2005-6 Objectives and Preliminary Results

This paper is primarily intended as a brief overview of progress on SW Pacific swordfish (Xiphias gladius) stock assessment, which will hopefully stimulate discussion for further development. The South-West Pacific Swordfish fishery has undergone a number of substantial changes over the last decade. The swordfish catch (in numbers) over the last 10 years have been almost double the previous 25 year period, with large increases in Australian, New Zealand and Pacific Island Nation catches, and declines in the Japanese catch. Australian inshore catch rates have declined substantially, and the fishery has responded with a progressive expansion further offshore. Given the general perception that swordfish are a highly migratory, straddling stock, we expect that events of local concern probably need to be interpreted in the context of a broader regional model of population dynamics. In this paper, we outline the available fisheries and biological data that we will draw on for an integrative assessment, and present a number of hypotheses about swordfish spatial and temporal dynamics. Initial results are presented from fitting Multifan-CL t