Grayling

Thymallus thymallus

Thymallus thymallus (Grayling)
Taxonomy
    • Osteichthyes
      • Salmoniformes
        • Salmonidae
          • Thymallus thymallus

Information


Author: João L. Saraiva
Version: 2.0 (2020-11-25) - Revision 2 (2022-07-20)

Cite

Reviewers: Pablo Arechavala-Lopez, Jenny Volstorf
Editor: Billo Heinzpeter Studer

Cite as: »Saraiva, João L.. 2022. Thymallus thymallus (Farm: Short Profile). In: FishEthoBase, ed. Fish Ethology and Welfare Group. World Wide Web electronic publication. First published 2017-05-29. Version 2.0 Revision 2. https://fishethobase.net.«





FishEthoScore/farm

Thymallus thymallus
LiPoCe
Criteria
Home range
Depth range
Migration
Reproduction
Aggregation
Aggression
Substrate
Stress
Malformations
Slaughter


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)

Legend

High
Medium
Low
Unclear
No findings



General remarks

Thymallus thymallus is reared for re-stocking and for feeding purposes. It is a highly appreciated species for sports fishing in northern Europe, where several initiatives have been undertaken for conservation of endangered populations. Its breeding in aquaculture relies mostly on wild parents, and many aspects of its rearing remain undisclosed. In addition, several welfare issues are probably not addressed so further research should focus mainly on substrate needs and stress effects of farming, spatial needs, reproduction without manipulation, aggregation, aggression, territoriality, and humane slaughtering.




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 medium amount of evidence.

Likelihood
Potential
Certainty

ALEVINS: WILD: remain in the same area 1 2, avoid downstream drift 3. FARM: hatchery tanks: 1m2 4.

JUVENILES: WILD: no data found yet. FARM: rearing tanks: 16 m2 (4x4 m) 5.

ADULTS: WILD: 18-34 m 6FARM JUVENILES

SPAWNERSWILD: pre-spawning: 10-950 m 7, spawning: 70-5,000 m 8 9, post-spawning: 66-144 m 9. FARM: concrete flow-through tanks 6-250 m2 (Mikolajczyk 2008)




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 farming conditions. It is high for high-standard farming conditions. Our conclusion is based on a medium amount of evidence.

Likelihood
Potential
Certainty

Eggs: WILD: 30-110 cm 10. FARM: hatchery: 30 cm 4.

ALEVINS: WILD: 50–60 cm 2 11, <1 m 10FARM Eggs

JUVENILES: WILD: usually 10-30 cm 12, <120 cm 11. FARM: Grow-out tanks: 1 m 5.

ADULTS: WILD: 100-200 cm 11 13FARM JUVENILES.

SPAWNERS: WILD: 20-55 cm 7. FARM: < 1 m (Mikolajczyk 2008).




3  Migration

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 high for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.

Likelihood
Potential
Certainty

ALEVINSWILD: non-migratory, inhabiting rivers with fast moving water 14 6 15FARM: freshwater tanks 4. For details on rearing systems  crit. 1 and 2.

JUVENILESWILD: non-migratory, inhabiting rivers with fast moving water 11 14FARM: freshwater tanks 5. For details on rearing systems  crit. 1 and 2.

ADULTSWILD: non-migratory, inhabiting rivers with fast moving water 13 14FARM: freshwater tanks 5. For details on rearing systems  crit. 1 and 2.

SPAWNERSWILD: may perform considerable displacements within freshwater systems 7 8 9FARM: freshwater tanks or river-like sytems (Mikolajczyk 2008). For details on rearing systems  crit. 1 and 2.




4  Reproduction

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.

Likelihood
Potential
Certainty

WILD: spring spawners 16 14. Males establish territories 14, females dig spawning pits in gravel and pebbles 16. FARM: very sensitive, require hormonal induction 17. All or at least some parents in farms are wild types 4 5 18.




5  Aggregation

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?

It is high for minimal and high-standard farming conditions. Our conclusion is based on a medium amount of evidence.

Likelihood
Potential
Certainty

ALEVINS: WILD: shoal 1 12 15 6. FARM: rearing density: 4-50 larvae/L 19 20.

JUVENILES: WILD: shoal in nature 21. FARM: up to 50 kg/m3 did not decrease growth or increase mortality 5.

ADULTS JUVENILES

SPAWNERS: WILD: form spawning aggregations 22 9. FARM: All or at least some parents in farms are wild types 4 5 18. All-female maturation tanks: 3.2-7 ind/m2; mixed-sex tanks: 0.5-2.6 ind/m2 (Mikolajczyk 2008).




