Populations Of Oreochromis Niloticus Research Articles

Morphological variation of Oreochromis niloticus (Lacépède, 1803) populations in stressed environment: Middle stream of Comoé River (Ivory Coast)

This work aims to assess the influence of environmental stress in the middle course of the Comoé River on the morphological characteristics of Oreochromis niloticus populations using the geometric morphometric approach. A total of 248 specimens of O. niloticus were collected from four sites (M'Basso, YèrèYèrè, Abradinou and Bettié). No specimen of O. niloticus has been collected from the Manzan River, which has a high level of gold panning activity. Nineteen (19) homologous landmarks were digitized on each individual. Data were studied using principal component analysis, canonical variable analysis, discriminant function analysis and allometric analysis. The PC1 and PC2 axes show an extension of the deformation grids at the level of the head and the caudal and dorsal fins. However, the PC3 axis almost exhibits a deformation grid that deforms at the caudal fin, pectoral fin, and dorsal fin. The results of the various analyzes showed significant differences between the morphology of the populations studied. These differences were observed mainly in the head, dorsal and pectoral fins. The disturbance of aquatic habitats has an impact on the morphology of specimens of O. niloticus from the middle course of the Comoé River. A slight deformation is recorded in the individuals of O. niloticus at M'Basso, considered the least disturbed site. On the other hand, a strong deformation is observed in specimens from the YèrèYèrè, Abradinou and Bettié sites which are more disturbed.

Effect of elevated fry rearing temperature on survival rate, growth performance, and sex ratio of three Oreochromis niloticus populations of Ethiopian Rift Valley Lakes

Sex-reversal in Oreochromis niloticus is used to produce mono-sex males which are desired in aquaculture for better growth performances and population control. The present study was aimed at studying the effect of elevated fry rearing temperature on survival, sex ratios, and growth performances of O. niloticus populations of Lakes Chamo, Koka, and Ziway. Fries from five separate brood pairs of each population were either treated (T) in elevated fry rearing temperature of 36 ± 1°C or kept at room temperature of 24 ± 1°C as control (C) groups for 10 days (phase-I) and then grown in outdoor ponds for six months (phase-II). Survival rates in T groups (74.0 to 91.7%) were lower than that of C groups (83.3 to 97.0%) in all the three populations in phase-I but not in phase-II. Chamo population was better in survival rate (88.4% and 95.4% in Phase-I, and 95.4% and 95.3% in phase-II) than Koka population (85.8% and 91.3% in Phase-I, and 93.9% and 93.5% in phase-II) and Ziway population (80.2% and 88.6% in Phase-I and 90.2% and 91.9% in phase-II) both in T and C groups respectively. The Chamo population also attained significantly (p<0.05) higher mean final weight of 31.58 ± 6.78 g and 24.26 ± 6.67 g in T and C groups respectively, followed by that of Koka population with 21.70 ± 5.10 g and 18.83 ± 4.16 g while Ziway population with mean final weight of 17.49 ± 4.60 g and 16.81 ± 4.15 g was the least both in T and C groups. The overall sex ratios in T groups were skewed towards male but balanced in all C groups of each population. Better growth was achieved only in T groups with higher male ratio than their corresponding C groups. The number of sensitive brooding pairs and the overall male ratio in T groups were higher in the Koka population (40%, 61.68%) than in Ziway (20%, 56.78%) and Chamo (20%, 56.39%) populations respectively. However, the sensitivity of sex reversal to elevated fry rearing temperature was wide between individuals within each population than across the three populations. Hence, sensitive individuals can be selected from the populations and their degree of sensitivity can be improved through continuous selection of progenies from temperature-sensitive parents.

