Short profile


FishEthoScore of the species

Abbreviated assessment of the species' likelihood and potential for fish welfare in aquaculture, based on ethological findings for 10 crucial criteria.

Criteria Li Po Ce
1 Home range
2 Depth range
3 Migration
4 Reproduction
5 Aggregation ?
6 Aggression
7 Substrate
8 Stress
9 Malformation
10 Slaughter
FishEthoScore 1 2 4
Li = Likelihood that the individuals of the species experience welfare under minimal farming conditions
Po = Potential overall potential of the individuals of the species to experience welfare under improved farming conditions
Ce = Certainty of our findings in Likelihood and Potential
 
                    ?     /  
  High    Medium     Low     Unclear  No findings
 
FishEthoScore = Sum of criteria scoring "High" (max. 10)



General remarks

Gadus morhua is one of the most important commercial fish species in Northern Europe and North America’s eastern coast. Cods stocks were heavily reduced during the 1980s, and today the fishery is very low compared to historical levels. Stock collapses increased the investments in cod aquaculture enterprises, both hatcheries and on-growing farms began to accelerate. Within a few years an annual production capacity in the order of 60 million juveniles and around 400 on-growing sites was built up in Norway alone. However, the financial market crisis in 2008, together with recover of natural stocks decreased aquaculture production. Despite the big investment in cod aquaculture, the living conditions and the husbandry systems that maximise the welfare of this species are still to be defined, developed and improved. This lack is quite incomprehensible, given the background and the availability of research performed on this species. To optimise fish welfare of this species, improvements are mainly needed to meet home range and depth range needs, reproduction without manipulation, deformation rate, aggression and stress reduction. 


1. Are minimal farming conditions likely to provide the home range of the species? Is there potential for improvement? How certain are these findings?

L
Likelihood
L
Potential
H
Certainty

Larvae: WILD: no data found yet. FARM: intensive system: tanks: 1.5 m3 [1] [2]; extensive system: 5-200,000 m3 [1] [2].

Juveniles: WILD: 0.5-15 km [3] [4] [5] [6] [7], or about 27 ha [8]. FARM: circular tanks: 5,000-9,000 L [9]. Sea cages: adapted from salmon, max 35x35 m or 90 m diameter [10].

Adults  Juveniles.

Spawners: WILD: home range 3-26 km [7]. FARM: tanks: >25 m3 [11]


2. Are minimal farming conditions likely to provide the depth range of the species? Is there potential for improvement? How certain are these findings?

L
Likelihood
L
Potential
H
Certainty

Larvae: WILD and FARM: no data found yet.

Juveniles: WILD: 15-165 m depth [12] [6] [7]. FARM: sea cages: adapted from salmon, max 50 m depth [10].

Adults: Juveniles.

Spawners: WILD: 50–200 m depth [13] [14]. FARM: no data found yet.


3. Are minimal farming conditions compatible with the migrating or habitat-changing behaviour of the species? Is there potential for improvement? How certain are these findings?

L
Likelihood
L
Potential
H
Certainty

Oceanodromous [15].

Larvae: benthopelagic [16] [17].

Juveniles: benthopelagic [16] [17]. Coastal/resident and ocean/migratory populations [16]. Migration <300 km [3] [4] [7].

Adults: ➝ Juveniles.

Spawners: ➝  Juveniles.

 


4. Is the species likely to reproduce in captivity without manipulation? Is there potential to allow for it under farming conditions? How certain are these findings?

L
Likelihood
L
Potential
M
Certainty

WILD: spawn February-April [18]. FARM: simulated natural photoperiod and temperature regime induce natural spawning [19] [20]


5. Is the aggregation imposed by minimal farming conditions likely to be compatible with the natural behaviour of the species? Is there potential to allow for it under farming conditions? How certain are these findings?

?
Likelihood
H
Potential
M
Certainty

Larvae: WILD: no data found yet. FARM: intensive conditions 150-300 larvae/L [21] FAO).

Juveniles: WILD: schooling and shoaling [22] Fahay et al.1999 [23]. FARM: tanks: 35-95 kg/m3 [24]; offshore cages: 15-35 kg/m3 [25]; usually 20 kg/m3 [26] the same used for the Salmo salar.

Adults:  Juveniles.

Spawners: WILD: form spawning aggregations [27] [13]. FARM: no data found yet.


6. Is the species likely to be non-aggressive and non-territorial? Is there potential for improvement? How certain are these findings?

L
Likelihood
M
Potential
M
Certainty

Larvae: WILD: no data found yet. LAB: cannibalistic [2] [28]. FARM: no data found yet.

Juveniles: WILD and FARM: cannibalistic [29]. LAB: aggressive behaviour [30] [31] [32] [9]; cannibalistic [33] [28]. Appropriate feed and feeding strategies reduce aggression and cannibalism [33] [30] [32] [9].

Adults:   Juveniles.

Spawners: WILD: mate competition [34]. FARM: no data found yet.


7. Are minimal farming conditions likely to match the natural substrate and shelter needs of the species? Is there potential for improvement? How certain are these findings?

L
Likelihood
M
Potential
M
Certainty

Larvae: WILD: use substrate [35]. FARM: no data found yet.

Juveniles: WILD: use substrate [3] [36] [36] [35]. FARM: no data found yet.

Adults: WILD and FARM:   Juveniles.

Spawners: WILD: use substrate [37] [38] [13]. FARM: no data found yet.


8. Are minimal farming conditions (handling, confinement etc.) likely not to stress the individuals of the species? Is there potential for improvement? How certain are these findings?

L
Likelihood
M
Potential
M
Certainty

Larvae: stressed by grading, netting and transporting [39].

Juveniles: stressed by grading, netting, transporting [39], anthropogenic noise [40], hypoxia [41] and increases in water temperature [42] [43].

Adults: stressed by anthropogenic noise [40], hypoxia [41] and increases in water temperature [42] [43].

Spawners: stressed by anthropogenic noise [40].


9. Are malformations of this species likely to be rare under farming conditions? Is there potential for improvement? How certain are these findings?

L
Likelihood
M
Potential
M
Certainty

Larvae: malformations of the vertebral column [44]. Further research needed on the percentage rate.

Juveniles: malformations of the vertebral column in 4.1% fed with zooplankton and 14.2% fed with rotifers during larvae stage [45]; malformations of the vertebral column in >20% of individuals [46] [47].

Adults:  Juveniles.


10. Is a humane slaughter protocol likely to be applied under minimal farming conditions? Is there potential for improvement? How certain are these findings?

H
Likelihood
H
Potential
H
Certainty

A protocol for electrical stunning and killing by bleeding is available. Most effective when stunned at 107 Vrms 0.5+0.2 Arms for 15 s and exsanguination immediately after stunning [48] [49]. Stunning in a bath containing AQUI-STM anaesthesia induces unconsciousness without recovery and permits to reduce the stunning time to 5 s without  avoidance behaviour or distress [49].


Side note: Domestication

DOMESTICATION LEVEL 4 [50], level 5 being fully domesticated.


Side note: Feeding without components of forage fishery

All age classes: WILD: omnivorous [51]. FARM: fish meal and fish oil may be partly* replaced by non-forage fishery components [52] [53] [54] [55].

*partly = <51% – mostly = 51-99% – completely = 100%

 


Glossary

DOMESTICATION LEVEL 4 = entire life cycle closed in captivity without wild inputs [50]


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