Parsons Darren M, MacDonald Iain, Buckthought Dane, Middleton Crispin
NIWA, Auckland, New Zealand.
Institute of Marine Science, University of Auckland, Auckland, New Zealand.
PLoS One. 2018 Jan 17;13(1):e0186889. doi: 10.1371/journal.pone.0186889. eCollection 2018.
Juvenile fish nurseries are an essential life stage requirement for the maintenance of many fish populations. With many inshore habitats globally in decline, optimising habitat management by increasing our understanding of the relationship between juvenile fish and nursery habitats may be a prudent approach. Previous research on post-settlement snapper (Chrysophrys auratus) has suggested that structure may provide a water flow refuge, allowing snapper to access high water flow sites that will also have a high flux of their pelagic prey. We investigated this hypothesis by describing how Artificial Seagrass Units (ASUs) modified water flow while also using a multi-camera set up to quantify snapper position in relation to this water flow environment. Horizontal water flow was reduced on the down-current side of ASUs, but only at the height of the seagrass canopy. While the highest abundance of snapper did occur down-current of the ASUs, many snapper also occupied other locations or were too high in the water column to receive any refuge from water flow. The proportion of snapper within the water column was potentially driven by strategy to access zooplankton prey, being higher on the up-current side of ASUs and on flood tides. It is possible that post-settlement snapper alternate position to provide opportunities for both feeding and flow refuging. An alternative explanation relates to an observed interaction between post-settlement snapper and a predator, which demonstrated that snapper can utilise habitat structure when threatened. The nature of this relationship, and its overall importance in determining the value of nursery habitats to post-settlement snapper remains an elusive next step.
幼鱼育幼场是许多鱼类种群维持所必需的生命阶段需求。鉴于全球许多近海栖息地正在减少，通过增进我们对幼鱼与育幼栖息地之间关系的理解来优化栖息地管理可能是一种审慎的做法。先前关于定居后笛鲷（Chrysophrys auratus）的研究表明，结构可能提供水流庇护所，使笛鲷能够进入水流湍急的区域，而这些区域也会有大量其浮游猎物。我们通过描述人工海草单元（ASUs）如何改变水流，同时使用多摄像头设置来量化笛鲷相对于这种水流环境的位置，对这一假设进行了研究。在人工海草单元下游一侧，水平水流有所减少，但仅在海草冠层高度处。虽然笛鲷数量最多的区域确实出现在人工海草单元下游，但许多笛鲷也占据其他位置，或者在水柱中位置过高，无法从水流中获得任何庇护。水柱中笛鲷的比例可能受获取浮游动物猎物策略的驱动，在人工海草单元上游一侧和涨潮时比例更高。定居后的笛鲷可能会交替位置，以提供觅食和水流庇护的机会。另一种解释与观察到的定居后笛鲷与一种捕食者之间的相互作用有关，这表明笛鲷在受到威胁时可以利用栖息地结构。这种关系的本质及其在确定育幼栖息地对定居后笛鲷价值方面的总体重要性，仍然是有待进一步探索的问题。
