Construction in ports, harbours, estuaries and waterways that involves blasting or piling operations can be harmful to fish within the immediate vicinity. Most sensitive are swimbladder fish such as cod, whiting and sea bass, as well as many freshwater species. ‘Soft-start’ techniques can in some cases be used to deter fish prior to the full emissions but use of acoustic fish deterrents provides a more controlled means of evacuating fish from the hazard area.
For blasting and piling operations, frame-mounted sound projector clusters are typically deployed from a patrol boat, with the Control Equipment aboard the vessel. Depending on the scale of the operation they can deployed from a fixed position near to the point of blasting / piling or moved in increasing distance from the centre point when a larger area needs to be protected.
When protection is required from elevated sound levels associated with construction activities either in rivers or on river banks there can be times when the regulator may only require a simple bubble curtain to be installed. Bubble curtains will only offer limited deflection efficiencies and so wouldn’t be recommended as a way to deflect fish, but can absorb sound emanating from construction works and reduce the disturbance on fish populations. FGS has experience of supplying bubble curtains to meet the regulators requirements and providing turnkey solutions for a variety of construction activities.
To specify an appropriate system FGS will need information on the application, distance/area to be covered and the water depths involved. For marine areas, water depths can be obtained from marine charts but when required FGS can also offer a rapid bathymetric survey option for river reaches.
All FGS’s systems are available for short-term hire, long-term lease or purchase.