Dragging the chain: anchor scour impacts from high-tonnage commercial vessels on a soft bottom macrobenthic assemblage

International shipping is the backbone of the global economy with ~80% of the world’s trade (by volume) transported by ship. The potential environmental impacts of this multi-billion-dollar industry have received considerable attention, particularly emissions into air and sea. Many of these large co...

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Main Authors: Andrew R. Davis, Allison Broad, Chantel Steele, Caitlin Woods, Rachel Przeslawki, W. A. (Tony) Nicholas, William Maher, Frank Krikowa, Bradley Morris, Timothy C. Ingleton, Sarah O’Hea Miller, Matthew J. Rees
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Language:English
Published: Frontiers Media S.A. 2025-03-01
Series:Frontiers in Conservation Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fcosc.2025.1487428/full
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author Andrew R. Davis
Allison Broad
Chantel Steele
Caitlin Woods
Rachel Przeslawki
Rachel Przeslawki
W. A. (Tony) Nicholas
W. A. (Tony) Nicholas
William Maher
Frank Krikowa
Bradley Morris
Timothy C. Ingleton
Timothy C. Ingleton
Sarah O’Hea Miller
Matthew J. Rees
author_facet Andrew R. Davis
Allison Broad
Chantel Steele
Caitlin Woods
Rachel Przeslawki
Rachel Przeslawki
W. A. (Tony) Nicholas
W. A. (Tony) Nicholas
William Maher
Frank Krikowa
Bradley Morris
Timothy C. Ingleton
Timothy C. Ingleton
Sarah O’Hea Miller
Matthew J. Rees
author_sort Andrew R. Davis
collection DOAJ
description International shipping is the backbone of the global economy with ~80% of the world’s trade (by volume) transported by ship. The potential environmental impacts of this multi-billion-dollar industry have received considerable attention, particularly emissions into air and sea. Many of these large commercial vessels lay at anchor for extended periods while awaiting their turn to enter port, and yet the impacts associated with anchoring remain virtually unexamined. Anchors can exceed 20 tonnes, with chains up to hundreds of metres in length and individual links weighing up to 200kg; there is potential for significant effects on seafloor biota where anchoring is concentrated. Filling knowledge gaps in deep-water wave-exposed environments is logistically challenging and expensive. To do so we used sediment grabs collected offshore from the Port of Newcastle (SE Australia) – the world’s largest coal export terminal – to sample infaunal assemblages in anchor-affected locations relative to reference locations (30 to 55m water depth). Polychaetes and crustaceans were the most abundant biota in the samples (~85%), whereas molluscs were very low in abundance (<3%), despite being well represented in terms of diversity (11 families of bivalves and 9 families of gastropods). Invertebrate abundance almost doubled in areas exposed to anchoring compared to reference areas. In contrast, invertebrate diversity declined with increasing anchoring activity, however this relationship was weak. Importantly, we observed major shifts in the overall invertebrate assemblage at anchored-affected locations – with reductions in suspension feeders mirrored by increases in scavengers and predators. We assert that suspension feeders were negatively impacted by sediment mobilisation or direct physical damage from anchor chains, while opportunistic scavengers and mobile predators benefitted from this disturbance. We contend that anchor disturbance is a global issue given burgeoning marine trade. Data on the effects of anchoring are urgently required to better inform the management of environments regularly used as anchorages.
