Saturday, 30 March 2013

Au revoir to Wight-Barfleur, bonjour Bassurelle!

Well the time has come to say au revoir to Wight-Barfleur Reef.  Despite the forces of nature trying to hinder our progress (strong currents over 3 knots and gale force winds) we've gathered a huge amount of data from Wight-Barfleur to assist in the development of management advice for the site.  The key stats are as follows:
  • 978 kilometers of multibeam (bathymetry and backscatter data) acquired
  • 317 kilometers of sidescan sonar data gathered
  • 117 camera transects achieved
To put that multibeam figure into perspective, 978 kilometres is further than driving from our mobilisation port of Portland on the south coast of England up to our JNCC office in Aberdeen! The map below gives a brief summary of our progress to date.  Despite our efforts, you can see what a vast area we were tackling on this first part of the survey.

Map showing new data gathered at Wight-Barfleur Reef; both camera transects (red dots) and acoustic data.  The black dots show existing data that was used as part of the Special Area of Conservation (SAC) recommendation.  Underlying bathymetry (c) copyright British Crown and UKHO.  All rights reserved.

Highlights for me have been seeing the amazing variety of colourful sponges covering the seabed in the ancient palaeovalley that Mike talked about earlier - every square inch of exposed rock on the seabed was an explosion of colour, plastered with marine life.  I've included some of my favourite images below. 

During the steam to our next site, we busied ourselves finalising all the data entry and record keeping from Wight-Barfleur - a less exciting but nevertheless crucial part of any survey.  We also had a marine ID session of the creatures captured on film at Wight-Barfleur together with our Cefas compatriots and the Endeavour crew and officers.

Encrusting orange and yellow sponges, anemones, the sponge Dysidea fragilis (in the foreground) and several crustaceans. Can you spot the scallops hiding in the crevice?
The massive sponge Pachymatisma johnstonia (Elephants hide sponge) along with several species of erect sponge including Raspailia ramosa (Chocolate finger sponge) on exposed bedrock.

A plethora of colourful Corynactis viridis (Jewel anemones) and the hydroid Tubularia spp. (a species characteristic of tideswept areas) on boulders in the palaeovalley.

Arriving at Bassurelle Sandbank in the early hours of Thursday morning, the night watch started acoustic data collection.  Everyone was preparing themselves for the grab sampling marathon that was soon to start - we've set aside 4 days on the survey for data collection within Bassurelle - things are going to get even busier in the days to come!

Posted by Neil