Dorset Seasearch

Dorset Seasearch

Mapping the seabed with Dorset Seasearch

Volunteer divers have been contributing to our knowledge of Dorset's seabed habitats and species for over 20 years. 

This information is being used in a variety of ways - to help map seabed habitats, to identify potential protected areas, to influence fishery management decisions and to inform the licensing of developments in the marine environment. 

Seasearch divers are also bringing back hundreds of images of the seabed - many divers now carry a compact camera/video camera 

The acquisition of detailed remote-sensing data (see DORIS) marked the start of a new chapter in Dorset Seasearch.  Divers are now able to accurately target a huge number of newly revealed seabed features, making the survey much more efficient.  It has also opened up a range of new dive-sites in Dorset, many of which are sure to become classic dives. 

How to become a seasearcher

There are three types of courses available: 

  • Seasearch Observer - for divers new to marine recording in British and Irish waters

  • Seasearch Surveyor - for experienced recorders who want to increase the value of the results 

  • Special Interest Courses - a range of ID and techniques courses for people who want to expand their knowledge  

  • Course Costs 

The cost of the courses varies depending on venue, costs incurred and if there is any local subsidy or diving involved. As a rough guide one-day courses cost £40-£50 and weekend courses, including diving, £80-£90.  

For more detailed information, visit the national Seasearch training page here.

2017 Dorset Seasearch highlights

  • 52 divers took part in ten days of Seasearch diving organised by Dorset Seasearch 

  • Lyme Bay – diving within an area closed to all types of bottom towed fishing gear since 2008.  Divers reported bedrock and boulders with a rich community of pink sea fans, sponges, bryozoans and sea-squirts.  Numbers of juvenile pink sea fans (2-3 years old) were noticeable – these have appeared after the 2014 storms. 

  • Poole Bay – Divers visited tide-swept rocky sites both inside and outside the Studland to Portland Special Area of Conservation.  The more offshore site revealed some deep rocky gullies with some huge Elephant’s Hide sponge colonies on the vertical rock walls.  Divers also visited sites around the Poole Rocks Marine Conservation Zone, providing evidence in support of extending the boundary of this marine protected area, and recorded (abandoned) black bream nests in Swanage Bay.  A visit to Southbourne Rough (a proposed MCZ for nesting black bream) provided supporting evidence for including rocky seabed habitats as a feature of this proposed MPA 

  • Weymouth Bay – diving included a fast drift-dive off the Fossil Forest, east of Lulworth Cove, which provided evidence of maerl (a free-living calcified seaweed and a potential MCZ feature).  Divers also visited a deep, tide-swept site off Grove Point, where the tidal currents are too strong for diving except for a 40-minute window.   

  • Lulworth Banks – divers reported huge colonies of boring sponge and ross-corals as well as numerous wrasse, many displaying cleaning behaviour.  For the last few years, wrasse have been targeted in Dorset for live transport to Scotland to act as cleaner fish in salmon farms, but there are very few records of this behaviour in the wild 

  • Unusual sightings – a record of a (dead) fanshell and a rarely recorded anemone, Mesacmea micheli, came from a deep dive in Lyme Bay and a first for Dorset, the Variable Blenny, Parablennius pilicornis, was spotted on the wreck of the Royal Adelaide, off Chesil Beach

2019 Seasearch Dive Dates

Click here to see a list of 2019 Seasearch dive dates or download the programme below.

Join Seasearch on social media

You can also join the Dorset Seasearch Facebook page here or follow the Twitter stream here.

Contact Seasearch

Contact the Seasearch Coordinator  via email: and click here to visit their website.

(A report based on Dorset Seasearch 1995-2004 is available on CD - contact the Dorset Seasearch Co-ordinator to request a copy. )

Seabed Imagery © Dorset Wildlife Trust Contains MCA data © Crown copyright Not to be used for navigation