Reviewer: Ana Roque
Editor: Billo Heinzpeter Studer

Initial release: 2013-12-15
Version information:

• Appearance: B
• Last minor update: 2022-01-22

Cite as: »Volstorf, Jenny. 2022. Sparus aurata (Dossier). In: fair-fish database, ed. fair-fish. World Wide Web electronic publication. Version B | 1.1. https://fair-fish-database.net.«

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• Unpredictable influence:
  • Observations WILD: 1.
• Competition:
  • Observations WILD: competition with native species 2.
  • FARM: ADULTS in offshore cages showed signs of spawning and were observed to release gametes into open sea, increasing competition with native conspecifics 3.
  • FARM/WILD: ADULTS released from a fish farm in a simulated escape used the same habitat and caught the same prey as native conspecifics 4.
• Disease transmission: no data found yet.
• Interbreeding:
  • Observations WILD: breeding with native populations 5 6 7 could reduce fitness and productivity in hybrids (because of the smaller genetic variability in farmed individuals) and eventually survival 8.

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• FARM: majority of released ADULTS were found on seagrass bottom, some also on 1) fine sandy bottoms, 2) a mixture of seaweed, seagrass, sandy, and rocky bottom, and 3) detritus and gravel bottoms 4.

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• For feeding → 9.
• For daily rhythm → 10.
• For migration and site fidelity → 10.
• For aggregating → 11 12 10 13 9.

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• For daily rhythm → 14 15 12.
• For swimming → 16 17.
• For acoustic communication → 18 19.
• For dominance and subordination → 20 21 22.
• For aggression → 23 21 22 24.
• For coping styles → 24.

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• Observations eastern Atlantic: 11 26. Bay of Cadiz, Atlantic, southern Spanish coast 27, Bay of Machico and Ribeira Brava, Atlantic, Madeira 2, Ria Formosa, southern Portuguese coast 10, Wexford Harbour, Irish Sea basin, Ireland 28.
• Observations Mediterranean: Bardawil lagoon, Mediterranean, Egypt 29, Beymelek lagoon, Mediterranean, southwestern Turkish coast 30, Gulf of Lions, Mediterranean, France 31 32, Mar Menor, Mediterranean, southern Spanish coast 33, Mellah lagoon, Mediterranean, Algeria 34, Messolonghi-Etoliko lagoon, Mediterranean 35, Mirna Estuary, Adriatic Sea, Croatia 36, Gulf of Olbia, Mediterranean, Sardinia 37, two lagoons on Thyrrenian coast, Mediterranean, Italy 38, Venice lagoon, northern Adriatic Sea, Italy 39.

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• Observations eastern Atlantic: Atlantic ocean, southern Madeiran coast 2.
• Observations Pacific ocean: Gulf of California, Mexico 1.

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• Plants: has been reported from seagrass beds:
  • Observations WILD: 11, Messolonghi-Etoliko lagoon, Mediterranean 35.
  • WILD: preferred seagrass over 1) patches where seagrass had been removed or 2) unvegetated coarse-sandy substrate 37.
• Rocks and stones: has been reported from rocky bottoms:
  • Observations WILD: Bay of Machico and Ribeira Brava, Atlantic, Madeira 2.
  • LAB: JUVENILES touched tank bottom with open mouth and closed mouth afterwards, grabbed or chewed gravel before ejecting it 40.
• Sand and mud: has been reported from salt marsh creeks and muddy bottoms:
  • Observations salt marsh creeks WILD: Bay of Cadiz, Atlantic, southern Spanish coast 27, Venice lagoon, northern Adriatic Sea, Italy 39, Ria Formosa, southern Portuguese coast 10, Mar Menor, Mediterranean, southern Spanish coast 33.
  • Observations muddy bottoms WILD: Venice lagoon, northern Adriatic Sea, Italy 39, Ria Formosa, southern Portuguese coast 10, Wexford Harbour, Irish Sea basin, Ireland 28, Beymelek lagoon, Mediterranean, southwestern Turkish coast 30, Mar Menor, Mediterranean, southern Spanish coast 33.
• Other substrate: no data found yet.

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• Plants: no data found yet.
• Rocks and stones: no data found yet.
• Sand and mud:
  • WILD: ADULTS might bury themselves in sand during night 10.
• Other cover: no data found yet.

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• Observations: 3.7±0.0 se 41.

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• Mainly carnivorous D1. The fishery that provides fish meal and fish oil has two major impacts:
  1. It contributes considerably to overfishing, as it accounts for 1/4 42 or even 1/3 43 of the world catch volume.
  2. It challenges animal welfare, because in the face of 450-1,000 MILLIARD wild fishes caught worldwide each year to be processed into fish meal or fish oil 44, the individual fish gets overlooked and, thus, suffering increases at rearing, live marketing, and slaughtering levels 45.

