Information
Version: B | 1.2 (2024-12-31)
- minor editorial changes plus new side note "Commercial relevance"
WelfareScore | farm
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
WelfareScore = Sum of criteria scoring "High" (max. 10)
General remarks
Silurus asotus is a catfish species that lives in Japan, east China, Mongolia, Russia, Korea, Vietnam, and Taiwan. It is cultivated in China, Taiwan, Japan, Korea, Malaysia, and Thailand. S. asotus lives for up to 12 years and reaches marketable size within a year. It lives in shallow waters of rivers and lakes, and it is commonly found in rice-fields, where it migrates to spawn. S. asotus has a complex mating ritual and does not reproduce naturally in captivity, maybe due to a lack of effort to simulate their natural environment during spawning season.
The welfare and survival of S. asotus in farms can be improved if measures are taken to prevent their aggressive and cannibalistic behaviour as well as to reduce their stress while in captivity, such as adding environmental enrichment, regular sizing, providing regular and abundant feeding, and reducing handling and environmental disturbances. Sizing becomes an arduous job due to females being larger than males, which increases the aggression rates from bigger to smaller IND. Some farms have tried to circumvent this problem by feminising males, but this measure generates malformations in the reproductive organs, which is detrimental for their welfare. Other farms breed sterile triploid IND to prevent them from investing energy in reproduction and prevent the negative natural impacts of possible escapes. Further research needs to be done to study the wild and farming conditions of S. asotus, especially in the areas of their social structure in the wild, specific stunning and slaughtering methods, and the measures taken in farms to provide them with their migration needs and to reduce their stress levels.
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 farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a low amount of evidence.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 medium for high-standard farming conditions. Our conclusion is based on a medium amount of evidence.3 Migration
Some species undergo seasonal changes of environments for different purposes (feeding, spawning, etc.), and to move there, they migrate for more or less extensive distances.
What is the probability of providing farming conditions that are compatible with the migrating or habitat-changing behaviour of the species?
It is unclear for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.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 of these circumstances?
It is low for minimal and high-standard farming conditions. Our conclusion is based on a high amount of evidence.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 unclear for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.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 farming conditions. It is medium for high-standard farming conditions. Our conclusion is based on a medium amount of evidence.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, turbidity).
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.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?
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.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?
It is unclear for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.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.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 342, 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)?
All age classes: WILD: carnivorous 3618. FARM: fish meal may be partly* replaced 4344, fish oil may be completely* replaced by sustainable or non-forage fishery components 4546, but no data found yet for ADULTS and SPAWNERS.
partly = <51% – mostly = 51-99% – completely = 100%
Side note: Commercial relevance
How much is this species farmed annually?
360,050 t/year 1990-2019 amounting to estimated 1,440,000,000 IND/year 1990-2019 47.
Glossary
DOMESTICATION LEVEL 3 = entire life cycle closed in captivity with wild inputs 42
FARM = setting in farming environment or under conditions simulating farming environment in terms of size of facility or number of individuals
FRY = larvae from external feeding on
IND = individuals
JUVENILES = fully developed but immature individuals
LAB = setting in laboratory environment
LARVAE = hatching to mouth opening
PHOTOPERIOD = duration of daylight
POTAMODROMOUS = migrating within fresh water
SPAWNERS = adults during the spawning season; in farms: adults that are kept as broodstock
WILD = setting in the wild
Bibliography
2 Nawang, Siti Umey Syahirah Mat, Ching Fui Fui, and Shigeharu Senoo. 2020. Biological Development and Growth of Amur Catfish, Silurus asotus Reared under Controlled Tropical Condition. Malaysian Applied Biology 49: 11–23.
3 Kim, Y. H., H. D. Kim, W. W. Lee, D. W. Lee, and B. H. Kim. 1990. Studies on the raising of four fish species in paddy field with growing rice. The Research Reports of the Rural Development Administration - Rice (Korea Republic).
