Dolphin Head and North East of Farnes Deep Offshore Survey (Blog #4): North East Farnes Deep Survey
By Stephen Duncombe-Smith
In the latest (fourth) blog post from our offshore survey team on their survey to Dolphin Head and North East of Farnes Deep HPMAs, the team update us on what they found during the survey of North East of Farnes Deep.
North East of Farnes Deep HPMA is approximately 55 km east of Berwick-upon-Tweed and the covers an area of nearly 500 km2. The depth of water in the area ranges from 50 m to 100 m deep. The seabed in this HPMA has a mix of mosaiced habitats, from coarse stony habitats, through to sandy and muddy habitats, with much of the area consisting of a mix of sediment types.
In areas of the site where the stable stony seabed is exposed, sessile epifauna can attach and grow. On these hard surfaces animals such as anemones, barnacles, and serpulid tube worms can be found (see Image 1). Amongst the muddy stones and gravel, large terebellid worms also make their homes and use “spaghetti” like tentacles to feed (Image 2).
Image 1: Anemone on exposed rock (© JNCC).
Image 2: Close up of a terebellid worm (Thelepus sp.) (© JNCC).
These stony areas are often home to some of the larger mobile crustaceans seen throughout the site, like the northern stone crab (Lithodes maja; Image 3). In Norway, these large spikey crabs are also known as troll crabs (trollkrabbe), thought to have come from the large size and fearsome appearance. They are relatively small when compared to their close relative, the Alaskan king crab, famous for its giant size.
Image 3: Northern stone crab (Lithodes maja) (© JNCC).
In some parts, the exposed rocks are covered in a 'turf' of colonial hydroids and bryozoans such as the bryozoan hornwrack (Flustra foliacea), whose fronds consist of lots of tiny zoids, animals that filter the water for food (Image 4). In the image below (Image 4), one small area of exposed rock is host to at least three squat lobsters, three hermit crabs and four shrimps (see if you can spot them all, answer at the end of the blog).
Image 4: Exposed rock with squat lobsters, hermit crabs, and shrimps (© JNCC).
In contrast to the coarse, stony areas of the site there are large expanses of soft muddy and sandy sediments. These softer sediments provide the ideal habitat for species like the phosphorescent sea pen (Pennatula phosphorea) and Norway lobster (Nephrops norvegicus) (Image 5). Each sea pen consists of colonies of polyps that form branch-like leaves which filter the water for food. The lower half of the sea pen acts like an anchor in the soft sediment against the current. The phosphorescent sea pen gets its name from its ability to luminesce a blue/green colour when disturbed.
Image 5: Norway lobster (Nephrops norvegicus) and sea pens (Pennatula phosphorea) (© JNCC).
The diverse habitats and invertebrate communities of the site are also reflected in the number of fish species we’ve seen whilst recording images of the seabed. These have included starry rays (Image 6), haddock, monkfish, gurnards, and the rather unfortunately named hagfish (Image 7). Hagfish are blind but have a very good sense of smell and are experts at finding dead or dying fish to feed on. They are also notorious for producing copious amounts of slime – their Latin name (Myxine glutinosa) comes from the ancient Greek word myxa for slime and the Latin word glutinosa for viscous and sticky.
Image 6: Starry rays (Amblyraja radiata) (© JNCC).
Image 7: Hagfish (Myxine glutinosa) swimming majestically over the seabed (© JNCC).
Flatfish have been a common sight on the seabed whilst we’ve been surveying the benthic habitats of the area. Throughout the area we have seen lemon sole, plaice, dab, sand-dab, and thickback sole (Image 8)
Figure 8: Lemon sole (Microstomus kitt) left, and plaice (Pleuronectes platessa) right (© JNCC).
Sometimes their camouflage colours or inclination to bury themselves in the sand can make them difficult to spot in the seabed images, see how quickly you can spot each flatfish in the images below (Image 9).
Image 9: Hidden flatfish (© JNCC).
The survey has been a great opportunity to document the diverse habitats and ecological communities of this HPMA. However, it’s sadly not uncommon to see some of the human impacts on the seabed, such as marine litter that has sunk to the seafloor (Image 10).
Image 10: Marine litter on the seabed (© JNCC).
If you missed our previous blog posts on this survey, you can catch up at the following links:
- Dolphin Head and North East of Farnes Deep Offshore Survey (Blog #1): Setting sail on our first HPMA offshore survey.
- Dolphin Head and North East of Farnes Deep Offshore Survey (Blog #2): BRUV (Baited Remote Underwater Video) footage.
- Dolphin Head and North East of Farnes Deep Offshore Survey (Blog #3): Drop Camera footage at Dolphin Head HPMA.
Answers to spot the creatures:
Locations of squat lobsters, hermit crabs, and shrimps (Image 4) (circled) (© JNCC).
Locations of hidden flatfish (Image 9) (circled) (© JNCC).