6  Aggression

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 low amount of evidence.

Likelihood
Potential
Certainty

ALEVINS: WILD and FARM: no data found yet.

JUVENILESWILD: no data found yet. FARM: aggressive 18.

ADULTSWILD and FARM: no data found yet.

SPAWNERS: WILD: territorial 14 and aggressive when spawning 22 7. FARM: aggressive when spawning 18.




7  Substrate

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.

Likelihood
Potential
Certainty

Eggs: WILD: adhesive 14, buried in the substrate 10. FARM: barren tanks or bottles 4 5.

ALEVINS: WILD: use substrate, prefer silt, sand, gravel 2 23 6 or pebbles 15FARM: Ponds of Salvelinus alpinus and S. fontinalis usually have stones, pebbles and gravel as substrate (pers. obs). Further research needed to determine whether this applies to T. thymallus as well.

JUVENILESWILD: use substrate, prefer pebbles and boulders 2 23FARM: Ponds of Salvelinus alpinus and S. fontinalis usually have stones, pebbles and gravel as substrate (pers. obs). Further research needed to determine whether this applies to T. thymallus as well.

ADULTS: WILD: use substrate outside spawning 2 23. FARM JUVENILES.

SPAWNERS: Use gravel 16, pebbles and stones as spawning substrate 16 7. May spawn in areas with branches and tree roots 16FARM: maturation ponds of Salvelinus alpinus and S. fontinalis usually have stones, pebbles and gravel as substrate (pers. obs). Further research needed to determine whether this applies to T. thymallus as well.




8  Stress

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 unclear findings for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.

Likelihood
Potential
Certainty

ALEVINSno data found yet.

JUVENILESno data found yet.

ADULTS: no data found yet.

SPAWNERS: very sensitive when spawning 17.




9  Malformations

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 farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a medium amount of evidence.

Likelihood
Potential
Certainty

Fry: WILD: NO DATA FOUND YET. FARM: 0.1% 20.

Juveniles: WILD: NO DATA FOUND YET. FARM: When fed with live zooplankton or formulated dry food with zooplankton (DFZO): 0.1% 20. When fed with commercial dry food for salmonids, 75% develop bent tails and enlarged abdomen 20. These malformations are reversible upon feeding back with live zooplankton or DFZO 20.

Adults: WILD, FARM: NO DATA FOUND YET. All or at least some parents in farms are wild types 4 5 18.




10  Slaughter

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.

Likelihood
Potential
Certainty

Common slaughter method: for the related O. kisutch, anaesthesia with high CO2 or iced water 24, then bled by cutting gill arches and immersing in iced water 24 25. High-standard slaughter method: for O. mykiss, indications that electrical stunning before killing by chilling or bleeding is most effective 26 27 28 29. For S. salar, electrical and percussive stunning and killing by bleeding 30 31 32 33. For S. trutta, electrical stunning immediately followed by ice-water slurry 34. Further research needed whether this applies to T. thymallus as well.




11  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 35, level 5 being fully domesticated.




12  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)?

All age classes: WILD: Carnivorous 1 36 (except for omnivorous FRY stage 1 37). FARM: Replacement of fish meal and fish oil not reported in literature.




Glossary


ALEVINS = larvae until the end of yolk sac absorption, for details Findings 10.1 Ontogenetic development
WILD = setting in the wild
FARM = setting in farming environment or under conditions simulating farming environment in terms of size of facility or number of individuals
JUVENILES = fully developed but immature individuals, for details Findings 10.1 Ontogenetic development
ADULTS = mature individuals, for details Findings 10.1 Ontogenetic development
SPAWNERS = adults that are kept as broodstock
DOMESTICATION LEVEL 3 = entire life cycle closed in captivity with wild inputs 35
FRY = larvae from external feeding on, for details Findings 10.1 Ontogenetic development