Study of genetic variation in populations of Coptodon zilliii, Oreochromis aureus, and Oreochromis niloticus in two areas South of Iraq, in Khaur Abdallah and Shatt Al-Arab Mitochondrial Cytochrome b Gene Analysis

This study has a specific goal in mind: Genetic Variation Study Within Populations of Coptodon zilliii, Oreochromis aureus, and Oreochromis niloticus, and analysed the partial Cytb gene sequence of mtDNA to determine genetic diversity among these species in the Khaur Abdallah and Shatt Al-Arab in the south of Iraq, where the mitochondrial cytochrome b gene was used.DNA was isolated from 40 specimens of the three species collected from two different sites and examined. The gene size for Coptodon zilliii,Oreochromis aureus, and Oreochromis niloticus was (439, 326 & 473 bp long (amplified Cytb gene)), respectively. The study found that two haplotypes in Khaur Abdallah and one in the Shatt-Al-Arab river in Coptodon zilliii populations, while was found one haplotype in Khaur Abdallah and one in the Shatt-Al-Arab in both Oreochromis aureus, and Oreochromisniloticus populations by using Software DnaSP v5.1. In each of the species Oreochromis aureus and Oreochromis niloticus, the research identified two types of unique haplotypes, one in Khaur Abdallah and the other in Shatt-Al-Arab. However, three haplotype patterns for Coptodon zilliii populations were discovered: one in the Shatt al-Arab River and two in Khaur Abdallah. Low nucleotide (π) and haplotype diversity (Hd) values were found in both Oreochromisaureus and Oreochromis niloticus populations in the Shatt Al-Arab river and Khaur Abdallah, indicating low genetic variation among populations for both species in the two regions. However, there was no diversity within the Oreochromis aureus population in both Shatt Al-Arab and Khaur Abdallah. The population of Oreochromis niloticus has the same indication. Three haplotypes for Coptodon zilliii indicate to genetic variance across populations in the Shatt Al-Arab riverand Khaur Abdallah regions, although no variety within the Coptodon zilliii species was found in the Shatt Al-Arab river. In the Khaur Abdallah district, there was little genetic diversity among them.

Biological invasion: evidence from a tropical reservoir (Eleiyele, South West Nigeria

The encroachment of freshwater territories by invasive species is a global issue with its associated co-existence, displacement and facilitation of native species. The blackchin tilapia, Sarotherodon melanotheron is one of the most successful biological invasive species. Data on its apparent ecological consequences on native species are rare in Nigerian inland waters. Based on stomach contents analyses, diets, feeding strategies, and dietary niche breadths of two sympatric invasive S. melanotheron and native Nile tilapia Oreochromis niloticus populations in a tropical domestic water supply were assessed for possible convergence. Both species exhibited generalist feeding strategies subsisting mostly on algae but fish eggs and larvae were conspicuous preys of S. melanotheron. Dietary niche of S. melanotheron was wider than that of O. niloticus. Dietary niche overlap was high and significant between these sympatric species. These findings imply that competitive feeding interactions-including predations on vulnerable early life stages may potentially promote invasion success of S. melanotheron in Eleiyele Reservoir.

Comparative study of the breeding performances of five populations of Nile tilapia (Oreochromis niloticus) (F1) in an experimental ongrowing system in Benin (West Africa)

ABSTRACT In order to investigate the breeding performances of five F1 populations of Oreochromis niloticus originated from wild broodstock of Nangbéto, Sohoumè and Togbadji in the Mono basin, Gobé in the Ouémé basin and Gbassa in the Niger basin, breeding tests were conducted for 10 weeks in an ongrowing experimental system. All tested populations were checked daily in order to collect spawn and to compare the reproductive performances. Compared with others, Sohoumè, Togbadji, and Gobé populations significantly (P < .05) displayed the best breeding performances in terms of rate of multi-spawning females (89.3 ± 15.2–92.3 ± 10.8%); mean relative fecundity (4 ± 2–6 ± 3 eggs/g of female), mean gonadosomatic index (3.1 ± 2–4.8% ± 2.6); mean absolute fecundity rates (865 ± 339–989 ± 547 eggs); mean fertilization rates (98 ± 4.3–99.3 ± 1.1%); and mean hatching rates (83.7 ± 10–88.9 ± 9.1%).