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• Food items: carnivorous:
  • Observations WILD, JUVENILES-ADULTS: 11.
• Food items and habitat: no data found yet.
• Food items and life stages: crustacean larvae or Nematoda as JUVENILES, Bivalvia and Gastropoda as ADULTS:
  • WILD: JUVENILES <30 mm mainly: Cirripedia larvae 48 or Nematoda 38, to a lesser extent: Amphipodia, Calanoida, Copepoda, Cyclopoida, Harapacticoida, and Polychaeta, only seldomly: Algae, Chironomidae larvae, Cladocera, Crustacea larvae, Echinodermata larvae, fish larvae, microalgae, Mysidacea, Ostracoda, plant detritus, and Rotatoria 48 38.
  • WILD: JUVENILES <85 mm: Amphipoda, Mysidacea, plant detritus, and Polychaeta, to a lesser extent: Fish eggs and larvae and Harpacticoida, only seldomly: Anthozoa, Bivalvia, Calanoida, Copepoda, Cumacea, Cyclopoida, Gastropoda, Isopoda, microalgae, Nematoda, Ostracoda, and Ruppida maritime 48 38.
  • WILD: JUVENILES >70 mm mainly: Bivalvia and Gastropoda, to a lesser extent: Amphipoda, Carcinus aestuarii, Cumacea, Cymodocea nodosa, Irregularia, Isopoda, Ostracoda, Tanaidacea, and Polychaeta, and only seldomly: algae, Bryozoa, Crustacea, Decapoda, Mysidacea, Nematoda, pisces, Ruppia maritima, and Urochordata 49 38 4.
• Food preference: no data found yet.
• Food partitioning: no data found yet.
• Prey density: no data found yet.
• Prey size selectivity: no data found yet.
• Particle size:
  • LAB: FRY <7 mm differed in food preferences between live and microencapsulated food, large and small prey. With microencapsulated food, they preferred smaller size compared to live food and soft shell 50.

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• LAB: feeding FRY rotifers enriched with arachidonic acid (long-chain n-6 poly unsaturated fatty acid) prior to stress increased stress tolerance and survival 51.
• LAB: supplementation with the probiotic Pdp11 (bacteria Shewanella putrefaciens) improved stress tolerance in JUVENILES to high stocking density of 30 kg/m³ by attenuating the increase in the plasma cortisol level 52.
• LAB: a diet lacking vitamin E decreased stress resistance and survival in JUVENILES 53.

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• WILD: individuals grabbed prey by partially burying their heads into the substrate 9.

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• FARM: in semi-submerged cages at stocking density of 3 kg/m³, individuals swam predominantly horizontally, towards the bottom, and with frequent turns, resembling random searching for food in the wild 54.
• LAB: feeding at random times results in arrhythmic pattern and constantly high frequency of JUVENILES and ADULTS locomotor activity 55 56 as well as high plasma cortisol levels indicating stress in ADULTS 56. Also, JUVENILES had a twofold higher level of blood glucose after feeding than scheduled-fed JUVENILES, suggesting poor regulation of blood glucose 55. Scheduled feeding, on the other hand, increased locomotor activity in JUVENILES 55 and ADULTS 56 and amylase and alkaline protease in ADULTS 56 some hours before mealtime, thereby anticipating feeding and optimizing food intake and nutrient use.

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• LAB, JUVENILES: high feed delivery rate increased the chewing rate, but relatively higher waste from chewing resulted in a worse, i.e. higher, FOOD CONVERSION RATIO than a slow delivery rate. To determine a proper feed delivery rate, pellet sinking rate and pellet size has to be taken into account and whether individuals may collect feed from the bottom of a tank or it is lost outside a sea cage 57.

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• LAB, JUVENILES: rations of 2 and 2.5% body weight increased swimming speed and frequency of sharper angled turns – indicating higher competition – during meals compared with higher rations. Ration of 3.5% body weight resulted in lower feeding intensity, higher waste, and therefore lower feeding efficiency. Ration of 3% body weight benefited growth compared to lower rations and reduced waste compared to higher rations 57.

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• LAB: competition for food works as a social mechanism regulating growth in captivity with ADULTS 20 and JUVENILES 21: when food was limited and defensible, dominance hierarchies set in, ADULTS grew better when surrounded by smaller ADULTS than when surrounded by larger ADULTS 20. Dominant JUVENILES had a higher relative specific growth rate 21 and a lower FOOD CONVERSION RATIO 22 than subordinate JUVENILES. Subordinate JUVENILES had lower plasma cortisol levels 58 and experienced immunosuppression 22.
• LAB: when food was unlimited, ADULTS surrounded by larger companions grew faster than when surrounded by smaller companions, probably to level out size differences in fish groups and avoid standing out in the eyes of predators 20.

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• Feeding and low temperatures: ceases ingestion below 12 °C:
  • WILD: JUVENILES-ADULTS decreased ingestion below 16 °C 49 and ceased ingestion below 12 °C 34.
  • LAB: ceased ingestion below 12 °C 59 60.
• Feedings and high temperatures:
  • WILD: JUVENILES ceased ingestion above 30 °C 61.

