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Maintenance was very low in this project because the soil is poor so that vegetation is not too abundant. At times floating trash has to be removed.
Remaining knowledge gaps are related to the behaviour of the juvenile fish (do they stay in the pond?) and if they don’t, what is the survival success if they swim into the docks? Large predators have been observed near the pipe exits at the dock side. Extra analysis is needed to decide which adaptations are needed in the construction to increase the survival of the juvenile fish.
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Fish spawning pond (“Vispaaiplaats”)
Table of content
- 1. Description of measure
- 1a. Measure description
- 1b. Monitoring
- 1c. Monitoring results
- 2. Execution of main effectiveness criteria
- 2a. Effectiveness according to development targets of measure
- 2b. Impact on ecosystem services
- 2c. Degree of synergistic effects and conflicts according to uses
- 3. Additional evaluation criteria in view of EU environmental law
- 3a. Degree of synergistic effects and conflicts according to WFD aims
- 3b. Degree of synergistic effects and conflicts according to Natura 2000 aims
- 4. Crux of the matter
- 5. References
Additional information
for this measure:
No further information available.
for this measure:
No further information available.
Crux of the matter
This pilot project shows that simple connection by pipes between pond and docks is sufficient to make the pond successful as spawning and juvenile area. Also, the pipe length of 30 m is not too long and the diameter of 600 mm is large enough. One pond is probably far from enough to contribute significantly to the fish stock in harbor docks or connected estuary. Sites without large-scale port development are preferable to create such fish spawning ponds. It is important to note that this measure was created behind the locks; it is unclear whether this kind of measure would be successful if the water level in the pipes is not being kept constant.Maintenance was very low in this project because the soil is poor so that vegetation is not too abundant. At times floating trash has to be removed.
Remaining knowledge gaps are related to the behaviour of the juvenile fish (do they stay in the pond?) and if they don’t, what is the survival success if they swim into the docks? Large predators have been observed near the pipe exits at the dock side. Extra analysis is needed to decide which adaptations are needed in the construction to increase the survival of the juvenile fish.