Int. J. Aquat. Biol. (2020) 8(4): 272-280 ISSN: 2322-5270; P-ISSN: 2383-0956 Journal homepage: www.ij-aquaticbiology.com © 2020 Iranian Society of Ichthyology Original Article Prey identification of invasive peacock bass from Telabak Lake Malaysia using DNA barcoding technique Aliyu Garba Khaleel1,2, Najlaa Nawwarah Rusli1, Nurul Izzati Mohd Radzif1, Aiman Syafiq Muhd Nasir1, Mohamad Zulkarnain Mohd Dali1, Norshida Ismail1, Hou Chew Ha1, Ahmad-Syazni Kamarudin*1 1School of Animal Science, Faculty of Bioresources and Food Industry, Universiti Sultan Zainal Abidin, Besut Campus, 22200 Besut, Terengganu, Malaysia. 2Department of Animal Science, Faculty of Agriculture and Agricultural Technology, Kano University of Science and Technology, Wudil, P.M.B. 3244 Kano State, Nigeria. s Article history: Received 7 June 2020 Accepted 21 August 2020 Available online 2 5 August 2020 Keywords: Conservation Feeding habit Invasive species Abstract: Invasive peacock bass Cichla spp. have recently invaded freshwater habitats across Malaysia. Stomach contents of 135 peacock bass captured from the Telabak Lake of East Coast of Peninsular Malaysia were analysed. The preys were examined using visual identification method and mitochondrial DNA barcoding technique to identify the partial digested and decaying preys in the stomach. The current study identified 7 prey species (6 fishes 43.0% and 1 shrimp 5.1%) belongs to 5 families in fishes’ stomach. The results revealed that peacock bass is highly predator and generalist feeder with an opportunistic feeding behaviour. It is highly important to reduce and monitor the abundance of this species for future survival of native species in the lake. Introduction The existence of an invasive fish species especially in inland waters is regarded as a crucial challenge in the conservation of tropical fish biodiversity (Clavero and Garcia-Berthou, 2005; Agostinho et al., 2005; Cucherousset and Olden, 2011; Matsuzaki et al., 2016). Non-native fish species are intentionally or accidentally introduced to a new habitat by human activities (Radkhah et al., 2016; Mousavi-Sabet and Eagderi, 2016; Eagderi et al., 2018). Peacock bass Cichla spp. are highly predatory fishes originated from the Amazon and introduced to many countries (Fugi et al., 2008; Kovalenko et al., 2009; Marques et al., 2016). These fishes were intentionally introduced into Malaysian freshwater by anglers in early 1990s (Rahim et al., 2013). Since then, it spreads to many freshwater bodies such as Temengor Reservoir and Lake, Raban Lake, Kapal Tujuh Lake, Kampar River (Hamid and Mansor, 2013; Desa and Aidi, 2013; Saat et al., 2014; Tan and Sze, 2017; Yap et al., 2016; Ng et al., 2018). Peacock bass exert high predation on prey fish population which may lead to the decreasing of the prey fish abundances and diversity in a *Correspondence: Ahmad-Syazni Kamarudin E-mail: ahmadsyazni@unisza.edu.my particular area (Zaret and Paine, 1973; Santos et al., 2001; Pelicice and Agostinho, 2008; Franco et al., 2017). These fishes are daytime active piscivorous that consume a wide range of prey and tend to ingest the whole prey (Zhao et al., 2014). To date, there is no documentation regarding their prey species across Malaysian freshwater bodies. Thus, diet composition study of this invasive fishes is necessary for better understanding of their ecological impacts on native biodiversity (Garvey and Chipps, 2012). Study on piscivorous fish diet composition is traditionally based on stomach contents analysis. Visual identification methods have been widely used in taxonomic identification of fish diet content (Morris and Akins, 2009; Layman and Allgeier, 2012; Côté et al., 2013). However, this method has failed to identify 70% prey content to the lowest taxonomic species level in the stomach content due to high digestion effect and prey degradation (Morris and Akins, 2009; Côté et al., 2013). This weakness, especially at low sample sizes may bias the ecological impact predictions since the detected prey might not represent the unknown percentage (Côté et al., 2013). 