and financial support. Nevertheless, even if not planned under best conditions, the
work shows a trend, which requires more research on this topic.
11.3.4.2 Candidate: Gadus morhua
Declining catches of Atlantic cod lead to a growing interest in aquaculture of this
species. For more than thirty years, the intensive production of cod has been
established (Moksness et al. 2004). The rearing of G. morhua requires the production of live food of different sizes and feeding protocols need to be followed
strictly (Moksness et al. 2004). Of all the gadoid species, cod is thought to have the
greatest potential for future development for aquaculture and some scientists
believe that within the next 20 years similarly high production levels can be
achieved as for the Atlantic salmon (Rosenlund and Skretting 2006). The suitability
of G. morhua for offshore aquaculture has been successfully demonstrated in
3000 m
3 submersible cages including automatic feeding buoys by the company Sea
Station™ off the coast of New Hampshire (Chambers and Howell 2006). As
G. morhua is a physoclist species, necessary pauses need to be included during
vertical movements of the cage (Korsøen 2011). One major problem for cod
aquaculture is their ability to bite through the mesh or other materials, which makes
them the fish species with the highest escapee rate (Jensen et al. 2010), which could
have a negative impact on wild population by cross-breeding (Davies et al. 2008).
The extreme temperature tolerance range from −1 to 23 °C and an optimum temperature range from 8 to 12 °C (Jobling 1988) make this species a candidate for
aquaculture in the German Bight. However, aquaculture companies should be
aware that the relatively high summer temperatures in the German Bight could
enhance the risk of infections, as G. morhua is prone to bacterial fish pathogens
such as Franciscella spec. or Aeromonas salmonicidae at prolonged temperatures
of more than 12 °C (Buck et al. 2012).
11.3.4.3 Candidate: Hippoglossus hippoglossus
The Atlantic halibut is a much valued aquaculture candidate as the species is
resistant to several common fish diseases, has high food conversion efficiency and a
good meat quality due to its firm texture and long shelf life (Daniels and Watanabe
2010). However, the rearing of fingerlings is difficult as larvae need the right
composition of live feed after the yolk sac stage and a precise temperature regime.
The on-growing of H. hippoglossus takes place either in land-based tanks or
troughs, or in net cages in the sea (Daniels and Watanabe 2010). The use of
submersible cages was successfully demonstrated for halibut (Howell and
Chambers 2005; Daniels and Watanabe 2010), offering significant advantages in
contrast to surface culture, such as avoidance of the exposure to the seasonal high
water temperatures and to the effect of UV radiation at the surface. The temperature
tolerance range for the Atlantic halibut reaches from −1.3 to approximately 18–20 °C,
284
B.H. Buck et al.
work shows a trend, which requires more research on this topic.
11.3.4.2 Candidate: Gadus morhua
Declining catches of Atlantic cod lead to a growing interest in aquaculture of this
species. For more than thirty years, the intensive production of cod has been
established (Moksness et al. 2004). The rearing of G. morhua requires the production of live food of different sizes and feeding protocols need to be followed
strictly (Moksness et al. 2004). Of all the gadoid species, cod is thought to have the
greatest potential for future development for aquaculture and some scientists
believe that within the next 20 years similarly high production levels can be
achieved as for the Atlantic salmon (Rosenlund and Skretting 2006). The suitability
of G. morhua for offshore aquaculture has been successfully demonstrated in
3000 m
3 submersible cages including automatic feeding buoys by the company Sea
Station™ off the coast of New Hampshire (Chambers and Howell 2006). As
G. morhua is a physoclist species, necessary pauses need to be included during
vertical movements of the cage (Korsøen 2011). One major problem for cod
aquaculture is their ability to bite through the mesh or other materials, which makes
them the fish species with the highest escapee rate (Jensen et al. 2010), which could
have a negative impact on wild population by cross-breeding (Davies et al. 2008).
The extreme temperature tolerance range from −1 to 23 °C and an optimum temperature range from 8 to 12 °C (Jobling 1988) make this species a candidate for
aquaculture in the German Bight. However, aquaculture companies should be
aware that the relatively high summer temperatures in the German Bight could
enhance the risk of infections, as G. morhua is prone to bacterial fish pathogens
such as Franciscella spec. or Aeromonas salmonicidae at prolonged temperatures
of more than 12 °C (Buck et al. 2012).
11.3.4.3 Candidate: Hippoglossus hippoglossus
The Atlantic halibut is a much valued aquaculture candidate as the species is
resistant to several common fish diseases, has high food conversion efficiency and a
good meat quality due to its firm texture and long shelf life (Daniels and Watanabe
2010). However, the rearing of fingerlings is difficult as larvae need the right
composition of live feed after the yolk sac stage and a precise temperature regime.
The on-growing of H. hippoglossus takes place either in land-based tanks or
troughs, or in net cages in the sea (Daniels and Watanabe 2010). The use of
submersible cages was successfully demonstrated for halibut (Howell and
Chambers 2005; Daniels and Watanabe 2010), offering significant advantages in
contrast to surface culture, such as avoidance of the exposure to the seasonal high
water temperatures and to the effect of UV radiation at the surface. The temperature
tolerance range for the Atlantic halibut reaches from −1.3 to approximately 18–20 °C,
284
B.H. Buck et al.