Parachanna Obscura Research Articles

Optimum stocking density for <em>Parachanna obscura</em> larvae fed at its optimum ration

Two experiments were conducted during 15 days respectively in re–circulating system composed of 15 plastic tanks containing 20L of water each. This study aims at estimating optimum feeding rate and stocking density for efficient growth, food utilization and survival rate of Parachanna obscura larvae (initial body weight = 0.1 ± 0.0 g and 0.15 ± 0.13 g). In the first experiment, five food rations (5, 10, 20, 25 and 30% of body weight per day) were tested in triplicate. Specific Growth Rate (SGR) and Feed Efficiency (FE) of larvae fed different rations varied significantly (P<0.05). Best SGR and FE were obtained with rations from 5 to 10% of body weight. Two mathematical models were used to analyse the relationships between feeding level and SGR. Optimum and maximum rations are 8.13% and 25% of body weight respectively. In the second experiment, five stocking densities (5, 20, 35, 50 and 65 larvae/L) were assigned in triplicate. Fish were fed manually with ration 8.13% of body weight. Results showed that SGR and FE obtained with different densities varied significantly (P<0.05). Highest final body weight and survival rate of fish were obtained with stocking density 20/L of water. Moreover, best SGR and FE were observed in larvae stocked at density 20 larvae/L (P<0.05). Thus, optimum stocking density of P. obscura fry (initial body weight = 0.15 ± 0.13 g) is 20/L.Keywords: Parachanna obscura, rations, stocking density, growth, Feed Efficiency

The biology of Parachanna obscura (Osteichthyes: Channidae) in Anambra River, Nigeria

The biology of a commercially important teleost, Parachanna obscura was studied for a period of twelve months. Monthly samples of the species were randomly collected from fishermen in the lower reaches of Anambra River, Southeastern Nigeria for the twelve months. The haematological profile established were mean haematocrit of 22.5%, mean blood haemoglobin concentration of 7.23 g/dl, mean red blood cell sedimentation rate 31.25 µm, mean red blood cell count 3.72 (106/L), white blood cell count 2.81×104/L, mean cell volume 60.75 µm3 and mean corpuscular haemoglobin 19.5 pg. The blood groups are O+(10%), O- (90%), genotype AA (88%) and AS (12%). Digestive enzymes assays in the different gut regions of P. obscura revealed an array of glycosidase, proteases and lipases. The pattern of distribution and relative activity of the enzymes is consistent with its predatory diet. Total length (TL) ranged from 23.4 to 28.5 cm and weight from 86.0 to 140 g; males were not longer or heavier than females. Maturity occurred earlier in males than females; 50% of both sexes matured at 24.7 cm TL. Fecundity ranged from 126 to 1580 oocytes (mean 896 ± 477 oocytes). Total length was a better predictor of fecundity than ovary weight. Index of food significance (IFS) showed that insect (51.67%) was the dominant food group, followed by fish (15.66%) and frog eggs (8.02%). Food items of primary importance were ephemeroptera nymphs, chiromomidae, unidentified insects and fishes. Key words: Anambra River, Parachanna obscura, digestive enzymes, haematological profile, blood groups.

A review of biology, ecology and prospect for aquaculture of Parachanna obscura

Parachanna obscura is the most common African Channidae. Various studies are being conducted on its biology and ecology. It lives in fresh water in quiet and muddy areas. It has accessory respiratory organs allowing it to live in hypoxic environment. It has a varied diet and feeds on fish, remains of fish, insects, other invertebrates and plant detritus. It is a species with iteroparous asynchronous oogenesis which breeds throughout the year but much more during and just after the flood. It size at first maturity is 24.5 cm. Eggs and larvae of P. obscura are yellow and guarded by one or both parents. Hardiness, rapid growth, high tasty flesh and commercial value of this species represent significant aquaculture potentiality. Natural stocks of P. obscura are overexploited and are not sufficient to met local demands. Its extensive farming system has already started in some African countries. Successful farming of this species in intensive systems and semi—intensive can help not only to preserve and enhance natural stocks of P. obscura but also to continuously produce fingerlings remediation technologies for direct human consumption.