273 Int. J. Aquat. Biol. (2020) 8(4): 272-280 Therefore, DNA barcoding technique is used for high taxonomic resolution of fish diet as a supplement to traditional method (Leray et al., 2011). Analysis of mitochondrial DNA is proven to be a useful tool for the study of genetic diversity (Ahmad- Syazni et al., 2017; Ha et al., 2017; Khaleel et al., 2019) and species identification (Li et al., 2019; Golani et al., 2019). Matching of a short DNA sequences from unknown samples to known sequences in global databases such as National Centre for Biotechnology Information (NCBI) and Barcode of Life Database (BOLD) is known as barcoding (Ratnasingham and Hebert, 2007; Moran et al., 2015). This approach has been used effectively to classify dietary components in fishes (Côté et al., 2013; Moran et al., 2015), small body sized larval fish (Riemann et al., 2010), rare deep-water sharks (Dunn et al., 2010), and coral reef fish with rich generalist diet (Leray et al., 2011). Telabak Lake is a man-made freshwater lake which play a pivotal socio-economic and ecosystem role for the people living in the surrounding area (Khaleel et al., 2020). Freshwater lakes in Malaysia are known for the vast diversity of the aquatic live and fishes (Shahabudin and Musa, 2018). However, the introduction of invasive species such as peacock bass which preying on native fishes might give a threatening effect on the fish diversity. In this regard, current study aimed to provide first information concerning the prey identification and feeding habit of peacock bass in Telabak Lake, Malaysia using DNA barcoding technique. Materials and Methods Sampling: A total of 135 peacock bass samples with average total body length of 24±2.1 cm and body weight of 244±2.3 g were collected from the Telabak Lake (5°37'56.9"N, 102°28'24.5"E), East Coast of Peninsular Malaysia from October 2018 to January 2019. The samples were immediately transferred to the Aquatic Laboratory, Faculty of Bioresources and Food Industry, University Sultan Zainal Abidin Malaysia for further analyses. Taxonomic classification and feeding habit: Fish were dissected to remove the stomach content based on Barbato et al. (2019). Following the protocol of Côté et al. (2013) with some modification, all prey items in the stomach were identified to the minimum taxonomic level. The highly digested preys with difficulty to identify were classified as fish and invertebrates, labelled separately and frozen. The feeding regime of Cichla spp. was measured in qualitative and quantitative methods based on Hynes (1950) and Sahtout et al. (2018). The following indices were used to evaluate the importance of different prey items in the diets of Cichla spp. 𝑉𝐶 (%) = 𝑁𝑜. 𝑜𝑓 𝑒𝑚𝑝𝑡𝑦 𝑠𝑡𝑜𝑚𝑎𝑐ℎ × 100 𝑁𝑜. 𝑜𝑓 𝑓𝑢𝑙𝑙 𝑠𝑡𝑜𝑚𝑎𝑐ℎ𝑠 (Peyami et al., 2018) 𝐹𝑂 (%) = 𝑁𝑜. 𝑜𝑓 𝑠𝑡𝑜𝑚𝑎𝑐ℎ 𝑐𝑜𝑛𝑡𝑎𝑖𝑛𝑖𝑛𝑔 𝑝𝑟𝑒𝑦 × 100 𝑁𝑜. 𝑜𝑓 𝑓𝑢𝑙𝑙 𝑠𝑡𝑜𝑚𝑎𝑐ℎ𝑠 (Ashelby et al., 2016) 𝑁𝐼 (%) = 𝑁𝑜. 𝑜𝑓 𝑖𝑛𝑑𝑖𝑣𝑖𝑑𝑢𝑎𝑙 𝑝𝑟𝑒𝑦 𝑖𝑡𝑒𝑚𝑠 × 100 𝑇𝑜𝑡𝑎𝑙 𝑁𝑜. 𝑜𝑓 𝑝𝑟𝑒𝑦𝑠 (Karimi et al., 2019) 𝑉𝐼 (%) = 𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑝𝑟𝑒𝑦 𝑖𝑡𝑒𝑚𝑠 × 100 𝑇𝑜𝑡𝑎𝑙 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑡𝑜𝑚𝑎𝑐ℎ 𝑐𝑜𝑛𝑡𝑒𝑛𝑡 (Karimi et al., 2019) 𝐼𝑅𝐼 = (%𝑁 + %𝑉) × %𝐹 (Barbato et al., 2019) Where VC is vacuity coefficient, FO = frequency of occurrence, NI = number of individuals, VI = volume of individuals and IRI = index of relative importance. Barcoding sample preparations: A small piece of the muscle tissue (2-3 mm3) was used from every frozen prey item identified as fish and invertebrates, respectively. Then, all samples were carefully taken from each prey (preferably from dorsal muscle). To minimize the sample contamination by peacock bass cells, approximately 1 mm top layer of the tissue muscle of the prey that has direct contact to stomach fluids were removed prior to sampling for barcoding. All tools were sterilized using 95% ethanol and Bunsen burner flame between each sample removing to avoid any possible contamination. Prey DNA extraction, amplification and sequencing: The total genomic DNA of each prey item was isolated using