Life‐stage and environmental influences on the recruitment of African freshwater eels into the
                    uThukela
                    River, South Africa

Rory McNeill; Matthew J. Burnett; Céline Hanzen; Colleen T. Downs

doi:10.1111/jfb.70239

journal article Open Access Sep 30, 2025

Life‐stage and environmental influences on the recruitment of African freshwater eels into the uThukela River, South Africa

Rory McNeill

Matthew J. Burnett

Céline Hanzen

Colleen T. Downs

Journal of Fish Biology Vol. 108 No. 1 pp. 307-317 · Wiley

View at Publisher Save 10.1111/jfb.70239

Abstract

Abstract

Anguillid eel recruitment into east‐flowing rivers along the east coast of Africa is poorly understood. The few harvest records of anguillid eels from South Africa have highlighted anthropogenically derived environmental stressors as risks for further decline. Our study aimed to determine environmental conditions and elver development associated with eel recruitment in the uThukela River, KwaZulu‐Natal, South Africa. Our study was conducted between November 2021 and September 2022 and compared the effect of high‐ and low‐flow conditions and the associated environmental variables on eel recruitment. We captured 519 eels and identified 220 (42%) which were classified into three species (
Anguilla bengalensis n
= 51,
Anguilla marmorata n
= 60 and
Anguilla mossambica n
= 120). We captured glass eels (
n
= 461) and elvers (
n
= 36), and included transitioning individuals (
n
= 22) between the stages. All eels were caught in high‐water‐flow conditions, which supports the hypothesis that eels prefer high water flow for recruitment, which usually occurs in rainy, warm austral summer months. We found a significant difference between the body lengths of the three identified species. We found a significant difference between the life stages present, which was primarily between glass eel and elver, with the transitional phase grouping in body length relative to glass eel body length. Our results highlighted the need to improve field identification of glass eels. In addition, an in‐depth understanding of the recruitment trends for African freshwater eels in east‐flowing rivers is needed.

Topics

No keywords indexed for this article. Browse by subject →

References

68

[1]

Africa L.(2024).Recruitment and presence of native migratory fish species in the uThukela River estuary and lower uMngeni River catchment KwaZulu‐Natal South Africa. MSc thesis University of KwaZulu‐Natal.

[2]

10.1016/j.heliyon.2020.e05176

[3]

10.1038/s41598-020-72788-9

[4]

10.1111/j.1095-8649.2012.03353.x

[5]

10.1093/icesjms/fsv116

[6]

10.1098/rspa.1980.0122

[7]

Bate G. C. Whitfield A. K. &Forbes A. T.(2011).A review of studies on the Mfolozi Estuary and associated flood plain with emphasis on information required by management for future reconnection of the river to the St Lucia System Report no. KV 255–10. Water Research Commission Pretoria South Africa. p. 264.

[8]

10.1051/kmae:2005001

[9]

10.1093/icesjms/fsac122

[10]

10.1051/kmae:2005002

[11]

10.1111/aje.13234

[12]

CoastKZN. (2024).Estuaries.https://www.coastkzn.co.za/themes/estuaries/know-your-estuaries/

[13]

10.1098/rsos.190812

[14]

10.1126/sciadv.1602007

[15]

10.3354/meps308231

[16]

10.1007/s11160-005-7431-x

[17]

Lecea A. M. (2016)

[18]

10.1093/icesjms/24.1.135

[19]

Department of Water Affairs and Forestry (DWAF) (2002)

[20]

10.1007/978-1-4020-9095-0_18

[21]

Elie P. "Definition of the limits of the pigmented stages of the civelle Anguilla anguilla L. (in French)" Vie et Milieu (1982)

[22]

10.2989/16085914.2021.1952158

[23]

10.1007/978-4-431-65907-5_14

[24]

10.1007/bf01983739

[25]

Gitonga L. M. (2022)

[26]

10.17159/sajs.2022/14020

[27]

10.1007/s10750-021-04581-2

[28]

10.1071/mf19390

[29]

10.1002/aqc.3823

[30]

10.1079/9781800629097.0004

[31]

10.2989/025776195784156601

[32]

10.1007/s11160-014-9356-8

[33]

ICES (2023)

[34]

10.1007/s11160-021-09658-8

[35]

10.1046/j.1095-8649.2003.00220.x

[36]

10.3354/ab00018

[37]

10.1016/j.ecss.2006.12.011

[38]

10.1016/j.ecss.2009.07.021

[39]

10.1111/j.1095-8649.2012.03357.x

[40]

10.1007/s10641-005-1367-9

[41]

10.1016/j.seares.2012.10.006

[42]

10.1093/icesjms/40.3.262

[43]

10.1111/j.1095-8649.1980.tb03723.x

[44]

10.3390/atmos11060623

[45]

Nel J. L. Murray K. M. Maherry A. M. Petersen C. P. Roux D. J. Driver A. Hill L. Van Deventer H. Funke N. Swartz E. R. &Smith‐Adao L. B.(2011).Technical report for the national freshwater ecosystem priority areas project. Water Research Commission Report Pretoria.

[46]

10.1016/j.pocean.2010.06.002

[47]

R Core Team (2022)

[48]

Reddering J. S. V. "Historical changes and sedimentary characteristics of southern African estuaries" South African Journal of Science (1990)

[49]

10.1111/j.1095-8649.2009.02284.x

[50]

10.1111/faf.12549

Showing 50 of 68 references

Metrics

0

Citations

68

References

Details

Published: Sep 30, 2025
Vol/Issue: 108(1)
Pages: 307-317
License: View

Authors

R

Rory McNeill

Centre for Functional Biodiversity, School of Life Sciences University of KwaZulu‐Natal Pietermaritzburg South Africa

M

Matthew J. Burnett

Centre for Functional Biodiversity, School of Life Sciences University of KwaZulu‐Natal Pietermaritzburg South Africa; Ecosystems Institute of Natural Resources NPC Scottsville South Africa

C

Céline Hanzen

Centre for Functional Biodiversity, School of Life Sciences University of KwaZulu‐Natal Pietermaritzburg South Africa

C

Colleen T. Downs

Centre for Functional Biodiversity, School of Life Sciences University of KwaZulu‐Natal Pietermaritzburg South Africa

Funding

Wellcome Trust Award: 227749/Z/23/Z

Western Indian Ocean Marine Science Association

Cite This Article

Rory McNeill, Matthew J. Burnett, Céline Hanzen, et al. (2025). Life‐stage and environmental influences on the recruitment of African freshwater eels into the uThukela River, South Africa. Journal of Fish Biology, 108(1), 307-317. https://doi.org/10.1111/jfb.70239

Life‐stage and environmental influences on the recruitment of African freshwater eels into the uThukela River, South Africa

You May Also Like