As an investor in one of the few new-build tuna longline vessels on the East Coast, Hayley Abbot has a strong personal interest in the future sustainability of the Eastern Tuna and Billfish Fishery (ETBF). Given the highly migratory nature of the target species (including yellowfin, bigeye, albacore and billfish) the future of the ETBF is inexorably linked to the status of the resource in the western Pacific and decisions made at the Western and Central Fisheries Commission (WCPFC).

With this connection, there is a need for fishers to have an understanding of, and where possible have industry input into, the international aspects of the management of the fishery.

Hayley has the potential to become a young industry leader in Australian fisheries. To achieve her potential, there is a need to expose her to a wide variety of relevant fisheries experiences - this opportunity will provide one of those experiences

At a personal level, Hayley will benefit greatly from gaining an understanding of the wider international context management of the fishery, the major industry players, researchers (SPC )and managers (FFA and other national delegations). Hayley will be able to use this knowledge, and especially the interaction with researchers, to enhance my input into ComRAC. The experience will build both her leadership experience and confidence.

Management of the ETBF is complex because of the cross-jurisdictional nature of the stocks and governance through the Commonwealth Harvest Strategy Policy and the WCPFC. Current assessments conducted by the WCPFC assume that these species comprise either single discrete stock units throughout the WCPFC area or across the Southern Hemisphere portion of the region and genetic methods used in the past have been unable to refute such assumptions. Biological information on growth rates and reproduction, movement data derived from tagging studies and spatial and temporal variability in catches of these species however, suggest that there is likely to be some structure to stocks throughout the WCPFC region and assumptions of single spawning populations may not be accurate.

More recently, traditional and next generation genomic methods have provided evidence of population structure in yellowfin tuna across the Pacific (e.g. Aguilar et al. 2015; Grewe et al. 2015) and provide some support to the hypothesis that yellowfin tuna fished by Australia’s tuna fisheries may be a localised stock within the Coral and Tasman Sea region. If yellowfin tuna and if any of the other principal species occurring in the ETBF do comprise localised stocks, this has obvious implications for the management both within national and regional contexts. Clarification of the connectivity and population structure of species in Australia’s Tropical Tuna fisheries with the broader WCPFC region is required for appropriate governance through the Commonwealth Harvest Strategy Policy and the WCPFC, to ensure any risks to regional stock biomass are minimised and to improve stakeholder concern over stock management.

Several important questions and opportunities arise with the development of this new recreational fishery. Fishers have already demonstrated a willingness to release this species post-capture. Off the back of the successful post-release survival study on Southern Bluefin Tuna (FRDC project 2013-025) the fishers are interested to understand the post-release survival rates of Swordfish. While the impacts of the recreational fishery to Swordfish populations is expected to be relatively low, due to the niche nature of the fishery, it is truly positive that the recreational fishers would like to have the information at hand to make informed decisions when choosing to release this species as well as potentially reduce the impacts of catching and handling on animals post-release.

To address this question satellite tags will be deployed in fish caught using recreational fishing methods off the east coast of Tasmania to monitor their movement and behaviour post-release to determine survival. The methodologies will closely follow those developed and implemented during the successful post-release study on Southern Bluefin Tuna.

Another important question relates to whether the fish that are being caught off Tasmania are resident or migratory. The main swordfish population typically inhabit waters further north along the east coast of Australia well up into the Coral Sea. It is expected that the fish available to the recreational fishery off the coast of Tasmania are larger fish that migrate south. It is possible however, that the fish off Tasmania are resident and associating with seafloor features, as they have been found to do further up the coast of Australia (ETBF commercial fisher, pers. comm.).

If they are a resident population there is potential for localised depletion, but if their presence here is migratory then a recreational fishery, with appropriate management, can be developed into the long term as the main swordfish population in the Western and Central Pacific is considered to be in a healthy state. The results will also increase our understanding of Swordfish movement and migration by applying tags to fish further south than has been done previously.