4 Cruz, Catalino R. Dela. 1992. Rice-fish Research and Development in Asia. WorldFish.
5 The Fish Site. 2011. Changing Aquaculture Scene In Red River Delta, Viet Nam.
6 Kim, Seok Ryel, Jin Woo Jang, Bum Ju Kim, In Kwon Jang, Hyun Jeong Lim, and Su Kyoung Kim. 2019. Urban aquaculture of catfish, Silurus asotus, using biofloc and aquaponics systems. Environmental Biology Research 37: 545–553. https://doi.org/10.11626/KJEB.2019.37.4.545.
7 Kim, Jeong-Hui, Ju-Duk Yoon, Woo-Myung Heo, Dong-Sup Kim, Chulgoo Kim, and Min-Ho Jang. 2014. Movement patterns of three freshwater fish species after upstream transportation by fishway in the Jangheung Dam. Paddy and Water Environment 12: 141–148. https://doi.org/10.1007/s10333-014-0429-z.
8 Kang, Kyoung-Mi, and Hyeon-Ok Shin. 2010. Movement range and behavior of mandarin fish (Siniperca scherzeri) and catfish (Parasilurus asotus) in Chungju Lake [in Korean]. Bulletin of the Korean society of Fisheries Technology 46: 148–156. https://doi.org/10.3796/KSFT.2010.46.2.148.
9 Kumakura, Naoki, Kiyoshi Sakai, and Fumio Takashima. 2003. Reproductive cycle and human chorionic gonadotropininduced ovulation in hatchery reared Japanese catfish Silurus asotus. Fisheries science 69: 495–504. https://doi.org/10.1046/j.1444-2906.2003.00650.x.
10 Sariat, Sari Asfarina, Ching Fui Fui, and Shigeharu Senoo. 2020. Growth Performance and Gonad Maturation of Amur Catfish, Silurus asotus in Captivity. Malaysian Applied Biology 49: 71–79.
11 Arsin, Nur Efah, Abentin Estim, and Saleem Mustafa. 2018. Behaviour and Response of Japanese Catfish (Silurus asotus) in Captivity Provided with an Artificial Microhabitat Mosaic. Aquatic Research: 136–139. https://doi.org/10.3153/AR18015.
12 Miwa, Takeshi, Goro Yoshizaki, Hiroaki Naka, Michitoshi Nakatani, Kiyoshi Sakai, Makito Kobayashi, and Toshio Takeuchi. 2001. Ovarian steroid synthesis during oocyte maturation and ovulation in Japanese catfish (Silurus asotus). Aquaculture 198: 179–191. https://doi.org/10.1016/S0044-8486(00)00586-X.
13 Wang, Qidong, Lin Cheng, Jiashou Liu, Zhongjie Li, Shouqi Xie, and Sena S De Silva. 2014. Freshwater aquaculture in PR China: trends and prospects. Reviews in Aquaculture: 20.
14 Yu, Jin-Ha, Jung Jo Han, Kwon Sam Park, Kwan Ha Park, and Sung Woo Park. 2009. Edwardsiella tarda infection in Korean catfish, Silurus asotus, in a Korean fish farm. Aquaculture Research 41: 19–26. https://doi.org/10.1111/j.1365-2109.2009.02296.x.
15 Maehata, Masayoshi. 2002. Stereotyped sequence of mating behavior in the Far Eastern catfish, Silurus asotus , from Lake Biwa. Ichthyological Research 49: 202–205. https://doi.org/10.1007/s102280200028.
16 Funao, Toshinori, Takayoshi Nishida, Yoshimasa Kurashige, and Hiroichi Sawada. 2014. Different suitability of improved irrigation channels as reproductive sites for Cyprininae and Silurus asotus. Scientific Reports 4: 3588. https://doi.org/10.1038/srep03588.
17 Shirai, Nobuya, Hiramitsu Suzuki, Shigeru Toukairin, and Shun Wada. 2001. Spawning and season affect lipid content and fatty acid composition of ovary and liver in Japanese catfish (Silurus asotus). Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 129: 185–195. https://doi.org/10.1016/S1096-4959(01)00378-5.
18 Dulmaa, A. 1999. Fish and Fisheries in Mongolia. In Fish and Fisheries at Higher Altitudes: Asia, ed. T. Petr, 187–236. Rome: Food & Agriculture Org. of the United Nations.