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• Daily rhythm:
  • LAB, ADULTS: in the cold season (<20 °C, 9-11 h PHOTOPERIOD), peak around dusk, when temperatures increase 14 15. In the warm season (>20 °C, 12-14 h PHOTOPERIOD), either peaks after dawn and before dusk 14 or mid-day peak 15.
• Nocturnal activity and aggregation type:
  • WILD: larger ADULTS more active during night, probably because isolated. Smaller ADULTS more active during day, probably in a school 10.
  • LAB: ADULTS did not completely abandon swimming during resting periods, but were measurably active. In a school with 600 others, higher swimming activity during the day than at night, whereas in a group with three others or isolated, swimming activity highest at night 12.
• Phototaxis: photonegative:
  • LAB: newly hatched LARVAE benefited in first 60+ hours until mouth opening from dark surrounding: slower absorption of oil globule and yolk sac, higher survival rate without illumination in contrast to 24 hours 450 lux (results for 24 hours 30 lux in between), probably because LARVAE do not move as much and do not spend as much energy 62.
• For daily rhythm and depth → D6.

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• LAB: LARVAE survived with higher probability and grew bigger under a PHOTOPERIOD of 24 h than under 12 h 63.
• LAB: alteration of light/dark – not of light intensity – seems decisive to affect ADULTS 12, but JUVENILES grew better under 200 lux than 80 lux 64.
• LAB: keeping JUVENILES-ADULTS under a manipulated PHOTOPERIOD matching the longest day of the year increased growth 65.

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• LAB, JUVENILES: red light slightly increased brain dopaminergic activity, indicating stress, and slightly decreased growth rate and food efficiency 66.

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• Standard temperature range:
  • Observations WILD: 8-30 °C (ADULTS leave October-November): two lagoons on Thyrrenian coast, Mediterranean, Italy 38, 11-30 °C: Mellah lagoon, Mediterranean, Algeria 34 34; 2-30 °C (JUVENILES leave November-February): Gulf of Lions, Mediterranean, France 32, 13-30 °C: Beymelek lagoon, Mediterranean, southwestern Turkish coast 30, 11.2-30 °C: Mar Menor, Mediterranean, Southern Spanish coast 33.
• Temperature preference: no data found yet.
• Migration temperature:
  • Spring through autumn, FRY and ADULTS migrate to coastal lagoons when temperatures are 11-30 °C and leave to the open sea when temperatures are below that range → Standard temperature range, D7.
• For temperature and swimming speed → D8.

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• Lower and upper lethal limits:
  • LAB: LARVAE reared at 16-22 °C were healthy and survived but showed abnormalities and short survival below and above this temperature range. At 12 °C and 30 °C, LARVAE did not hatch at all 67.
  • LAB: survival decreased the longer LARVAE were reared in 24.5 °C water instead of 19 °C 23.
• Low temperatures and winter syndrome:
  • FARM: of JUVENILES-ADULTS reared in the northern Mediterranean sea, some developed “winter syndrome” or “winter disease”, a pathology including lethargy, abnormal swimming, starvation, immunosuppression, and ultimately resulting in death 68 69 70.
  • The disease is multifactorial, though, low temperatures alone may not be sufficient:
    • Observations JUVENILES: FARM 69. LAB: 71 60.

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• Temperature must exceed: no data found yet.
• Temperature must not go beyond: no data found yet.
• Optimal temperature for growth:
  • WILD/LAB, JUVENILES-ADULTS: better growth in Atlantic compared to Mediterranean due to less fluctuations in temperatures in the first 72.
  • FARM: 25 °C 73↶61.
• For temperature and feeding → D9.

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• Salinity tolerance:
  • Natural and introduced distribution in seawater D10 D11, but adjusts to brackish water as well D7 D12.
• Standard salinity range: no data found yet.

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• Lower and upper lethal limits:
  • LAB: adaptability to different salinities increases with age. More than half of LARVAE three days post hatching survived in salinities from 10-25.5‰, whereas from 30 days post hatching on, LARVAE survived salinities of 5.1-45.1‰ 74.
• Salinity change and stress: no data found yet.

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• LAB: 3.5-fold higher survival, better swim bladder inflation, and higher weight of 30 day old FRY in 25‰ salinity than in 40‰ salinity 75.
• LAB: higher growth of FRY under 18-28‰ than 8‰ or 38‰. FRY could adapt to larger range when gradually rather than abruptly introduced to certain salinity levels 76.
• LAB: JUVENILES, acclimated to brackish water with a salinity of 12‰, grew better than under 6‰ or 38‰ salinities 77.

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• Swimming type: carangiform:
  • Observations FARM: 78.
• Ontogenesis of swimming behaviour:
  • LAB, JUVENILES: changes with developmental stage and environment: streamline body shape at early metamorphosis (<20 mm) more appropriate for fast swimming in pelagic larval niche; deep and relatively laterally compressed body shape at later metamorphosis (>25 mm) more suited for manoeuvrability in demersal juvenile environment 17.

