WAMSI Node 4.4.2-3 - Spatially explicit assessment models for the west Coast demersal scalefish fishery

The capacity of management areas to sustain abundances of exploited species depends upon the dynamics of recruitment, and in particular the extent of dispersal between areas and the age classes contributing to dispersal. Like other marine fishes with pelagic larval stages (ca. the first 20-30 days), the dispersal of larval dhufish is likely to be profoundly influenced by oceanic currents. There is extensive evidence that the pole-ward flowing Leeuwin Current is responsible for the long-distance transport of marine fauna in the south-western Australian area (Hutchins & Pearce, 1994, Caputi et al., 1996, Beckley et al., 2009, Pearce & Hutchins, 2009). In addition, during the austral summer (December-February), when most spawning occurs in dhufish, wind driven currents drive flows along the west coast northwards and inshore of the Leeuwin current (the Capes Current; Pearce & Pattiaratchi, 1999, Feng et al., 2010), and these are believed to transport the larvae of marine fishes (Lenanton et al., 1996, Lenanton et al 2009b). The dhufish is characterised by inter-annual variation in recruitment (Lenanton et al., 2009), and it has been speculated that this may in part reflect variation in the strength of the prevailing currents.

The aim of the study, in including alternate hydrodynamic conditions, was to explore the potential influence of a range of realistic larval dispersal scenarios on dhufish population dynamics.

管理区域维持被开发物种种群数量的能力取决于补充动态（recruitment dynamics），尤其取决于区域间的扩散程度以及参与扩散的年龄组。与其他具有浮游幼体阶段（约前20-30天）的海洋鱼类类似，杜夫鱼（dhufish）幼体的扩散可能受到洋流的深刻影响。大量证据表明，向极地流动的李温洋流（Leeuwin Current）是澳大利亚西南部海域海洋生物长距离迁移的主要原因（Hutchins & Pearce, 1994；Caputi等，1996；Beckley等，2009；Pearce & Hutchins，2009）。此外，在南半球夏季（12月-2月）——此时杜夫鱼的产卵活动最为频繁——风驱动的洋流会沿西海岸向北流动，并进入李温洋流的近岸区域（即开普洋流（Capes Current）；Pearce & Pattiaratchi，1999；Feng等，2010），这些洋流被认为是海洋鱼类幼体的迁移载体（Lenanton等，1996；Lenanton等，2009b）。杜夫鱼的补充具有年际变化特征（Lenanton等，2009），据推测这在一定程度上反映了主导洋流强度的变化。

本研究通过纳入不同的水动力条件，旨在探讨一系列真实的幼体扩散情景对杜夫鱼种群动态的潜在影响。