Fish underwater - Alison_Moore - RS34068__P9122360

We're surveying fish in Plymouth Sound as part of a new project, PLYMFISH, to better understand fish populations in this well-managed Marine Protected Area.


Our MPA Researcher, Frith Dunkley, and Jean-Luc Solandt, our Principal Specialist of MPAs have recently joined a three-year project with our partners, applied Marine Ecosystems Research (aMER) - University of Plymouth and the help of our funders, Princess Yachts, in Plymouth.

As part of PLYMFISH, we've been monitoring the effectiveness of Marine Protected Areas, and taking the pressure off seagrass beds with installation of Advanced Mooring Systems in the past decade – all within Plymouth Sound.

Now, we want to find out more about which animals are using the diverse marine habitats off Plymouth’s shores. This will give us a picture of the range of habitats and species found in the UK’s first marine park, and more widely in UK seas.

To assess fish populations associated with different habitats and areas off Plymouth’s shores, we're using ‘Baited Remote Underwater Videos’ (BRUVs) to collect video footage of animals on the seabed.

BRUVs have become an established technique used to gain an understanding of fish populations in particular habitats or areas at a particular time.

PLYMFISH BRUV camera Eddystone

The team deploying a BRUV over the side at Eddystone

Credit: Frith Dunkley

What's involved?

To capture the footage the team uses a bespoke device equipped with a video camera placed into a water-proof housing, a separate light source, and bait to attract the fish.

The bait (100 grams of mackerel) is held in a mesh cage which sits on the end of a pole, with the camera focusing on it one metre away.

The device is then lowered from the boat to the seabed, where it’s left for around an hour – plenty of time for surrounding animals to be attracted to the bait and move into shot.

PLYMFISH BRUV device Frith

Frith Dunkley setting up a couple of BRUVs

Credit: Jean-Luc Solandt

What's the footage used for?

These devices have been used in Scottish and English scientific studies to understand species movements in and around areas protected from particular types of fishing and in different habitats.

Understanding how fish use different habitats allows us to make a better case for protecting the seabed and essential fish habitat. This has had the effect of allowing regulators to better protect areas of the sea.

Mapping habitats in Plymouth Sound

We’ve been working in Plymouth Sound for years. We’ve mapped a substantial number of habitats in our collaborations with universities and local citizen scientists through our Seasearch dive programme, and have recently been involved in mapping seabed animals at the Eddystone reef complex 12 miles south. We’ve also recently been surveying seagrass beds in and around Advanced Mooring Systems in Cawsand to the west of the sound.

With PLYMFISH, we’ve now undertaken our first year of BRUVs surveys in these habitats – inside and outside seagrass beds, in the far offshore kelp-dominated upper reefs at Eddystone, and within the deeper sediment-dominated areas.

What are we recording?

We’re recording the marine life – the different species and habitats – that call Plymouth Sound ‘home’. We’re likely to find catshark, cuckoo, ballen and goldsinny wrasse, and maybe the odd conger eel and cuttlefish.

We want to know if some habitats are more important than others for certain species. As part of the ReMEDIES project, which is improving the seabed condition of seagrass in inshore sites, and the FISH INTEL project, which tracks the movement of bass and pollack, we know the information from BRUVs at Plymouth will further help us to clearly define habitats of importance to fish.

PLYMFISH BRUV camera map

The locations where the BRUVs were deployed

Local importance

Now that Plymouth has been declared as the UK's first ‘marine park’, we believe our Ocean Recovery projects can help understand the importance of different areas and habitats within the Sound for our spectacular UK wildlife.

Cawsand Seagrass bed map

The Cawsand seagrass bed, including the positions of the four Advanced Mooring Systems

We would like to thank our partners, The University of Plymouth, and funders, Princess Yachts.