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• Absolute swimming speed:
  • LAB, JUVENILES: the absolute critical swimming speed increases with body length 16.
• Relative swimming speed:
  • LAB, JUVENILES: the relative critical swimming speed decreases with body length 16 17.
  • LAB: spontaneously swimming ADULTS do not swim faster than 0.5 body lengths/s, although the size of the respirometer may have an influence on the velocity. When forced to swim, ADULTS reach 3.5 body lengths/s 79.
• Swimming speed and temperature:
  • LAB, JUVENILES: bell-shaped relationship between speed and temperature with the maximum relative critical swimming speed at 25 °C 17.

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• WILD: ADULTS released at capture site moved little, whereas those released 4 km away moved back to the capture site 10.
• WILD: otoliths pointed to use of various lagoons 32.
• FARM: majority of ADULTS stayed within radius of 800 m around release site for first five days. Food pellets in stomachs even two months after release indicated site fidelity in some ADULTS 4.

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• Depth range in the wild:
  • Observations ≤3 m WILD: 0-2 m: Gulf of Olbia, Mediterranean, Sardinia 37, 0.9-3 m: two lagoons on Thyrrenian coast, Mediterranean, Italy 38, 1±0.3 m: Venice lagoon, northern Adriatic Sea, Italy 39, average 0.8 m: Messolonghi-Etoliko lagoon, Mediterranean, Greece 61, 0.5-3 m: Bardawil lagoon, Mediterranean, Egypt 29.
  • Observations ≤5 m WILD: average 3.5 m: Mellah lagoon, Mediterranean, Algeria 34, 0.8-4 m: Gulf of Lions, Mediterranean, France 32, 0.5-5 m: Beymelek lagoon, Mediterranean, southwestern Turkish coast 30, average 3.6 m: Mar Menor, Mediterranean, southern Spanish coast 33.
  • Observations ≤30 m WILD: <30 m 11; 15-30 m: Mirna Estuary, Adriatic Sea, Croatia 36, 10-12 m: Bay of Machico and Ribeira Brava, Atlantic, Madeira 2.
  • WILD: seldomly until 150 m, depending on geographical region 11 → D10 D11.
• Depth in cages or tanks: no data found yet.
• Depth preference: no data found yet.
• Depth and daily rhythm:
  • FARM, ADULTS: after planned release, greater swimming depth during morning hours (7-17 m) compared to night time (1-5 m), but might be due to farm feeding at 6 a.m.. Escapees could have fed on waste feed beneath cages 4.
• Depth and low temperatures: no data found yet.
• Depth and high temperatures: no data found yet.
• Position in habitat and age: no data found yet.
• Depth and light intensity: no data found yet.
• Depth and noise: no data found yet.
• Depth and threat: no data found yet.

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• LARVAE hatch in the open sea. FRY move to coastal lagoons or estuaries where they remain as JUVENILES and ADULTS most of the year D12:
  • Observations lagoon abundance WILD, JUVENILES-ADULTS: 48 34 80 61 32.
• JUVENILES-ADULTS return to the sea in winter, probably due to sensitivity to temperatures D13.

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• Observations time from fertilisation until hatching: no data found yet.
• Observations size: ca 1 mm 81, 0.84-0.99 mm 82, FARM: 0.94-0.98 mm 83.
• Observations weight: no data found yet.

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• Observations age at yolk sac absorption and mouth opening FARM: day 4 84.
• Observations age at yolk sac absorption and mouth opening LAB: day 2-5 85, day 4-5 86, day 3 62, day 4 87, day 2-3 88.
• Development goes alongside pigmentation of the eye (FARM 84), formation of the digestive tract (FARM 84​), inflation of the swim bladder (LAB 88), and improvement of swimming abilities (LAB 89).
• Observations TOTAL LENGTH LAB: 2.5 mm 89, 2.7 mm 62.
• Observations weight: no data found yet.

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• Observations age at beginning of exogenous feeding LAB: day 4-6 89, day 5 88.
• Observations age and TOTAL LENGTH LAB: 5.5-7.5 mm, day 28: notochord started to flex; 10.5 mm, day 40: fin ray formation; 13 mm, day 70: body pigmentation started to show; 25 mm, day 100: squamation started; 25-71.5 mm, day 100-160: scale cover complete 88.
• Observations weight: no data found yet.

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• Observations age: → D14.
• Observations age, TOTAL LENGTH, and weight WILD: 17-25 cm: two lagoons, Mediterranean, western Italian coast 80, 0-1 year, 2-25.2 cm: Gulf of Lions, Mediterranean, France 31, 11.8-20.1 cm: Gulf of Lions, Mediterranean, France 32, 10.6-26 cm, 0.02-0.3 kg: Beymelek lagoon, Mediterranean, southwestern Turkish coast 30.
• Sexual maturity for 50% of JUVENILES: first or second year of life, 20.5-32.6 cm:
  • Observations age and TOTAL LENGTH WILD: end of year 1, 27.6±1.34 cm: Banyuls-sur-Mer, Mediterranean, France 91, 18 months, 32.6 cm: Mellah lagoon, Mediterranean, Algeria 34,1.67 years, 25.8 cm: Port Said, southeastern Mediterranean, Egypt 92, 0.47 years, 20.5 cm for males and 0.83 years, 22.8 cm for females: Bardawil lagoon, Mediterranean, Egypt 29, 24 cm: Gulf of Lions, Mediterranean, France 31.

