Effects of pile driving sound on local movement of free-ranging Atlantic cod in the Belgian North Sea. (1st May 2022)

• Record Type: Journal Article
• Authors: van der Knaap, Inge; Slabbekoorn, Hans; Moens, Tom; Van den Eynde, Dries; Reubens, Jan
• Is Part Of: Environmental pollution. Volume 300(2022)
• Publication Date: 2022-05-01
• Subjects: Pile driving -- Atlantic cod -- Acoustic telemetry -- Wind farm -- Movement behaviour; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2022.118913
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Offshore energy acquisition through the construction of wind farms is rapidly becoming one of the major sources of green energy all over the world. The construction of offshore wind farms contributes to the ocean soundscape as steel monopile foundations are commonly hammered into the seabed to anchor wind turbines. This pile driving activity causes repeated, impulsive, low-frequency sounds, reaching far into the environment, which may have an impact on the surrounding marine life. In this study, we investigated the effect of the construction of 50 wind turbine foundations, over a time span of four months, on the presence and movement behaviour of free-swimming, individually tagged Atlantic cod. The turbine foundations were constructed at a distance ranging between 2.3 and 7.1 km from the cod, which resided in a nearby, existing wind farm in the southern North Sea. Our results indicated that local fish remained in the exposed area during and in-between pile-driving activities, but showed some modest changes in movement patterns. The tagged cod did not increase their net movement activity, but moved closer to the scour-bed (i.e. hard substrate), surrounding their nearest turbine, during and after each piling event. Additionally, fish moved further away from the sound source, which was mainly due to the fact that they were positioned closer to a piling event before its start. We found no effect of the time since the last piling event. Long-term changes in movement behaviour can result in energy budget changes, and thereby in individual growth and maturation, eventually determining growth rate of populations. Consequently, although behavioural changes to pile driving in the current study seem modest, we believe that the potential for cumulative effects, and species-specific variation in impact, warrant more tagging studies in the future, with an emphasis on quantification of energy budgets. Graphical abstract: Image 1 Highlights: We studied the response of free-ranging Atlantic cod to nearby pile-driving. The pile-driving sound exposure did not result in cod leaving the area. Pile driving did result in cod moving away from the source and toward the scour bed. We found no evidence of behavioural habituation to repeated pile-driving activities. Cod behaviour was not affected by the interval in-between subsequent piling events.