Action: Limit, cease or prohibit anchoring from ships/boats/vessels
Key messagesRead our guidance on Key messages before continuing
- We found no studies that evaluated the effects of setting limits, ceasing or prohibitinganchroing from ships/boats/vessels on subtidal benthic invertebrate populations.
‘We found no studies’ means that we have not yet found any studies that have directly evaluated this intervention during our systematic journal and report searches. Therefore, we have no evidence to indicate whether or not the intervention has any desirable or harmful effects.
Anchors are designed to dig into or hook onto the seabed to secure a vessel’s position and prevent it from drifting with the winds or currents. Anchoring of recreational and/or commercial vessels can impact subtidal benthic invertebrates through physical damage, disturbance to and penetration into the seabed from anchors and chains (Griffith et al. 2017; Lloret et al. 2008; Whitfield et al. 2002). Structurally complex seabed habitats, such as seagrass and mussel beds, or oyster and coral reels, are considered particularly at risks from recreational anchoring (Hammerstrom et al. 2007). The areas where vessels (commercial or recreational) are allowed to anchor could be limited or ceased, for instance by restricting the activity in space and time (limits on duration and occurrence) or restricting the number of anchors allowed at any one time. Anchoring could also be ceased by setting a permanent or temporary closure (e.g. seasonal closure), or prohibited through bylaws and the creation of no-anchoring zones (Griffith et al. 2017). This may help reduce the intensity of the threats associated with anchoring and potentially allow subtidal benthic invertebrate communities to persist or recover over time.
For evidence related to recreational anchoring within a marine protected area, see “Habitat protection – Designate a Marine Protected Area and set a no-anchoring zone”. Evidence for other interventions related to anchoring is summarised under “Threat: Transportation and service corridors – Use a different type of anchor” and “Provide additional moorings to reduce anchoring”.
Griffiths C.A., Langmead O.A., Readman J.A.J. & Tillin H.M. (2017) Anchoring and Mooring Impacts in English and Welsh Marine Protected Areas: Reviewing sensitivity, activity, risk and management. A report to Defra Impacts Evidence Group.
Hammerstrom K.K., Kenworthy W.J., Whitfield P.E. & Merello M.F. (2007) Response and recovery dynamics of seagrasses Thalassia testudinum and Syringodium filiforme and macroalgae in experimental motor vessel disturbances. Marine Ecology Progress Series 345,83–92.
Lloret J., Zaragoza N., Caballero D. & Riera V. (2008) Impacts of recreational boating on the marine environment of Cap de Creus (Mediterranean Sea). Ocean & Coastal Management, 51, 749–754.
Whitfield P., Kenworthy W., Hammerstrom K. & Fonseca M. (2002) The role of a hurricane in the expansion of disturbances initiated by motor vessels on seagrass banks. Journal of Coastal Research, 86–99.