Description of biotope or habitat type
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Hydroids, ephemeral seaweeds and Littorina littorea in shallow eulittoral mixed substrata pools
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Moderately exposed, Sheltered |
| Tidal streams | |
| Substratum | Cobbles; pebbles; gravel; sand |
| Zone | Eulittoral |
| Depth Band | Mid shore |
| Other Features | Rockpool or standing water |
Download comparative physical and biological data. The comparative tables enable a rapid comparison of the species composition and principal physical characteristics between a given set of biotopes.
- Records used to define the biotope (core records)
- Other records assigned to this biotope, marked as 'certain'
- Other records assigned to this biotope, marked as 'uncertain'
Point data based on records in the UK Marine Recorder Snapshot.
Description
Shallow pools on mixed cobbles, pebbles, gravel and sand characterised by abundant hydroids. Species present may include Obelia geniculata, O. dichotoma, O. longissima, Sertularia cupressina, Tublaria indivisa and Thuiaria thuja. The difficulty in identifying hydroids suggests many more species may be also be present. Other species typically found in this biotope include ephemeral green algae (Ulva spp. and Ulva sp.), red algae (Chondrus crispus and Coralline algae) and the winkle Littorina littorea. Within the pools, patches of sand may be occupied by the lugworm Arenicola marina and sand mason worms Lanice conchilega. These pools are often associated with mussel beds (MytX), with Mytilus edulis frequently recorded within the pools. Barnacles (Semibalanus balanoides and Austrominius modestus) and the keel worm Spirobranchus triqueter may be attached to shells and small stones. Mobile species typical of rock pool habitats, such as Crangon crangon and Pomatoschistus minutus will also be found within the pool.
Situation
No situation data available.
Temporal variation
No temporal data available.
Characterising species
| Taxon | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|
| Arenicola marina | 21-40% | |
| Austrominius modestus | Frequent | 41-60% |
| Carcinus maenas | Rare | 41-60% |
| Chondrus crispus | Occasional | 41-60% |
| Corallinaceae | Frequent | 41-60% |
| Crangon crangon | 21-40% | |
| Fucus vesiculosus | Rare | 21-40% |
| Hydrozoa | Abundant | 81-100% |
| Lanice conchilega | Occasional | 41-60% |
| Littorina littorea | Common | 41-60% |
| Mytilus edulis | Abundant | 61-80% |
| Obelia longissima | Common | 21-40% |
| Semibalanus balanoides | Frequent | 41-60% |
| Spirobranchus triqueter | Rare | 21-40% |
| Ulva | Rare | 61-80% |
Similar biotopes or habitat types
Not applicable or unknown.
Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1996 (6.95) | RKP.H |
| 1995 | LMXD.HYD |