Version: B | 1.1 (2022-12-22)
Condensed assessment of the species' likelihood and potential for good fish welfare in aquaculture, based on ethological findings for 10 crucial criteria.
Li = Likelihood that the individuals of the species experience good welfare under minimal farming conditions
Po = Potential of the individuals of the species to experience good welfare under high-standard farming conditions
Ce = Certainty of our findings in Likelihood and Potential
FishEthoScore = Sum of criteria scoring "High" (max. 10)
Over the last ten years the Pangasianodon hypophthalmus has emerged as a new aquaculture whitefish product on the world market. The rapid and dramatic increase in production of the species was essentially due to the development of hormone spawning techniques which have led to mass production capabilities. The few findings available show that P. hypophthalmus tolerate high intensive culture conditions in floating cages, ponds or net pens and reach 1 kg harvest size of within 8-10 months. Nowadays, the semi-intensive conditions represent 56.7%, and the intensive conditions represent 36.7% of total cages. Further research is needed under all 10 reported criteria on both natural behaviour and physiological effects of farming practices in order to provide recommendations for improving fish welfare.
1 Home range
Many species traverse in a limited horizontal space (even if just for a certain period of time per year); the home range may be described as a species' understanding of its environment (i.e., its cognitive map) for the most important resources it needs access to. What is the probability of providing the species' whole home range in captivity?There are unclear findings for minimal farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a medium amount of evidence.
LARVAE: WILD: no data found yet. FARM: hatcheries: 0.2-15 ha, ponds: 0.05-10 ha 1.
JUVENILES: WILD: 0.2-15 km 2. FARM: extensive conditions: <288 m3 3; semi-intensive conditions: 288-720 m3 3; intensive conditions: >720 m3 3.
ADULTS: ➝ JUVENILES.
SPAWNERS: WILD: no data found yet. FARM: spawning ponds: 0.02-3.0 ha 1.
2 Depth range
Given the availability of resources (food, shelter) or the need to avoid predators, species spend their time within a certain depth range. What is the probability of providing the species' whole depth range in captivity?There are unclear findings for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.
Some species undergo seasonal changes of environments for different purposes (feeding, spawning, etc.) and with them, environmental parameters (photoperiod, temperature, salinity) may change, too. What is the probability of providing farming conditions that are compatible with the migrating or habitat-changing behaviour of the species?There are unclear findings for minimal farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a medium amount of evidence.
LARVAE: WILD: drift downstream with the water current 3. FARM: fresh water 3. For details of holding systems ➝ crit. 1 and 2.
JUVENILES: WILD: seasonal variation in the distribution: move upstream October-February and return to the main stream June-August 3. FARM: fresh water 3. Stressed by salinities >10 g/L 5. For details of holding systems ➝ crit. 1 and 2.
ADULTS: WILD: ➝ JUVENILES. FARM: ➝ LARVAE.
SPAWNERS: WILD: spawn upstream at the beginning of the rainy season (June-August) 3. FARM: ➝ LARVAE.
A species reproduces at a certain age, season, and sex ratio and possibly involving courtship rituals. What is the probability of the species reproducing naturally in captivity without manipulation?It is low for minimal farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a low amount of evidence.
Species differ in the way they co-exist with conspecifics or other species from being solitary to aggregating unstructured, casually roaming in shoals or closely coordinating in schools of varying densities. What is the probability of providing farming conditions that are compatible with the aggregation behaviour of the species?There are unclear findings for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.
LARVAE: WILD: no data found yet. FARM: 400-500 IND/m2 till yolk sac absorption 4.
FRY: WILD: no data found yet. FARM: at 0.3-1 g: 400-500 IND/m2, at 14-20 g: 150-200 IND/m2 4.
JUVENILES: WILD: no data found yet. FARM: ponds: 40-60 IND/m2 (yields reach 250-300 tonnes/ha/crop), net cages: 100-150 IND/m3 (yields reach 100-120 kg/m3/crop), net pens: 40-60 IND/m2 (yields reach 300-350 tonnes/ha/crop) 4.
