Point system

Start with a guess

During the initial phase of the BeachExplorer the value points for reported sightings rely on experience and estimated abundancies. Only at an advanced state when thousands of records will be available a statistic calculation of relative "values" will be possible.

Different countries, different points

As some species are unevenly distributed in the North Sea, different point values were fixed for records from six different geographical regions: The Netherlands, Lower Saxony & Hamburg, Schleswig-Holstein, the Danish Wadden Sea, the west coast of Danmark and the Kattegat. 

Definition of point values:

1 point        

• everywhere very abundant
• probably present in more than 80 % of the southern North Sea               
• sometimes more than 10,000 specimens per 100 m of coastline
• example: Common cockle

2 points

• everywhere abundant
• probably present in more than 70 % of the southern North Sea                 
• often more than 1,000 specimens per 100 m of coastline
• example: Blue mussel                  

3 points      

• almost everywhere, usually abundant
• probably present in more than 60 % of the southern North Sea                 
• often more than 100 specimens per 100 m of coastline
• example: Softshell clam                                  

4 points

• widely distributed, sometimes abundant
• probably present in more than 50 % of the southern North Sea                 
• often more than 10 specimens per 100 m of coastline
• example: American piddock           

5 points

• only locally distributed, usually single specimen                         
• probably present in more than 40 % of the southern North Sea                 
• rarely more than 10 specimens per 1,000 m of coastline
• example: Oval piddock

6 points

• only 5 - 10 squares of this region with records, usually single specimen                       
• probably present in more than 30 % of the southern North Sea                 
• rarely more than 1 specimen per 1,000 m of coastline
• example: Variegated scallop

7 points

• always single specimen, recorded in not more than 4 squares of this region                          
• probably present in more than 20% of the southern North Sea                 
• rarely more than 1 specimen per 1,000 m of coastline                             
• example: Sand slug

8 points

• very rare, recorded in not more than 3 squares of this region                                                 
• probably present in more than 10% of the southern North Sea                 
• always single specimen
• example: Poorly ribbed cockle

9 points

• only 1 or 2 records from this area                             
• probably present in less than 10% of the southern North Sea               
• always single specimen
• example: Mediterranean striped mussel

10 points

• no records so far from this area     
• example: Manila clam