LevelPressureEnvironment

ImpactPressureWaterColumn

ImpactPressureSeabedHabitats

ImpactPressureFunctionalGroup

NIS2_1

NISWaterColumnHabitat2_2

NISSeabedHabitats2_2

NISFunctionalGroups2_2

MarineCoast, MarineShelf

ShallSand

NotRelevant

NotAssessed

NotAssessed

NotAssessed

NotAssessed

Unknown_NotAssessed

Unknown_NotAssessed

Unknown_NotAssessed

Unknown_NotAssessed

NotRelevant

NotRelevant

NotRelevant

NotRelevant

Insufficient monitoring data and lack of established assessment methods

Insufficient monitoring data and lack of established assessment methods

Insufficient monitoring data and lack of established assessment methods

Insufficient monitoring data and lack of established assessment methods

There is a lack of information to assess the effects of NIS on functional groups

There are 47 known established non-indigenous species in the Dutch part of the North Sea (including estuaries and the Wadden Sea). These mainly concern algae, crustaceans, shellfish (molluscs) and worms. Sixteen of these non-indigenous species are known to be harmful to the ecosystem. Two non-indigenous species whose introduction has had major consequences are the Atlantic jackknife clam (Ensis directus) and the Pacific oyster (Crassostrea gigas). The Atlantic jackknife clam currently represents 90% of the biomass in the coastal zone seabed. Twenty years ago, Spisula subtruncata was still the most common species in this area, forming large-scale banks. Spisula decreased unexpectedly. Subsequently, the Atlantic jackknife clam took over the ecological niche (and possibly that of other indigenous bivalves) with an as yet poorly understood success. This shift probably also led to the decline in numbers of the common scoter, which feeds mainly on Spisula.

There are 47 known established non-indigenous species in the Dutch part of the North Sea (including estuaries and the Wadden Sea). These mainly concern algae, crustaceans, shellfish (molluscs) and worms. Species like the ctenophore Mnemiopsis leidyi and the tunicate Didemnum vexillum have the potential to become highly problematic, as is seen in other areas where they have been introduced. These two species are transported to the North Sea by both natural distribution and by ships.

There are 47 known established non-indigenous species in the Dutch part of the North Sea (including estuaries and the Wadden Sea). These mainly concern algae, crustaceans, shellfish (molluscs) and worms. Sixteen of these non-indigenous species are known to be harmful to the ecosystem. Two non-indigenous species whose introduction has had major consequences are the Atlantic jackknife clam (Ensis directus) and the Pacific oyster (Crassostrea gigas). The Atlantic jackknife clam currently represents 90% of the biomass in the coastal zone seabed. Twenty years ago, Spisula subtruncata was still the most common species in this area, forming large-scale banks. Spisula decreased unexpectedly. Subsequently, the Atlantic jackknife clam took over the ecological niche (and possibly that of other indigenous bivalves) with an as yet poorly understood success. This shift probably also led to the decline in numbers of the common scoter, which feeds mainly on Spisula. The Pacific oyster, the second example, not only proved a formidable competitor of indigenous species, it also brought with it the pathogen Bonamia. The indigenous flat oyster (Ostrea edulis) has all but become extinct in the Dutch part of the North Sea: due to overfishing in the first half of the 20th century, competition from the Pacific oyster and susceptibility to Bonamia. This parasite is possibly also preventing the return of the flat oyster.

ICES has identified 30 non-indigenous species that have adverse impacts on ecosystems or human health within the North East Atlantic. Many non-indigenous species have been found in the North Sea. The main vector for the initial introduction of these species has been mariculture followed by ballast water from ships, hull fouling and fishing. The most important and widespread impacts are changes to habitats and competition for food and space with indigenous organisms. Many of these species also have economic impacts. Almost all the species concerned were introduced before the current measures, some as long as several hundred years ago.

Moderate

Non related GES component

Moderate

Non related GES component

Unknown_NotAssessed

Be stable

The introduction of non-indigenous species as a result of shipping became a significant factor from the late Middle Ages onward, and particularly from the 16th century, when merchant shipping to Africa, Japan, India, Indonesia and Northern and Central America got underway. Introduction came about via the hulls of the slow-moving sailing ships and as a result of ships' lowering ballast rocks or cargo. A well-known example is the introduction in 1731 of the shipworm, which eroded wooden sea walls. The number of introductions during this period may very well be higher than assumed, as many species that have long been considered indigenous originally travelled to our regions by ship. From the 18th century onward, introductions of non-indigenous species as a result of shipping increased because of the use of ballast water tanks in steel ships. Taking on ballast water and dumping it far from its origin (at sea and in sea ports) serves as a highly effective vehicle for non-indigenous species. Non-indigenous species can also enter the Dutch part of the North Sea by natural means (on driftwood in sea

The introduction of non-indigenous species as a result of shipping became a significant factor from the late Middle Ages onward, and particularly from the 16th century, when merchant shipping to Africa, Japan, India, Indonesia and Northern and Central America got underway. Introduction came about via the hulls of the slow-moving sailing ships and as a result of ships' lowering ballast rocks or cargo. A well-known example is the introduction in 1731 of the shipworm, which eroded wooden sea walls. The number of introductions during this period may very well be higher than assumed, as many species that have long been considered indigenous originally travelled to our regions by ship. From the 18th century onward, introductions of non-indigenous species as a result of shipping increased because of the use of ballast water tanks in steel ships. Taking on ballast water and dumping it far from its origin (at sea and in sea ports) serves as a highly effective vehicle for non-indigenous species. Non-indigenous species can also enter the Dutch part of the North Sea by natural means (on driftwood in sea

The introduction of non-indigenous species as a result of shipping became a significant factor from the late Middle Ages onward, and particularly from the 16th century, when merchant shipping to Africa, Japan, India, Indonesia and Northern and Central America got underway. Introduction came about via the hulls of the slow-moving sailing ships and as a result of ships' lowering ballast rocks or cargo. A well-known example is the introduction in 1731 of the shipworm, which eroded wooden sea walls. The number of introductions during this period may very well be higher than assumed, as many species that have long been considered indigenous originally travelled to our regions by ship. From the 18th century onward, introductions of non-indigenous species as a result of shipping increased because of the use of ballast water tanks in steel ships. Taking on ballast water and dumping it far from its origin (at sea and in sea ports) serves as a highly effective vehicle for non-indigenous species. Non-indigenous species can also enter the Dutch part of the North Sea by natural means (on driftwood in sea

The introduction of non-indigenous species as a result of shipping became a significant factor from the late Middle Ages onward, and particularly from the 16th century, when merchant shipping to Africa, Japan, India, Indonesia and Northern and Central America got underway. Introduction came about via the hulls of the slow-moving sailing ships and as a result of ships' lowering ballast rocks or cargo. A well-known example is the introduction in 1731 of the shipworm, which eroded wooden sea walls. The number of introductions during this period may very well be higher than assumed, as many species that have long been considered indigenous originally travelled to our regions by ship. From the 18th century onward, introductions of non-indigenous species as a result of shipping increased because of the use of ballast water tanks in steel ships. Taking on ballast water and dumping it far from its origin (at sea and in sea ports) serves as a highly effective vehicle for non-indigenous species. Non-indigenous species can also enter the Dutch part of the North Sea by natural means (on driftwood in sea

• "Shipping & floating structures (all vessels
• Aquaculture
• NotReported

• "Shipping & floating structures (all vessels
• Aquaculture
• NotReported

• "Shipping & floating structures (all vessels
• Aquaculture
• NotReported

• "Shipping & floating structures (all vessels
• Aquaculture
• NotReported