African Journal of Aquatic Science

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First record of capensis (Smith, 1841) in the Crocodile River (West) system: another successful non-native freshwater fish introduction in South

JH Erasmus, W Malherbe, R Gerber, OLF Weyl, B Sures, V Wepener & NJ Smit

To cite this article: JH Erasmus, W Malherbe, R Gerber, OLF Weyl, B Sures, V Wepener & NJ Smit (2019) First record of Labeo￿capensis (Smith, 1841) in the Crocodile River (West) system: another successful non-native freshwater fish introduction in South Africa, African Journal of Aquatic Science, 44:2, 177-181, DOI: 10.2989/16085914.2019.1616529 To link to this article: https://doi.org/10.2989/16085914.2019.1616529

Published online: 08 Jul 2019.

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Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=taas20 African Journal of Aquatic Science 2019, 44(2): 177–181 Copyright © NISC (Pty) Ltd Printed in South Africa — All rights reserved AFRICAN JOURNAL OF AQUATIC SCIENCE ISSN 1608-5914 EISSN 1727-9364 https://doi.org/10.2989/16085914.2019.1616529

First record of Labeo capensis (Smith, 1841) in the Crocodile River (West) system: another successful non-native freshwater fish introduction in South Africa

JH Erasmus1* , W Malherbe1 , R Gerber1, OLF Weyl2,3 , B Sures4, V Wepener1 and NJ Smit1

1 Water Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa 2 DST/NRF Research Chair in Inland Fisheries and Freshwater Ecology, South African Institute for Aquatic Biodiversity, Grahamstown, South Africa 3 Centre for Invasion Biology, South African Institute for Aquatic Biodiversity, Grahamstown, South Africa 4 Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen, Essen, Germany *Corresponding author, e-mail: [email protected]

South Africa is one of six global fish invasion hotspots and as a result, non-native fishes are common components of the fish assemblages in all of the major river systems. The rate of establishment for introduced fish into South African rivers is high (79%) and the vector responsible for the highest establishment rate is interbasin transfer schemes with 80%. Introductions of non-native fish into river systems can negatively affect native fish species through hybridisation, competition for food sources and predation, and the introduction of associated parasites and diseases. The aims of the current study were to provide evidence of the introduction of Labeo capensis into the Crocodile River (West) system, using morphological and molecular techniques, and to record the fish health and gonadosomatic index to determine the invasive status of L. capensis. From the fish health assessment index and gonadosomatic index of L. capensis collected from Olifantsnek Dam, it can be concluded that L. capensis is a healthy reproducing population. Because this fish species can survive and reproduce in newly colonised river systems, it has the potential to compete with the native fish species for food and habitat, but can also hybridise with native Labeo species.

Keywords: fish health, genetic barcode, gonadosomatic index, invasion hotspots, translocation

Introduction

Fifty-five fish species (27 alien, 28 extralimital) have the opening of the Orange-Fish River tunnel in 1975, been introduced into or translocated within South African L. capensis were soon sampled from Grassridge Dam in freshwater ecosystems (Ellender and Weyl 2014). These 1977 and from the Great Fish River in 1980 (de Moor and introductions are associated with human activities, such Bruton 1988). The completion of the Cookhouse tunnel in as recreational angling (35%), conservation translocation 1978 facilitated the dispersal of this species to the Sundays (22%), aquaculture (17%), ornamental fish trade (11%), River system (Woodford et al. 2013). Similarly, the Thukela- interbasin transfer schemes (IBTs) (9%) and bio-control Vaal and Grootdraai emergency augmentation schemes are (9%) (Bruton and van As 1986; Ellender and Weyl 2014). likely to be responsible for the occurrence of L. capensis As a result of a high establishment rate (79%) following in Kilburn Dam (SAIAB specimen No.: 130019; 132857; translocation of species, South Africa is one of six 133024; 37045), and in the downstream Majaneni stream global fish invasion hotspots (Leprieur et al. 2008), and (SAIAB specimen No.: 36072; 36074), Kilburn Dam on the non-native fishes are common components of the fish Thukela River (SAIAB specimen No.: 131402; 200731) assemblages in all of South Africa’s major river systems and in the Groot Olifants (Limpopo River catchment) in (Ellender and Weyl 2014). Mpumalanga (SAIAB Specimen No.: 203357). Labeo capensis (Smith, 1841) is a fish species endemic Given the demonstrated ability of L. capensis to to the Orange-Vaal River system (Jubb 1965; de Moor hybridise with the closely related moggel, Labeo umbratus and Bruton 1988; Skelton 2001), which has successfully (Smith 1841) in their introduced range (Ellender and Weyl used human-built corridors to disperse to regions where it 2014), there is concern that these translocations will did not previously occur. The best example is the Orange- compromise the genetic integrity of the Thukela labeo, Fish-Sundays River IBT, which was constructed in the late Labeo rubromaculatus (Gilchrist and Thompson 1913) and 1970s to transfer water from the Orange River catchment the rednose labeo, Labeo rosae (Steindachner 1894) in to support agriculture in the Great Fish and Sundays the Limpopo River catchment. It is therefore important that River catchments (Cambray and Jubb 1977). Following these fish, and the extent of other invasions, are monitored.

