1 Overview

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2 General

  • Escapes: rear only in environments where it naturally occurs [F1] and prevent escapes. Else, escapees from fish farms have negative or at most unpredictable influences on the local ecosystem [F2]. Prepare for sexual maturity (and thus spawning) from 10 months or 472 g on for males and 19 months or 2.3 kg on for females [F3] and take measures against spawning into the wild.

3 Designing the (artificial) habitat

3.1 Substrate and/or shelter

  • Substrate:
    • Substrate: no ethology-based recommendation definable so far.
    • For substrate and spawning [R1].
  • Shelter or cover:
    • Cover: no ethology-based recommendation definable so far.
    • Vegetation: no ethology-based recommendation definable so far.
    • Shelters: no ethology-based recommendation definable so far.

3.2 Photoperiod

  • Photoperiod: given the distribution [F1] [F4], natural photoperiod is 12-14 hours, depending on the season. Provide access to natural (or at least simulated) photoperiod and daylight. Some evidence to best keep fry in dark surrounding [F5]. Further research needed.
  • Light intensity: for higher survival and lower aggression in fry, keept at low light intensity (≤0.1 lux) [F6]. For higher survival and better growth in juveniles, keep at 100 lux [F6]. Further research needed.
  • Light colour: for higher tendency of survival and growth, keep fry and juveniles under yellow, white, or red light [F7] [F8]. Further research needed.
  • Resting period: allow Pangasius a resting period at night or in the dark.

3.3 Water parameters

  • Temperature: no clear temperature preference, probably best kept at 28-32 °C [F9] [F10]. Below and above may mean lower survival, higher stress [F11], and lower growth [F12]. Adjust temperature when you notice avoidance behaviour [F13] or deformities [F14]. Avoid sudden changes in water temperature of 12 °C or more, as it increases stress and mortality [F11].
    Implemented in aquaculture, temperatures >22 °C demand excellent oxygen levels [F15] and a fine-tuned flow-through system to prevent bacterial load.
    For temperature and spawning  [R1].
  • Water velocity: no clear velocity preference [F16]. Provide variations in the direction and the velocity of the water inlet. Further research needed. To avoid entanglements and thus mortality in fry (probably erroneously considered cannibalism), avoid current (or even movement, e.g. by transport) during the age of 46-105 h [F17].
  • Oxygen: avoid severe hypoxia or even anoxia [F18]. Maintain oxygen level that ensures welfare depending on temperature ( Temperature) and stocking density ( [R2]).
  • Salinity: given the potamodromous migration type, natural salinity is at freshwater level from egg to adult stage [F19] [F20]. Avoid salinity >10 ppt, as it increases stress and mortality (but it depends on acclimatisation) [F21] and it decreases growth [F22]. Further research needed.
  • pH: in the wild, pH is at 6.8-8.0 [F23]. For the most natural solution, maintain this range. Further research needed.
  • Turbidity: no ethology-based recommendation definable so far.

3.4 Swimming space (distance, depth)

  • Distance: no ethology-based recommendation definable so far. Provide enough space, bearing in mind the planned stocking density [R2].
  • Depth:
    • Depth range: in the wild, found at 2-6 m [F18]. Provide at least 2-4 m, ideally up to 6 m, bearing in mind the planned stocking density [R2]. Individuals should be able to choose swimming depths according to life stage and oxygen range [F18].
      For depth and spawning [R1].
    • Flight: provide enough depth for the flight response to light [F18].
    • Temperature layers: in habitats with water layers with different temperatures, prepare for individuals migrating to layers with preferred temperatures [F9], and avoid crowding in these layers by providing enough space.

