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 0 0 1
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

Salvelinus fontinalis is farmed not only for feeding purposes but also for recreational fishing, especially in North America. Considered invasive in several countries, where adverse ecological impact after introduction has been reported. Nevertheless, there are many biological and ethological aspects that are not respected in usual farming conditions. This species naturally swims long distances, which makes it challenging for rearing facilities to fulfill its spatial needs. Reproduction is induced through highly invasive techniques, and substrate needs are complex to assure in farms. In addition, there is a severe lack of knowledge concerning its biology, namely in aspects that are directly related to farming such as stress, malformation rates and sustainable feeds. Further research should be directed into these issues, as well as on manipulation (e.g. spawning, humane stunning and slaughtering protocols) and environmental enrichment. Selecting non-migratory strains for rearing could help to minimize harmful effects of confinement.


1. Are minimal farming conditions likely to provide the home range of the species? What overall welfare potential can be achieved? How certain are these findings?

L
Likelihood
M
Potential
M
Certainty

ALEVINS:  WILD: >1 km [1]. FARM: hatchery troughs for fry: usually 3.5-4.5 m x 0.3-0.5 m [2].

JUVENILES: WILD: usually 100-200 m, up to 3300 m [3] or several kilometres [4] [5]. FARM: grow-out circular tanks: 5.7 m3 [6]; concrete tanks: usually 10-30 x 2-3 m [2].

ADULTS JUVENILES.

SPAWNERS: WILD: 65-100 km in anadromous morphs [7], dozens of km in freshwater morphs [4] [5]. FARM: no data found yet.


2. Are minimal farming conditions likely to provide the depth range of the species? What overall welfare potential can be achieved? How certain are these findings?

?
Likelihood
M
Potential
M
Certainty

ALEVINS: WILD: benthic, 0.3-8 m depth [8] [9]. FARM: hatchery troughs for fry 23-30 cm depth [2].

JUVENILES: WILD: 0-1 m [10] [11]. FARM: grow-out circular tanks 5.7 m3 [6]; concrete tanks usually 1-1.5 m [2].

ADULTS: WILD: spawn at 0.3-7.8 m depth [8] [9], increasing depth with increasing female size [9]. FARM: no data found yet.

 


3. Are minimal farming conditions compatible with the migrating or habitat-changing behaviour of the species? What overall welfare potential can be achieved? How certain are these findings?

?
Likelihood
M
Potential
M
Certainty

Some populations ANADROMOUS, others stationary in fresh water [12] [13] [1] [14] [7] [15] [16].

ALEVINS: WILD: fresh water [12] [1]FARM: freshwater troughs [2].

JUVENILES: WILD: Some populations and individuals anadromous, others stationary in fresh water [12] [13] [1] [14] [7] [15] [16]FARM: freshwater tanks [2] [6].

ADULTS JUVENILES

SPAWNERSWILD JUVENILESFARMno data found yet.


4. Is the species likely to reproduce in captivity without manipulation? What overall welfare potential can be achieved? How certain are these findings?

L
Likelihood
L
Potential
M
Certainty

WILD: Spawn October-January [2]. Female builds nest [2] [17] [18], male courts female [2]. FARM: eggs of ripe females are stripped either manually or by inserting compressed air into the abdominal cavity of females to push eggs from vent, reported to be less stressful. Milt is also stripped from males. Anaesthesia is recommended [2]. Triploidy induction is common [19].


5. Is the aggregation imposed by minimal farming conditions likely to be compatible with the natural behaviour of the species? What overall welfare potential can be achieved? How certain are these findings?

L
Likelihood
L
Potential
L
Certainty

ALEVINS: WILD: 0.02-1.1 individuals/m2 [20]. FARM: ca 3,000 to 6,000 fry/m2 [2].

JUVENILES: WILD: 0.01-11 individuals/m2 [21] [20] [22]. Plastic species, shoal aggregation is dependent on environmental conditions [22]. FARM: ca 160 individuals/m2 (assuming harvest weight of 250 g) [6].

