Liquid lens aids study of murky water dwellers

Developed by Swansea University doctoral student Robyn Jones, the lens - a clear liquid optical chamber (CLOC) – was added to a baited remote underwater video (BRUV) system in order to help scientists observe the fish that live around our shallow coastal seas.

While similar chambers have been previously used by the marine surveying industry assessment of habitats at the bottom of deep water, the university claims that adding the CLOC to the BRUV system as a way to assess the movement of fish is new.

Hi-tech subsea inspection system trialled in Cornwall 

Wriggling fish inspire improved robot design

According to Jones, the equipment could be used to study fish communities living around marine renewable structures, such as offshore wind, tidal, and wave energy developments, where the waters are typically cloudy.

“It has long been a challenge for scientists to find a way to study biodiversity in these cloudy waters in a way does not disrupt these sensitive and complex habitats,” explained Jones. “While underwater cameras do help improve our knowledge of the coastal environment, the main drawback is their restricted use in low visibility environments. However, it is vital for us to be able to examine these areas as they are commonly considered critically important for biodiversity, fisheries, energy and increasingly ecosystem services.”

The system was tested in both controlled and field conditions with results showing a drastic improvement in visibility - with scientists able to identify fish to species level.

“With increases in marine renewable developments globally, there is a need to have a simple, reliable, safe, and repeatable method of monitoring the wildlife communities living around these developments,” added Jones.  “This CLOC‐BRUV system will allow scientists around the world to closely monitor these environments while minimising the risk of damage to the seabed infrastructure.”

A paper on the project appears in the journal Limnology and oceanography methods

The liquid lens research stems from a collaborative project between SEACAMS 2, Ocean Ecology Limited and Swansea University (part funded by Knowledge Economy Skills Scholarships).

Ross Griffin at Ocean Ecology stated “This research is a perfect example of industry and academia working together to develop a novel methodology that can be applied in the real world. It's particularly exciting as it presents an approach to better assess the poorly studied marine biological communities found in low visibility environments not just in the UK but globally”.