Relationships and biogeography of the fossil and living African snakehead fishes (Percomorpha, Channidae, Parachanna)

ABSTRACT The ability to determine relationships of Cenozoic fossil fishes relies heavily on having osteological information from their extant relatives with which to compare the fossil remains. For many higher teleost fishes, these osteological data do not exist. For example, †Parachanna fayumensis, from Eocene and Oligocene deposits of Egypt, was placed in the Recent snakehead genus Parachanna, but in the absence of data from extant members of the genus, this hypothesis could not be tested. Three other fossil channids were each given their own new genera, without an analysis of their relationships to one another or to the living genera. In order to properly test the relationships of these fossil species, the osteological information for living species is needed. This paper documents the osteology of the African snakehead, Parachanna obscura, for the first time. The documentation of the osteology forms the basis of a phylogenetic study of the relationships of the African fossil, †Parachanna fayumensis, with living African snakeheads. This study supports the generic placement of †P. fayumensis as being correct, as well as reciprocal monophyly of the two living snakehead genera and monophyly of the family. Monophyly of the Asian genus Channa and the relationships of the other fossil species need to be further assessed using a broader range of species, but this preliminary study is an essential first step. Apomorphic osteological characters are given for the family and genera, as well as a discussion of the biogeographical relationships of species of Parachanna.

Dietary Pattern of the Population of Parachanna obscura (Gunther 1861) in River Owo, South West, Nigeria

Dietary Pattern of the Population of Parachanna obscura (Gunther 1861) in River Owo, South West, Nigeria

Food and diet relationships of <i> Parachanna obscura </i> (Gunther) and <i> Clarias gariepinus <i/> (Burchell) in a newly impounded Osinmo reservoir, Ejigbo, Nigeria

The food and diet of two economically important freshwater fish species, Parachanna obscura and Clarias gariepinus were examined in Osinmo reservoir. Gill-net, cast-net and traps were the fishing gears used to collect fish specimens. Morphometric parameters of each fish were taken. Stomach fullness was noted and each stomach preserved in 4% formalin. Frequency of occurrence and Numerical methods was used to analyse the stomach contents of each fish. The study observed by frequency of occurrence that insects, fish, and algae, constituted 73% of the stomach contents of P. obscura throughout the sampling period. Similarly the stomach contents of C. gariepinus were dominated to the tune of 79% by detritus, mud, fish, algae, insects and diatoms. Slight variation in food items was observed during the dry and rainy seasons. The percentage of non- empty stomachs in dry and rainy seasons increased from 80% to 89% in P. obscura and from 74.6% to 83.4% in C. gariepinus . The two species of fish fed on many related food items and Schoener overlap index values of 0.05 and 0.02 indicated no diet overlap and competition in dry and rainy seasons.

Reproductive biology, length-weight relationship and condition factor of the African snake head, Parachanna obscura , from River Oshun, South-west Nigeria

Aspects of the biology of the African snake head, Parachanna obscura, obtained from River Oshun, South-west Nigeria, from August 2006 to February 2007, were studied. Fish were captured with gill nets. The species attained a maximum total length of 36.4 cm and body weight of 389.36 g. The length/weight relationship indicated allometric growth for males and isometric growth for females. Gonado-somatic index ranged between 1.1 and 2.8% in the females. Values of condition factor were high for males. There were more females than males, and immature fish dominated the catch. Eggs ranged in size between 0.88 and 1.11 mm, while fecundity estimates ranged between 1711 and 4000 and were not related to length and body weight. P. obscura in this study did not show any distinct seasonal pattern of breeding. Key words: Parachanna obscura, River Oshun, Nigeria, reproductive biology.

Preliminary study on the aspects of the biology of snakehead fish parachanna obscura (günther) in a Nigerian wetland