Variations in Reproductive Characteristics among Oreochromis niloticus Populations of Three Ethiopian Rift Valley Lakes

Variations in Reproductive Characteristics among Oreochromis niloticus Populations of Three Ethiopian Rift Valley Lakes

Aquaculture facilities drive the introduction and establishment of non-native Oreochromis niloticus populations in Neotropical streams

This study investigated whether aquaculture facilities drive the introduction and establishment of the non-native Nile tilapia (Orechromis niloticus) in Neotropical streams, Brazil. Samples were taken from nine streams with different aquaculture occupation intensities (no, moderate, and intense) using the percentage of occupation of micro-watersheds by aquaculture ponds as a proxy for propagule pressure. The presence of aquaculture facilities and the percentage of aquaculture occupation were good predictors of the catch frequency and of densities of tilapias in the adjacent natural environment. In the streams under intense propagule pressure, females prevailed and high densities of young individuals comparing to adults were recorded. It suggests that the species was reproductively successful in the natural environment. In the streams under moderate propagule pressure, males prevailed, which indicates the likely capture of individuals escaped from aquaculture facilities. In general, our results show the positive influence of propagule pressure on the introduction and establishment of Nile tilapia in natural ecosystems, showing that aquaculture expansion of O. niloticus poses a threat to the conservation of aquatic biodiversity.

Reproductive Parameters of Three Populations of Oreochromis Niloticus (Linnaeus, 1758) in the Sudano-Guinean Altitude Zone of Cameroon

In order to contribute to the improvement of aquaculture production, reproductive parameters of three populations of Oreochromis niloticus of Cameroon were studied between March and May 2019 at the research station of Foumban. At this effect, a total of 81 parents (27 males and 51 females with respective weight 124 ± 6g and 144 ± 5​​g) coming from three hydrogeographicals origins (Niger, Sanaga and IRAD Station) were randomly distributed in triplicate in nine concrete tanks of a m² each with a sex ratio of one male for two females (1♂/2♀). Throughout the test, six females carrying eggs in the oral cavity were collected in each population and 45 days after the start of the trial, all the offspring were collected and the adults sacrificed. At the end of experiment, the IRAD population presented highest significant values (p ≤ 0.05) regardless of the performances considered. The values of the gonado-somatic and the gonado-metric characteristics significantly lower (p ≤ 0.05) were obtained in Niger population (GSR = 0.04 ± 0.02, GSI = 0.05 ± 0.03 and GMR=0.19 ± 0.08;GMI= 0.24±0.07). Considering sex, males presented the lowest significant values (p ≤ 0.05) for all the characteristics studied (GSR = 0.04±0.01, GSI = 0.04±0.01 and GMR= 0.23±0.08;GMI= 0.29±0.09).

Phenotypic variability of natural and cultivated populations of Oreochromis niloticus from Haut Sassandra region (Côte d'Ivoire)

1 ABSTRACT The phenotypic characterization of four populations of Oreochromis niloticus (Linnaeus, 1758) from the Haut-Sassandra region was carried out using 147 specimens. Among them, 39 were from the natural environment (Sassandra River) and 108 from three fish farms in the town of Daloa. The body weight, sixteen (16) metric characters and fifteen (15) meristic characters recorded on each individual made it possible to analyze the phenotypic variability of the four populations. Twenty-eight (28) on the 31 morphometric characters studied differentiated populations (P &lt;0.001). Based on these 28 characters, Principal Correspondence Analysis (PCA) and Hierarchical Classification Analysis (HCA) grouped the individuals into two groups, a group consisting of Guessabo and PK 12(Kilometer 12 fish farm located at the end of the city of Daloa) specimens and the other group consisting of APDRACI and Quartier Manioc (two fish farms in the city) individuals. Six morphometric characters (PrAL. IOD. LDF. DAL. AFL and SsL) were the most relevant in the discrimination of these two groups. Discriminant factor analysis (DFA) has also classified these populations into two clusters identical to those of the PCA and the HCA. The brood stocks of PK 12 farm is morphologically identical to specimens of the natural environment (Guessabo). The waters of the PK 12 farm have similar characteristics to the natural environment. The PK 12 farm compared to the others (APDRACI and Quartier Manioc) would be better managed.

Genetic Variation Between Cultured and Wild Populations of Oreochromis niloticus Deduced from Randomly Amplified Polymorphic DNA (RAPD) Markers

Genetic Variation Between Cultured and Wild Populations of Oreochromis niloticus Deduced from Randomly Amplified Polymorphic DNA (RAPD) Markers

An Important Natural Genetic Resource of Oreochromis niloticus (Linnaeus, 1758) Threatened by Aquaculture Activities in Loboi Drainage, Kenya