Favorgen DNA extraction Kit (Favorgen Biotech Corp., Ping-Tung 908, Taiwan) by following manufacturer’s protocol. The partial COI gene of mitochondrial DNA was amplified by PCR using the universal primers COI-Fish2 F (5’TCGACTAATCA 274 Khaleel et al./ Invasive peacock bass prey identification in Malaysia TAAAGATATCGGCAC3’) and COI-Fish2 R (5’ACTTCAGGGTGACCGAAGAATCAGAA3’) (Ward et al., 2005) for unidentified fish samples and LCO1490: 5'-GGTCAACAAATCATAAAGATATT GG-3' and HCO2198: 5'-TAAACTTCAGGGTGAC CAAAAAATCA-3' (Folmer et al., 1994) for unidentified invertebrates. For both fish and invertebrates preys, the PCR was carried out in a 25 μl reaction volume containing 18.2 μl sterile distilled water, 2.5 μl Taq buffer, 2.0 μl dNTP Mix (2.5mM), 0.5 μl of each primer (10 μM), 0.3 μl of 5 unit/μl Taq polymerase (TaKaRa) and 1 μl template DNA (1-50 ng/μl) on a thermal cycler PCR machine Veriti 96 Well Thermal Cycler (Applied Biosystem, California, USA), under the following thermal cycling conditions. Initial denaturation at 95°C for 5 min, 35 cycles including denaturation at 95°C for 30s, annealing at 50°C for 30s and elongation at 72°C for 10 min, followed by final extension for 10 min at 72°C and the PCR product was maintained at 4°C. Sequencing was succeeded using BigDye Terminator v3.1 cycle sequencing kit (Applied Biosystems) following manufacturer's instructions, performed on an ABI Prism 3730xl Genetic Analyser (Applied Biosystems). Data analysis: Unknown sequences from fish and invertebrates were aligned and edited using ClustalW multiple sequence alignment program in MEGA 7 (Kumar et al., 2016). DnaSP software was used to determine the variable sites among the sequence (Librado and Rozas, 2009). To discover the taxonomy of each prey species, the obtained haplotypes were queried using basic local alignment search tool (BLAST) against National Center for Biotechnology (NCBI) nucleotide database. A top species match was identified with a sequence similarity of at least >94% to avoid false positives. Number of observed and detected prey species in the stomach of peacock bass was computed in percentages using Minitab 16 software. Results Feeding intensity of peacock bass: Among 135 examined stomach contents monthly from October 2018 till January 2019, 70 were empty (average 51.8%) with high value in December (87%) and sudden decline in January (26%) (Fig. 1). Using visual identification method, the remaining prey samples were successfully identified as fish and invertebrates with their percentages (Fig. 2B, C, respectively). Table 1. Monthly variations of peacock bass dietary items with respect to their percentage frequency of occurrence (%FO), percentage number of individual (%NI), percentage volume of individuals (%VI) and percentage index of relative importance (%IRI). Variables Prey Oct. Nov. Dec. Jan. Male Female FO (%) Fish 68.4 85.7 66.7 78.6 42.2 04.7 Invertebrates 42.1 25.0 33.3 42.9 26.6 32.8 NI (%) Fish 64.5 80.5 20.0 65.2 38.0 31.0 Invertebrates 35.5 19.5 80.0 34.8 05.0 26.0 VI (%) Fish 67.1 42.1 62.7 57.5 23.5 31.1 Invertebrates 04.1 01.1 04.4 02.5 01.9 00.7 IRI (%) Fish 84.4 87.2 32.8 85.8 92.6 96.3 Invertebrates 15.6 12.8 67.2 14.2 07.4 04.7 Figure 1. Monthly variations of vacuity index of peacock bass stomachs examined between October 2018 and January 2019. 275 Int. J. Aquat. Biol. (2020) 8(4): 272-280 However, it failed to classify prey to their lowest taxonomy due to high ingestion effect and degradation. Table 1 provides the overall results of the classification and diet composition on prey of the examined peacock bass between October 2018 and January 2019. The fish preys dominated the entire diet with the exception of December at which high number values of invertebrates were recorded. Mitochondrial DNA barcode: A total of 656 base pair (bp) of COI for fish species and 679 bp of COI for invertebrates were obtained after deletion of low- quality nucleotides at the 5’ and 3’ ends. Six different sequences were obtained from COI of fishes (PSC01, PSC02, PSC03, PSC04, PSC05, and PSC06) and