Optimal Stocking Densities and High-Density Stress Response Mechanisms in Two Size Classes of Juvenile Largemouth Bass (Micropterus salmoides)

Yaqing Xu; Kaipeng Zhang; Jie Wei; Zhaohua Huang; Dieyan Zhang; Yongming Ran; Zhulan Nie

doi:10.53941/ale.2026.100007

Abstract

To clarify the optimal stocking density and density stress mechanism of Micropterus salmoides juveniles of different sizes, two size classes of M. salmoides (size 1: 8.0 ± 0.5 g, size 2: 50 ± 3.2 g) were selected as the research objects. Five stocking density gradients (0.25, 0.75, 1.25, 1.75 and 2.25 kg·m⁻³) were set up. After 30 days of culture, the growth performance, feeding and swimming behaviors, oxidative stress, and water quality indices were determined. The results showed that the survival rates of 0.25, 0.75 and 1.25 kg·m⁻³ groups had no significant difference and were significantly higher than those of high-density groups. The optimal stocking density of size 1 M. salmoides was 0.75–1.25 kg·m⁻³, which could balance optimal growth and high survival; beyond this range, the growth performance decreased significantly. High stocking density led to intensified feeding competition, increased stress-induced swimming activity, aggravated oxidative damage and water quality deterioration. In addition, size 2 M. salmoides was more sensitive to high-density stress, with a significantly narrower optimal density window, and its optimal stocking density was identified as 0.75 kg·m⁻³. Density stress exerted its effects through the pathway of spatial competition → behavioral abnormalities → oxidative damage → growth inhibition, and formed a negative feedback loop with water quality deterioration. This study provides a scientific basis for the precision regulation of stocking density in intensive culture of M. salmoides.

