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)
Carassius carassius is a freshwater fish that inhabits ponds, lakes, rivers, and reservoirs in several countries in Asia and Europe. This carp appears in IUCN Red List with a substantial decline in most of its native range in Europe. It is found in rich vegetation in slow-moving waters with sand and gravel and can tolerate a wide range of environmental conditions – including anoxia – but usually does not occur in waters with rich ichthyofauna. This carp, which migrates in fresh water to spawn when the temperature is warmer, is considered a relatively inactive fish. Aquaculture of C. carassius was limited to China and Japan until the 1960s and then gradually expanded to many other countries. It is considered an omnivore fish with relatively slow growth that explores the water column, especially dwelling in the bottom layer, thus being difficult to harvest. Despite that, it occupies a high position among all cultured freshwater fishes worldwide, being reared also for conservation programmes. C. carassius is frequently cultured in earthen ponds, also in pens and rice paddies. Polycultures with other carps is common. This fish is usually sold live or fresh in local markets, and this can happen before it reaches maturity. Further studies about wild information, especially about migration, aggregation, and aggression of this species, are needed. Considering farming conditions, the need for future research focused on depth range, substrate availability, stress response, and stunning and slaughter processes is highlighted. Moreover, as most available information about farms are from sources focused on conservation purposes, more research about production conditions are still needed.
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 low 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 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?
It is low for minimal farming conditions. It is high for high-standard farming conditions. Our conclusion is based on a low 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 low 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?
It is low for minimal and high-standard farming conditions. Our conclusion is based on a medium 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 high 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?
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.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 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 36, 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: omnivorous 6 17 14, LARVAE and FRY feeding on zooplankton 6 3, older age classes on plankton, BENTHIC invertebrates 6 3 14, plant materials, and detritus 6 14. FARM: feed usually consists of by-products from grain processing and oil extraction with <10% fish meal, but no fish meal is necessary when C. carassius is kept as a secondary species in polycultures 6.