The need to improve food security in Africa through culture of tilapias has led to transfer of different species from their natural ranges causing negative impacts on wild fish genetic resources. Loboi swamp in Kenya is fed by three hot springs: Lake Bogoria Hotel, Chelaba and Turtle Springs, hosting natural populations of Oreochromis niloticus. The present study aimed at better genetic characterization of these threatened populations. Partial mtDNA sequences of the D-loop region and variations at 16 microsatellite loci were assessed in the three hot spring populations and compared with three other natural populations of O. niloticus in the region. Results obtained indicated that the hot spring populations had mitochondrial and nuclear genetic variability similar to or higher than the large closely related populations. This may be attributed to the perennial nature of the hot springs, which do not depend on rainfall but rather receive permanent water supply from deep aquifers. The study also revealed that gene flow between the three different hot spring populations was sufficiently low thus allowing their differentiation. This differentiation was unexpected considering the very close proximity of the springs to each other. It is possible that the swamp creates a barrier to free movement of fish from one spring to the other thereby diminishing gene flow. Finally, the most surprising and worrying results were that the three hot spring populations are introgressed by mtDNA genes of O. leucostictus, while microsatellite analysis suggested that some nuclear genes may also have crossed the species barrier. It is very likely that the recent intensification of aquaculture activities in the Loboi drainage may be responsible for these introgressions. Taking into account the importance of these new genetic resources, protection and management actions of the Loboi swamp should be accorded top priority to prevent the loss of these spring populations.

Fillet Yields from Four Strains of Nile Tilapia (Oreochromis niloticus) and a Red Variety

Tilapia (Oreochromis, spp.) have been introduced globally and domesticated, resulting in a number of different strains. This diversity offers the potential for difference in body morphology and, in turn, fillet yields. A trial was conducted at Auburn University, Auburn, Alabama, to compare processing characteristics of four populations of Oreochromis niloticus using two domesticated strains (Egypt and Ivory Coast), two less domesticated strains (Sagana and Lake Victoria), and a red variety (Santa Fe). Male tilapia (N = 25/strain) were manually processed and the dress-out percentage and visceral fat calculated. Mean individual weights of pre-processed fish were similar (range = 403.8 ± 27.6 g to 413.8 ± 24.5 g) with the exception of the larger Sagana strain (434.2 ± 15.4 g). The Ivory Coast strain had the highest percent dress out (33.1% ± 2.1%), while the Sagana strain had the lowest (29.6% ± 1.5%). The Red strain had the greatest percent visceral fat (2.3% ± 1.0%) and the Sagana had the lowest (0.2% ± 0.4%).

Flesh quality differentiation of wild and cultured Nile tilapia (Oreochromis niloticus) populations

Variation in chemical composition and carcass traits among different wild and cultured Nile tilapia, Oreochromis niloticus populations were analyzed to study and compare the differences among different wild (Manzalah lake, Nile river and Edku lake) and cultured Nile tilapia populations. Data of body composition of different Nile tilapia ( O. niloticus ) populations showed that, the highest mean value of moisture content (80.32 ± 0.39%) was shown by cultured population and differ significantly (P≤0.05) from those of other populations studied. The highest mean value of protein content (58.14 ± 0.51%) was shown by cultured population but did not differ significantly (P≤0.05) from that of River Nile population. Lipids content showed lower mean (21.74 ± 0.06%) by River Nile population but did not differ significantly (P≤0.05) from that of cultured population. The results of carcass traits show insignificant differences (P≤0.05) in all parameters among different Nile tilapia populations studied. The evaluation of flesh quality of different wild and cultured populations of Nile tilapia studied can result in a genotype suitable for aquaculture. Key words : Flesh quality, wild, cultured, Nile tilapia, population.

Juvenile growth of two tilapia species in lakes Naivasha and Baringo, Kenya

Abstract – Tilapia species in East African lakes often form the basis of commercial fisheries, with information on their population biology assisting their management. This study utilised otolith microstructure, with validation by modal progression analysis, to provide growth data for two tilapia species in two Kenyan lakes for the first time. Otolith microstructure revealed the growth rate of Oreochromis niloticus baringoensis, a sub‐species endemic to Lake Baringo, was fast compared with populations of Oreochromis niloticus; mean daily growth rates were &gt;0.50 mm·d−1 in fish between 12 and 53 mm total length. Growth of Oreochromis leucostictus in Lake Naivasha was also relatively fast when compared with the growth rates of other tilapia species, with mean daily growth rates of approximately 0.35–0.48 mm·d−1 in fish between 10 and 56 mm total length. Growth rates of both species were well described by the Gompertz model and were corroborated by modal progression analysis that revealed similar daily growth rates in modes of young‐of‐the‐year fish.

