Fish Guidance Systems

New Queensferry Crossing opened by the Queen

Six years after construction started, the new Queensferry Crossing over the Firth of Forth in Scotland has recently been opened by the Queen.

Linking Edinburgh at South Queensferry, with Fife at North Queensferry, the new bridge is the third major crossing of the Firth of Forth. It is situated close to the existing Forth Road Bridge and the original Forth Bridge – a railway bridge which opened in 1890. The new bridge carries the M90 motorway and provides a new strategic north-south link, providing much-needed relief to the existing road crossing.

Britain’s newest road bridge is suspended by 23,000 miles of cabling, and at 1.6 miles (2.7km), the Queensferry Crossing is the longest bridge of its type in the world.

Early in the construction period, blasting was required, and concerns were raised about the effect this would have on the local fish population, including salmon and sea trout. Fish Guidance Systems was commissioned to design and provide a behavioural fish deflection system for the site.

An initial assessment was conducted to determine the most suitable system for the location, and the project was led by Dr. David Lambert of FGS. Commenting on the project, he explained “it was anticipated that blasting would only be undertaken for a relatively short period of time, so from the outset it was realised that the project was likely to be temporary. With that in mind, we devised a solution based on a mobile Sound Projector Array (SPA) system deployed from the back of a boat”.

For FGS this was a potentially difficult deployment, as we knew from prior experience of using a suspended system, that the SPA deployment frame can spin in the water. However, the deployment was entirely successful, allowing the blasting to be carried-out with minimal disturbance to the local fish population.

With the recent opening of the new crossing, the Queen said the structure, the UK’s tallest bridge, was a "breathtaking sight" and one of three "magnificent structures" across the Forth. Looking back, Dr. Lambert said “it is interesting to recall the success of our involvement in the early days of the construction of the Queensferry Crossing and the impressive results achieved by the system designed and used by FGS”.


For more information about this project please see the FGS Case Study at:

Second Forth Road Crossing, Scotland.pdf