Stuck in the Middle

Hello from Bassurelle Sandbank Site of Community Importance (SCI), on this our penultimate day on survey! Bassurelle Sandbank SCI encompasses a sandbank in the Dover Strait which straddles the boundary between UK and French waters, and is formed by tidal currents. The part of the sandbank that extends into French waters is also a Habitats Directive site, and is managed by the French government. Back on the UK side, the site has a surface area of 67km2, so 20 Bassurelles could fit inside the Wight-Barfleur site that we've just come from. Bassurelle is also in the middle of the Dover Strait Traffic Separation Area. This means that we are surrounded by two of the busiest shipping lanes in the world, which is a bit like being on a lawnmower in the central reservation of a motorway with lots of trucks (in this case oil tankers and container ships) zipping past at high speeds!



A large ship (Photo Neil Golding, JNCC)

The Bassurelle Triangle!



As well as being smaller than Wight-Barfleur Reef, Bassurelle Sandbank is also much shallower- so much so that there is an area in the centre of the site that we've dubbed the "Bassurelle Triangle", as if we stray in there without a good tide underneath us we may have to get out and push!

Another thing that has changed is our sampling strategy. A sandy seabed means that we can use the camera sled instead of the drop camera- this runs along the surface of the seabed as opposed to being suspended above it. Using this on rock is not advised! So far we've seen sandeels, gobies, weaver fish, dabs, red gurnards, lemon sole, hermit crabs, masked crabs and razor shells.

Camera Sled (Photo Joey O'Connor, JNCC)

We've also taken a lot of sediment samples with the Hamon grab (the day shift completed 3 fully processed samples in three locations during one particularily productive 30 minute spell yesterday afternoon). Samples have contained mainly fine sand with shells, but there have been some fish (sandeels and a weaver fish), small crabs, razor shells, sea urchins, a variety of worms and a boring bivalve (the name is because they bore into soft rock).

Boring Bivalve, possibly from Pholadidae family) (Photo Neil Golding, JNCC)

Above the water, we have been joined by a large flock of seabirds. These tenacious birds have followed us day and night since we arrived here a few days ago. Though it is nice to believe that the seabirds are with us because we're good company, a cynic might argue that our ships' size, slow speed and habit of deploying and hauling in gear have resulted in the birds mistaking us for a trawler, and that they're hoping for a free dinner!  We have yet to ascertain whether the birds are English or French....  

Tenacious seabirds of ambiguous origin (Photo Neil Golding, JNCC)

 

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

Down in the Valleys

Today we set our sights on the palaeovalley that runs through the bottom of Wight Barfleur Reef cSAC. This enormous valley is thought to have been scoured out thousands of years ago, when the chalk ridge that joined England and France collapsed and a huge glacial lake (in what is now the North Sea) spilled down into the Channel.  The ancient river bed, with its tributaries and islands, can still be seen clearly in the bathymetric data used to map the area.


The palaeovalley in the English Channel (purple) and Wight Barfleur cSAC (red). Underlying bathymetry copyright British Crown and UKHO, image adapted from Wight Barfleur Reef Selection Assessment Document.



We targeted our drop cam over the edge of some of the small undersea "islands" that poke up from the valley floor to see if we could get a good look at these features. The results were pretty spectacular, with sheer cliffs and huge boulders encrusted with tiny bright green jewel anemones and huge elephant hide sponges. Hats off to the deck crew, who skillfuly avoided losing the camera down any of the chasms along the way!

An Elephant Hide sponge and some green Jewel Anemones on the descent. Oh, and an Edible Crab!



Elsewhere on the ship, the day watch scientists have been spending their off-shift time keeping fit with 'Body Pump' and 'Insanity Workout' Mr Motivator-esque DVD classes. Meanwhile the Night Watch ponder the fate of their mascot, Wilson, who was mysteriously kidnapped during the night (well, the day)...





Have you seen Wilson?!