African Journal of Aquatic Science is co-published by NISC (Pty) Ltd and Informa UK Limited (trading as Taylor & Francis Group) Published online 08 Jul 2019 178 Erasmus, Gerber, Weyl, Sures, Wepener and Smit

Invasions are seen and normally described on a global Materials and methods scale, whereas less attention is paid to within-country or between watershed translocations. Many studies focus Study area on the primary invasive species (i.e. Common carp, The Hex River is located in the North West province in Cyprinus carpio (Linnaeus 1758), Largemouth bass, South Africa and drains in a northerly direction into the Micropterus salmoides (Lacepède 1802) and Rainbow Crocodile River, forming part of the Limpopo River system trout, Oncorhynchus mykiss (Walbaum 1792)) that have (Almécija et al. 2017). Three impoundments are situated successfully invaded across continents. The smaller within the Hex River system, Olifantsnek Dam in the upper scale invasions, would also result in non-endemic fish reaches, Bospoort Dam in the middle reaches and Vaalkop species for certain ecosystems, which might have severe Dam in the lower reaches (Figure 1). Olifantsnek Dam is impacts on the natural fish communities. These within- mainly used for irrigation, but is also used for recreational country or between watershed translocations place purposes i.e. fishing and sailing. closely related fish, but usually naturally separated, into the same environment, which can lead to interbreeding Fish collection and total introgression. Surveys were conducted in May and November 2017 in the The current paper provides evidence of the introduction Hex River, as well as in Olifantsnek and Bospoort Dams. of L. capensis into the Crocodile River (West) system, The necessary permit (HO 09/03/17–125 NW, North West Limpopo River catchment, North West province, and uses province, Department of Rural, Environmental and Agricultural an evaluation of fish health and reproductive status to infer Development) and ethical clearance (NWU-00282-17-A5) its establishment. for collecting and euthanizing fish were obtained prior to

Legend AFRICA Study site River Limpopo South Translocated occurence Africa NAMIBIA Native distribution range iver Crocodile h R Olifants is Hardap Dam Water body F Town 25° S Vaalkop Dam Roodekopjes Dam Bospoort Dam Hartebeespoort Dam Hex r e OLIFANTSNEK DAM v i

R

MOZAMBIQUE h

s i al F Vaal Dam Va

Bloemhof Dam Orange/Vaal catchment Sterkfontein Dam O ra n Spioenkop Dam g Kilburn Dam e Thukela

Katse Dam

30° S Vanderkloof Dam Durban

SOUTH AFRICA Gariep Dam

Grassridge Dam

ATLANTIC G INDIAN r OCEAN e OCEAN a t Fi sh S East London Darlington Dam u nd a ys Cape Town 150 km Port Elizabeth