one sequence for invertebrate (PSC07). After blasting, in NCBI, following our criterion of >94% sequence similarities, 7 prey species belong to five families were Cichla ocellaris, Pristolepis fasciata, Parambassis ranga, Rasbora trilineata, Cyprinus carpio and Cyclocheilichthys enoplos (Table 2). The percentage of each prey species identified (% N0) using DNA barcode were also recorded with high value of 15.2% in P. fasciata. Discussions The introduction of peacock bass into Telabak Lake was accompanied by a sharp and gradual decline of small-sized fishes (personal communication). This study showed that the decrease in fish diversity might be associated with feeding habit of peacock bass in the Lake, since the observed prey items in the peacock bass stomach confirm its piscivorous feeding habit on targeted native prey species. We used traditional visual identification method and further DNA barcoding technique to identify its preys. The highest vacuity coefficient was observed in December indicating their breeding and spawning season (Gomiero et al., 2009) which limits their hunting time. High vacuity coefficient during breeding season was also reported from other fish species such as Diplodus vulgaris (Pallaoro et al., 2006), Caranx rhonchus (Sley et al., 2008), Pagellus erythrinus (Šantić et al., 2011). Table 2. BLAST sequence match showing percentage identity of prey in peacock bass using barcode. Sequence Family Species Accession No. % Identity % N0 PSC01 Cichlidae Cichla ocellaris KU878410 99.20 5.1 PSC02 Pristolepididae Pristolepis fasciata MK049486 99.07 15.2 PSC03 Ambassidae Parambassis ranga MK448145 94.87 10.1 PSC04 Cyprinidae Rasbora trilineata KU569018 99.99 2.5 PSC05 Cyprinus carpio LN591958 94.03 2.5 PSC06 Cyclocheilichthys enoplos KU692459 99.68 7.6 PSC07 Palaemonidae Macrobrachium lanchesteri KP759429 98.18 5.1 % N0 = species percentage number identified after barcoding Figure 2. Visual identification of 135 peacock bass stomach content from October 2018 to January 2019 captured in Telabak Lake, (A) 51.8% Empty stomach, (B) 43.1% unidentified fish species and (C) 5.1% unidentified invertebrate species. 276 Khaleel et al./ Invasive peacock bass prey identification in Malaysia The lowest vacuity coefficient observed in January (26.3%) revealed its feeding initiation after breeding period. Full recovery to feeding activity helps fishes to compensate the energy used during breeding (Derbal et al., 2007). Fish dominates the entire diet of the peacock bass in all months, except in December where invertebrates (prawn) were dominated. Macrobrachium lanchesteri (Prawn) spawns throughout the year with a peak at November (Phone et al., 2005). Therefore, it could be more available in December for peacock bass. Another explanation for high predation of peacock bass on fish prey species might be related to naturally clear transparency of Telabak Lake. It is reported that peacock bass thrive well in clear freshwater for excellent predation (Kovalenko et al., 2010). Visual identification has failed to identify the prey items to the lowest species level due to the degradation of essential features such as fin ray shape and body coloration. However, only 48.2% of the ingested prey into fish and invertebrates were visually distinguished. This percentage is closer to the results of other similar studies (Côté et al., 2013; Dahl et al., 2017). Only few species were successfully identified to the lowest species taxonomic level using visual method similar to other works (Morris and Akins, 2009; Côté et al., 2013; Moran et al., 2015; Mzaki et al., 2017; Sahtout et al., 2018). All identified prey species were native to Malaysia freshwater except for C. carpio and Cichla spp. Opportunistic feeding habit of Cichla spp. is one of the serious aspects that helped them adapt to a new environmental condition. The presence of Cichla spp. in the stomach as a prey item might be due to cannibalism, and as proof of its opportunistic feeding habit in nature. It was previously examined that cannibalism is more