Fish of the Yongala shipwreck and nearby deep water shoals, central Great Barrier Reef (CRC Reef Research Centre Project)

Five fish surveys were conducted on the wreck of the Yongala between June 1996 and September 1997. In addition, surveys of fish on two nearby deep water shoals, Tink Shoal and the unnamed "Small" Shoal were carried out in May 1997.Fish were surveyed by a visual census method using Log5 abundance estimates. Two dives along the length of the shipwreck were conducted during each visit to the Yongala, with a total observation time of 45 minutes. The bottom of the shipwreck was surveyed on the first dive and during the second dive fish visible from midway down the shipwreck were surveyed. The second dive built on the estimates and species recorded during the first dive. All fish in sight on the shipwreck were counted.A single 25 minute dive was made at each of the shoals. Each dive covered approximately 200m straight line distance and Log 5 abundance of fishes was recorded in an estimated 10m band along the swimming path. Dives on the shoals began at 30m depth and finished on the reef slope at around 15m.Additional observations recorded included habitat type, visibility, currents, the presence of other vessels with divers and fish behaviour. The objective of this project was assess the significance of the Yongala wreck as a fish refuge in the inshore region of the Great Barrier Reef. To achieve this objective the following tasks were identified:1. to compile an species list of the fish associated with the Yongala wreck2. to compare the Yongala fish community with those of nearby deep water shoals3. to assess the relative abundance of different fish species and temporal changes in abundance

1996年6月至1997年9月期间，针对永格拉号沉船（Yongala Wreck）开展了5次鱼类调查。此外，1997年5月对附近两处深水沙洲——廷克沙洲（Tink Shoal）与未命名‘小’沙洲（unnamed "Small" Shoal）开展了鱼类调查。本次鱼类调查采用视觉普查法（visual census method），结合Log5丰度估计（Log5 abundance estimates）开展记录。每次造访永格拉号沉船时，均沿船体全长开展2次潜水，总观测时长合计45分钟：首次潜水对沉船底部进行普查，第二次潜水则针对沉船中段可视范围内的鱼类开展普查。第二次潜水以首次潜水记录的丰度估计值与物种数据为基础，对沉船视野内的全部鱼类进行计数。两处沙洲各开展单次25分钟的潜水作业。每次潜水沿直线行进约200米，沿游泳路径估算10米带宽内的鱼类Log5丰度并予以记录。沙洲潜水作业始于30米水深，最终在约15米的礁坡处结束。本次调查额外记录的内容涵盖栖息地类型、水体能见度、海流状况、其他载有潜水员的船只的出现情况以及鱼类行为。本项目旨在评估永格拉号沉船作为大堡礁（Great Barrier Reef）近岸鱼类庇护所的重要性。为达成该目标，拟定以下三项研究任务：1. 编制与永格拉号沉船相关联的鱼类物种名录；2. 对比永格拉号沉船海域的鱼类群落与周边深水沙洲的鱼类群落；3. 评估不同鱼类物种的相对丰度及其丰度的时间变化。