8 Review: Dredging pressures on finfishGo back to program
About the theme
Dredging can have significant impacts on aquatic environments, but the direct effects on fish have not been critically evaluated. Here, a meta-analysis following a conservative approach is used to understand how dredging-related stressors, including suspended sediment, contaminated sediment, hydraulic entrainment and underwater noise, directly influence the effect size and the response elicited in fish across all aquatic ecosystems and all life-history stages.
This is followed by an in-depth review summarising the effects of each dredging-related stressor on fish. Across all dredging-related stressors, studies that reported fish mortality had significantly higher effect sizes than those that describe physiological responses, although indicators of dredge impacts should endeavour to detect effects before excessive mortality occurs.
To make recommendations about the areas where further research should be prioritised we listed all of the key research questions identified during the workshop and review and then asked workshop participants to rank the gaps from the perspective of generating outcomes which would assist managers to minimising impacts to dredging and the potential threats to species of concern.
- Identify critical ecological processes (such as spawning, recruitment and early post- recruitment growth) and associated environmental windows.
- Identify pressure parameters and the intensity associated with dredging.
- Assess likely sensitivities/tolerances of the ecological processes and windows to dredge related activities.
- Provide recommendations on key areas of concern and potential mitigation.
- To assess the information presented in the literature review and to identify (by a workshop) gaps in the knowledge and highlight priority areas for future laboratory/field experiments.
- Study identifies water quality thresholds to protect fish during dredging
- Everything you ever wanted to know about how dredging impacts fish
Wenger A, Rawson C, Wilson S, Newman S, Travers M, Atkinson S, Browne N, Clarke D, Depczynski M, Erftemeijer P, Evans R, Hobbs JP, McIlwain J, McLean D, Saunders B, Harvey E (2018) Management strategies to minimize the dredging impacts of coastal development on fish and fisheries. Conservation Letters https://doi.org/10.1111/conl.12572
Wenger A, Harvey E, Wilson S, Rawson C, Newman SJ, Clarke D, Saunders BJ, Browne N, Travers MJ, Mcilwain JL, Erftemeijer PLA, Hobb JPA, Mclean D, Depczynski M, Evans RD (2017) A critical analysis of the direct effects of dredging on fish. Fish Fish. 2017;00:1–19. https://doi.org/10.1111/faf.1221/full