4 Feeding

  • Alternative species: omnivorous [F24], trophic level 3.1 [F25]. If you have not yet established a Pangasius farm, you might consider to opt for a species that can be fed without or with much less fish meal and fish oil in order not to contribute to overfishing by your business [F26].
  • Protein substitution: if you run a Pangasius farm already, try to substitute protein feed components that have so far been derived from wild fish catch, while taking care to provide your fishes with a species-appropriate feed [F24]:
    • Invite a feed mill and other fish farmers in your country to jointly establish a recycling syndicate that converts the remainders and the offcuts of fish processing into fish meal and fish oil, separating the production line corresponding to the species of origin in order to avoid cannibalism  fair-fish farm directives (point 6).
    • Inform yourself about commercially tested substitutes for fish meal and fish oil, like insect or worm meal or soy, with an appropriate amino and fatty acid spectrum.
  • Feed delivery:
    • Feeding frequency and time, feed delivery, self-feeders: probably visual forager [F27], fry seem to be nocturnal [F5], but adjust to feeding under higher light intensity [F13]. For higher survival in fry, choose a lower rather than higher feeding frequency (6 times/day) [F28], for higher growth in fry, feeding time seems to be more important than feeding frequency (16:00 h rather than 08:00 h) [F29] [F13]. Further research needed. For higher growth in juveniles, choose a higher rather than lower feeding frequency (3 times/day) [F29]. Further research needed. Alternatively, install a self-feeder and make sure all Pangasius adapt to it. No ethology-based recommendation definable so far on feeding in the wild and speed and pattern of feed delivery. Note decreased feeding at temperatures ≥36 °C and black tanks [F13] and reduce the amount of food offered accordingly (if not using a self-feeder).
    • Food competition: make sure to provide sufficient feed from 24 h [F13] [F30]. For higher survival and growth provide fry with three Artemia nauplii per individual [F24] and make sure that individuals accept it, as insufficient food might be a reason for cannibalism [F17].
  • Particle size: for higher growth in juveniles, provide rather fine than coarse feed [F24].
  • Feed enrichment: to improve stress tolerance, enrich feed for juveniles with levamisole, lipopolysaccharide, beta-glucans, astaxanthin, or mannan oligosaccharide [F31].

5 Growth

  • Maturity: in the wild, matures before 3-4 years old [F32]. Even if manipulating time of maturity were possible, refrain from it, as we have not found studies reporting possible long-term effects on welfare FishEthoBase's understanding of fish welfare.
  • Manipulating sex: even if manipulating sex were possible, refrain from it, as we have not found studies reporting possible long-term effects on welfare FishEthoBase's understanding of fish welfare.
  • Sex ratio: no ethology-based recommendation definable so far.
  • Size-grading: mortality in fry seems to be due to movement (e.g., by water current or transportation), high density, and suboptimal water conditions, not size difference [F17]. Thereafter, hardly aggressive. So size-grading does not seem beneficial.
  • Other effects on growth:
    • Incubator type: eggs do not seem to be sensitive to agitation, adhesion, water exchange or absence of these factors [F33]. Further research needed. So, choose your preferred incubator type.
    • Aquaculture system: for better growth in juveniles, prefer cages over ponds [F33]. Further research needed.
    • Tank colour: for lower mucous cell count, prefer green tanks [F34], for higher growth, green or white tanks [F35]. Further research needed. Note alignment of skin colour to tank colour (darker in green and black tanks than white tanks) [F36].
    • Polyculture: in the wild, co-exists with Basa, Shortbarbel pangasius, various Pangasius species [F37]. Possible benefit of polyculture, but depends on the other species [F33]. Further research needed.
  • Deformities and malformations: rather prone to diseases than deformities. For fewer deformities, avoid heat shock (42 °C) shortly after fertilisation [F14]. Further research needed.
  • For growth and...
    ...light intensity and light colour  [R3],
    ...water temperature and salinity [R4],
    ...feeding frequency  [R5],
    ...stocking density  [R2].