References

1.
Qi, Z.; Xu, Y.; Liu, Y.; et al. Transcriptome Analysis of Largemouth Bass (Micropterus salmoides) Challenged with LPS and polyI:C. Fish Shellfish Immunol. 2023, 133, 108534. https://doi.org/10.1016/j.fsi.2023.108534.
2.
Cheng, T.; Chen, J.; Tan, B.; et al. Effects of α-Lipoic Acid (LA) Supplementation in High-Fat Diet on the Growth, Glycolipid Metabolism and Liver Health of Largemouth Bass (Micropterus salmoides). Fish Shellfish Immunol. 2025, 157, 110072. https://doi.org/10.1016/j.fsi.2024.110072.
3.
Yu, P.; Chen, H.; Liu, M.; et al. Current Status and Application of Largemouth Bass (Micropterus salmoides) Germplasm Resources. Reprod. Breed. 2024, 4, 73–82. https://doi.org/10.1016/j.repbre.2024.01.004.
4.
Li, Z.Y.; Zhang, L.B.; Gao, C.; et al. Experimental Summary on the Intensive Aquaculture of Largemouth Bass “Youlu No. 1” in Pond in-Pond Raceway Systems with Air-Push Water Circulation. Sci. Fish Farming 2015, 6, 36–37. https://doi.org/10.14184/j.cnki.issn1004-843x.2015.06.020.
5.
Li, M.; Yang, L.; Liu, Y. Transcriptomic Changes of Telencephalon and Hypothalamus in Largemouth Bass (Micropterus salmoides) under Crowding Stress. Biology 2025, 14, 809. https://doi.org/10.3390/biology14070809.
6.
Yang, S.; Zhao, J.; An, N.; et al. Updates on Infectious Diseases of Largemouth Bass: A Major Review. Fish Shellfish Immunol. 2024, 154, 109976. https://doi.org/10.1016/j.fsi.2024.109976.
7.
Zhang, B.; Shen, Q.J.; Xu, H.; et al. Effects of Stocking Density on Water Quality and Nutritional Quality of Largemouth Bass (Micropterus salmoides) in Aquaculture. J. Fish. Res. 2025, 47, 508–520. https://doi.org/10.14012/j.jfr.2025007.
8.
Wang, L.; Shi, D.J.; Zhu, J.Y.; et al. Effects of Planting-Rearing Density and Feeding Frequency on the Growth of Largemouth Bass (Micropterus salmoides) and Water Quality in an Aquaponics System. J. Agric. Sci. Technol. 2025, 27, 43–55. https://doi.org/10.13304/j.nykjdb.2025.0203.
9.
Wang, R. Research on the Optimal Stocking Density for Largemouth Bass (Micropterus salmoides) and Northern Snakehead (Channa argus) Based on the TOPSIS Method. Master’s Thesis, Foshan University, Foshan, China, 2025.
10.
Huang, W.Q.; Huang, L.; Lai, M.J.; et al. Effects of Feeding Frequency, Water Temperature, and Stocking Density on Growth Performance, Intestinal Structure, and Hepatic Expression of Growth-Related Genes in Largemouth Bass (Micropterus salmoides). Guangdong Agric. Sci. 2022, 49, 111–119. https://doi.org/10.16768/j.issn.1004-874X.2022.08.014.
11.
Sangiao-Alvarellos, S.; Guzmán, J.M.; Láiz-Carrión, R.; et al. Interactive Effects of High Stocking Density and Food Deprivation on Carbohydrate Metabolism in Several Tissues of Gilthead Sea Bream Sparus auratus. J. Exp. Zool. 2005, 303A, 761–775. https://doi.org/10.1002/jez.a.203.
12.
Yan, D.D. Effects of Crowding Stress and Heat Stress on Intestinal Cell Apoptosis in Largemouth Bass (Micropterus salmoides). Master’s Thesis, Guizhou University, Guiyang, China, 2025.
13.
Zhang, H.T. Effects of Crowding Stress and Low Salinity on Growth, Antioxidant Capacity, and Stress Response in Juvenile Largemouth Bass (Micropterus salmoides). Master’s Thesis, Zhejiang Ocean University, Zhoushan, China, 2024.
14.
Mo, J.H.; Li, C.Z.; Wang, X.B.; et al. Growth Characteristics of Largemouth Bass (Micropterus salmoides) at Different Stocking Densities in Indoor Industrial Recirculating Aquaculture Systems. Freshw. Fish. 2022, 52, 98–104. https://doi.org/10.13721/j.cnki.dsyy.2022.03.001.
15.
Martínez, G.; Peña, E.; Martínez, R.; et al. Survival, Growth, and Development in the Early Stages of the Tropical Gar Atractosteus tropicus: Developmental Critical Windows and the Influence of Temperature, Salinity, and Oxygen Availability. Fishes 2021, 6, 5.
16.
Miyanishi, H.; Oikawa, S. Ontogenetic Phase Shifts in Metabolism in a Flounder Paralichthys olivaceus. Sci. Rep. 2014, 4, 7135. https://doi.org/10.1038/srep07135.