35° S 20° E 25° E 30° E

Figure 1: Map of the endemic and translocated distribution of Labeo capensis, as well as the study site (new translocated distribution site in the Olifantsnek Dam in the Crocodile River (West) system, South Africa). GBIF Occurrence Download doi:10.15468/dl.ijxwsh accessed via GBIF.org on 8 Sept 2018 African Journal of Aquatic Science 2019, 44(2): 177–181 179 sampling. Fish were collected using multifilament gill nets VF1 t1 (5’-TTCTCAACCAACCACAAAGACATTGG-3’) (45 × 3 m, consisting of five 9 × 3 m sections with stretch mesh (Ivanova et al. 2006) and the reverse primer VR1 t1 sizes of 45, 60, 75, 100 and 145 mm), that were deployed (5’-TAGACTTCTGGGTGGCCAAAGAATCA-3’) (Ward et al. shortly after dawn for nine hours and were checked every 2005). The PCR thermal cycler profile was as follows: initial three hours. Other equipment used included fyke nets (5 m DNA denaturation for 3 min. at 95 °C followed by 35 cycles total length, height of 50 cm (D-ring) with a mesh size of with 30 sec. DNA denaturation at 94 °C, 30 sec. primer 15 mm) and seine nets (25 × 1 m × 25 mm mesh). annealing at 55 °C, and 2 min. at 72 °C for primer extension. The specimens were identified a priori using the key by A final extension step of 7 min. at 72 °C was followed by Skelton (2001) on the basis of the number of lateral line storage at 4 °C. The PCR products were run on 1% agarose scales, number of scales between the lateral line and base gel and visualised with EZ-Vision®Blue Light DNAdye to of the dorsal fin, number of scales between the lateral line verify successful amplification. Amplified PCR products and base of the pelvic fin and number of scales around were sent to a commercial sequencing company (Inqaba the caudal peduncle. They were subsequently euthanized Biotechnical Industries Pty Ltd. Pretoria, South Africa) for by means of percussive stunning followed by pithing (SOP sequencing. Products were sequenced directly using the NWU-00267-17-S5). These individuals were euthanised in PCR primers. Contiguous sequences were assembled and order to perform the fish health assessment index (FHAI) edited using Geneious ver. 11 (Biomatters. Available from and calculate the condition factor (CF) and gonadosomatic http://www.geneious.com). Unique COI haplotypes were index (GSI) after Adams et al. (1993). These indices identified using DnaSP ver. 6 (Rozas et al. 2003). were assessed because they provide evidence to the Genetic distance matrices (uncorrected p-distance) successfulness of invasion in terms of establishment, were calculated in MEGA ver. 6. The newly generated COI for example the overall fish health and maturity status of sequence for the specimens of L. capensis from Olifantsnek the invasive population. Externally the eyes, skin, fins, Dam (n = 11) (GenBank No.: MK746140; MK746141; gills and opercula were inspected, whereas internally the MK746142; MK746143; MK746144; MK746145; MK746146; bile, mesenteric fat, liver, spleen, hindgut, kidney and MK746148; MK746149; MK746150) and from the Vaal River visceral parasites were assessed. A blood sample was catchment (n = 6) (GenBank No.: MK746151; MK746152; also collected to assess the haematocrit of the fish. Six MK746153; MK746154; MK746155; MK746156) were L. capensis specimens were collected from their native aligned with reference to the amino acid translation, using distribution range in the Vaal River approximately 20 km the vertebrate mitochondrial code (transl_table = 2) with downstream of the Vaal Dam for genetic comparisons. MUSCLE implemented in Mega v.6 (Tamura et al. 2013).

Sequence generation Results Left pelvic fin clippings were taken from the 11 Olifantsnek Dam specimens and the six L. capensis specimens from The meristic measurements of the 15 specimens (range the Vaal River catchment for comparison purposes and 150–355 mm TL) collected from Olifantsnek Dam were genetic sequencing. Genomic DNA was isolated from consistent with those for L. capensis in Skelton (2001). left pelvic fin clippings preserved in 70% ethanol using Three specimens were collected during the May 2017 the standard protocol for the Kapa Express Extract kit survey and 12 in November 2017. Two specimens (Kapa Biosystems, Cape Town, South Africa). Partial (Specimens 14 and 15; Table 1) were retained as vouchers fragment of mitochondrial cytochrome c oxidase subunit (Figure 2; SAIAB Voucher No.: 207729) and lodged in I (COI) gene was amplified using the forward primer the collection of the South African Institute for Aquatic

Table 1: Individual Labeo capensis biometric information and calculated index factor for fish health assessment index (FHAI), condition factor (CF) and gonadosomatic index (GSI) collected from Olifantsnek Dam in the Crocodile River (West) system in May and November 2017

