11.6.2 Data for the Economic Analysis
(1) See Table 11.6
(2) As the best and safest working conditions are to maximize onshore activities
(Sørensen et al. 2001), the setup of all longline devices should take place on
land-based facilities and transferred to the aquaculture site during spring to
allow settlement in May of the same year. It was planned to install two full
mussel plots, which were scaled up in the following year, which would then be
equivalent to four mussel plots in operation. Exchange of longline devices after
its operating life expectancy can automatically be done during or after maintenance or harvest procedures. Consumption mussels reach market size after
approximately 1.5 years; therefore, the farm will operate at full scale in the
second year, which results in a form of shifting cultivation (Bartlett 1956).
While only in the first year of the enterprise no mussels can be harvested due to
their growth period to reach market size, in the following years two plots can be
Table 11.6 Site-specific data of the offshore wind farm-aquaculture multi-use concept at the
offshore lighthouse “Roter Sand” (modified after Buck et al. 2010, based on Buck 2004 and Buck
et al. 2008a, b)
Basic data
Distance to shore (City of Bremerhaven)
17 nautical miles
Number of planned wind turbines/power
18/5 MW-class
Salinity
20–33‰ (due to tidal current and the influence of
the Weser estuary)
Depth
10–15 m
Condition of the sea bottom
Soft bottom (Wadden Sea)
Turbidity and light
High sediment load (due to the Wadden Sea)
Wave climate
exposed
Current velocity
0–1.2 m s
−1 (depending on the tide)
Significant wave heights
0–6 m
Nutrients
Eutrophic situation
Water temperature
1.5–18 °C
Wind velocities
Up to 8 Beaufort
Distance between turbines
Approx. 1,000 m
Minimum spacing between turbines and
any aquaculture co-use
150 m
Size of aquacultural area (single mussel
plot)
700 Â 700 m
(490,000 m
2 = 0.49 km
2 = 49 ha = 121 acre)
Number of single mussel plots
4 (196 ha = 484 acre)
Total length of the collector harness per
longline
1675 m (335 V-shaped collector pairs having each
a length of 2 Á 2.5 m = 5 m,
71 Á 1675 m = 118,925 m per single mussel plot
Biomass of mussels per meter of
collector
10–15 kg (16.75 metric tons Á longline
−1
,
1190 metric tons Á plot
−1
)
11 The German Case Study: Pioneer Projects of Aquaculture …
331
(1) See Table 11.6
(2) As the best and safest working conditions are to maximize onshore activities
(Sørensen et al. 2001), the setup of all longline devices should take place on
land-based facilities and transferred to the aquaculture site during spring to
allow settlement in May of the same year. It was planned to install two full
mussel plots, which were scaled up in the following year, which would then be
equivalent to four mussel plots in operation. Exchange of longline devices after
its operating life expectancy can automatically be done during or after maintenance or harvest procedures. Consumption mussels reach market size after
approximately 1.5 years; therefore, the farm will operate at full scale in the
second year, which results in a form of shifting cultivation (Bartlett 1956).
While only in the first year of the enterprise no mussels can be harvested due to
their growth period to reach market size, in the following years two plots can be
Table 11.6 Site-specific data of the offshore wind farm-aquaculture multi-use concept at the
offshore lighthouse “Roter Sand” (modified after Buck et al. 2010, based on Buck 2004 and Buck
et al. 2008a, b)
Basic data
Distance to shore (City of Bremerhaven)
17 nautical miles
Number of planned wind turbines/power
18/5 MW-class
Salinity
20–33‰ (due to tidal current and the influence of
the Weser estuary)
Depth
10–15 m
Condition of the sea bottom
Soft bottom (Wadden Sea)
Turbidity and light
High sediment load (due to the Wadden Sea)
Wave climate
exposed
Current velocity
0–1.2 m s
−1 (depending on the tide)
Significant wave heights
0–6 m
Nutrients
Eutrophic situation
Water temperature
1.5–18 °C
Wind velocities
Up to 8 Beaufort
Distance between turbines
Approx. 1,000 m
Minimum spacing between turbines and
any aquaculture co-use
150 m
Size of aquacultural area (single mussel
plot)
700 Â 700 m
(490,000 m
2 = 0.49 km
2 = 49 ha = 121 acre)
Number of single mussel plots
4 (196 ha = 484 acre)
Total length of the collector harness per
longline
1675 m (335 V-shaped collector pairs having each
a length of 2 Á 2.5 m = 5 m,
71 Á 1675 m = 118,925 m per single mussel plot
Biomass of mussels per meter of
collector
10–15 kg (16.75 metric tons Á longline
−1
,
1190 metric tons Á plot
−1
)
11 The German Case Study: Pioneer Projects of Aquaculture …
331