Alien Fish Species in the Mbô Floodplain Rivers in Cameroon
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Hindawi International Journal of Biodiversity Volume 2018, Article ID 5349341, 9 pages https://doi.org/10.1155/2018/5349341 Research Article Alien Fish Species in the Mbô Floodplain Rivers in Cameroon Claudine Tekounegning Tiogué ,1 David Nguenga,2 Minette Eyango Tomedi-Tabi,3 Joseph Tekwombuo,4 Guegang Tekou,3 and Joseph Tchoumboué4 1 Laboratory of Applied Ichthyology and Hydrobiology, School of Wood, Water and Natural Resources (Ebolowa Antenna), Faculty of Agronomy and Agricultural Sciences, University of Dschang, P. O. Box 786, Ebolowa, Cameroon 2Regional Center MINRESI/CRRI-West, Ministry of Scientifc and Technical Research, P. O. Box 665, Bafoussam, Cameroon 3Department of Aquaculture, Institute of Fisheries and Aquatic Sciences at Yabassi, University of Douala, P. O. Box 2701, Douala, Cameroon 4Laboratory of Applied Ichthyology and Hydrobiology, Department of Animal Productions, Faculty of Agronomy and Agricultural Sciences, University of Dschang, P. O. Box 222, Dschang, Cameroon Correspondence should be addressed to Claudine Tekounegning Tiogu´e; [email protected] Received 21 February 2018; Accepted 15 July 2018; Published 13 August 2018 Academic Editor: Franck Courchamp Copyright © 2018 Claudine Tekounegning Tiogu´e et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te aim of this study was to identify diferent alien fsh species introduced in the MbˆoFloodplain(MF)RiversinCameroonand to study their life-history traits. For this purpose, a total number of 237 fshes with a total length (TL) of 24.50 ± 5.97 cm and total weight of 199.50 ± 106.78 g collected by traditional fshing gears were used for taxonomic identifcation. Four species grouped into three families were identifed: Clariidae (Clarias gariepinus), Cichlidae (Oreochromis niloticus and Tilapia cameronensis), and Channidae (Parachanna obscura). Tere are two types of fsh introduction: accidental introduction and intentional transfer. All fsh species collected and examined were of large sizes (TL > 25 cm). Te regression coefcient b of the length-weight relationship ranged from 3.00 (C. gariepinus)to3.37(T. cameronensis)(3.18± 0.17). Fish species showed a monthly and seasonal fuctuation in abundance in number of individuals. Alien fsh species in the Mbˆo Floodplain showed two types of somatic growth: isometric and positive allometric. 75% of overall alien fsh species were established and they recorded a mean K factor of 0.70 ± 0.40. Only 25.00% of the sampled species had more females than males. 1. Introduction of enriching poor settings in species due to their geolog- ical history [10, 11], they are also practiced to remedy the An alien species or alien genotype is a species, subspecies, depletion of indigenous stocks subject to overfshing [12], or lower taxon occurring as a result of human action in an and they can be used for the development of recreational area or ecosystem in which it is not native [1]. Introduced activities such as sport fshing [13] and for the market of species concern any population, species, or race intentionally ornamental species. Nonnative fsh species have also been or accidentally transported and released by man into an used in biological control and biomanipulation [14, 15]. environment outside its native range [2–6]. Te introduc- Te uses of exotic fsh species to control unwanted aquatic tion of alien fsh species in freshwater is a common and organisms were concerned principally with the attempted old practice in many parts of the world [7]. Exotic fshes eradication of mosquito larvae. Control of mosquito larvae by have become accidentally introduced outside their natural small larvivorous fsh species (e.g., Poecilia latipinna, Poecilia range by escaping from captivity, natural difusion, and reticulata, and Gambusia afnis) is highly efective [16]. Te accidental transportation with other species and more rarely introduction of molluskivorous (Astatoreochromis alluaudi) as stowaways in the ballast-water tanks of transoceanic fshes has been proposed for controlling the aquatic snail vessels [8, 9]. Te purposes for which species have been vector of Schistosomiasis (bilharzia) [17]. Other fsh species intentionally introduced are various: they can be a means such as Mylopharyngodon piceus and more recently Heterotis 2 International Journal of Biodiversity niloticus have been reported to feed widely on gastropod humidity of 49%; and the rainy season occurring the rest mollusks [18]. of the year with temperature that oscillate between 17 and ∘ Fish introduced or transferred also contributed to the 26 C [34]. Te average rain fall is 1860 mm and the relative change in the functioning of aquatic ecosystems and in the humidity is 98%. Te rivers of the MF come down from the control or eradication of the aquatic weed. Tis is the case of Bambouto Mountain (Menoua River), from the Manengouba grass carp Ctenopharyngodon idella and Hypophthalmichthys Massif (Nkam River and Black Water