19 Maehata, Masayoshi. 2007. Reproductive ecology of the Far Eastern catfish, Silurus asotus (Siluridae), with a comparison to its two congeners in Lake Biwa, Japan. Environmental Biology of Fishes 78: 135–146. https://doi.org/10.1007/s10641-006-9083-7.
20 Mashiko, K. 1981. Periodic nocturnal activities in the catfish Silurus asotus in captivity. Japanese Journal of Ichthyology 28: 148–156. https://doi.org/10.11369/jji1950.28.148.
21 Tabata, M., Mitsuo, Maung Minh-Nyo, Hiroshi Niwa, and Mikio Oguri. 1989. Circadian Rhythm of Locomotor Activity in a Teleost, Silurus asotus. Zoological Science 6: 367–375.
22 Tabata Mitsuo, Minh-Nyo Maung, and Oguri Mikio. 1991. The Role of the Eyes and the Pineal Organ in the Circadian Rhythmicity in the Catfish Silurus asotus. Nippon Suisan Gakkaishi 57: 607–612. https://doi.org/10.2331/suisan.57.607.
23 Hata, Kenji. 2002. Field Experiment on the Migration of Fishes to a Paddy Field with a Small Fishway. Japan Agricultural Research Quarterly: JARQ 36: 219–225. https://doi.org/10.6090/jarq.36.219.
24 Inaba, D. 1976. Freshwater Aquaculture. Tokyo: Koseisha Koseikaku.
25 Katano Osamu, Saitoh Kenji, and Koizumi Akio. 1988. Scatter-spawning of the catfish,Silurus asotus. Ichthyological Research 35: 203–211. https://doi.org/10.1007/BF02905407.
26 Gao, Yang, Sun-Gyu Kim, and Jeong-Yeol Lee. 2011. Effects of pH on Fertilization and the Hatching Rates of Far Eastern Catfish Silurus asotus. Fisheries and Aquatic Sciences 14: 417–420. https://doi.org/10.5657/FAS.2011.0417.
27 Park, In-Seok. 2019. The Anesthetic Effects of Clove Oil and MS-222 on Far Eastern Catfish, Silurus asotus. Development & Reproduction 23: 183–191. https://doi.org/10.12717/DR.2019.23.2.183.
28 Yada, Osamu, and Atsushi Furukawa. Relationship between External and Internal Morphological Changes and Feeding Habits in the Fry Stage of Japanese Catfish Silurus asotus. UJNR Technical Report 28.
29 The Shiga Society of Naturalists. 2001. Flora And Fauna Of Rural Biotopes In Shiga. Shiga, Japan: Sunrise-syuppan.
30 Saito, Saburo, and Kaname Yokoi. 1955. On the Fresh Water Catfish, Parasilurus asotus (Linnaeus) from Hokkaido. 北海道大學水産學部研究彙報 5: 336–337.
31 Miyadi, D., H. Kawanabe, and N. Mizuno. 1976. Coloured illustrations of the freshwater fishes of Japan. Hoikusha, Osaka: Japanese.
32 Hur, Jun Wook, Dae Hee Kim, and Jeong-Yeol Lee. 2015. Physiological Responses to Three Different Levels of Vibration Stress in Catfish, Silurus asotus. Ecology and Resilient Infrastructure 2: 337–344. https://doi.org/10.17820/ERI.2015.2.4.337.
33 Hur, Jun Wook, Jeong Yeol Lee, and Jin Chul Joo. 2018. Effects of Noise and Vibration on Oxygen Consumption and Ammonia Excretion in Cultured Catfish (Silurus asotus). Ecology and Resilient Infrastructure 5: 105–109. https://doi.org/10.17820/eri.2018.5.2.105.
34 Baron, V. D., and V. M. Olshansky. 2009. Monopolar electric discharges of the catfish Parasilurus asotus (Siluridae, Siluriformes). Journal of Ichthyology 49: 403–408. https://doi.org/10.1134/S0032945209050063.
