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)
Hypophthalmichthys nobilis is one of the four Chinese major carps, together with H. molitrix, Ctenopharyngodon idella and Mylopharyngodon piceus. H. nobilis is a native freshwater fish from lakes, rivers, and reservoirs of south and central China, but has already been introduced in many countries. This eurythermic carp dwells in the upper layer of the water column, being considered a planktivorous fish – especially feeding on zooplankton – but it can also feed on detritus and BENTHIC organisms on the bottom opportunistically. It is one important aquaculture species that has been farmed for more than a thousand years and, together with H. molitrix, is one of the most intensively cultured fish species in Asia. H. nobilis is frequently used as a filter-feeding fish in polyculture ponds in China, stocked for water quality improvement and as a biocontrol method for phytoplankton. Besides ponds, this carp is also commonly raised in pens, cages or reservoirs with other carps or other fish species as Ictalurus punctatus and Polyodon spathula. A competition for food may be expected with Labeo catla or with other FISHES with similar feeding habits in such polycultures. It is a fast growing fish that can be sold before reaching maturity. In natural conditions, this carp migrates to the upper reaches of rivers to spawn during early summer, with rising water level as the essential stimulus for this. Despite its commercial importance, most wild information is still missing for this species. After being harvested, very little handling and processing is used with this fish, as it is usually consumed fresh, mainly locally. Further research about the slaughtering process is needed as well as about substrate use, stress response, and malformations under farming conditions.
Note: The age class "Adults" for farming conditions refers to large juveniles and young adults due to farmers estimating age class by size rather than by maturity status. Also, “Adults” refers to individuals to become spawners or for algae control, as the literature does not always specify.
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?
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.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 high 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 no findings for minimal and high-standard farming conditions.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 unclear findings for minimal and high-standard farming conditions. Our conclusion is based on a low 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 5 38, 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: planktonic feeder, mainly on zooplankton 3 25 26 23, but can also eat detritus 21-22 23. FARM: no additional feed in polyculture or extensive culture, but applied fertiliser (animal manure or plant wastes) increases zooplankton mass 25. Zooplankton feeder 25 17, but can also feed on phytoplankton 17, especially when cultured in cages 4 5, probably by filter-feeding 5. All age classes accept artificial feed (e.g., by-products from grain processing, trout pellets) 25 4.
