An innovative technology is making substantial advancements in aquatic research. Visual remote underwater survey methods have long been the backbone of biomass estimation and ecological observations. However, limitations in these methods, particularly their reliance on light, sensitivity to turbidity, and visual obstructions have prompted researchers to seek alternative approaches.
Imaging sonars, at the forefront of underwater exploration utilizing sound waves instead of light, represent a pioneering advancement. Engineered with high-frequency multibeam systems (≥700 kHz), these acoustic cameras introduce a novel dimension to aquatic studies. Unlike optical cameras, they operate independently of ambient light, overcoming challenges posed by low visibility and turbidity. The intricate details and high sampling rates of imaging sonars unveil morphometric features and behaviours, even in the absence of light.
One of the key advantages lies in the ability to resolve multiple objects along a linear plane, surpassing the limitations of visual methods. In situations where turbidity obscures the nearest focal point, imaging sonars remain unobscured, providing unprecedented insights into underwater ecosystems.
However, like any scientific tool, imaging sonars have their limitations. To address these challenges, researchers often pair them with optical camera systems, other sonars, or complementary gears for ground truthing species composition, depending on the study's objectives. Data processing also poses challenges, requiring careful consideration and strategic approaches.
To evaluate the efficacy of imaging sonars in aquatic ecological and fisheries studies, a comprehensive meta-analysis was conducted. Examining 155 studies utilizing imaging sonars in situ, the authors of the latest Editor’s Choice article explored their performance in studying inter- and intra-specific interactions, associations with complex habitats, and effectiveness in low-visibility environments. The analysis also delved into evaluating traditional fisheries sampling gears, emphasizing the versatility of imaging sonars.
Beyond exploration, the review article scrutinized data processing and analytical methods, aiming to refine taxonomic resolution, manage time use, and address autocorrelation through subsampling. These methods also facilitated the extraction of behavioural metrics applied to ecological processes, as well as automating abundance estimates and image classification.
By summarizing the diverse applications of imaging sonars, the authors provide a valuable resource for researchers planning future studies with this advancing technology. As imaging sonars become more accessible, their role in studying aquatic ecosystems and fisheries is set to expand, promising a deeper understanding of our underwater world.
