Knowledge of the stock structure and migration patterns is fundamental to ensuring effective stock assessment and management of a fishery. While this knowledge is scanty for many Commonwealth fisheries, swordfish structure and movements are particularly poorly known. The stock harvested by the ETBF is locally depleted, suggesting population structure, but there are no direct data on movement or distribution available. Parameterizing a model of movement for swordfish would clarify the stock structure and provide a mechanism for incorporating their movements into spatial management or assessment models.

The recent Ministerial Directive to AFMA has highlighted the lack of knowledge regarding swordfish. Key initiatives in the directive are 1) develop harvest strategies for its fisheries to ensure sustainable management; 2) recover overfished stocks; and 3) end overfishing on stocks. Furthermore, the directive urges AFMA to move to spatial management. Critical to the design of harvest strategies, determination of stock status, and development of spatial management measures is a sound knowledge of the connectivity between stocks fished locally and in other parts of the Pacific basin. In order to ensure equity in limitations due to management arrangements, Australia will need to pursue policies that ensure other nations protect shared stocks within the context of the Western Central Pacific Fisheries Commission - requiring clear evidence of the amount of movement between locally and regionally harvested stocks and empirically validated assessment models.

The March 2005 AFMA/ComFRAB Research Gap Analysis and Priority Setting Workshop, held jointly by AFMA and ComFRAB underlined the needs outlined above for swordfish in the ETBF specifically – identifying both spatial management measures to rectify the localized depletion and provision of science and policy advice into the WCPFC. The ETBF research priorities and FRDC’s strategic challenges both identify these same issues, as discussed in the Background section.