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Writing the sea-pen story at the Central Fladen Marine Protected Area (Survey 0723S Blog #1)

By Anamika Poyil on behalf of the JNCC 0723S Survey Team

Offshore Survey Central Fladen MPA0723S

Our offshore survey team are out on survey once again, this time onboard MRV Scotia with the Marine Directorate of the Scottish Government, to the Central Fladen Marine Protected Area (Survey 0723S).

 As the survey season begins, we have once again set sail aboard the MRV Scotia into the North Sea from Aberdeen (Scotland’s Granite City). JNCC and the Marine Science Directorate of the Scottish Government are collaborating on a survey of the Central Fladen Marine Protected Area (MPA) (see Map, Figure 1), to collect robust datasets of the animal communities that burrow into the muddy seabed within the MPA. Monitoring the site is crucial to understanding the changes in burrowed mud communities over time and informing site-management decisions.

Figure 1: Map displaying the location of the Central Fladen MPA.


Named after the German word "fladen" meaning "flat cake", the Central Fladen MPA resides within the large and muddy Fladen Grounds in the northern North Sea. It spans an area of 925 km2 with depths ranging between 100 m and 280 m. The MPA was designated in July 2014 and is home to burrowed mud, an OSPAR Threatened and/or Declining habitat (visit Sea-Pen & Burrowing Megafauna for more information), and its distinctive inhabitants. The burrowed mud habitat is characterised by sea-pens (feather-like soft corals) that anchor to the muddy seabed (see Figure 2).

Figure 2: Still photographs from the Central Fladen MPA, showing: Left – tall sea-pens (Funiculina quadrangularis) with brittle stars attached to them, and anemones; Right – the phosphorescent sea-pen (Pennatula phosphorea) (© JNCC & Cefas).


The variety of species within the MPA ranges from crustaceans like the mud shrimp and the Norway lobster (Nephrops norvegicus) (see Figure 3) to the nationally rare tall sea-pen (Funiculina quadrangularis). The burrowed mud community is instrumental in sustaining life in this habitat, by oxygenating mud and releasing nutrients. Long-standing burrows provide refuge to other marine organisms from predators such as sea urchins and sea stars. The tall sea-pen also acts as an elevated perch for the filter-feeding brittle stars.

Figure 3: Still photograph showing the burrowing Norway lobster (Nephrops norvegicus) in the Central Fladen MPA (© JNCC & Cefas).


The Central Fladen MPA also encompasses a sub-glacial tunnel-valley that represents part of a Key Geodiversity Area known as the 'Fladen Deeps' or 'The Holes' and is surmised to have been created by the erosional processes of meltwater under an ice sheet in previous ice ages.

Over the course of the survey, physical infaunal grab samples and particle size analysis sub-samples of the burrowed mud feature are being collected across various monitoring sites in the MPA. The survey also intends to obtain multibeam data of the walls of the sub-glacial tunnel-valley.

(Hero image (top of page): © JNCC/Marine Science Directorate of Scottish Government/Cefas/NLB)

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