River), and several molitrix that have, respectively, been used successfully for the other streams (such as Metschie and Mfouri) from the Bana elimination of aquatic weed and algal blooms in Europe [14, Massif [34]. All these rivers are drained by the Wouri River 19]. In most African countries, introductions have been made which fows into the Atlantic Ocean (Figure 1) [35]. to produce high quality fsh protein, alleviate poverty and hunger, and provide employment, control disease vectors, 2.2. Fish Samples. Fishes were surveyed once every month and weeds [20–22]. In the FAO database, these diferent fromOctober2014toOctober2015.Fishspecieswere purposes have been grouped into three main classes: aquacul- collected from the fshermen. Tey were captured in the con- ture development, biological control and capture, and sports fuence zones of the rivers and the intermediate zones (nearest fsheries [14, 23, 24]. to the paved road), by means of traditional fshing gears Of the 478 fshes introduced into Africa for improving (bow nets, hooks, and gill nets). Taxonomic identifcation objectives fshing (commercial and recreational) by supple- was performed according to Stiassny et al. [24]. Te origin mentation of natural populations and biological control (e.g., andtypeofintroductionoffshspeciesweremadefrom a few species were introduced in Lower Guinea as biological direct interviews with fshermen and with documents on control agents, such as Astatoreochromis alluaudi Pellegrin, this subject [24]. Fishes were counted; the relative abundance 1904, for snail control and most probably some killifshes per species was estimated as the ratio of number of fsh (Poeciliidae) for mosquito control [14, 24]; 212 freshwater per species and the total number of fshes collected in the fsh species were for aquaculture purposes and only 33 (16%) > month. Ten frequency of occurrence (FO) by month of have enabled the development of an aquaculture activity ( 10 a giving specie was calculated by the formula: FO (%) = t/year) [25]. Of these 33 fsh species, 10 (30%) concern the relative abundance X 100. Te total length was measured to common carp from Asia and Europe and 7 (21%) concern the the nearest 0.01 cm. Te body weight was measured using Nil tilapia from other African countries [14]. In Cameroon, all an electronic balance (Sartorius Competence) to the nearest aquaculture species are exotic or translocated. Tese include 0.01 g. Te sex of each fsh was determined by macroscopic the common carp (Cyprinus carpio), the Nile tilapia (Ore- examination of genital papilla, number of abdominal orifces, ochromis niloticus), the African catfshes (Clarias gariepinus or the gonads afer dissection. and Heterobranchus longiflis), the Arapaimidae Heterotis Te length-weight relationship (LWR) was determined niloticus, the African snakehead fsh Parachanna obscura,and by using the data on the measurement of length and weight Tilapia cameronensis [26–32]. To our knowledge, with the of alien fsh species. Te LWR is expressed by using the exception of the Arapaimid Heterotis niloticus in the river b equation: W = aL , where W is body weight of the samples in Nyong [9, 33], the status and bioecology of species introduced g, TL is length of the sample in cm, a is constant (intercept), or transferred into Cameroonian’s Rivers have not been and b is constant (slope of regression line) [36, 37]. studied. Te Mboˆ Floodplain of Cameroon has many important rivers whose fshery resources play a signifcant role in the 2.3. Statistical Analysis. Data of the collected fsh species economy and food habits of the local populations [34]. through the study area were analysed using descriptive statis- tics (mean, standard deviation, and percentage). Sex ratio Tis area is subject to many introductions and transfers 2 of fsh species [24]. Tis situation raises questions on the of the fsh was studied using Chi-square root test (� ). Te origin (types of introductions), number and populational pa- LWR equation was not transformed into a linear form; the equation was maintained as power, so in a curved line. Te rameters of alien fsh species in this area. To answer these 2 questions, the following aims were defned: to identify dif- statistical signifcance of r (determination coefcient) was ferent alien fsh species, to determine their origin, to estimate estimated and the b value tested using the t-test to verify their monthly frequency of occurrence in the captures, and if it was signifcantly diferent from the isometric (b = 3.0) to evaluate their ability in terms of the length-weight rela- [38]. Fulton’s index is used for calculating the body condition tionship, the condition factor (K), and sex ratio in the Mboˆ in those cases when the growth is isometric (b= 3.0), once Floodplain Rivers. the isometry has been determined via statisticat test. If the growth is allometric (b diferent that 3.0), then the LeCren b 2. Materials and Methods index Kn = W/TL X100 should be used, where W is weight (g), TL is total length (mm), and b is slope of the length- 2.1.