Anchor and chain scour as disturbance agents in benthic environments: trends in the literature and charting a course to more sustainable boating and shipping

Broad, Allison; Rees, Matthew J.; Davis, Andrew R.

doi:10.1016/j.marpolbul.2020.111683

Cited by 25 publications

(20 citation statements)

References 85 publications

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“…Bathymetry data presented in this study confirm these modelling results (Fig. 2 A), and demonstrate that anchoring excavates the seabed at scales comparable to bottom trawling gear 11 , 12 . The penetration depth of trawling gear in soft sediment substrates ranges from a few centimetres (Otter Trawl) to ~ 16 cm (Hydraulic dredge), with the associated adverse impacts on benthos increasing with the penetration depth of the trawling equipment 18 – 20 .…”

Section: Discussionsupporting

confidence: 85%

“…Periodic disturbance by anchors of all ship types and sizes (from recreational to cargo) has been shown to adversely affects all habitat types (e.g., rocky reef or soft sediment) 12 , 62 , 63 . Seabed habitat recovery from benthic trawling is estimated to be faster for coarse-sediment (sand) regions compared to fine-sediment regions (mud) 19 , 60 , 61 , the latter being the preferred substrate for anchoring 64 .…”

Section: Discussionmentioning

confidence: 99%

“…While the economic fallout of the pandemic on the global shipping industry is well reported 1 , 8 – 10 , the associated environmental impacts due to intensifying anchorage use have been little considered. The short-term deployment of anchors has been referred to as a “hidden cost” of the shipping industry 11 due to the associated, and mostly unaccounted for, seabed damage 11 , 12 . The global pandemic has shone a spotlight on surging marine port congestion 1 , 13 , 14 .…”

Section: Introductionmentioning

confidence: 99%

“…Physical damage to the seabed by ship anchors is increasingly considered a threat to the health of benthic communities 11 , 12 , 16 – 23 , due to physical destruction and associated changes in sediment type and ecosystem function 24 . The physical footprint of anchoring is likened to that of bottom trawling, the most widespread human impact on global continental shelves 20 , 25 , 26 .…”

Section: Introductionmentioning

confidence: 99%

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The footprint of ship anchoring on the seafloor

Watson

Ribó

Seabrook

et al. 2022

Sci Rep

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With the COVID-19 pandemic came what media has deemed the “port congestion pandemic”. Intensified by the pandemic, the commonplace anchoring of high-tonnage ships causes a substantial geomorphologial footprint on the seabed outside marine ports globally, but isn’t yet quantified. We present the first characterisation of the footprint and extent of anchoring in a low congestion port in New Zealand-Aotearoa, demonstrating that high-tonnage ship anchors excavate the seabed by up to 80 cm, with the impacts preserved for at least 4 years. The calcuated volume of sediment displaced by one high-tonnage ship (> 9000 Gross Tonnage) on anchor can reach 2800 m3. Scaled-up globally, this provides the first estimates of the footprint of anchoring to the coastal seabed, worldwide. Seafloor damage due to anchoring has far-reaching implications for already stressed marine ecosystems and carbon cycling. As seaborne trade is projected to quadruple by 2050, the poorly constrained impacts of anchoring must be considered to avoid irreversible damage to marine habitats.

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Section: Discussionsupporting

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The footprint of ship anchoring on the seafloor

Watson

Ribó

Seabrook

et al. 2022

Sci Rep

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“…Some ships at anchor in ports are commonly taken as business as usual; a necessary inventory to accommodate the uncertainty of ship arrivals in light of variable ocean and port conditions. This may account for academic articles on anchorage dealing not with the economics of ships at anchor but with their safety, the utilisation of areas for anchorage, Zhong and Ai (2017) and Oz et al (2015), and the effects of anchorage on the marine ecosystem, Broad et al (2020). Studies modelling aspects of port terminal operations and performance, usually container terminals, do not examine the effects of management practices on the level of anchorage, Golias et al (2009), Legato and Mazzo (2020).…”

Section: Literature Reviewmentioning

confidence: 99%

Reducing Anchorage in Ports: Changing Technologies, Opportunities and Challenges

Heaver

2021

Front. Future Transp.

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Developments in digitisation and the need to reduce carbon emissions have increased attention on port call optimisation. Just-in-time arrival for ships is recognised in the literature as being achieved more readily in container trades than in bulk trades. This paper examines the governance and trade logistics conditions in the bulk trades of Vancouver, Canada, as the increasing number of ships at anchor gives rise to the need to explore the absence of initiatives to limit anchorage and to identify what is done elsewhere to manage the incidence of anchorage. Newcastle, Australia, is used to identify critical governance and logistics factors that played a role in the development of innovative practices to reduce anchorage. The major obstacles to port call optimisation lie in the organisational and behavioural aspects of maritime logistics, not in the technology of digitisation.

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A long‐term shift in the summer distribution of Hector’s dolphins is correlated with an increase in cruise ship tourism

Carome

Slooten

Rayment

et al. 2022

Aquatic Conservation

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Before the 2020 COVID‐19 pandemic, cruise ship tourism had been one of the fastest growing segments of global tourism, presenting a range of potential impacts. At Akaroa Harbour, Aotearoa New Zealand, the number of annual cruise ship visits more than quadrupled following earthquake damage to Ōtautahi Christchurch's Lyttelton Port in 2011. Akaroa Harbour is an area of core use for endangered and endemic Hector’s dolphins (Cephalorhynchus hectori). Dolphins here are exposed to some of the highest levels of cetacean tourism in Aotearoa New Zealand. Relationships were examined between growth in cruise ship visits, as well as tours focused specifically on dolphins, and long‐term trends in summer distribution of Hector’s dolphins at Akaroa Harbour, from 2000 to 2020. Core use areas for Hector’s dolphins within the harbour were quantified via kernel density estimation using data from 2,335 sightings from over 8,000 km of standardized survey effort. Data were allocated into four periods based on varying levels of tourism. Dolphin habitat preference varied over time, with the greatest change occurring between 2005–2011 and 2012–2015. When comparing these periods, the spatial overlap of core habitat was less than 24%. Dolphin distribution shifted towards the outer harbour after 2011 and has remained relatively consistent since. The observed shift in distribution coincided with the more than fourfold increase in annual cruise ship visits to Akaroa Harbour. Several pressures related to cruise ship tourism are likely to have influenced habitat preferences of dolphins. Further investigation into causal factors of the observed shift is warranted. In the wake of the COVID‐19 pandemic, the future of cruise ship and wildlife tourism is in flux. Our findings suggest that the future re‐development of this industry should follow a precautionary approach, with the onus on industry to provide evidence of sustainability before proceeding.

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Anchor and chain scour as disturbance agents in benthic environments: trends in the literature and charting a course to more sustainable boating and shipping

Cited by 25 publications

References 85 publications

The footprint of ship anchoring on the seafloor

The footprint of ship anchoring on the seafloor

Reducing Anchorage in Ports: Changing Technologies, Opportunities and Challenges

A long‐term shift in the summer distribution of Hector’s dolphins is correlated with an increase in cruise ship tourism

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