Location and transport of early life stages of West Australian Dhufish, Glaucosoma hebraicum.

A combination of methods have been developed and tested to locate for the first time early life stages (eggs and larvae) of West Australian Dhufish Glaucosoma hebraicum and provide a detailed map of their distribution at two sites off south-western Australia. The project demonstrated that: - The use of a hydrodynamic model can optimise and guide oceanographic sampling when there is a paucity of knowledge on spawning locations. - The shipboard detection of larvae allows adaptive sampling maximising the chances of success. - A properly interpreted particle (larvae) tracking model can throw light on early life history of G. hebraicum. - There is high variability in the currents along the continental shelf between Cape Leeuwin and Cape Naturaliste (Western Australia), with clear implications for larval transport of West Australian Dhufish and other species important to commercial, recreational and charter fishers. - There is variability in food supply for fish larvae in the Capes region that has consequences for larval survival. The project developed: - A species-specific PCR assay to detect G. hebraicum DNA from mixed zooplankton samples allowing near real time processing of plankton samples. - A proof of concept for use of quantitative PCR analysis to establish an index of the biomass of West Australian Dhufish eggs and larvae in real time.

本研究开发并验证了多种方法，首次实现西澳大利亚红鳍鲷（West Australian Dhufish，Glaucosoma hebraicum）早期生活史阶段（鱼卵与幼体）的定位，并为澳大利亚西南海域两处采样站点的该物种分布绘制了高精度分布图。本项目证实了以下结论：
1. 在产卵场信息匮乏的场景下，水动力模型（hydrodynamic model）可优化并指导海洋学采样工作；
2. 幼体船载检测技术可支撑自适应采样，最大化采样成功率；
3. 经合理解析的粒子（幼体）追踪模型，可助力阐明斜纹裸颌鱼（G. hebraicum）的早期生活史；
4. 西澳大利亚卢因角（Cape Leeuwin）与自然角（Cape Naturaliste）之间的大陆架海域海流存在显著时空变异，这对西澳大利亚红鳍鲷及其他具备商业捕捞、休闲垂钓及包船作业价值的物种的幼体输运过程具有关键影响；
5. 凯佩斯海域（Capes region）的鱼类幼体饵料供给存在变异，进而对幼体存活率产生直接影响。
本项目还开发了以下核心技术与方法：
1. 建立了物种特异性PCR检测方法（species-specific PCR assay），可从混合浮游动物样本中检出斜纹裸颌鱼（G. hebraicum）的DNA，实现浮游动物样本的近实时处理；
2. 完成了定量PCR（quantitative PCR）分析的概念验证，可实时构建西澳大利亚红鳍鲷鱼卵与幼体的生物量指数。