ADULTS JUVENILES

SPAWNERSWILD: form spawning shoals [9] [23], of ca 3 individuals/m2 [9]. FARM: no data found yet.

 


6. Is the species likely to be non-aggressive and non-territorial? What overall welfare potential can be achieved? How certain are these findings?

L
Likelihood
L
Potential
L
Certainty

ALEVINS: WILD: aggressive [24] [25]. FARM: no data found yet.

JUVENILES: WILD: Aggressive [26]FARM: aggressive [26] [27].

ADULTS JUVENILES

SPAWNERS: WILD: aggressive males [28]. FARM: no data found yet.


7. Are minimal farming conditions likely to match the natural substrate and shelter needs of the species? What overall welfare potential can be achieved? How certain are these findings?

L
Likelihood
M
Potential
H
Certainty

Eggs: WILD: layed in substrate [17]FARM: barren troughs, jars and incubators [2].

ALEVINS: WILD: seek shelter [29], stay concealed in substrate [17] [18]. FARM: substrate enrichment not reported in literature . Cobbles are reported to improve welfare of fingerlings in other salmonids [30]. Ponds usually have stones, pebbles and gravel as substrate (pers. obs).

JUVENILES: WILD: use sand, gravel, rubble and boulders [10]FARM: Ponds usually have stones, pebbles and gravel as substrate (pers. obs).

ADULTS JUVENILES

SPAWNERS: WILD: spawn in gravel and rubble [2]. Usually require groundwater at spawning sites [31] [32] [8]. FARM: Coarse substrate and artificial groundwater flow improved natural spawning in farms [31], maturation ponds usually have stones, pebbles and gravel as substrate (pers. obs).


8. Are minimal farming conditions (handling, confinement etc.) likely not to stress the individuals of the species? What overall welfare potential can be achieved? How certain are these findings?

L
Likelihood
M
Potential
L
Certainty

ALEVINS: WILD and FARMno data found yet.

JUVENILES: WILD: no data found yet. FARM: acute stress response to handling  [33] [34], confinement, removal of members of the shoal [33], sub-lethal temperature of 23º C [35] and transport [36] [34].

ADULTS JUVENILES

SPAWNERS: WILD: elevated summer temperatures delay spawning [37]. FARM JUVENILES

 


9. Are malformations of this species likely to be rare under farming conditions? What overall welfare potential can be achieved? How certain are these findings?

/
Likelihood
/
Potential
/
Certainty

ALEVINSno data found yet.

JUVENILESno data found yet.

ADULTSno data found yet.


10. Is a humane slaughter protocol likely to be applied under minimal farming conditions? What overall welfare potential can be achieved? How certain are these findings?

L
Likelihood
M
Potential
M
Certainty

Common slaughter method: no data found yet. High-standard slaughter method: indications that electrical stunning after 30 s DC 9.6 V/cm at 1,000 Hz is most effective for trout in general [38]. Further research needed to confirm for farming conditions.


Side note: Domestication

DOMESTICATION LEVEL 5 [39], fully domesticated.


Side note: Feeding without components of forage fishery

All age classes: WILD: Carnivorous [40] [41] [25] [24]. FARM: No protocol available for feeding without components of forage fishery. Replacement of fish meal and fish oil not reported in literature.

 


Glossary

ADULTS = mature individuals, for details Findings 10.1 Ontogenetic development
ALEVINS = larvae until the end of yolk sac absorption, for details Findings 10.1 Ontogenetic development
ANADROMOUS = migrating from the sea into fresh water to spawn
DOMESTICATION LEVEL 5 = selective breeding programmes are used focusing on specific goals [39]
FARM = setting in farm environment
JUVENILES = fully developed but immature individuals, for details Findings 10.1 Ontogenetic development
SPAWNERS = adults that are kept as broodstock
WILD = setting in the wild


Bibliography

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[27] NOT FOUND
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[30] NOT FOUND
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