Between October 2000 and March 2001, a preliminary study on the aspects of the biology of Parachanna obscura, was carried out. Sex ratio revealed female preponderance (÷2 = 4.733, df = 1, P range 9.0-18.0 cm comprises ten food items. The items were re-classified into seven major groups consisting of detritus [coarse and fine detritus], fish [juvenile and remains of fish], insects (un-identified adult and remains of insects, macrophyte materials, mud, nematode, and biogenic sand. Fish, insects and nematodes were eaten as primary food items. There was a complete ingestion of the array of the dietaries by both sexes of Parachanna obscura. Exception of one item (coarse detritus), during the wet season, Parachanna obscura consumed all the dietaries during the seasons. Nevertheless, the later season increased in the ingestion of nine out of 10 items in conformity with optimal foraging theory. Parachanna obscura is considered a piscivore-insectivore-invertivore in feeding habits. In the wake of doubt about the viability and prospects of aquaculture, farming of P. obscura could be desirable. This species possesses a number of positive attributes when it comes to aquaculture. It is likely that efforts to culture this hardy carnivorous and fast-growing fish will spread in the coming years in Nigeria, if breeders and fish farmers will give it a chance. Further studies are, however, required to delineate the full biology of P. obscura in order to highlight its viability for domestication and cultivability. P. obscura is widely enjoyed by natives of its natural habitats all over the world as a source of protein.

Deux espèces nouvelles deMyxidium(Myxosporea : Myxidiidae) parasites de poissons d’eau douce du Cameroun

The study of Myxosporidia infecting Clarias pachynema Boulenger, 1903 (Clariidae), Ctenopoma petherici Günther, 1864 (Anabantidae) and Parachanna obscura (Günther, 1861) (Channidae) from the basin of Nkam in Cameroon, revealed the presence of two new species of Myxosporidia of the genus Myxidium Bütschli, 1882, all found in the gall bladder of their hosts. These new species were: Myxidium nkamensis n. sp., found in Clarias pachynema and M. sangei n. sp. found in the gall bladder wall of Parachanna obscura. Two other species, Myxidium petrocephali Fomena and Bouix, 1986 and M. distichodi Kostoïngué, Faye and Toguebaye, 1998 were found in new hosts. The list of Myxidium species parasitizing African fresh water fishes is given.

The Biology Of The West African Clariid, Clarias macromystax Gunther, 1864 (Osteichthyes: Clariidae) In A Nigerian River Basin

The biology of the West African clariid, Clarias macromystax, was studied in Anambra river basin, Nigeria. The clariid occurred more abundantly and frequently in forest floodplain ponds than in other habitats, and was totally absent in the river systems. Length ranged from 9.7 to 30.2 cm TL and weight from 9 to 168 g; females were heavier, but not longer, than males. The b-values (2.4190-2.5209) of the total length-weight relationships exhibited negative allometric function. Mean relative condition, Kn, was better in females than males but showed a definite cycle in both sexes. Over 50% of both sexes were mature at 15.1-20.0 cm TL in their first year of life. Fecundity ranged from 2.136 x 103 to 37.250 x 103 (mean 14.942 x 103± 11.248 x 103) and correlated highly and positively with length, body weight and ovary weight. Ovary weight was the best predictor of fecundity. Communal spawning involving C. macromystax and C. agboyiensis occurred. Feeding was carried out throughout the day with higher feeding intensity at night. Food of primary importance were Caridina niloticus, Sudanonautes africanus, Odonata naiad, terrestrial Orthoptera, formicoid Hymenoptera, Dytiscidae, Oreochromis niloticus, Parachanna obscura, fruits and seeds, plant detritus and mud. Diet breadth was season-dependent. The clariid fed by foraging, shoveling and surfacefeeding. E. clarias, Procamallanus laevichonchus and a larval spiruroid parasitized various organs. C. macromystax is a new host record for these helminth parasites. Keywords: Clarias macromystax, Abundance, Reproduction, Food, Parasites, Anambra river basin, Nigeria. Animal Research International Vol. 1 (3) 2004 pp. 190-199

Digestive Enzyme Assays In The Gut Of Oreochromis Niloticus Linnaeus 1757, Parachanna (Channa) Obscura Gunther 1861 And Gymnarchus Niloticus Cuvier 1829

Digestive enzyme assays in the different gut regions (oesophagus, stomach, caecum, duodenum, ileum, and rectum) of three commercial African freshwater fish species: Nile tilapia Oreochromis niloticus, African snakehead fish Parachanna obscura, and African long knife fish, Gymnarchus niloticus, revealed an array of glycosidases (amylase, sucrase, maltase, lactase, and cellulase); proteases (chymotrypsin, pepsin, and trypsin) and lipases. The pattern of distribution and relative activity of the enzymes showed that the fishes are capable of digesting carbohydrates, proteins and lipids such that they complemented the different dietary habits of the three fish species. Enzyme activity was not detected in the oesophagus and rectum of the three fish species. The relative distribution and activity of the various enzymes were possibly induced by the nutritional requirements of the fishes.