6 Reproduction

  • Nest building: no nest building [F38], river spawner in rocky area at tree roots [F39] [F40]. For the most natural solution, provide submerged terrestrial vegetation.
  • Courtship, mating: no ethology-based recommendation definable so far.
  • Spawning conditions: for spawning substrate Nest building (above). Respect natural spawning season in summer at 26-31 °C in fresh water in deep pools [F39]. Further research needed. No ethology-based recommendation definable on spawning time, water velocity, spawning density and spawning sequence. Successful spawning has been achieved in male:female ratios of 1:1 to majority of males (2:1) or majority of females (1:3) [F41]. Further research needed for wild ratios.
  • Fecundity: in the wild, ca 1,000,000 eggs per female [F42]. Further research needed. Although manipulating fecundity is possible [F43], refrain from it, as we have not found studies reporting possible long-term effects on welfare FishEthoBase's understanding of fish welfare.

7 Stocking density

  • Maximum: the businessplan should be calculated on the basis of a maximum stocking density that will never exceed the tolerable maximum with regard to fish welfare.
  • Stocking:
    • Stocking larvae: no ethology-based recommendation definable so far.
    • Stocking juveniles and adults: in captivity, fry build schools. Further research needed on aggregation in the wild. Mixed results on effects of density that might be due to prey density ( [R5]) and light intensity ( [R3]). To be on the safe side, for higher survival, keep at 10 individuals/L. Further research needed. In juveniles, schooling and mixed results, too. For higher growth, keep at <25 individuals/m3 [F44] [F45]. Further research needed.
  • Restriction:
    • Habitat structuring: consider loss of space due to structures inside and outside the system [R6] and calculate density accordingly.
    • Environmental conditions: in the wild, displays a large variability in preferences for depth [F18]. Consider increased density at places with preferential conditions [R7] and calculate density accordingly.
    • Aggregation: in captivity, individuals build schools [F46]. Consider increased density at places due to formation of schools and calculate density accordingly.
    • Aggression: hardly aggressive [F47]. For cannibalism  [R5] and for what has probably been erroneously considered to be cannibalism in fry  [R4].
    • Territoriality: no ethology-based recommendation definable so far.
  • Interaction: as show the above influence factors, stocking density is only one part of a complex interaction of factors to affect welfare. It should never be considered isolatedly.

8 Occupation

  • Food search: no ethology-based recommendation definable so far.
  • Challenges: if after decreasing stress [R8] and providing everything welfare assuring, you still notice stereotypical behaviour or vacuum activities or sadness, then provide mental challenges, diversion, variety, and check reactions.

9 Handling, slaughter

9.1 Handling

  • Stress coping styles: individuals differ in their ability to cope with stress, so assume the smallest common denominator during stressful situations and handle with care and high efficiency.
  • Stress measurement:
  • Stress reduction:
    • Noise: no ethology-based recommendation definable so far.
    • Directing individuals: no ethology-based recommendation definable so far.
    • Cage submergence: no ethology-based recommendation definable so far.
    • Pain treatment: no ethology-based recommendation definable so far.
    • Handling: handle as carefully as possible, as it causes stress [F50].
    • Confinement: no ethology-based recommendation definable so far.
    • Crowding: no ethology-based recommendation definable so far.
    • Transport: avoid live transport, as it causes stress [F51]. If unavoidable, after transport, let recuperate for some time. Especially avoid moving fry, as it increases entanglement and thus mortality [F17].
    • Disturbance: no ethology-based recommendation definable so far.
    • For stress reduction and...
      ...light intensity, light colour  [R3],
      ...water temperature, salinity  [R4],
      ...feeding frequency, feed enrichment [R5],
      ...tank colour, deformities  [R9],
      ...stocking density  [R2],
      ...stunning  [R10].

9.2 Slaughter

  • Stunning rules: render individuals unconscious as fast as possible and make sure stunning worked and they cannot recover [F52].
  • Stunning methods: prefer percussive stunning, because it renders individuals unconscious fast if administered correctly and with sufficient force [F53]. Alternatively, use electrical stunning. Further research needed for a specific protocol.
  • Slaughter methods: bleed or gut individuals immediately after stunning, i.e. while unconscious.

