CEFAS24-134 Contract for a geophysical & bathymetric survey of The Wash

Description

The Marine Protected Area (MPA) monitoring programme is funded by the Department for Environment, Food and Rural Affairs (DEFRA) and through this programme, Cefas co-ordinates some of the evidence collection for the monitoring of MPAs in English waters. The Ross Worm Sabellaria spinulosa is a sedentary, epifaunal polychaete worm which builds tubes by consolidating particles of sediment (Limpenny et al, 2010). S. spinulosa is abundant in UK waters, largely existing in solitary form or within small, low-lying aggregations (Hayward and Ryland, 1990). However, under the right environmental conditions they also can establish dense colonies and form biogenic reefs. These biogenic reefs are protected as an Annex I habitat under the EU Habitats Directive (EEC, 1992), and Special Areas of Conservation (SACs) are designated for their protection. Important areas of consistently occurring reef have been found across The Wash where extensive areas of subtidal mixed sediments in the tide-swept approaches provide the right conditions for reefs to form, particularly in deeper waters. These reefs are an important but understudied feature of both The Wash and North Norfolk Coast (WNNC) SAC and Inner Dowsing, Race Bank and North Ridge (IDRBNR) SAC - named as 'The Wash and its approaches' hereafter. Requirement: With the aim of improving our understanding of the extent, distribution, and nature of S. spinulosa biogenic reef (i.e. reefiness) across The Wash and its approaches, Cefas has commissioned this Contract to deliver a geophysical and bathymetric survey of 9 blocks, with varying prioritisation. The primary acquisition will be Side Scan Sonar (SSS), with a desire for Multi Beam Echo Sounder (MBES) bathymetry to be acquired on an opportunistic basis (i.e. concurrent to acquiring SSS data within blocks 1 & 3), and not resulting in 100% coverage of MBES within those blocks. The evidence gathered in this acoustic survey will seek to allow for the identification of Annex I Sabellaria spinulosa reefs (not a part of this contract). This evidence will be used to support conservation advice, condition assessment and management of the WNNC SAC and the IDRBNR SAC, its designated sites and protected features, i.e. Reefs (including S. spinulosa biogenic reef) habitat. This information will inform statutory advice on MPAs and assist in the assessment of both SAC sites' condition.