35 Hatai, Shinkishi, and Noboru Abe. 1932. The Responses of the Catfish, Parasilurus Asotus, to Earthquakes. Proceedings of the Imperial Academy 8: 375–378. https://doi.org/10.2183/pjab1912.8.375.
36 Yang, Won Seok, Hyun Woo Gil, Gwang Yeol Yoo, and In-Seok Park. 2015. Identification of Skeletal Deformities in Far Eastern Catfish, Silurus asotus under Indoor Aquaculture Condition. Development & Reproduction 19: 153–161. https://doi.org/10.12717/DR.2015.19.3.153.
37 Humane Slaughter Association. 2018. Humane slaughter of finfish farmed around the world. Humane Slaughter Association.
38 Bowan, Jennifer, and Albin Gräns. 2019. Stunning and Killing of Tropical and Subtropical Finfish in Aquaculture during Slaughter.
39 Lambooij, E, R J Kloosterboer, C Pieterse, M A Gerritzen, and J W Van de vis. 2003. Stunning of farmed African catfish (Clarias gariepinus) using a captive needle pistol; assessment of welfare aspects. Aquaculture Research 34: 1353–1358. https://doi.org/10.1046/j.1365-2109.2003.00966.x.
40 Sattari, A., E. Lambooij, H. Sharifi, W. Abbink, H. Reimert, and J. W. van de Vis. 2010. Industrial dry electro-stunning followed by chilling and decapitation as a slaughter method in Claresse® (Heteroclarias sp.) and African catfish (Clarias gariepinus). Aquaculture 302: 100–105. https://doi.org/10.1016/j.aquaculture.2010.01.011.
41 Lambooij, E., R. J. Kloosterboer, M. A. Gerritzen, and J. W. van de Vis. 2006. Assessment of electrical stunning in fresh water of African Catfish (Clarias gariepinus) and chilling in ice water for loss of consciousness and sensibility. Aquaculture 254: 388–395. https://doi.org/10.1016/j.aquaculture.2005.10.027.
42 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.
43 Kim, Kyoung-Duck, Sang-Gu Lim, Ju-Ae Hwang, Jin-Do Kim, and Yong-Jin Kang. 2009. Evaluation of Soybean Meal as a Partial Substitute for Fish Meal in Diet and Experimental Practical Diet for Growth in the Far Eastern Catfish (Silurus asotus). Korean Journal of Fisheries and Aquatic Sciences 42: 349–353. https://doi.org/10.5657/kfas.2009.42.4.349.
44 Katya, Kumar, Yong-hyun Yun, Gunhyun Park, Jeong-Yeol Lee, Gwangyeol Yoo, and Sungchul C. Bai. 2014. Evaluation of the Efficacy of Fermented By-product of Mushroom, Pleurotus ostreatus, as a Fish Meal Replacer in Juvenile Amur Catfish, Silurus asotus: Effects on Growth, Serological Characteristics and Immune Responses. Asian-Australasian Journal of Animal Sciences 27: 1478–1486. https://doi.org/10.5713/ajas.2014.14038.
45 Kim, Kyoung-Duck, Jin-Do Kim, Sang-Gu Lim, Yong-Jin Kang, and Maeng-Hyun Son. 2010. Effects of Dietary Lipid Sources on the Growth and Body Composition of the far Eastern Catfish, Silurus asotus. Korean Journal of Fisheries and Aquatic Sciences 43: 445–450. https://doi.org/10.5657/kfas.2010.43.5.445.
46 Asdari, Roslianah, Amal Biswas, Shinichi Yamamoto, Hideo Araki, Ken Kawashima, Roshada Hashim, and Kenji Takii. 2014. Effect of Dietar y Palm Oil and Medium Chain Triglycerides on Growth and Fatty Acid Profiles of Japanese Catfish Silurus asotus Juveniles. Aquaculture Science 62: 45–54. https://doi.org/10.11233/aquaculturesci.62.45.
47 Mood, Alison, Elena Lara, Natasha K. Boyland, and Phil Brooke. 2023. Estimating global numbers of farmed fishes killed for food annually from 1990 to 2019. Animal Welfare 32: e12. https://doi.org/10.1017/awf.2023.4.
