Version: B | 1.1 (2022-06-23)
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)
Scophthalmus maximus is a left-eyed flatfish of the family Scophtalmidae, a DEMERSAL predator, mainly in the area from the Black and Mediterranean Sea to the North Atlantic and the Baltic Sea. S. maximus is a relatively scarce “gourmet” fish and is highly prized in the market. S. maximus farming started in the 1970s in the United Kingdom and subsequently established in France, Spain, and Portugal. In the beginning, the production was restricted by a limited juvenile supply, but technological developments since 2007 have led to an expansion in production. Only few findings are available on both natural behaviour and physiological effects of farming practices. They clearly demonstrate the importance of sandy substrate and low stocking densities to improve 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?It is low for minimal and high-standard farming conditions. Our conclusion is based on a high amount of evidence.
ADULTS: ➝ JUVENILES.
SPAWNERS: WILD: no data found yet. FARM: tanks: 20-40 m3 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?It is low for minimal and 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.
ADULTS: ➝ JUVENILES.
SPAWNERS: WILD: migrations from deeper to shallower areas to spawn 2. 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 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: semi-intensive conditions: 2-5 IND/L; intensive conditions: 15-20 IND/L 1.
ADULTS: WILD and FARM: no data found yet.
SPAWNERS: WILD and FARM: no data found yet.
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 farming conditions. It is medium for 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 medium for high-standard farming conditions. Our conclusion is based on a medium amount of evidence.
Eggs and LARVAE: WILD: no data found yet. FARM: for details of holding systems ➝ crit. 1.
ADULTS: ➝ JUVENILES.
SPAWNERS: WILD: no data found yet. FARM: for details of holding systems ➝ crit. 1.
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 medium 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 medium 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 37, level 5 being fully domesticated.
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: carnivorous 5. FARM: for JUVENILES and ADULTS, fish meal and fish oil may be partly* replaced by non-forage fishery components 38 39 40 41. For LARVAE and SPAWNERS, no data found yet on replacement of fish meal and fish oil.
*partly = <51% – mostly = 51-99% – completely = 100%
12L = 12 h light
20L = 20 h light
4D = 4 h dark
ADULTS = mature individuals, for details ➝ Findings 10.1 Ontogenetic development
DEMERSAL = living and feeding on or near the bottom of a body of water, mostly benthopelagic, some benthic
DOMESTICATION LEVEL 3 = entire life cycle closed in captivity with wild inputs 37
FARM = setting in farming environment or under conditions simulating farming environment in terms of size of facility or number of individuals
IND = individuals
JUVENILES = fully developed but immature individuals, for details ➝ Findings 10.1 Ontogenetic development
LARVAE = hatching to mouth opening, for details ➝ Findings 10.1 Ontogenetic development
OCEANODROMOUS = living and migrating in the sea
PHOTOPERIOD = duration of daylight
SPAWNERS = adults during the spawning season; in farms: adults that are kept as broodstock
WILD = setting in the wild
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