pronounced during the spawning periods with scarcity of alternative foods, like small indigenous species of fish (Junior and Gomiero, 2010). In addition, low rates of cannibalism observed in this study might be due to native prey abundance (Carvalho et al., 2014). Once Cichla spp. is introduced into a lake, they prey on variety of available fish species, shrimps and cichlids (Pereira et al., 2015; Mendonça et al., 2018). All native species found in the stomachs are of least concern (IUCN Red List, 2012) but they contribute largely in aquaculture, and as a source of income for the local community e.g. M. lanchesteri is used as food by locals (Phone et al., 2005; Aznan et al., 2017). The studies on introduction peacock bass have indicated a negative effect on local fish species (Zaret and Paine, 1973; Molina et al., 1996; Pinto-Coelho et al., 2008; Pelicice and Agostinho, 2008; Rahim et al., 2013). Previous works of the fish population in Lake Redonda of Cuba from 1989 to 1990, documented that many local fish species have been extinct after the introduction of peacock bass (Molina et al., 1996). Recently, Menezes et al. (2012) reported that the introduction of peacock bass in the coastal Lakes of Rio Grande do Norte Brazil had reduced native fish abundantly with a negative impact on their diversity. The invasion and adaptation of peacock bass in Telabak Lake might likely lead to the reduction of native fish species. The existence of these highly adaptive and fast-growing piscivorous fish may cause severe damages to the local aquatic populations through competition, predation and cascade effects across the trophic chain. Although peacock bass attracts recreational anglers (Mendonça et al., 2018), but local people depends on native aquatic species in the Telabak Lake. The lake plays a significant role for their daily needs and incomes. As our finding, 48.2% of the prey items submitted for barcoding were 100% identified to species level. Other studies identified less than 70% when submitted for barcoding (Morris and Akins, 2009; Côté et al., 2013), which is due to species differences. Without using DNA barcoding technique, most of the prey items could have been labelled as partially digested unidentified prey, leading to missing information, misidentification and less understanding of invasive peacock bass impact in the lake. Conclusion This study provided useful information about feeding habits of Cichla spp. for better understanding of the relationship between fish species and other living organisms in Telabak Lake. The presence of this invasive species may affect the government effort on 277 Int. J. Aquat. Biol. (2020) 8(4): 272-280 boosting and promoting the lake as recreational and aquaculture centre. The technique of DNA barcoding has proved to be a useful tool in discovering diet of the Cichla spp. in the lake. The information gathered in this recent study is important for stakeholders and policy makers in considering the management of biodiversity of the lake in the future. Acknowledgment The authors would like to thank the Mr Mohamad Amirul Aimi Md Kamail and Mohd Hanafiah Mohd Jayapal for helping in fish sampling. This study is funded by Fundamental Research Grant Scheme (FRGS/1/2018 /WAB13/UNISZA/02/2) awarded to Dr. Ahmad Syazni Kamarudin by the Ministry of Higher Education, Malaysia. References Agostinho A.A., Thomaz S.M., Gomes L.C. (2005). Conservation of the biodiversity of Brazil’s inland waters. Conservation Biology, 19: 646-652. Ahmad-Syazni K., Khaleel A.G., Norshida I., Connie F.K., Nguang S.I., Ha H.C. (2017). Population structure of swamp eel Monopterus albus in East Coast of Peninsular Malaysia inferred from 16S mitochondrial DNA. World Applied Sciences Journal, 35: 1392-1399. Ashelby C.W., De Grave S., Johnson M.L. (2016). Diet analysis indicates seasonal fluctuation in trophic overlap and separation between a native and an introduced shrimp species (Decapoda, Palaemonidae) in the tidal river Thames (UK). Crustaceana, 89: 701-719. 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