Genetic structure of domestic and natural populations of the Nile tilapia, Oreochromis niloticus in Burkina Faso, West Africa

The present study is part of an aquaculture developmental program held in Burkina Faso. The final aim is to generate a genetic selection program for an Oreochromis niloticus strain presenting good performances in both growth and reproduction. A characterization of the genetic diversity within and between wild and domestic populations was performed using Restricted Fragment Length Polymorphism (RFLP) of the mitochondrial DNA (mtDNA). Muscle or fins were sampled from 142 individuals in 7 different sites on the 3 main hydro-graphic basins of Burkina Faso (Comoe, Volta and Niger). DNA was extracted using a commercial kit (Promega). The fragment Nd-5/6 (2 500 bp) of mtDNA was amplified by PCR using primers C-GLU and C-LEU3. The amplified products were then digested using one of the six following restriction enzymes: AluI, HaeIII, HinfI, HpaII, RsaI, and Taq I. Haplotype frequencies of the mtDNA per population were calculated from the mtDNA data. When using TaqI, we obtained 4 haplotypes in the basin of Comoe, 3 in that of Volta and only one in the basin of Niger. While the haplotype B is fixed in the Niger basin and the haplotype C dominants in the Comoe basin, haplotype A is only found in the Volta basin. Within the Volta basin, we observed differences in the C haplotype frequencies when we compared the domesticated Bazega population with the wild population of Bama. The populations of Bazega could have been introgressed by those coming from Kompienga as the frequency of haplotype C is higher in the Kompienga population, also visible in the Bazega population. It appears that some individuals of Kompienga population are also maintained in the same rearing station of Bazega. This distribution revealed heterogeneity of the Oreochromis niloticus populations of Burkina Faso. A larger number of individuals are being analysed presently with Taq I in order to validate these results. Further studies will consider the possible association of these genetic population differences, with growth and reproduction performances. (Texte integral)

Fatty acid composition of muscle and heart tissue of Nile perch, Lates niloticus, and Nile tilapia, Oreochromis niloticus, from various populations in Lakes Victoria and Kioga, Uganda

The fatty acid composition in the heart tissue and muscle tissue of the Nile perch, Lates niloticus, and Nile tilapia, Oreochromis niloticus populations from Lakes Kioga and Victoria was determined by methanolysis and gas chromatography of the resulting fatty acid methyl esters. The analytical data were treated by multivariate principal component analysis. The most abundant individual fatty acids were palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1n9), vaccenic acid (18:1n7), arachidonic acid (20:4n6) and docosahexaenoic acid (22:6n3). Due to high levels of both n6 and n3 fatty acids, the ratios of n3 to n6 were between 1 and 2, typical for freshwater fish species. Two Lake Victoria and one Lake Kioga populations of Nile tilapia and Nile perch were distinguished by the fatty acid profiles in their heart and muscle tissue. The heart tissue showed better separation than muscle tissue, due to dominance of polar phospholipids. It is rationalised that genetics are more important than diet in determining the fatty acid composition of the tissues.

Evaluasi Pertumbuhan Empat Populasi Ikan Nila (Oreochromis niloticus) di Kolam Percobaan Cijeruk, Bogor

The objective of the present study was to obtain good populations of Oreochromis niloticus based on their growth performances. Four populations, i.e GIFT-6, Tempe, Local, and GIFT-3 were used in this study. Sixteen 16 cages laid in four earthen ponds in the Cijeruk Research Installation, Bogor, were used as replication. The results showed that there were no significant difference among four populations for biomass, but a significant difference among populations was observed on length parameter (F < 0.01),in which the local population was the best.

