAP including OCS re-negotiations.

In addition, management action taken to address issues facing target or bycatch species (e.g. spatial and/or temporal closures) may have considerable impacts on the take of economically-important, byproduct species. A wholistic approach is required and this approach needs to be supported by complete information from the fishery including all available information on byproduct species. As evidence for the significance of byproduct species to operators and managers it should be noted that operators in the Eastern Tuna and Billfish Fishery have launched legal proceeding against AFMA twice since 1999 specifically in relation to byproduct species (i.e. southern bluefin tuna and pelagic sharks).


1. Identify key byproduct species in Australia's pelagic longline fisheries, through spatial and temporal analyses of catch and economic data
2. Determine co-occurrence in catch of key byproduct species with both target species and with other key species

Final report

Author: James Findlay
Final Report • 2006-10-23


The longline sector of the Eastern Tuna and Billfish Fishery (ETBF) and the Southern and Western Tuna and Billfish Fishery (SWTBF) target four main species and incidentally take over 80 other species as “bycatch”. Significant amounts of these species are often retained for sale, and are referred to as  “byproduct”. Total retained byproduct increased through the 1990s to peak at over 1300 metric tonne (mt; 20% of total catch) in the ETBF in 2002. In the SWTBF, which has lower fishing effort levels and higher discarding rates, total retained byproduct was over 190 mt (9%) in 2002.
Byproduct species have received relatively little management attention because they are of lower value, are not targeted, and there is scant validated data available for the provision of scientific and economic advice. In recent years, retention has increased and logbook and observer programs have been improved or established. As economic pressures in the fisheries increase, fishers have called for increased access to byproduct e.g. dolphinfish and shark fin. There is also a clear requirement for the consideration of these species in fisheries management and policy making as required by the Fisheries Management Act (1991) and the Commonwealth Bycatch Policy.
This report assesses the reliability of logbook data, describes spatial and temporal trends in catches, assesses the economic value of byproduct and examines patterns in co-occurrence of byproduct species and target species. This information is used to identify opportunities and threats to sustainable fisheries management that are presented by increasing catches and retention of byproduct species.

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