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spelling doaj-art-959602475bdb4535bdafdc14b652d2bc2025-08-20T02:48:54ZengFrontiers Media S.A.Frontiers in Conservation Science2673-611X2025-03-01610.3389/fcosc.2025.14874281487428Dragging the chain: anchor scour impacts from high-tonnage commercial vessels on a soft bottom macrobenthic assemblageAndrew R. Davis0Allison Broad1Chantel Steele2Caitlin Woods3Rachel Przeslawki4Rachel Przeslawki5W. A. (Tony) Nicholas6W. A. (Tony) Nicholas7William Maher8Frank Krikowa9Bradley Morris10Timothy C. Ingleton11Timothy C. Ingleton12Sarah O’Hea Miller13Matthew J. Rees14Centre for Environmental Futures and School of Earth, Atmospheric and Life Sciences University of Wollongong, Wollongong, NSW, AustraliaCentre for Environmental Futures and School of Earth, Atmospheric and Life Sciences University of Wollongong, Wollongong, NSW, AustraliaCentre for Environmental Futures and School of Earth, Atmospheric and Life Sciences University of Wollongong, Wollongong, NSW, AustraliaCentre for Environmental Futures and School of Earth, Atmospheric and Life Sciences University of Wollongong, Wollongong, NSW, AustraliaCentre for Environmental Futures and School of Earth, Atmospheric and Life Sciences University of Wollongong, Wollongong, NSW, AustraliaGeoscience Australia, National Earth and Marine Observations Group, Canberra, ACT, AustraliaCentre for Environmental Futures and School of Earth, Atmospheric and Life Sciences University of Wollongong, Wollongong, NSW, AustraliaGeoscience Australia, National Earth and Marine Observations Group, Canberra, ACT, Australiab Research School of Earth Sciences, Australian National University, Canberra, ACT, Australiab Research School of Earth Sciences, Australian National University, Canberra, ACT, AustraliaWaters, Wetlands and Coasts Science, New South Wales Department of Climate Change, Energy, the Environment and Water, Lidcombe, NSW, AustraliaCentre for Environmental Futures and School of Earth, Atmospheric and Life Sciences University of Wollongong, Wollongong, NSW, AustraliaWaters, Wetlands and Coasts Science, New South Wales Department of Climate Change, Energy, the Environment and Water, Lidcombe, NSW, AustraliaCentre for Environmental Futures and School of Earth, Atmospheric and Life Sciences University of Wollongong, Wollongong, NSW, AustraliaNew South Wales Department of Primary Industries and Regional Development, Huskisson, NSW, AustraliaInternational shipping is the backbone of the global economy with ~80% of the world’s trade (by volume) transported by ship. The potential environmental impacts of this multi-billion-dollar industry have received considerable attention, particularly emissions into air and sea. Many of these large commercial vessels lay at anchor for extended periods while awaiting their turn to enter port, and yet the impacts associated with anchoring remain virtually unexamined. Anchors can exceed 20 tonnes, with chains up to hundreds of metres in length and individual links weighing up to 200kg; there is potential for significant effects on seafloor biota where anchoring is concentrated. Filling knowledge gaps in deep-water wave-exposed environments is logistically challenging and expensive. To do so we used sediment grabs collected offshore from the Port of Newcastle (SE Australia) – the world’s largest coal export terminal – to sample infaunal assemblages in anchor-affected locations relative to reference locations (30 to 55m water depth). Polychaetes and crustaceans were the most abundant biota in the samples (~85%), whereas molluscs were very low in abundance (<3%), despite being well represented in terms of diversity (11 families of bivalves and 9 families of gastropods). Invertebrate abundance almost doubled in areas exposed to anchoring compared to reference areas. In contrast, invertebrate diversity declined with increasing anchoring activity, however this relationship was weak. Importantly, we observed major shifts in the overall invertebrate assemblage at anchored-affected locations – with reductions in suspension feeders mirrored by increases in scavengers and predators. We assert that suspension feeders were negatively impacted by sediment mobilisation or direct physical damage from anchor chains, while opportunistic scavengers and mobile predators benefitted from this disturbance. We contend that anchor disturbance is a global issue given burgeoning marine trade. Data on the effects of anchoring are urgently required to better inform the management of environments regularly used as anchorages.https://www.frontiersin.org/articles/10.3389/fcosc.2025.1487428/fullanchoringinfaunamarine invertebrateshuman impactsdisturbanceAIS
spellingShingle Andrew R. Davis
Allison Broad
Chantel Steele
Caitlin Woods
Rachel Przeslawki
Rachel Przeslawki
W. A. (Tony) Nicholas
W. A. (Tony) Nicholas
William Maher
Frank Krikowa
Bradley Morris
Timothy C. Ingleton
Timothy C. Ingleton
Sarah O’Hea Miller
Matthew J. Rees
Dragging the chain: anchor scour impacts from high-tonnage commercial vessels on a soft bottom macrobenthic assemblage
Frontiers in Conservation Science
anchoring
infauna
marine invertebrates
human impacts
disturbance
AIS
title Dragging the chain: anchor scour impacts from high-tonnage commercial vessels on a soft bottom macrobenthic assemblage
title_full Dragging the chain: anchor scour impacts from high-tonnage commercial vessels on a soft bottom macrobenthic assemblage
title_fullStr Dragging the chain: anchor scour impacts from high-tonnage commercial vessels on a soft bottom macrobenthic assemblage
title_full_unstemmed Dragging the chain: anchor scour impacts from high-tonnage commercial vessels on a soft bottom macrobenthic assemblage
title_short Dragging the chain: anchor scour impacts from high-tonnage commercial vessels on a soft bottom macrobenthic assemblage
title_sort dragging the chain anchor scour impacts from high tonnage commercial vessels on a soft bottom macrobenthic assemblage
topic anchoring
infauna
marine invertebrates
human impacts
disturbance
AIS
url https://www.frontiersin.org/articles/10.3389/fcosc.2025.1487428/full
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