ADULTS: WILD: no data found yet. FARM: ➝ JUVENILES.
SPAWNERS: WILD: no data found yet. FARM: 2-3 kg/m2 1.
There is a range of adverse reactions in species, spanning from being relatively indifferent towards others to defending valuable resources (e.g., food, territory, mates) to actively attacking opponents. What is the probability of the species being non-aggressive and non-territorial in captivity?There are unclear findings for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.
Depending on where in the water column the species lives, it differs in interacting with or relying on various substrates for feeding or covering purposes (e.g., plants, rocks and stones, sand and mud). What is the probability of providing the species' substrate and shelter needs in captivity?There are unclear findings for minimal farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a low amount of evidence.
Eggs: WILD: stick to the vegetation or other types of substrate 3 4. FARM: for details of holding systems ➝ crit. 1 and 2.
LARVAE: WILD: no data found yet. FARM: ➝ Eggs.
JUVENILES: WILD: no data found yet. FARM: ➝ Eggs.
ADULTS: WILD: no data found yet. FARM: ➝ Eggs.
SPAWNERS: WILD: no data found yet. FARM: ➝ Eggs.
Farming involves subjecting the species to diverse procedures (e.g., handling, air exposure, short-term confinement, short-term crowding, transport), sudden parameter changes or repeated disturbances (e.g., husbandry, size-grading). What is the probability of the species not being stressed?There are unclear findings for minimal farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a low amount of evidence.
LARVAE: no data found yet.
JUVENILES: stressed by transport 11. For stress and salinity ➝ crit. 3.
ADULTS: no data found yet.
SPAWNERS: no data found yet.
Deformities that – in contrast to diseases – are commonly irreversible may indicate sub-optimal rearing conditions (e.g., mechanical stress during hatching and rearing, environmental factors unless mentioned in crit. 3, aquatic pollutants, nutritional deficiencies) or a general incompatibility of the species with being farmed. What is the probability of the species being malformed rarely?There are no findings for minimal and high-standard farming conditions.
The cornerstone for a humane treatment is that slaughter a) immediately follows stunning (i.e., while the individual is unconscious), b) happens according to a clear and reproducible set of instructions verified under farming conditions, and c) avoids pain, suffering, and distress. What is the probability of the species being slaughtered according to a humane slaughter protocol?It is low for minimal farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a low amount of evidence.
Side note: Domestication
Teletchea and Fontaine introduced 5 domestication levels illustrating how far species are from having their life cycle closed in captivity without wild input, how long they have been reared in captivity, and whether breeding programmes are in place. What is the species’ domestication level?
DOMESTICATION LEVEL 3 13, level 5 being fully domesticated. Cultured since 1960 3.
Side note: Forage fish in the feed
450-1,000 milliard wild-caught fishes end up being processed into fish meal and fish oil each year which contributes to overfishing and represents enormous suffering. There is a broad range of feeding types within species reared in captivity. To what degree may fish meal and fish oil based on forage fish be replaced by non-forage fishery components (e.g., poultry blood meal) or sustainable sources (e.g., soybean cake)?
WILD: omnivorous 14 4. FARM: for JUVENILES, fish meal and fish oil may be mostly* replaced 15 16 17, but no data found yet for LARVAE and ADULTS.
*partly = <51% – mostly = 51-99% – completely = 100%
DOMESTICATION LEVEL 3 = entire life cycle closed in captivity with wild inputs 13
FARM = setting in farming environment or under conditions simulating farming environment in terms of size of facility or number of individuals
FRY = larvae from external feeding on, for details ➝ Findings 10.1 Ontogenetic development
IND = individuals
JUVENILES = fully developed but immature individuals, for details ➝ Findings 10.1 Ontogenetic development
LAB = setting in laboratory environment
LARVAE = hatching to mouth opening, for details ➝ Findings 10.1 Ontogenetic development
POTAMODROMOUS = migrating within fresh water
SPAWNERS = adults during the spawning season; in farms: adults that are kept as broodstock
WILD = setting in the wild
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