17.
Zhang, L. Studies on Energy Budget and Bioenergetics-Based Optimal Growth Model of Yellow Catfish (Pelteobagrus fulvidraco). Ph.D. Dissertation, Huazhong Agricultural University, Wuhan, China, 2010.
18.
Wang, S.; Yu, X.L.; Gong, Y.X.; et al. Effects of Stocking Density on Growth Performance and Economic Benefits of Acrossocheilus fasciatus Cultured in Ponds in Plain Areas. Freshw. Fish. 2025, 55, 85–90. https://doi.org/10.13721/j.cnki.dsyy.2025.06.002.
19.
Upadhyay, A.; Swain, H.S.; Das, B.K.; et al. Stocking Density Matters in Open Water Cage Culture: Influence on Growth, Digestive Enzymes, Haemato-Immuno and Stress Responses of Puntius sarana (Ham, 1822). Aquaculture 2022, 547, 737445. https://doi.org/10.1016/j.aquaculture.2021.737445.
20.
Xiao, J.C.; Zhao, Y.F.; Shi, Y.H.; et al. Effects of Stocking Density on Growth, Physiology, and Reproduction of Blue Parrotfish (Amphilophus sp.). J. Trop. Biol. 2025, 16, 304–311. https://doi.org/10.15886/j.cnki.rdswxb.20240124.
21.
Vaishali; Mandal, A.; Holeyappa, S.A.; et al. Growth Performance, Health Status and Flesh Quality of Striped Catfish (Pangasianodon hypophthalmus) Reared in Variable Stocking Densities in Biofloc System. Aquaculture 2024, 590, 741047. https://doi.org/10.1016/j.aquaculture.2024.741047.
22.
Chen, L.T.; Wu, J.F.; Tao, Z.M.; et al. Effects of Stocking Density on Growth Performance of Tilapia and Water Quality in a Closed Water Body. Guangxi Sci. 2024, 31, 279–286. https://doi.org/10.13656/j.cnki.gxkx.20240619.008.
23.
Li, X. Fundamental Research on Characteristic Indicator Factors Based on Fish Welfare in Recirculating Aquaculture Systems. Ph.D. Dissertation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China, 2012.
24.
Li, L.; Shen, Y.; Yang, W.; et al. Effect of Different Stocking Densities on Fish Growth Performance: A Meta-Analysis. Aquaculture 2021, 544, 737152. https://doi.org/10.1016/j.aquaculture.2021.737152.
25.
Ribeiro, F.F.; Forsythe, S.; Qin, J.G. Dynamics of Intracohort Cannibalism and Size Heterogeneity in Juvenile Barramundi (Lates calcarifer) at Different Stocking Densities and Feeding Frequencies. Aquaculture 2015, 444, 55–61. https://doi.org/10.1016/j.aquaculture.2015.03.029.
26.
Spada, N.N.; Fairchild, E.A.; Trushenski, J.T. Tolerance of Juvenile Lumpfish (Cyclopterus lumpus) to High Rearing Densities. J. World Aquac. Soc. 2024, 55, e13089.
27.
Zhang, X.H.; Li, W.Y.; Liu, B.L.; et al. Effects of Density Stress on Growth and Physiology of Epinephelus fuscoguttatus♀ × E. lanceolatus♂. Prog. Fish. Sci. 2025, 46, 71–81. https://doi.org/10.19663/j.issn2095-9869.20240307001.
28.
Qin, M. Effects of α-Lipoic Acid on Growth Performance, Antioxidant Capacity, and Muscle Quality of Largemouth Bass (Micropterus salmoides) under High-Density Aquaculture Conditions. Master’s Thesis, Huazhong Agricultural University, Wuhan, China, 2024.
29.
Wang, Y.; Chen, C.G.; Zhang, J.R.; et al. Effects of Stocking Density on Growth, Feed Utilization, and Intestinal Antioxidant Stress Capacity of Juvenile Megalobrama pellegrini. Prog. Fish. Sci. 2022, 43, 106–114. https://doi.org/10.19663/j.issn2095-9869.20200920001.
30.
Majhi, S.S.; Singh, S.K.; Biswas, P.; et al. Stocking Density Affects Immune and Stress-Related Gene Expression of Butter Catfish (Ompok bimaculatus) Fry in Biofloc Landscapes. Fish Shellfish Immunol. Rep. 2023, 5, 100112. https://doi.org/10.1016/j.fsirep.2023.100112.
31.
Hou, M.H.; Han, H.W.; Zhang, L.L.; et al. Effects of Stocking Density on the Performance of Atlantic Salmon (Salmo salar) in a Recirculating Aquaculture System. Trans. Oceanol. Limnol. 2020, 2, 113–121. https://doi.org/10.13984/j.cnki.cn37-1141.2020.02.014.
32.
