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)
Cirrhinus mrigala is – besides Labeo catla and L. rohita – one of the three Indian major carps cultivated widely in Southeast Asian countries. This species can be found in fresh waters of northern India, Bangladesh, Burma, and Pakistan and has been introduced into waters of other parts of India and adjacent countries – including China – and to parts of Asia as well as Europe. Despite that, there is limited information about this species in natural conditions, especially about substrate and aggregation needs. C. mrigala is often raised in polyculture systems with other carps, and structures such as bamboo poles can be used as periphyton substrate in these systems, reducing competition for food between carps with different feeding habits. This species has a narrow range in food variety. As a bottom feeder, complete harvesting of C. mrigala is possible only through draining, and such difficulty makes this species the least preferred one among the three Indian major carps for farmers. Moreover, its entire life cycle is closed in captivity, but apparently it is still necessary to induce the reproduction by hormonal manipulation. Information about adults under farming conditions is scarce, probably because this species is sold before reaching maturity. C. mrigala is mostly sold fresh in local markets, but it is a common practice that fishes are harvested, packed with crushed ice at a ratio of 1:1 in rectangular plastic crates, and transported – sometimes for long distances – to be sold as fresh as possible. Thus, post-harvest processing of this species is almost non-existent. Further research is needed on the stunning and slaughter process, besides the stress response of this species.
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 and high-standard farming conditions. Our conclusion is based on a medium amount of evidence.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?
It is low for minimal farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a medium 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?
It is low for minimal farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a medium amount of evidence.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 and high-standard farming conditions. Our conclusion is based on a medium 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 medium amount of evidence.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?
It is low for minimal farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a medium amount of evidence.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 and high-standard farming conditions. Our conclusion is based on a low amount of evidence.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?
It is low for minimal farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a medium amount of evidence.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.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 4 31, level 5 being fully domesticated.
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)?
All age classes: WILD: detritivorous 1, bottom feeder 1 32 and omnivorous 32. FARM: fish meal may be partly* 5 to mostly* 7 replaced by sustainable sources. LAB: fish oil 33 34 and fish meal may be partly* replaced by sustainable sources, especially when the diet is supplemented with 1,000 phytase activity units/kg 34.
*partly = <51% – mostly = 51-99% – completely = 100%