On-farm and on-station comparison of wild and domesticated Cameroonian populations of Oreochromis niloticus

Wild (Sanaga River) and domesticated populations of Oreochromis niloticus were compared on-farm and on-station in the Central Province of Cameroon to determine the degree to which genetic deterioration of stocks may have occurred during the process of domestication and subsequent breeding. On-station, average weight at harvest was 284.3±16.2 and 178.1±9.9 g for Sanaga and domesticated populations, respectively. On-station specific growth rate was 0.0660±0.0022 and 0.0555±0.0016 g/day for Sanaga and domesticated populations, respectively. On-station standing stock at harvest was 5747.3±624.4 and 4170.3±233.4 kg/ha for Sanaga and domesticated populations, respectively. Differences in average weight at harvest and specific growth rate on-station are significant at P<0.003. Differences in standing stock at harvest on-station are significant at P<0.015. On-farm, average weight at harvest was 121.1±26.5 and 87.5±17.2 g for Sanaga and domesticated populations, respectively. On-farm specific growth rate was 0.0442±0.0057 and 0.0358±0.0047 g/day for Sanaga and domesticated populations, respectively. On-farm standing stock at harvest was 2454.2±445.6 and 1667.8±352.2 kg/ha for Sanaga and domesticated populations, respectively. Differences in average weight at harvest on-farm are significant at P<0.05. Differences in specific growth rate on-farm are significant at P<0.04. Differences in standing stock at harvest on-farm are significant at P<0.015. The Sanaga River population consistently out-performed the domesticated population. Final individual weight of domesticated fish averaged 39% less than wild fish on-station and 42% less than wild fish on-farm.

The use of xenoantigenic antisera for the identification of tilapiine species: comparative laboratory and field studies

Summary Rapid and reliable identification of tilapiine taxa and strains is essential for selective breeding purposes and the conservation of natural genetic resources. There is evidence that antisera-mediated erythrocyte agglutination assays can fit these requirements. We evaluated the applicability of agglutination tests by studying the capacity of species characteristic antisera to recognize erythrocytes from individuals of 10 natural Ghanaian populations of Oreochromis niloticus and Sarotherodon melanotheron. The vast majority of the 218 tested individuals could be identified based on antisera-mediated erythrocyte recognition. Controls indicated the specificity of these reactions. Still, erythrocytes from 16% of all tested specimens did not respond to any antiserum (zero responders), indicating the possible existence of blood group properties in tilapias. We discuss the specificity of the antisera, the relevance of zero responses and the applicability of these tests in aquaculture and field studies.

Rapid evolution of an established feral tilapia (Oreochromis spp.): the need to incorporate invasion science into regulatory structures

Outside of Asia exotic tilapiine fishes (Trewavas 1983) were not imported directly as native genetic resources from Africa but arrived as transits from third or fourth party sources. Founder populations of exotic tilapia species may be morphologically and meristically distinct in Africa but are still reproductively compatible due to their relatively recent divergence. As a result, feral tilapias have hybridized and introgressed in aquaculture settings before escaping to the wild. Reproductively viable hybrids have resulted, making the use of conventional systematics based upon external morphometric characterizations for species determinations useless. Microsatellite DNA marker studies of 139 tilapia from 10 locations (6 feral, 4 in culture) in southern California, USA, were conducted. Genetic similarities to a worldwide tilapia genetic database were compared by formulating a neighbor-joining dendrogram. The hypothesis that the pattern found arose by chance was tested by bootstrap resampling of 4 microsatellite loci at the 95% level of significance. A significant number of bootstrap re-samples showed that a tilapia species in aquaculture and a feral Colorado River tilapia population were 'monophyletic', meaning they originated from a single source relative to the total variation in the data. A significant number of bootstrap re-samples grouped these two populations with the reference populations of Oreochromis niloticus taken worldwide. This 'niloticus' group was found significantly distinct from a second large grouping that included all of the other California tilapia samples and a large group of O. mossambicus reference samples taken from a worldwide database. Any regulatory structure attempting to control movements of exotic tilapias based upon discerning 'species' using morphometric and meristic measurements of tilapias is inadequate. California, for example, does not permit O. niloticus for aquaculture, but the genetic signature for this species exists in feral stocks collected from the wild in California. There are likely many other places where a certain tilapia `species' are not permitted but the genetic material exists in established wild stocks within its political jurisdiction. It is recommended that a system of ecotypes (code names) based upon presence of unique DNA microsatellite markers be developed to label and regulate feral tilapia strains, and that hybrid strains be collected into a 'registry' of species based upon unique DNA markers. Such a registry could be used by regulators to better manage exotic tilapias and aquaculture developments.