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• Maturation and PHOTOPERIOD manipulation:
  • LAB: keeping JUVENILES under a manipulated PHOTOPERIOD matching the longest day of the year postponed gonadal development and reproduction 93 65 and increased growth 65.
• Maturation and temperature manipulation: no data found yet.

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• Observations age, TOTAL LENGTH, and weight WILD: 0-1 years, 20.5-32.6 cm D15, 70 cm 11, 5 years and average 46.7 cm: Mediterranean, off Alexandrian coast, Egypt 94, 68 cm: Atlantic, off Sines and Sagres coast, Portugal 95, 12 years, 57.5 cm, 2.5 kg: Mirna estuary, northern Adriatic, Croatia 36, 44.4 cm: Ria Formosa, Algarve, Portugal 49, 3-7 years, average 44.2-54.9 cm, 1.5-2 kg, maximum 61 cm, 3.4 kg: Mellah lagoon, Algeria 34, 6 years, 50.8 cm: Gulf of Lions, northwest Mediterranean, France 31, 4 years, 26.3-39 cm: Gulf of Lions, northwest Mediterranean, France 32.

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• Protandric hermaphrodite: JUVENILES develop first into males at 2-3 years, 10-30 cm, then turn into females at 2-3 years, 15-45 cm:
  • Observations males: 2 years, 20-30 cm 82, 2-3 years, 20-30 cm 9; WILD: 22 cm: Mellah lagoon, Mediterranean, Algeria 34, 10-17 cm: Port Said, southeastern Mediterranean, Egypt 92, 22 cm: Gulf of Lions, Mediterranean, France 31.
  • Observations females: 2-3 years 11, 2-3 years or 33-40 cm 82, 35-40 cm 9; WILD: 43-45 cm: Mellah lagoon, Mediterranean, Algeria 34, 15-27 cm: Port Said, southeastern Mediterranean, Egypt 92, 28 cm: Gulf of Lions, Mediterranean, France 31.
• Ambisexual gonad = can develop into testis or ovary (ovotestis) 91.
• Terminal sex: female sex is terminal sex: males can continue as males or convert to females, females cannot revert (e.g. 96).
• Conversion from male to female:
  • In males, after spawning → D16, ca May-August, decreasing testicular and increasing ovarian portion form ambisexual gonad. The testicular portion remains latent, the ovarian portion grows, oogonia differentiate follicles 97.
  • At ca September+, gonads recognizably develop into ovaries (future females) or testes (future males) and grow 97. For more details → 96 91.

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• Sex and temperature manipulation: no data found yet.
• Sex and hormone treatment: no data found yet.
• Sex and genetic manipulation: no data found yet.
• Sex and other manipulation: for sex and manipulation and male:female ratio → D17.

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• Growth: halts during annulus formation 94 which takes place November-March, as revealed by scale readings and otolith investigations:
  • Observations scale readings WILD: December-February 94, November 34.
  • Observations otolith investigations WILD: January 92, November-March 31, December 32.
• Natural growth rate: 100-200 g per year depending on environmental conditions:
  • Observations WILD: 94 36 34 92 30.
• Growth heritability:
  • LAB: weight and length are heritable 98.

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• Growth and aquaculture system:
  • FARM: muscle tissue from JUVENILES reared in offshore cages was comparable to that from wild-caught individuals 99.
• Growth and music:
  • LAB, JUVENILES: better growth when exposed to music than in a control environment without music 64.

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• WILD/FARM: of wild-caught LARVAE, 31.9% with malformations (mild to serious); of hatchery-reared, 98.3-100%. Of wild-caught, 4.2% with at least one serious anomaly (kyphosis, lordosis, vertebrae fusion or deformation, splanchnocranium deformities); of hatchery-reared, 47.9-100% 100.
• WILD/FARM: in 71-86.2% of hatchery-reared JUVENILES (intensive conditions), lateral line differed from that of wild-caught JUVENILES 101.
• FARM: 5.4% of LARVAE developed body deformations: large head, compressed body, lordosis, kyphosis, kypholordosis, disoriented rays, frayed gills, notch in opercular cover, tumour in swim bladder; another 2.4% with mild kypholordosis 102.
• FARM: 27% of LARVAE born with serious anomalies like axial deviations (e.g., lordosis), operculum atrophies, or cranial abnormalities 85.
• FARM: of intensively reared LARVAE, 15.6-16.7% with opercular complex deformity 103.
• FARM: of intensively reared LARVAE, 10% grew to ADULTS with 39 types of deformations: 17 affecting spinal column (lordosis, vertebral fusion), maxilar, operculum, jaw, and dorsal fin, 22 being different combinations of at least two of the above 104.
• FARM: of LARVAE, 5.6% with lordosis, 7.9% with lacking operculum 105.
• LAB: of 31 JUVENILES and ADULTS, 14 with lordosis (45.2%) 106. More recent research needed to see if deformities continue to be a current issue.