Ni, J.J.; Wang, Y.Y.; Xu, G.C.; et al. Effects of Stocking Density on Growth, Physiological Indices, and Expression of GH and IGF-I Genes in Largemouth Bass (Micropterus salmoides) Cultured in an In-Pond Raceway System. J. Dalian Fish. Univ. 2020, 35, 805–813. https://doi.org/10.16535/j.cnki.dlhyxb.2019-299.
33.
Jacobson, B.; Grant, J.W.A.; Peres-Neto, P.R. The Interaction Between the Spatial Distribution of Resource Patches and Population Density: Consequences for Intraspecific Growth and Morphology. J. Anim. Ecol. 2015, 84, 934–942. https://doi.org/10.1111/1365-2656.12365.
34.
Keeley, E.R. Demographic Responses to Food and Space Competition by Juvenile Steelhead Trout. Ecology 2001, 82, 1247–1259. https://doi.org/10.1890/0012-9658(2001)082[1247:DRTFAS]2.0.CO;2.
35.
Santos, G.A.; Schrama, J.W.; Mamauag, R.E.P.; et al. Chronic Stress Impairs Performance, Energy Metabolism and Welfare Indicators in European Seabass (Dicentrarchus labrax): The Combined Effects of Fish Crowding and Water Quality Deterioration. Aquaculture 2010, 299, 73–80. https://doi.org/10.1016/j.aquaculture.2009.11.018.
36.
Basrur, T.V.; Longland, R.; Wilkinson, R.J. Effects of Repeated Crowding on the Stress Response and Growth Performance in Atlantic Salmon (Salmo salar). Fish Physiol. Biochem. 2010, 36, 445–450. https://doi.org/10.1007/s10695-009-9314-x.
37.
Sadoul, B.; Alfonso, S.; Cousin, X.; et al. Global Assessment of the Response to Chronic Stress in European Sea Bass. Aquaculture 2021, 544, 737072. https://doi.org/10.1016/j.aquaculture.2021.737072.
38.
Andrew, J.E.; Holm, J.; Kadri, S.; et al. The Effect of Competition on the Feeding Efficiency and Feed Handling Behaviour in Gilthead Sea Bream (Sparus aurata L.) Held in Tanks. Aquaculture 2004, 232, 317–331. https://doi.org/10.1016/S0044-8486(03)00528-3.
39.
Yu, H.N. Effects of Environmental Stress on Behavior, Growth and Physiological Activity of Macrobrachium rosenbergii and Litopenaeus vannamei. Ph.D. Dissertation, Jinan University, Guangzhou, China, 2007.
40.
Li, H.W.; Brocksen, R.W. Approaches to the Analysis of Energetic Costs of Intraspecific Competition for Space by Rainbow Trout (Oncorhynchus mykiss). J. Fish Biol. 1977, 11, 329–341. https://doi.org/10.1111/j.1095-8649.1977.tb04126.x.
41.
Tao, Y.; Hua, J.; Lu, S.; et al. Ultrastructural, Antioxidant, and Metabolic Responses of Male Genetically Improved Farmed Tilapia (GIFT, Oreochromis niloticus) to Acute Hypoxia Stress. Antioxidants 2024, 13, 89. https://doi.org/10.3390/antiox13010089.
42.
Zhou, Q.S.; Ren, X.Y.; Xu, Y.; et al. Effects of Ammonia-Nitrogen Stress on Metabolic Enzyme and Antioxidant Enzyme Activities in Ornate Spiny Lobster (Panulirus ornatus). Prog. Fish. Sci. 2022, 43, 147–156. https://doi.org/10.19663/j.issn2095-9869.20210125002.
43.
Mentesana, L.; Adreani, N.M. Acute Aggressive Behavior Perturbates the Oxidative Status of a Wild Bird Independently of Testosterone and Progesterone. Horm. Behav. 2021, 128, 104913. https://doi.org/10.1016/j.yhbeh.2020.104913.
44.
Kwatra, M.; Ahmed, S.; Gangipangi, V.K.; et al. Lipopolysaccharide Exacerbates Chronic Restraint Stress-Induced Neurobehavioral Deficits: Mechanisms by Redox Imbalance, ASK1-Related Apoptosis, Autophagic Dysregulation. J. Psychiatr. Res. 2021, 144, 462–482. https://doi.org/10.1016/j.jpsychires.2021.10.021.
45.
Sanchez-Aceves, L.M.; Gómez-Olivan, L.M.; Pérez-Alvarez, I.; et al. Effects of Effluents from the Villa Victoria Reservoir (Mexico) on the Development of Danio rerio at Early Life Stages Through Apoptotic Response and Oxidative-Induced State. Sci. Total Environ. 2024, 957, 177581. https://doi.org/10.1016/j.scitotenv.2024.177581.
46.
Xu, D.D.; Wang, C.H.; Bi, J.Q.; et al. Physiological and Behavioral Responses to Social Isolation and Starvation in a Social Fish. Appl. Anim. Behav. Sci. 2024, 278, 106384. https://doi.org/10.1016/j.applanim.2024.106384.

Scilight Press

Author Information

Abstract

Keywords

References

About Scilight

Journals

Publishing Policies

Contact Us