The Big Grey

Things have definitely started to liven up a bit out here! It turns out that the start of our cruise, full of resplendent sunshine and postcard perfect, calm, blue seas, was, in fact, a false dawn. We are now getting a far grittier (though more realistic) impression of how the English Channel generally looks in March- everything is now grey!

"Moderate" conditions off the stern (Photo Neil Golding, JNCC)

Things are also a bit more dynamic than they were in those halcyon early days. A dastardly combination of strong winds and tides have resulted in our good ship Endeavour having to plough up and down through a variety of sea states. Luckily for the experienced majority on board and in the locality, the conditions are considered "moderate". However, this does not provide much comfort to those of us with limited seafaring experience (i.e. me)...

... and off the bow (Photo, Neil Golding, JNCC)

Unperturbed locals- Gannet (Photo Neil Golding, JNCC) and Red Gurnard (Photo JNCC/Cefas)

While the weather may have dampened our equipment, it has yet to dampen our spirits, and we have been able to continue making good progress on collecting acoustic, camera and grab data.

Deploying the sidescan sonar towfish off the stern (Photo Neil Golding, JNCC)

 

Hamon-Grabs at Dawn

Brittle stars and Dahlia Anemones are just some of the myriad of life found so far

So far we've been making good progress at Wight Barfleur Reef. Another two 'nested' boxes of acoustic survey have been completed, with a fourth well under way. These data are being processed onboard which is really helpful as it allows us to build up a detailed picture of the sea floor while we're still on survey,  enabling us to make more informed decisions of where to target additional camera stations.

Up close and personal with a Terebellidae (photo Mike Nelson, JNCC)

Many of the stations we've visited so far have been teeming with life. While some of the larger species, such as brittle stars and sea anemones, are easy to identify, others like encrusting sponges appear as little more than orange smudges on the rocks when captured on film. To help better identify these species, it's really useful to take samples back to dry land where they can be further analysed under a microscope. In particular, the spicules (tiny structures that form the skeleton of the sponge) are often distinctive and therefore easier to ID accurately.

Deploying the Hamon Grab (photo Neil Golding, JNCC)

To collect some sponge-harbouring rock specimens, the full size Hamon Grab (we'd been previously used the Mini Hamon) was deployed for the first time on this survey. After several attempts, a successful grab was finally achieved in the small hours of Friday morning. Although not quite the haul of boulders we'd hoped for, there was enough sponge present for a tiny scraping to be taken which should help accurately identify some of the more abundant species we've seen so far at the site. A small victory, but sufficient to cheer the weary night watch at least!

Collecting sponge samples for spicule analysis (photo  Mike Nelson, JNCC)

Of Tows and Grabs

Yesterday marked the beginning of our groundtruthing campaign here at Wight Barfleur Reef cSAC. Groundtruthing means taking a sample of the seabed to enable us to see which habitats and species are below us. This can be used with the acoustic data we collect from the multibeam and sonar systems to make habitat maps, which in turn are used to inform management decisions for areas of conservation importance. Having accurate maps is important, as we can only protect species and habitats that we know about! We used two techniques yesterday to sample the seabed. The first of these is the "Drop Camera". As it's name suggests, this is a camera we drop over the side of the Endeavour. The camera is mounted on a frame, which houses lights and other equipment, and also protects the camera from any "bumps". This unit is then lowered to just above the seabed, and we tow it for about 10 minutes, recording video footage and taking pictures. So far we've seen Annex I stony and bedrock reef, habitats named after the Annex of the EC Habitats Directive in which they appear. We have also seen gravels and sands, as well as some starfish, sunstars, fish, crabs, mussels and lots of impressive sponges, bryozoans and anemones.  

Flustra foliacea (bryozoan- beige with erect fronds) and Hemimycale columella (encrusting sponge- also beige, to right) on current swept circalittoral rock

Pachymatisma johnstonia (Elephants ear sponge- white), an axinellid sponge (yellow) and Tubularia indivisa (Hydroid sps- green) on current swept circalittoral rock

Recovering the Hamon Grab (Photo Neil Golding, JNCC)

The second groundtruthing tool we've used is the "Hamon Grab". This is also dropped over the side of the ship (though, like the camera, remains attached to the boat by a cable and wire!). When the Hamon Grab reaches the seabed it scoops up a small sample of sediment. This is then hauled back up to the ship, where excited scientists wait to see what is contained in the sample. As Wight Barfleur is quite rocky, we have been using the Drop Camera more than the Hamon Grab, though this is set to change at Bassurelle Sandbank cSAC.

