Evaluation of test sites

A number of test sites have been investigated and evaluated in this project, mainly in the regions of Langeland, South Zealand including Møn, Skive, Odsherred, and Aarhus. These areas historically have had issues dealing with macro algae. For all sites we have been in dialogue with local authorities (the local municipalities) in order to get an understanding of the size of the issues with macro alga is in the area, and in order to get the relevant permissions.

The types of algae which are most commonly found in ports and beaches in Denmark are:

  • Eelgrass or seagrass (Zostera marina). Flowering plants (angiosperms) which grow in marine environments. There are about 60 species of fully marine seagrasses. Seagrass are technically not counted as an algae but is often mixed up with algae when washing up on the shores.
  • Sea lettuce (Ulva lactuca). Individual blades of Ulva can grow to be more than 400 mm (16 in) in size, but this occurs only when the plants are growing in sheltered areas.
  • Bladder wrack (Fucus vesiculosus). Growing up to 35 inches (90 cm) tall, bladderwrack grows along the coastlines of the Atlantic and Pacific Oceans, the North and Baltic Seas, and various waters in Canada and the United States.
  • Ectocarpus siliculosus which is filamentous brown alga.
  • Toothed wrack (Fucus serratus). This is a seaweed of the north Atlantic Ocean, known as toothed wrack or serrated wrack
  • Beach wrack. A term used to describe the accumulation of seaweed, seagrass and other specimens from the sea which collects near the shore and on beaches.

The table below is a summary of the findings of the evaluation of the sites.

RegionLocationType of algaeQuantity on beachQuantity in water
LangelandSpodsbjergEelgrassLowLow
LangelandRudkøbing/BellevueEelgrass/beach wrackMediumHigh
MønHjelm bugtEelgrass/beach wrackLowLow
MønHårballe havnEelgrassHigh
MønHårballe strandEelgrass/beach wrackMediumLow
MønUffshale StrandEelgrassMediumMedium
South ZealandFakse LadepladsEelgrass/beach wrackHighMedium
South ZealandKite SpotEelgrass/beach wrackHighLow
South ZealandEnø StrandEelgrass/bladder wrackLowLow
South ZealandVesterhave StrandEelgrassHighLow
South ZealandPræstø FjordLowLow
South ZealandOre StrandEelgrassHighMedium
Skive FjordLyby StrandEelgrass/sea lettuceLowLow
Skive FjordGrønning StrandEelgrass/bladder wrackMediumMedium
OdsherredHøve HundeskovEelgrass/beach wrackHighMedium
OdsherredNordstrandEelgrass/beach wrackMediumLow
OdsherredMogens HerringsvejEelgrass/beach wrackHighLow
AarhusTangkrogenEelgrass/Ectocarpus /beach wrackLowLow
AarhusMarselisborgEelgrass/beach wrackHighMedium