Fish Date Sex Weight (g) TL (mm) SL (mm) FHAI CF GSI (%) SAIAB No. GenBank No. 1 05/17 M 60.32 190 160 10 1.47 0.77 200951 – 2 05/17 M 44.92 175 145 10 1.47 0.15 200951 – 3 05/17 J 33.70 150 125 10 1.73 ND 200951 MK746140 4 11/17 J 84.16 215 175 10 1.57 ND 200950 MK746141 5 11/17 F 340.00 345 275 10 1.63 11.93 200950 MK746142 6 11/17 M 90.78 225 180 10 1.56 0.26 200950 MK746143 7 11/17 M 91.12 225 180 10 1.56 0.50 200950 MK746144 8 11/17 M 220.00 290 235 10 1.70 4.96 200950 MK746145 9 11/17 M 74.63 215 170 10 1.52 0.55 200950 MK746146 10 11/17 M 280.00 315 255 30 1.69 4.52 200950 MK746147 11 11/17 J 82.14 215 170 10 1.67 ND 200950 MK746148 12 11/17 M 180.00 270 215 10 1.81 0.43 200950 MK746149 13 11/17 M 520.00 355 305 10 1.83 7.66 200950 MK746150 14 11/17 ND 49.86 195 155 ND 1.34 ND 207729 – 15 11/17 ND 70.22 205 170 ND 1.43 ND 207729 – M – male, F – female, J – juvenile, TL – total length, SL – standard length, ND – not determined. 180 Erasmus, Gerber, Weyl, Sures, Wepener and Smit

Figure 2: Labeo capensis (Smith, 1841) collected from Olifantsnek Dam in the Crocodile River (West) system (SAIAB specimen No.: 207729)