Bibliography


[1] Scott, Alasdair. 1985. Distribution, Growth, and Feeding of Postemergent Grayling Thymallus thymallus in an English River. Transactions of the American Fisheries Society 114: 525–531. https://doi.org/10.1577/1548-8659(1985)114<525:DGAFOP>2.0.CO;2.
[2] Sempeski, P., and P. Gaudin. 1995. Habitat selection by grayling-II. Preliminary results on larval and juvenile daytime habitats. Journal of Fish Biology 47: 345–349. https://doi.org/10.1111/j.1095-8649.1995.tb01903.x.
[3] Bardonnet, A., and P. Gaudin. 1990. Diel pattern of first downstream post-emergence displacement in grayling, Thymallus thymallus (L., 1758). Journal of Fish Biology 37: 623–627. https://doi.org/10.1111/j.1095-8649.1990.tb05895.x.
[4] Carlstein, Mikael. 1993. Natural food and artificial, dry starter diets: effects on growth and survival in intensively reared European grayling. Aquaculture International 1: 112–123. https://doi.org/10.1007/BF00692615.
[5] Carlstein, Mikael. 1995. Growth and survival of European grayling reared at different stocking densities. Aquaculture International 3: 260–264. https://doi.org/10.1007/BF00118108.
[6] Nykänen, M, and A Huusko. 2004. Transferability of habitat preference criteria for larval European grayling (Thymallus thymallus). Canadian Journal of Fisheries and Aquatic Sciences 61: 185–192. https://doi.org/10.1139/f03-156.
[7] Darchambeau, F., and P. Poncin. 1997. Field observations of the spawning behaviour of European grayling. Journal of Fish Biology 51: 1066–1068. https://doi.org/10.1111/j.1095-8649.1997.tb01545.x.
[8] Parkinson, D., J.-C. Philippart, and E. Baras. 1999. A preliminary investigation of spawning migrations of grayling in a small stream as determined by radio-tracking. Journal of Fish Biology 55: 172–182. https://doi.org/10.1111/j.1095-8649.1999.tb00666.x.
[9] Ovidio, Michaël, Denis Parkinson, Damien Sonny, and Jean-Claude Philippart. 2004. Spawning movements of European grayling Thymallus thymallus in the River Aisne (Belgium). Folia Zoologica 53: 87.
[10] Nykänen, Mari. 2004. Habitat selection by riverine grayling, Thymallus thymallus L. University of Jyväskylä.
[11] Mallet, J. P., N. Lamouroux, P. Sagnes, and H. Persat. 2000. Habitat preferences of European grayling in a medium size stream, the Ain river, France. Journal of Fish Biology 56: 1312–1326. https://doi.org/10.1111/j.1095-8649.2000.tb02145.x.
[12] Bardonnet, Agnes, Philippe Gaudin, and Henri Persat*. 1991. Microhabitats and diel downstream migration of young grayling (Thymallus thymallm L.). Freshwater Biology 26: 365–376. https://doi.org/10.1111/j.1365-2427.1991.tb01404.x.
[13] Nykanen, M., A. Huusko, and M. Lahti. 2004. Changes in movement, range and habitat preferences of adult grayling from late summer to early winter. Journal of Fish Biology 64: 1386–1398. https://doi.org/10.1111/j.0022-1112.2004.00403.x.
[14] Northcote, Thomas G. 1995. Comparative biology and management of Arctic and European grayling (Salmonidae, Thymallus). Reviews in Fish Biology and Fisheries 5: 141–194. https://doi.org/10.1007/BF00179755.
[15] Cattanéo, Franck, David Grimardias, Marie Carayon, Henri Persat, and Agnès Bardonnet. 2014. A multidimensional typology of riverbank habitats explains the distribution of European grayling (Thymallus thymallus L.) fry in a temperate river. Ecology of Freshwater Fish 23: 527–543. https://doi.org/10.1111/eff.12106.
[16] Sempeski, P., and P. Gaudin. 1995. Habitat selection by grayling-I. Spawning habitats. Journal of Fish Biology 47: 256–265. https://doi.org/10.1111/j.1095-8649.1995.tb01893.x.
[17] Szmyt, Mariusz, Stefan Dobosz, Dariusz Kucharczyk, Joanna Grudniewska, and Adam M. Lejk. 2012. Impact of selected hormonal agents on the effectiveness of controlled reproduction of cultivated female European grayling. Fisheries & Aquatic Life 20: 289–297. https://doi.org/10.2478/v10086-012-0033-z.
[18] Salonen, Annamari, and Nina Peuhkuri. 2006. The effect of captive breeding on aggressive behaviour of European grayling, Thymallus thymallus, in different contexts. Animal Behaviour 72: 819–825. https://doi.org/10.1016/j.anbehav.2005.12.012.