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• Bacteria:
  • LAB: higher frequency of bacteria detection in lordotic compared to normal individuals in swim bladder (50% versus 17.6%), brain (14.3% versus 0%), vertebral column (7.1% versus 0%), and liver (7.1% versus 0%). Authors suspect higher susceptibility to infection is not cause for but consequence of increased stress from abnormality 106.
• Uninflated swim bladder:
  • LAB: among FRY with functional swim bladder no observed lordosis over 2 months. Of FRY without swim bladder, majority developed lordosis from ca 0.8 g on: more incidences of lordosis (90% versus 20%) under forced swimming compared to static water (20 cm/s water current versus <0.5 cm/s). Steeper lordotic angle (70° versus 30°) under forced swimming compared to static water. Deformities mostly in spine region affected by muscle pressure during swimming. Although swim bladder secondarily inflated in 100% of deformed individuals at 54 g body weight the latest, this did not correct deformity. Lordotic angle increased as body weight increased 107.
• Missing natural selection in aquaculture environment:
  • LAB: suspected 85.
• Physical stress:
  • WILD/FARM: differing lateral line of hatchery-reared JUVENILES compared to wild-caught JUVENILES not due to osteological malformations of spinal chord (skoliosis, lordosis, kyphosis) 101.
  • WILD/LAB: increase in frequency of serious anomalies from semi-intensive (47.9-54.5%) to intensive culture (69.2-100%) 100.
  • LAB: opercular complex deformity initially observed at 23 mm (not before), increasing frequency until day 65, maintaining frequency until day 100. Hint of physical stress as cause, because ossification of bones begins at size of around 6 mm. Other factors (nutritional, metabolic, behavioural) possible 103.
• Inheritance:
  • LAB: high frequency (6.5%) of triple column abnormality (lordosis-scoliosis-kyphosis) in one family hints on polygenic origin 104. Weak tendency of heritability for lacking operculum but not for lordosis – authors suggest to look for external parameters in aquaculture for explanation 105.

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• Nest building and substrate: no data found yet.
• Nest building and water velocity: no data found yet.
• Nest building and water depth: no data found yet.
• Nest building: no data found yet.
• For breeding type → D12.

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• Attraction and body colour:
  • LAB, ADULTS: beginning in July, the pigmentation intensity of the yellow belly strip, orange operculum spot, and yellow marking behind the pelvic fin increased every month until October. Whereas the colours faded for males after October, they remained unchanged for females through spawning. In general, females have more intense orange operculum colour and yellow belly strip colour than males. The role of the colouring in courtship or attraction is unclear 108.

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• Spawning substrate: no data found yet.
• Spawning season: October-March, but can extend to May or June depending on environmental factors 81:
  • Observations WILD: October-December 11, November-December 91, December 34, November-February, peaking in December 92.
  • Observations FARM: until May 81, until June 83.
  • Observations LAB: December-January 109, December-March 97, February 110, peaking in February 108.
• Spawning (day)time: no data found yet.
• Spawning temperature: for lower and upper lethal limit for hatching → D24.
• Spawning salinity: seawater → D7.
• Spawning and water velocity: no data found yet.
• Spawning depth: no data found yet.
• Spawning density: no data found yet.

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• Male:female ratio resulting in spawning: no data found yet.
• Composition of broodstock:
  • FARM: in small groups of ADULTS, grouped females fluctuated less in the number of eggs than single females, and more eggs were fertilised by the males 111.
  • FARM, ADULTS: females spawn in large groups or schools, so minimally 5-7 females should be kept together to reduce stress and induce spawning in artificial environments 112↶83.
  • Adding young individuals caused older males to develop into females; adding females caused older males to stay males 81.
  • LAB, ADULTS: when spermiating males were removed from small groups of mixed sex shortly before spawning, the number of released eggs decreased, vitellogenic oocytes underwent atresia, and ovulatory oocytes degenerated. Separation from the females did not affect spermiation by the males, though 113.

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• Spawning sequence: no data found yet.
• Spawning duration:
  • WILD/LAB, ADULTS: females injected with human chorionic gonadotropic spawned 10-30 min 114. For frequency → D25.

