harvested biennially each year (6 harvests in four years). Once the longline is
transferred at sea, deployed and ready for cultivation the production undergoes
two cycles: Spat collection (April–June) in year one and maintenance of
longlines to remove fouling organisms and modify buoyancy (August–May) in
year one as well and grow-out to consumption size within 15–18 months
(market size: <5.5 cm) and harvest in August–November in the second year.
(3) All costs were itemized by scenarios of production for consumption mussels
(Buck et al. 2010 also calculate seed mussel production). Cost calculations
were based on data gathered from existing traditional nearshore mussel cultivation activities. Some nearshore cultivation plots have a distance of 10–55
nautical miles to the port of trans-shipment, which is within the scale of the
planned offshore site (17 nautical miles) (BSH 2016). Offshore operations are
more labour and time intensive than nearshore sites. Much of the labour is for
maintenance that includes deploying or retrieving of moorings or other parts of
the construction harness, which may lead to generally higher operation and
production costs. However, some production steps necessary for nearshore
operations cease to exist offshore, which in turn leads to cost reduction. The
annual fixed costs consist of depreciation, licenses, motor overhaul, interest on
fixed capital and miscellaneous costs like insurance premium and administrative cost. Interest rate was assumed to be 7%. Variable costs are fuel expenses,
wages, repairs and maintenance, miscellaneous costs and interest on variable
costs. Fuel was assumed to cost 0.55 € liter
−1 , wages are calculated with
3,333 € month
−1 . When using existing capacities of mussel farming in Lower
Saxony, an investment for retrofitting at the beginning of the enterprise will be
required. In the scenarios where new capacities have to be established,
investment into a new appropriate vessel as well as into a new land facility was
considered. All other costs are assumed to be similar to those used for the basic
scenario.
(4) A sensitivity analysis was calculated to explore the effects of changes in the key
parameters that reflect uncertainty, such as the biomass gain and/or the
development of costs and prices. Here, NPV and IRR for different mussel
prices, different biomass gain, different developments of single cost components as well as an increase in overall costs were calculated as well as different
discount rates on NPV.
11.6.3 Calculation and Results
Following the data of the Federal Agency for Agriculture and Food (2007) and the
State Fisheries Agency, Bremerhaven, Germany (SFA) (2008), the average market
price per kg of consumer mussels has been relatively stable until 1975 (below
0.2 € kg
−1 ). Afterwards, the price has been subject to fluctuations ranging between
332
B.H. Buck et al.
transferred at sea, deployed and ready for cultivation the production undergoes
two cycles: Spat collection (April–June) in year one and maintenance of
longlines to remove fouling organisms and modify buoyancy (August–May) in
year one as well and grow-out to consumption size within 15–18 months
(market size: <5.5 cm) and harvest in August–November in the second year.
(3) All costs were itemized by scenarios of production for consumption mussels
(Buck et al. 2010 also calculate seed mussel production). Cost calculations
were based on data gathered from existing traditional nearshore mussel cultivation activities. Some nearshore cultivation plots have a distance of 10–55
nautical miles to the port of trans-shipment, which is within the scale of the
planned offshore site (17 nautical miles) (BSH 2016). Offshore operations are
more labour and time intensive than nearshore sites. Much of the labour is for
maintenance that includes deploying or retrieving of moorings or other parts of
the construction harness, which may lead to generally higher operation and
production costs. However, some production steps necessary for nearshore
operations cease to exist offshore, which in turn leads to cost reduction. The
annual fixed costs consist of depreciation, licenses, motor overhaul, interest on
fixed capital and miscellaneous costs like insurance premium and administrative cost. Interest rate was assumed to be 7%. Variable costs are fuel expenses,
wages, repairs and maintenance, miscellaneous costs and interest on variable
costs. Fuel was assumed to cost 0.55 € liter
−1 , wages are calculated with
3,333 € month
−1 . When using existing capacities of mussel farming in Lower
Saxony, an investment for retrofitting at the beginning of the enterprise will be
required. In the scenarios where new capacities have to be established,
investment into a new appropriate vessel as well as into a new land facility was
considered. All other costs are assumed to be similar to those used for the basic
scenario.
(4) A sensitivity analysis was calculated to explore the effects of changes in the key
parameters that reflect uncertainty, such as the biomass gain and/or the
development of costs and prices. Here, NPV and IRR for different mussel
prices, different biomass gain, different developments of single cost components as well as an increase in overall costs were calculated as well as different
discount rates on NPV.
11.6.3 Calculation and Results
Following the data of the Federal Agency for Agriculture and Food (2007) and the
State Fisheries Agency, Bremerhaven, Germany (SFA) (2008), the average market
price per kg of consumer mussels has been relatively stable until 1975 (below
0.2 € kg
−1 ). Afterwards, the price has been subject to fluctuations ranging between
332
B.H. Buck et al.