Broadscale habitat (EUNIS level 3) for North West of Jones Bank recommended Marine Conservation Zone (rMCZ)

Description

A broadscale habitat layer was produced by analysising and interpreting the acoustic and ground truth data collected by Gardline onboard the MV Tridens onboard 29th February and 31st March 2012and RV Cefas Endeavour between 11th and 12th July 2012 . PSA data were used to assign each sample a EUNIS class which then informed theexpert visual interpretation process of map production. Updated version of earlier broadscale habitat feature class NWJB_20140912_BSH_DRAFT, with all polygons less than 200 sqm in area merged to neigbouring polygon with the longest shared border. Bathymetry and backscatter data collected by Gardline onboard the MV Tridens onboard 29th February and 31st March 2012 were used in conjunction with ground thruth samples to produce a Broadscale habitat map of North West of Jones Bank. Ground thruth samples were collected on both Gardline and Cefas survey cruises from 50 stations. Benthic grabs were taken at 44 stations. An underwater camera system was deployed at 17 stations to collect video and still information. Sediment samples were collected with a grab system consisting of a 0.1 m2 mini Hamon grab and Day Grab. On recovery, the grab was emptied into a large plastic bin and a representative subsample of sediment (approx. 0.5 litres) taken for particle size analysis (PSA). The remaining sample was photographed, then sieved over a 1 mm mesh to collect the benthic macrofauna. Camera deployments lasted a minimum of 10 minutes, with the vessel using its dynamic positioning capability to move along the planned transect at c. 0.5 knots (c. 0.25 ms-1) across a 100 m ÔÇÿbullringÔÇÖ centred on the sampling station. Still photographic images were captured at one minute intervals and opportunistically if features of interest were observed. Video and photographic still images were processed by Envision Mapping Ltd in accordance with the guidance documents developed by Cefas and the JNCC for the acquisition and processing of video and still data (Coggan and Howell, 2005). Particle size analysis (PSA) was carried out by Cefas following standard laboratory practice, and results were checked by Cefas specialist staff following the recommendations of the National Marine Biological Analytical Quality Control (NMBAQC) scheme (Mason, 2011). Setup and operation followed the MESH ÔÇÿRecommended Operating Guidelines (ROG) for underwater video and photographic imaging techniquesÔÇÖ (Cogganet al., 2007).

Resources

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Tags

  • marine-habitat-mapping
  • habitats

Topics

  • ENVI

Categories