[19] Luczynski, M., R. R. Zaporowski, and J. S. Golonka. 1986. Rearing of European grayling, Thymallus thymallus L., larvae using dry and live food. Aquaculture Research 17: 275–280. https://doi.org/10.1111/j.1365-2109.1986.tb00114.x.
[20] Lahnsteiner, Franz, and Manfred Kletzl. 2015. Suitability of different food types for on-feeding and juvenile production of European grayling, Thymallus thymallus, under intensive farming conditions. Journal of Agricultural Science 7: 161.
[21] Suter, WERNER. 1997. Roach rules: shoaling fish are a constant factor in the diet of cormorants Phalacrocorax carbo in Switzerland. Ardea 85: 9–27.
[22] Poncin, P. 1996. A field observation on the influence of aggressive behaviour on mating success in the European grayling. Journal of Fish Biology 48: 802–804. https://doi.org/10.1111/j.1095-8649.1996.tb01475.x.
[23] Greenberg, Larry, PåL Svendsen, and Atle Harby. 1996. Availability of microhabitats and their use by brown trout (Salmo trutta) and grayling (Thymallus thymallus) in the river Vojmån, Sweden. Regulated Rivers: Research & Management 12: 287–303. https://doi.org/10.1002/(SICI)1099-1646(199603)12:2/3<287::AID-RRR396>3.0.CO;2-3.
[24] Fairgrieve, W. 2009. Cultured Aquatic Species Information Programme. Oncorhynchus kisutch. Rome: FAO Fisheries and Aquaculture Department.
[25] LocalCoho Farms. 2021. Personal communication.
[26] Robb, D H F, and S C Kestin. 2002. Methods Used to Kill Fish: Field Observations and Literature Reviewed. Animal Welfare 11: 269–282.
[27] Lines, J. A., D. H. Robb, S. C. Kestin, S. C. Crook, and T. Benson. 2003. Electric stunning: a humane slaughter method for trout. Aquacultural Engineering 28: 141–154. https://doi.org/10.1016/S0144-8609(03)00021-9.
[28] European Food Safety Authority (EFSA). 2009. Species-specific welfare aspects of the main systems of stunning and killing of farmed fish: Rainbow Trout. EFSA Journal 7: 1012. https://doi.org/10.2903/j.efsa.2009.1012.
[29] Concollato, Anna, Rolf Erik Olsen, Sheyla Cristina Vargas, Antonio Bonelli, Marco Cullere, and Giuliana Parisi. 2016. Effects of stunning/slaughtering methods in rainbow trout (Oncorhynchus mykiss) from death until rigor mortis resolution. Aquaculture 464: 74–79. https://doi.org/10.1016/j.aquaculture.2016.06.009.
[30] Robb, D. H. F., S. B. Wotton, J. L. McKinstry, N. K. Sørensen, S. C. Kestin, and N. K. Sørensen. 2000. Commercial slaughter methods used on Atlantic salmon: determination of the onset of brain failure by electroencephalography. Veterinary Record 147: 298–303. https://doi.org/10.1136/vr.147.11.298.
[31] Roth, Bjorn, Erik Slinde, and David H. F. Robb. 2007. Percussive stunning of Atlantic salmon (Salmo salar) and the relation between force and stunning. Aquacultural Engineering 36: 192–197. https://doi.org/10.1016/j.aquaeng.2006.11.001.
[32] European Food Safety Authority (EFSA). 2009. Species-specific welfare aspects of the main systems of stunning and killing of farmed Atlantic Salmon. EFSA Journal 7: 1011. https://doi.org/10.2903/j.efsa.2009.1011.
[33] Lambooij, E., E. Grimsbø, J. W. van de Vis, H. G. M. Reimert, R. Nortvedt, and B. Roth. 2010. Percussion and electrical stunning of Atlantic salmon (Salmo salar) after dewatering and subsequent effect on brain and heart activities. Aquaculture 300: 107–112. https://doi.org/10.1016/j.aquaculture.2009.12.022.
[34] Castanheira, Maria Filipa. 2017. Personal communication.
[35] Teletchea, Fabrice, and Pascal Fontaine. 2012. Levels of domestication in fish: implications for the sustainable future of aquaculture. Fish and Fisheries 15: 181–195. https://doi.org/10.1111/faf.12006.
[36] Hellawell, J. M. 1971. The food of the grayling Thymallus thymallus (L.) of the River Lugg, Herefordshire. Journal of Fish Biology 3: 187–197. https://doi.org/10.1111/j.1095-8649.1971.tb03662.x.
[37] Turek, J., P. Horký, V. Žlábek, J. Velíšek, O. Slavík, and T. Randák. 2012. Recapture and condition of pond-reared, and hatchery-reared 1 + European grayling stocked in addition to wild conspecifics in a small river. Knowledge and Management of Aquatic Ecosystems: 10. https://doi.org/10.1051/kmae/2012016.






© 2022 fair-fish international

Imprint
Data privacy