The Sussex Kelp Recovery Project follows the rewilding ethos of letting nature lead. This means removing manageable pressures (such as trawling) that have prevented habitats from returning, and observing to learn where, when and how the ecosystem recovers.
But waiting and watching is not as simple as it sounds…
Assessing changes in such a complex and dynamic ecosystem and over such a large scale (the total Sussex Nearshore Trawling Byelaw zone is 304km2) is a huge challenge. Marine research is inherently more complicated than on land and there’s no single technique or activity that can evaluate kelp recovery on its own. Hence the environmental side of the SKRP’s research programme includes a variety of methods from eDNA and underwater cameras to the observations of local divers.
Environmental monitoring sites
SKRP’s research is initially focused on the western part of the Sussex Nearshore Trawling Byelaw area between Selsey Bill and Shoreham by Sea, which has a shoreline roughly 50 miles long. As it is not feasible to analyse what’s happening across the full area, the research creates a representative view based on a systematic survey of the area.
The map below shows SKRP’s environmental monitoring sites. Sites are both in and outside the Byelaw area for comparison and extend outwards from the shore in triplicate so that a range of depths can be assessed.
Some of the methods used in SKRP research:
BRUV are Baited Remote Underwater Video cameras. To understand what species are using the area and how this changes over time, bait is attached to a camera and is used to attract different species of fish and crustaceans. These are recorded making it easy for researchers to identify and count them.
BRUVs are deployed at 28 sites across SKRP’s focus area and provide a non-extractive, cost effective way of recording the presence of reef-associated and benthic (bottom dwelling) species and assessing diversity and abundance.
Towed underwater benthic cameras
At 25 points in and outside of the Byelaw zone, cameras are towed in a transect (straight-line) for around 300m to record the seabed terrain. Researchers analyse the videos based on four criteria:
Substrates: What substrates do we see (sand, pebbles, shingle etc.) and which are suitable for kelp?
Kelp: How much kelp do we see? Where is it? Which species are present?
Other habitats: Which essential fish habitats are in the area?
Notable species: What is the presence and abundance of habitat forming species?
These surveys are conducted annually and generate 7.5km of footage every year.
Environmental DNA (eDNA) is genetic material - or traces of DNA - contained within the microscopic skin cells, scales and faeces that animals leave behind in the environment. This is like an organism leaving a ‘fingerprint’ that shows they have been in an area. With eDNA these creatures can still be detected in aquatic environments between 7-21 days after they’ve left.
This method enables researchers to build a more detailed understanding of which species live in the environment than is possible by identifying them on sight.
Kelp population genetics
To answer questions such as how diverse Sussex kelp are and whether Sussex has unique kelp populations, samples of DNA from kelp species along the south coast are collected and analysed. This helps reveal how groups are related and interconnected and is important to assess their potential durability - the higher the genetic diversity, the more likely Sussex populations are to be resilient and healthy.
Observations from divers
To assess an area as large as the Sussex Nearshore Trawling Byelaw zone for signs of kelp recovery, multiple methods are used, and the observations from the diving community are an essential part of this. Various diving groups including Sussex Seasearch, Sussex Underwater and other volunteer divers, provide their sightings of kelp and other essential fish habitats to the SKRP.
Any kelp spotted is added to the Sussex Kelp Recording database and used to create kelp distribution maps.
Autonomous Reef Monitoring Systems (ARMS)
Three Autonomous Reef Monitoring Systems (ARMS) have been deployed in Sussex to assess kelp spore availability and the diversity of life on the seabed. The units have been installed at the wreck of the Indiana which is located about one mile south of Worthing Pier. Panels will be examined after one year to assess the species composition of newly settled organisms