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• Number of spawns:
  • WILD/LAB, ADULTS: wild-caught females stocked individually with two mature males and injected with low (100-400 i.u./kg body weigth) or high dose (up to 1,200 i.u./kg body weigth) dose of human chorionic gonadotropin. More females spawned four successive days or more when injected low dose of human chorionic gonadotropic than control group (17/40 versus 5/50); 14 low-dose females spawned on 1-3 days; nine low-dose females and 45 control females did not spawn. Spawning females continued spawning every 24 h over 4-100 days 114.
• Fecundity per spawn:
  • Observations absolute fecundity WILD, ADULTS: 20,000-80,000 eggs per day 82.
  • WILD/LAB, ADULTS: wild-caught females injected with 100-400 i.u./kg body weight human chorionic gonadotropin: ca 4,200-41,000 eggs/spawn 114.
  • Observations relative fecundity WILD, ADULTS: 0.5-2 times females' body weight in eggs 81.

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• Fecundity and lunar cycle:
  • FARM, ADULTS: the sum of eggs recorded during full moon almost doubled that recorded during new moon. Egg sum peaked on the first full moon day every month 115.

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• Fecundity and temperature manipulation:
  • LAB, ADULTS: increasing the temperature from 14 °C to 18 °C induced 25% of females to release eggs 111.
• Fecundity and hormone treatment:
  • Injecting females carrying oocytes in the last stages of vitellogenesis with human chorionic gonadotropin induced spawning (LAB 109 114), but mammalian gonadotropin-releasing hormone analogue (GnRHa) is as effective and more advantageous, for example by stimulating the female's own gonadotropin hormone 81.
  • GnRHa was – at low doses – more effective in inducing gonadotropin hormone release and ovulation in females than the more expensive salmon GnRHa 116↶81.
  • GnRHa implants or microspheres prolonged the effect of a single injection and induced a highly predictable spawning pattern in over 80% of the treated females (as compared with 25% induced by a single injection) for periods ranging up to four months 81. Compared to natural spawning, GnRHa delivery systems produced similar or even higher number and viability of eggs (LAB 111) and hatching and survival rates of LARVAE 81.

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• Breeding type: sea spawner:
  • Observations: → D7.
• Nursery grounds:
  • Lagoons are considered nursery grounds: the shallow brackish water excludes many predators 117↶32, offers higher temperatures 17 D9 D24 D21 and lower salinities 75 76 77 D26 D22 than the open sea, as well as abundant prey 32.

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• Vision and foraging:
  • LAB: 20 day old FRY increased ingestion of a microdiet by 50-60% when given visual access to Artemia nauplii compared to absence of Artemia nauplii 118.

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• LAB, JUVENILES: more interactions with the bottom in the first week in tanks with blue and red-brown glass gravel than green or no glass gravel. No difference in aggressive acts in tanks with blue and red-brown glass gravel, but higher aggression with green and highest aggression without glass gravel 64.

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• LAB, ADULTS: rarely responsive to steroids, bile acid, prostaglandins. More responsive to amino acids, especially short-chain neutral and basic amino acids, and urine. Even more responsive to conspecific seminal and egg fluid. Highest amplitude of response to intestinal fluid of conspecifics, because probably a source of pheromones 119.

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• Olfaction and foraging:
  • LAB: 20 day old FRY increased ingestion of a microdiet by 50-60% in the presence of filtrate water from an Artemia nauplii culture tank. In combination with visual access to Artemia nauplii, ingestion rates increased to 120% compared to the absence of visual or chemical Artemia stimuli 118.

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• Hearing type:
  • LAB, ADULTS: hearing GENERALIST 64.
• Hearing spectrum: no data found yet.

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• Hearing and orientation:
  • LAB: acoustic stimuli prevented JUVENILES from swimming near the wall boundary layer of the tank 17.

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• Inverse effect:
  • LAB: acoustic stimuli with frequency band of 0.1-1 kHz increased amount of movement and haematocrit levels in ADULTS, indicating stress 122.
• Direct effect:
  • LAB: in an environment simulating offshore noises, JUVENILES grew better and had lower stress indices than JUVENILES in an onshore or control environment 123.

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• Lateral line system and sensing water movement and vibrations:
  • Detects local water movements, so that individual perceives and localises prey, enemies, and sexual partners 124↶101.
  • Detects surface and low frequency waves in the vicinity of the fish body, indirectly detects vibrations from sound waves 125↶101.
• Involved body parts:
  • Neuromast receptor located in the scale is connected to the lateral line nerve 126↶101.
  • Body lateral line contains 73-85 scales 127↶101.

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• LAB: during an aggressive act, ADULTS 108 and JUVENILES 40 displayed darker body colouration, JUVENILES erected their dorsal fin 40.

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• LAB: contracting sonic muscles excite the swim bladder they enclose which results in sounds like single knocking (percussion) and series of pulsed sounds (pulse trains) 18 19.

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• WILD: lived solitary or in small to large aggregations 11 12 13 9, probably correlated with body length: larger individuals isolated, smaller ones in schools 10.
• For aggregation type and daily rhythm → D28.