Excited Scientists! (Photo Bill Meadows, Cefas)

Above the water, we've also come across some of Her Majesty's finest. So far we've been flirted with by an RN Lynx helicopter and warship, as well as a Border Agency launch. However, pictures remain classified...





For now, we will continue to gather evidence at Wight Barfleur, and will let you know what we find!

Joey

Workin' Day and Night

We left Portland yesterday with a crisp early spring's sun already beginning it's descent at our backs. Having boarded Cefas' good ship Endeavour at around 09:00 that morning, we were already making ourselves at home in the myriad of passageways and decks that encompass the vessel which will be our home for the next fortnight. We also passed the time meeting the crew, having a safety induction, discussing the survey plan with our colleagues, putting last touches to our preparation work and getting acquainted with the mess (and all the lovely food and tea available there!). At around 15:30 the Portland pilot vessel came alongside, and by 16:00 we were underway. Steaming south-easterly, we steered a course for Wight-Barfleur Reef cSAC, the first of two such sites we hope to gather seabed data from during coming fortnight. More information on these sites can be found on our website (www.jncc.gov.uk).

Mustering for survival! (Photo Neil Golding, JNCC)

Portland Pilot (Photo Neil Golding, JNCC)

To maximise the amount of valuable data that can be collected while at sea, the crew were divided into 12-hour day and night shifts so that work could continue round the clock. The first night shift can be a bit of a shock to the system as it takes time to adapt to the nocturnal lifestyle. Fuelled by good old fashioned tea power, the first task for the night watch was to finish collecting acoustic data from an area larger than Lake Windermere on the eastern edge of Wight Barfleur Reef cSAC. Multibeam and sidescan sonar use sound to measure the depth of the sea bed and can give an indication of the type of seabed habitat likely to be present. Although it can be a bit monotonous, so far this work looks like it will yield some good quality data to help us better describe the undersea features of this area, including what could be an undiscovered shipwreck!

Undiscovered shipwreck?!

Joey & Mike

Offshore survey of Wight-Barfleur Reef cSAC and Bassurelle Sandbank cSAC

On Monday 18th March a two week survey will commence of two candidate Special Areas of Conservation (cSACs) within the English Channel. Three members of JNCC staff will join the Cefas Endeavour research vessel, and over the next two weeks, will undertake a detailed survey of both the Wight-Barfleur Reef cSAC and Bassurelle Sandbank cSAC.

Bassurelle Sandbank was submitted to the European Commission in 2010 as an example of Annex 1 sandbank and has since been approved as a Site of Community Importance. Bassurelle is located in the Dover Strait which straddles the boundary between UK and French waters and our site is aligned with the French site "Ridens et dunes hydrualiques du Detroit du Pas de Calais". Wight-Barfleur Reef was submitted to the European Commission in 2012 for Annex 1 bedrock and stony reef and is located in the central English Channel.

Bassurelle Sandbank is a linear sandbank with sandwaves and megaripples on it, with biological communities include those typical of sand sediments dominated by polychaete worms. Sand eels and weever fish are characteristic of the fish species present. The depth within the Wight-Barfleur Reef cSAC ranges from 25m to 100m, with the deepest areas to the south, and within the palaeovalley which runs along the south-east part of the SAC. The large area of bedrock reef within the SAC is characterised by a series of well-defined exposed bedrock ridges, up to 4m high whereas in the south of the site the reef is flat and smooth with overlying coarse sediment which in places forms stony reef. The bedrock and stony reef areas support a diverse range of reef fauna, with many types of sponges present, tube worms, anemones and sea squirts.

The main aim of this survey is to gather additional information to aid the development of management measures for these sites.