Biodiversity (SAIAB). Of the 13 dissected specimens, one Discussion was female, nine were male and three were juveniles of indeterminate sex (Table 1). The information presented here is the first report of L. capensis occurring in the Crocodile River (West) tributary of the Genetic identification Limpopo River catchment. Genetic assessment demonstrated The final alignment was 688 nucleotides (nt) long. The genetic that haplotypes were shared between L. capensis from divergence (uncorrected p-distance) between the sequences Olifantsnek Dam (translocated site) and the Vaal River within alignment ranged from 0.1 to 0.7% (1–5 nt difference). (endemic range). This, in conjunction with the absence of an This level of intraspecific divergence is below the maximum IBT scheme between the two rivers and the close proximity level observed for 35 species from 25 genera in eight cyprinid of the Vaal River to the Olifantsnek Dam, suggests human subfamilies (0–3.81%) (Shen et al. 2016). Accordingly, assisted translocation. Labeo capensis is a popular target all isolates collected from Olifantsnek Dam and the Vaal species for recreational anglers (Weyl and Cowley 2016; River catchment represent the same species, L. capensis. Barkhuizen et al. 2017) and angling-based introductions are Fifteen novel sequences for L. capensis were collapsed into a major pathway of fish introductions in South Africa (Ellender 9 haplotypes. Of these, four unique haplotypes were identified and Weyl 2014; Marr et al. 2017). Anecdotal reports from local in isolates of L. capensis from Olifantsnek Dam and three anglers suggest that angling-based introduction was also the unique haplotypes from the Vaal River. Two haplotypes of pathway of L. capensis introduction into Olifantsnek Dam. L. capensis were shared between specimens collected from At least one female and three male fish were large enough the Olifantsnek Dam and the Vaal River. to be reproductively capable and all exhibited GSI consistent with gonadal development during the summer reproductive Gonadosomatic index season of this fish (see Winker et al. 2012). As a result of the The gonadosomatic index (Table 1) indicates sexual presence of both, spawning capable and juvenile individuals maturity and spawning seasons in fish. The GSI calculated in the population (Table 1), we conclude that L. capensis is for the specimens collected from the Olifantsnek Dam established in the Olifantsnek Dam. High FHAI scores also indicated that ovaries in the female specimen(s) comprised suggest that the population is in a healthy condition. According 11.9% of the body mass, and the testes up to 7.7% of body to van As and Basson (1984), five species of parasites mass in male specimens. (Lernaea sp. (Linnaeus, 1746), Lernaea barnimiana (Hartman, 1865), Apiosoma sp. (Blanchard, 1885), Argulus japonicus Fish health assessment index (Thiele, 1900) and Chonopeltis australis (Boxshall, 1976)) The FHAI scores indicated that the fish were in a healthy are associated with L. capensis in its endemic range, of condition (Table 1). All the fish had haematocrit readings which A. japonicus is an alien to southern Africa (Smit et al. above the normal range, hence receiving a score of 10. A 2017). Translocation of L. capensis into the Crocodile River single specimen had a higher score (30), as a result of black (West) system can consequently facilitate the spread of these spot caused by an encysted larval trematode (Digenea) parasites to other native fish species within this system and parasite. Although five parasite species are known to therefore warrants additional investigation. parasitise L. capensis (see van As and Basson 1984) in Introductions of non-native fish into river systems can have its native range, these parasites were not present in the impacts on the native fish species through hybridisation, specimens collected during this study. genetic impacts and introgression, competition for food African Journal of Aquatic Science 2019, 44(2): 177–181 181 sources and predation, as well as the introduction of Bruton MN, van As JG. 1986. Faunal invasions of aquatic associated parasites and diseases (Ellender and Weyl 2014; ecosystems in Southern Africa, with suggestions for their Smit et al. 2017). Although neither the full extent, nor the management. In: MacDonald IAW, Kruger FJ, Ferrar AA (Eds). The Ecology and Management of Biological Invasions in ecological consequences of this invasion are currently known, Southern Africa. Cape Town: Oxford University Press. pp 47–61. L. capensis has the potential to hybridise with other species of Cambray JA, Jubb RA. 1977. Dispersal of fishes via the Orange- the genus Labeo and the closely related native L. rosae might Fish tunnel, South Africa. Journal of the Limnological Society of be at risk (Ellender and Weyl 2014). Because the species Southern Africa 3: 33–35. has also been sampled from the Limpopo catchment in de Moor IJ, Bruton MN. 1988. Atlas of alien and translocated Mpumalanga (SAIAB Specimen No.: 203357) we recommend indigenous aquatic in Southern Africa. South African surveys to establish the extent of the L. capensis invasion National Scientific Programmes Report 144. Pretoria: Council for in this system. There is still a lack of information regarding Scientific and Industrial Research. all aspects of the invasion process, from the introduction Ellender BR, Weyl OLF. 2014. A review of current knowledge, risk phase to the establishment, spread and the impacts thereof and ecological impacts associated with non-native freshwater fish introductions in South Africa. Aquatic Invasions 9: 117–132. (Ellender and Weyl 2014). Recreational anglers are the Ivanova NV, deWaard JR, Hebert PDN. 2006. An inexpensive, main culprit of human associated fish introductions in South automation-friendly protocol for recovering high-quality DNA. Africa. A sterner effort must be made by Management and Molecular Ecology Notes 6: 998–1002. Conservation authorities, as well as Educational Institutions, Jubb RA. 1965. Freshwater fishes of the Cape province. Annals of to inform the public about the harmful environmental impacts the Cape Provincial Museums 4: 1–72. of translocating fish from one watershed to another. Leprieur F, Beauchard O, Blanchet S, Oberdorff T, Brosse S. 2008. Fish invasions in the World’s River Systems: When Natural Processes Acknowledgements — The financial assistance of the NRF (National Are Blurred by Human Activities. PLoS Biology 6: 404–410. Research Foundation, South Africa, project GERM160623173784, Marr SM, Ellender BR, Woodford DJ, Alexander ME, Wasserman grant 105875: NJ Smit, PI), and BMBF/PT-DLR (Federal Ministry RJ, Ivey P, Zengeya T, Weyl OLF. 2017. Evaluating invasion risk of Education and Research, Germany, grant 01DG17022: B for freshwater fishes in South Africa. Bothalia 47: 10 pg. Sures, PI), towards this research is hereby acknowledged. OLFW Rozas J, Sanchez-DelBarrio JC, Messeguer X, Rozas R. 2003. acknowledges support from the NRF – South African Research DnaSP, DNA polymorphism analyses by the coalescent and Chairs Initiative of the Department of Science and Technology other methods. Bioinformatics 19: 2496–2497. (Grant No. 110507). Opinions expressed, and conclusions arrived at, Shen Y, Guan L, Wang D, Gan X. 2016. 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Received: 14 January 2019; Revised: 15 April 2019; Accepted: 2 May 2019 Associate Editor: K Reinecke