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• FARM, ADULTS: stocking density of >70 kg/m³ resulted in vigorous movement and earlier onset and resolution of rigour mortis 128. Density of control condition was 30 kg/m³, so level at which stress commences could be <70 kg/m³ – further research needed.
• LAB: stocking density of >22 kg/m³ resulted in increased plasma cortisol levels 129 130 131 132 and decreased immune parameters 129 133 in JUVENILES and earlier onset and resolution of rigour mortis in ADULTS 134. Density of control conditions was 3-10 kg/m³ for JUVENILES (7 kg/m³ 129, 4 kg/m³ 130, 3-10 kg/m³ 131, 9 kg/m³ 133, 7 kg/m³ 132) and 17 kg/m³ for ADULTS 134, so level at which stress commences could be <22 kg/m³ – further research needed.

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• LAB, JUVENILES: being able to swim freely and with a certain velocity positively affected weight gain 60.

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• Hierarchy and group size: in small groups, JUVENILES establish linear dominance hierarchies:
  • Observations LAB, JUVENILES: between four individuals 21; groups of two individuals: one dominant, one subordinate, groups of five: one dominant, two betas, two subordinates, groups of 10: two dominants, four betas, four subordinates 22.
  • LAB: in small groups, JUVENILES recognised each other or conspecifics with certain behaviour and based on that established dominance hierarchies 135↶20.
  • LAB: in large groups, JUVENILES constantly adjusted position to conspecifics and lived in anonymity 20.
  • LAB: no dominance hierarchy established in a group of 75 JUVENILES 22.
• Establishing hierarchy:
  • LAB: among groups of four JUVENILES, hierarchy was established via fighting. Most interactions occurred during feeding. Rank usually matched size. Hierarchy among mixed-size JUVENILES was established faster (day 4 versus day 10) than among same-size JUVENILES. Number of aggressive acts increased the longer the JUVENILES were held together 21.
• For linear hierarchy in food competition and growth → D19.

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• Features of dominance:
  • LAB: dominant JUVENILES stayed in place where food accumulates, were highly mobile in that area, and showed more aggressive behaviour than subordinate JUVENILES 22 21.
  • LAB: dominant JUVENILES had a higher cortisol level than beta and control JUVENILES but lower than subordinates 22.

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• Features of subordination:
  • LAB: to avoid confrontations with higher-ranked individuals, subordinate JUVENILES displayed vertical swimming in the upper water level 21, hardly moved in the tank, and kept a position away from food 21 22.
• Hierarchy and stress:
  • LAB: subordinate JUVENILES displayed decreased immunological parameters and an increased cortisol level compared to dominant, beta, and control JUVENILES 22.

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• Size-matched pairs:
  • LAB, JUVENILES: in single-size groups, short interactions, predominantly front and rear attacks, retreats. Few longer-lasting interactions included repeated elements of mutual frontal threat head-to-head display, circling, chasing, and nipping. No difference in order of aggressive acts to mixed-size groups 21.
• Non-matched pairs:
  • LAB: in mixed-size populations, larger FRY displayed aggression and cannibalism towards smaller FRY 23.
  • LAB: dominant JUVENILES chased and nipped subordinate JUVENILES 22.

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• Aggression and sex:
  • LAB, ADULTS: no clear sex bias in aggressive behaviour 108.

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• LAB: prior handling experience might increase aggression level, as JUVENILES with restraining experience exhibited more aggressive behaviour (lower latency to chase and higher number of chases) than control individuals 24.

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• Fighters and non-fighters:
  • LAB: after restraining experience, JUVENILES differed in cortisol levels (range: 6.2-117.3 ng/mL). When paired in dyads with naïve individuals for an aggressiveness test three months later, previously restrained JUVENILES varied in number of chases from 0 to 103. Fighters displayed lower cortisol levels than non-fighters, only accounting for 21% of the variation in aggressiveness, though. Further studies needed to find other reasons for different coping styles 24.
• For aggressiveness and...
  ...establishing hierarchy → D4,
  ...dominance → D5,
  ...subordination → D32,
  ...size-grading → D33.

^{In the structure of menu item 16 and the definition of "AGGRESSIVENESS", we follow 136.}

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• Handling and confinement: causes stress:
  • LAB, JUVENILES: handling and confinement caused stress, measured as increased plasma cortisol levels 132.
  • ADULTS: pre-slaughter handling and confinement caused stress, indicated by great activity and vigorous movements (FARM 128), later death (FARM 128), as well as earlier onset and earlier resolution of rigour mortis (FARM 128; LAB 134).

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• Stunning rules: to minimise pain reactions and enhance welfare before slaughter:
  1. induce insensibility as fast as possible,
  2. prevent recovery from stunning,
  3. monitor effectiveness (observations, neurophysiological measurements) 137.

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• Pre-slaughter struggle time:
  a) percussive stunning: ADULTS: 0 min 138,
  b) electrical stunning: ADULTS: for at least 10 s with >200 mA: 0 min 138,
  c) immersion in ice slurry: ADULTS: 5 min 138,
  d) immersion in chilled water: FARM, ADULTS: 25 min 128,
  e) asphyxia in air: 4-50 min:
  • Observations: FARM: 20-50 min 128; 5 min at 0.1 °C, 5.5 min at 22 °C 137; 4 min 138.

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