Abstract: An underwater detection apparatus for detecting a presence of one or more bubbles within an aquatic environment includes a first structure including a lower peripheral edge for defining an area over which the apparatus is operable to collect the one or more bubbles, a second structure for spatially concentrating the one or more bubbles received within the area defined by the lower peripheral edge into a detection region, and a detection arrangement for detecting the one or more bubbles concentrated in operation by the bubble concentrating structure passing into the detection region and generating an output signal indicative of the one or more bubbles passing through the detection region. The apparatus is optionally mounted upon an aquatic remotely operated vehicle (ROV).