Species and Habitats

The coastal waters of the Southern District are rich in marine life and display ample examples of a wide range of temperate marine habitats. These habitats are important for all commercial marine species at different stages of their lifecycle; therefore it is important to support equally both the status of the commercial species concerned and also the habitats which they depend upon.

Below is a brief guide through the marine habitats in the Southern IFCA District with contributions from the Hampshire and Isle of Wight Wildlife Trust and the Dorset Wildlife Trust.
 
      


Hampshire and Isle of Wight
 

Mud

Large areas of mud flats are found across the District, particularly in the Solent Harbours (Portsmouth, Langstone and Chichester) where water movement is relatively limited. Worms, crustaceans and molluscs burrow in the mud providing a food source for fish and, importantly, for birds when large areas of the mudflats are exposed at low water. Both intertidal and subtidal muddy habitats support many commercially important species such as oysters and clams.

The Solent has a small population of harbour seals, which can be seen resting on the exposed mud in some areas and grey seals sometimes pass through.  Further offshore, around the Isle of Wight, the mud is home to burrowing spoon worms and nationally scarce mantis shrimps.
 

Seagrass

Significant areas of seagrass beds are found in many locations across Hampshire and the Isle of Wight, both intertidally and subtidally.  These are important spawning and nursery areas for many species – including commercially important species – and provide protection for rare animals such as stalked jellyfish and seahorses. Seagrass beds also perform a range of ecosystem services such as sediment stabilisation, carbon storage and oxygen production.

 

Rock, Peat and Clay

There are numerous areas of rocky reef and chalk reefs around the Isle of Wight, including colourful corals, anemones and sponge communities providing shelter and food for large fish and crustacean species.

Some of the best peat exposures in the region are found at both intertidal and subtidal locations around the island, particularly the large underwater peat cliffs off Bouldnor.  Piddocks burrow into the peat and also the many clay exposures and these habitats support diverse plant and animal communities.




 

Sand and Gravel

Sand and gravel habitats are common throughout the area. Sandy habitats can be colonised and stabilised by ross worms and are important for juvenile fish such as sand eels. Gravel is more stable and therefore supports a wider range of species which attract larger fish and even seahorses



Dorset

These communities are commonly found subtidally at the stretch of coast between West Lulworth and Swanage. These habitats develop on wave-exposed bedrock and boulders that have a strong tidal stream which is needed to bring in the nutrients for the stationary animals to feed on. The main sessile animals found in these areas which usually create a dense animal turf including bryzoans, hyrdoids and corals which further attract a range of mobile species such as starfish, hermit crabs, edible crabs, lobsters and wrasses.

Similar habitats occur at the Poole Rocks Marine Conservation Zone in Swanage Bay. Depending on depth, these diverse habitats also support a rich algal community too.


 

Rocky Reefs

Lyme Bay and Studland to Portland are famous for their reef habitats. This includes an array of delicate organisms that colonise and grow slowly, including rare species such as ross coral and pink sea fans. The intricate topography of the seabed, firm substrate and optimal tidal stream allow for the development of a wide range of animals ranging from corals, nudibranchs and lobsters to fish.

Dense Animal Aggregations

Large clusters of organisms spanning great areas (sometimes tens of kilometres) have also been witnessed in Dorset, including mussels, slipper limpets and brittle stars. Some of these single-species aggregations support a diverse community of organisms. For example, aggregations of mussels south of Portland Bill demonstrate their ability to provide food and shelter for species such as corals, sponges, sea squirts, crustaceans and fish species.
 

Mixed Kelp Communities

Stable, tide-swept rock characterised by dense kelp forest on scoured coralline-encrusted rock. This biotope occurs in sheltered narrows and sills such as west of St Alban’s Head, where there is an increase in tidal flow. Kelp communities provide excellent sheltering locations for a host of mobile species, especially during vulnerable life stages e.g. juvenile fish.
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