Project number: 1999-108
Project Status:
Budget expenditure: $187,516.30
Principal Investigator: Jock Young
Organisation: CSIRO Oceans and Atmosphere Hobart
Project start/end date: 4 Jan 2000 - 10 Nov 2002


The broadbill swordfish fishery has risen in the space of three years from an annual catch of less than 50 tonnes to ~1500 tonnes presently. A number of fishers with dormant licenses in the east coast longline fishery are now changing their boats over to take advantage of this new fishery. Others that have been in the fishery since its start are now upgrading their boats or buying new ones to improve their catches. At present there are ~ 100 licenses in operation with a further 100 still to become operational. However, there is as yet no idea of the size of the stock on which this fishery is based. Without a concerted effort to establish basic population parameters upon which suitable management advice can be given the swordfish fishery is in danger of reaching unsustainable levels of fishing. In the northern hemisphere, swordfish fisheries are already managed under strict quotas. Recently, there have been moves off Florida, USA to halt fishing of swordfish for up to three months to allow juveniles to grow through to maturity (Anon. 1998). There is a pressing need, therefore, to supply basic population parameters upon which effective management can be given.

The need for such information has been recognised by the Eastern Tuna MAC. They provided a list of 11 priority issues for the east coast tuna industry many of which related to the lack of understanding of the population parameters of broadbill swordfish. They concluded that research was needed for broadbill swordfish on stock structure (priority 1), determination of age and biological characteristics (priority 5), spatial and temporal dynamics of broadbill distribution (priority 7) and seasonal movement and migration patterns (priority 9). All of these priorities cannot be fully addressed without an understanding of the reproductive dynamics of this species.

Anonymous (1998) Florida asks U.S. to halt commercial swordfishing. National Fisherman


1. To provide information on the size-at-maturity and spawning dynamics of swordfish occurring in the eastern AFZ. Also determine sex-ratio of swordfish in catches.
2. Determine whether the aggregations of broadbill off eastern Australia are the result of a spawning migration into Australian waters or some other factor.
3. Determine impact of fishing on spawning biomass by determining the proportion of the catch consisting of adult fish.
4. Determine linkages in seasonal changes in CPUE with seasonal changes in the oceanic environment.

Final report

Related research


Determination of the spatial dynamics and movement rates of the principal target species within the Eastern Tuna and Billfish Fishery and connectivity with the broader western and central Pacific Ocean – beyond tagging

1. Investigate the presence of stock structure in the five principal species caught in Australia’s Eastern Tuna and Billfish Fishery and the western Pacific Ocean across spatial scales of relevance using new generation genomic methods
CSIRO Oceans and Atmosphere Hobart