Ecological Risk Assessment of Underwater Sounds from Dredging Operations

Abstract

There is an increasing international focus to understand and quantify the potential ecological risks of low‐frequency underwater sounds produced from anthropogenic activities (e.g., commercial shipping, dredging, construction, and offshore energy production). For dredge operations, a risk‐based approach has been proposed for identifying, assessing, and managing risks; however, specific details of the framework and demonstration of the approach are lacking. Thus, the goal of this study was to provide a practical, concise, and reliable framework for assessing the effects of dredging sounds on aquatic life. The specific objectives were to 1) further specify a risk assessment approach for assessing underwater sounds from dredging operations, 2) demonstrate the utility of the approach in practice using a case study, and 3) document the strengths and challenges of the approach. The risk framework was adapted for underwater sounds to include a project formulation step, an analysis step to analyze and assess exposure and biological responses, a risk characterization process in which the preceding steps are integrated and uncertainty is addressed, and a risk management step. A key beneficial component of this framework is the use of a phased approach, whereby a screening step offers a process that utilizes existing or readily available information to evaluate risk. In general, a limitation of evaluating risks due to dredge operations is the degree of uncertainty surrounding effect thresholds for many marine species; however, this approach emphasizes the importance of documenting and communicating uncertainty to regulators, stakeholders, and practitioners in the decision‐making process. A case study example is included to illustrate how the framework can be applied in practice. The primary strength of this method is the intrinsic flexibility of the framework to adapt as the scientific understanding improves and new data become available in the rapidly evolving field of underwater acoustics. Integr Environ Assess Manag 2020;16:481–493. © 2020 SETAC

Juvenile Atlantic Sturgeon Survival and Movement in Proximity to an Active Cutterhead Suction Dredge

“…Based upon examination of limited sturgeon audiogram data, Popper and Calfee [32] reached tentative conclusions that sturgeon can detect sound from below 50 Hz to 500 to 1,000 Hz, and that sturgeon may have reduced capabilities to localize sound direction in comparison to other fishes. Interactions between sturgeon and underwater sound can be addressed in a risk assessment framework [33,34], but technical and logistical challenges make collection of necessary input data difficult. Quantifying sound source and propagation parameters under field conditions, particularly when a dredge is involved, requires specific expertise and instrumentation.…”

“…Interactions between sturgeon and underwater sound can be addressed in a risk assessment framework [33,34], but technical and logistical challenges make collection of necessary input data difficult. Quantifying sound source and propagation parameters under field conditions, particularly when a dredge is involved, requires specific expertise and instrumentation.…”

La Contaminación Acústica Y Su Impacto en El Desarrollo De La Vida Marina

“…En ese sentido, las operaciones de dragado a nivel mundial resultan importantes para la construcción y el mantenimiento de este tipo de estructuras, además de participar en otras actividades como la extracción de arena y grava para la construcción, mantenimiento de ríos y playas, remediado de sedimentos contaminados, etc. (McQueen et al, 2020). En estos casos, la contaminación acústica submarina se produce no de manera intencional, sino como un subproducto de estas actividades marinas (Farcas et al, 2016).…”

Fish responses to underwater sounds depend on auditory adaptations: An experimental test of the effect of motorboat sounds on the fish community of a large fluvial lake

“…Sounds produced by human activities in the aquatic environment, such as motorized transport, dredging, seismic exploration, or installation of underwater structures, have the potential to impact a range of aquatic organisms (McQueen et al., 2020 ; Popper et al., 2020 ; Shannon et al., 2016 ). Merchant ships, in particular, are known to negatively affect the behavior of organisms across taxonomic groups in the marine environment, including large mammals (Chion et al., 2017 ; Richardson et al., 2013 ) and fish (Handegard et al., 2003 ; Picciulin et al., 2010 ; Vabø et al., 2002 ; Whitfield & Becker, 2014 ).…”