Ecological and behavioral data on mobile, low density, benthopelagic animals is difficult to collect in the abyssal environment. However, these species occupy an important position in the abyssal food chain. At-depth ROV-mounted echosounder studies provide a powerful tool to gather in-situ information on abyssal benthopelagic assemblages and discern their distribution, behavior and habitat associations. This study presents a new perspective on mobile benthopelagic assemblages at the long-term study site, Station M (∼4000 m), using a Seabat T20-S MBES mounted on the ROV Doc Ricketts. The targets (∼45 m off the seafloor) are believed to be the abyssal grenadier of the species Coryphaenoides armatus or C. yaquinae, species known to dominate the mobile benthopelagic fauna at Station M. The swimming behavior of the targets indicated little evidence of avoidance or attraction to the slowly moving ROV and demonstrates the effectiveness of this platform to collect data on benthopelagic fish. The information on targets in close (<1 m) association with the seafloor from the MBES corresponded well to target densities recorded by the video transects. However, in addition the MBES resolved the distribution of targets up to 45 m above the seafloor. Target density had a small peak close to the seafloor (<1 m) but increased in density with height above the seafloor, exceeding the maximum near-bottom density by ∼50 times. ROV-mounted MBES surveys can effectively provide data on the distribution and behavior of benthopelagic fish and further understanding of the pelagic-benthic links in the abyssal deep-sea.

在深渊环境中很难收集有关流动性低密度底栖动物的生态和行为数据。但是，这些物种在深海食物链中占有重要地位。深入安装ROV的回声测深研究提供了一个强大的工具，可以收集深海底栖上层组合的原位信息，并识别它们的分布，行为和栖息地关联。这项研究使用安装在ROV Doc Ricketts上的Seabat T20-S MBES，在长期研究地点M站（约4000 m）上提出了移动性上层鱼类组合的新观点。目标（离海底约45 m）被认为是Coryphaenoides armatus或C. yaquinae物种的深海榴弹兵。，这些物种已知会在M站的活动底栖动物区系中起主导作用。目标的游泳行为几乎没有证据表明对缓慢移动的ROV有回避或吸引的迹象，并且证明了该平台收集底栖鱼类数据的有效性。来自MBES的与海底紧密相关（<1 m）的目标信息与视频样条记录的目标密度很好地对应。但是，此外，MBES还解决了目标在海平面以上45 m处的分布问题。目标密度在靠近海底（<1 m）处有一个小峰值，但随着海底上方高度的增加，其密度增加，超过最大近底密度约50倍。