Resources

Biology - Marine Biology

• Biology
• Bembridge Marine Life
• Dog whelks, Nucella lapillus, and TBT
• Limpets
• Topshells
• Common Shore Crab

Topshells

The purple topshell, Gibbula umbilicalis, is an intertidal gastropod found on sheltered rocky shores. It is a Lusitanian (southern) species and until 2001 it was not found further east than Bembridge. Since 1990 it has considerably increased its density at Bembridge, and is now one of the most abundant organisms found on the middle ledge.

G.umbilicalis is a grazer and feeds on microscopic benthic algae on the seashore. It is predated on by birds, fish and crabs.

G.umbilicalis reproduces during the summer (July to September) by releasing gametes into the plankton, which are then fertilised and settle out within a few days. The young spat are particularly sensitive to cold winter temperatures; although the recent warm winters have resulted in increased recruitment.

Download data for G.umbilicalis at Bembridge, Isle of Wight (password protected)

• Size-frequency data 
• Size-frequency graphs 

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