10 Certification

  • Certification: fair-fish international association warmly advises to follow one of the established certification schemes in aquaculture in order to improve the sustainability of aquafarming. Adhering to the principles of one of these schemes, however, does not result in animal welfare by itself, because all these schemes do not treat animal welfare as a core issue or as an issue at all. Therefore the FishEthoBase has been designed as a complement to any of the established certification schemes. May it help practitioners to improve the living of the animals they farm based on best scientific evidence at hand.
  • To give you a short overview of the most established schemes, we present them below in descending order of their attention for animal welfare (which is not necessarily the order of their sustainability performance):
    • The fair-fish farm directives are not present on the market, we cite them here as a benchmark. The directives address fish welfare directly by being committed to FishEthoBase: for each species, specific guidelines are to be developed mirroring the recommendations of FishEthoBase; species not yet described by FishEthoBase cannot be certified. In addition, the directives address a solution path for the problem of species-appropriate feeding without contributing to overfishing.
    • The Naturland Standards for Organic Aquaculture (Version 06/2018) generally address  animal welfare with words similar to the fair-fish approach: "The husbandry conditions must take the specific needs of each species into account as far as possible (…) and enable the animal to behave in a way natural to the species; this refers, in particular, to behavioural needs regarding movement, resting and feeding as well as social and reproduction habits. The husbandry systems shall be designed in this respect, e.g. with regard to stocking density, soil, shelter, shade and flow conditions".
      In the details, however, the standards scarcely indicate tangible directives, the only ones for Pangasius being: no growout in artificial tanks, stocking density limited to 10 kg fish/m3 max, natural vegetation (in ponds only) on at least 5% of the production area.
    • The GAA-BAP Finfish and Crustacean Farms Standard (Issue 2.4, May 2017) directly addresses animal welfare: "Producers shall demonstrate that all operations on farms are designed and operated with animal welfare in mind." Farms shall "provide well-designed facilities", "minimize stressful situations" and train staff "to provide appropriate levels of husbandry". Yet the standard does not provide tangible and detailed instructions for the practitioner, let alone species-specific directives.
      In September 2017, GAA-BAP received a grant from the Open Philanthropy Project to develop best practices and proposed animal welfare standards for salmonids, tilapia, and channel catfish. Thus, fish welfare on GAA-BAP certified farms might become more tangible in the future.
    • The GlobalG.A.P. Aquaculture Standard (Version 4.0, March 2013) "sets criteria for legal compliance, for food safety, worker occupational health and safety, animal welfare, and environmental and ecological care". The inspection form includes criteria like "Is the farm management able to explain how they fulfil their legal obligations with respect to animal welfare?", "If brood fish are stripped, this should be done with the consideration of the animal's welfare." or "Is a risk assessment for animal welfare undertaken?". The scheme claims that 45 out of a total of 249 control points cover animal protection, yet it does not provide any tangible directives, let alone species-specific directives.
    • The ASC Aquaculture Stewardship CouncilThe ASC standards address fish welfare only indirectly, as a function of a “minimum average growth rate" per day, a "maximum fish density at any time", and a "maximum average real percentage mortality". fair-fish sees animal welfare as an intrinsic value, not just as a result of optimising neighbouring values like health care and management procedures. 
      The ASC standard for Pangasius (version 1.1, March 2019) specifies threshold values for mortality indirectly, but not for growth rate and stocking density.
      In November 2017, ASC received a grant from the Open Philanthropy Project to develop an evidence-based fish welfare standard that is applicable to all ASC-certified species. ASC intends to share its approach to fish welfare with all farms engaged with the ASC program and encourage adoption of it, which means that the fish welfare standard will function as a non-mandatory add-on to the ASC certification.
    • The Friend of the Sea (FOS) Standards for freshwater aquaculture of fish (revised October 2016) do not even address animal health or animal welfare issues.
      In May 2017 however, FOS signed a Memory of Understanding with fair-fish international on developing fish welfare criteria for the FOS standard. In November 2017 fair-fish international association received a grant from the Open Philanthropy Project to assess the welfare of fish on FOS certified farms, develop farm-specific recommendations, and to develop animal welfare criteria for the FOS standard. Thus, fish welfare on FOS certified farms might become tangible in the future.