Haematological Profile Of <i>Parachanna (Channa)</i> Obscura Gunther 1861, <i>Malapterurus electricus</i> Gmelin 1789 And <i>Malapterurus minriya</i> Sagua 1987

Reference values for some haematological indices of Parachanna obscura, Malapterurus electricus and Malapterurus minjiriya were determined. The mean ± SD values for erythrocyte count (Ec), leucocyte count (Lc), haematocrit (Hct), haemoglobin concentration (Hbc), erythrocyte sedimentation rate (ESR), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), and plasma protein content (g/dl) determined for P. obscura were 2.00 ± 0.71 x 10 12 /litre, 40.10 ± 1.32 x 10 9 /litre, 26.40 ± 3.89 %, 11.48 ± 1.55 g/dl, 13.12 ± 1.26 mm/h, 131.70 ± 108.20 fl, 57.28 ± 43.25 pg, 43.48 ± 6.97 g/dl, 62.90 ± 9.70 g/dl respectively. Ec, Lc, Hct, Hbc, ESR, MCV, MCH, MCHC and plasma protein content determined for M. electricus were 1.96 ± 0.17 x 10 12 /litre, 31.87 ± 2.30 x 10 9 /litre, 32.03 ± 1.94 %, 7.08 ± 0.22 g/dl, 2.56 ± 0.53 mm/h, 158.59 ± 5.16 fl, 35.24 ± 1.79 pg, 0.225 ± 0.018 g/dl and 52.89 ± 7.23 g/dl, respectively. Ec, Lc, Hct, Hbc, ESR, MCV, MCH, MCHC and plasma protein content determined for M. minjiriya were 2.09 ± 0.21 x 10 12 /litre, 38.48 ± 3.10 x 10 9 /litre, 34.04 ± 2.15 %, 8.28 ± 0.25 g/dl, 2.71 ± 0.58 mm/h, 168.15 ± 8.01 fl, 36.43 ± 2.17 pg, 0.255 ± 0.027 g/dl and 50.85 ± 9.86 g/dl, respectively.

Effect Of Smoke-Drying On The Proximate Composition Of Tilapia Zillii, Parachanna Obscura And Clarias Gariepinus Obtained From Akure, Ondo-State, Nigeria

The proximate composition of fresh, smoked and deterorated fish samples (Tilapia zilli, Parachanna obscura and Clarias gariepinus) were determined using standard methods o analyses. It was revealed that Tilapia zilli contained; moisture 411 - 6733%, protein 20.10 – 6590%, ash 3.41 – 14.64 %, fat 4.44 – 7.73 % and carbohydrate 4.72 – 11.89 %, Parachanna obscura had moisture 6.47 - 68.61%, protein 18.23 – 6467%, ash 2.68 – 13.20 %, fat 3.55 – 8.87 % and carbohydrate 6.79 – 10.25 %, while Clarias gariepinus produced moisure 461- 56.99% protein 17.21 – 68.05%, ash 4.82 – 15.32 %, fat 4.79 – 8.19% and carbohydrate 1.92 – 17.35%. It wasobserved that smoke drying methods increased the protein, ash and fat contents of the samples. The low fat content observed for the deteriorating sample might be due o rancidity with the resultant rancid odour. Keywords: Tilapia zillii, Parachanna obscura, Clarias gariepinus, Smoke-drying, Proximate compositionAnimal Research International Vol. 3 (2) 2006 pp. 478-480

Changes in physicochemical and sensory characteristics of smoke-dried fish species stored at ambient temperature

This study assessed the comparative changes in the physical and chemical components of five different species of smoked freshwater fish: Bony tongue, Heterotis niloticus, African carp, Labeo coubie, Snake fish, Parachanna obscura, Nile Tilapia, Oreochromis niloticus and African mud catfish, Clarias gariepinus during storage. The fish were smoke-dried to average moisture content of 10.41 ± 0.02% and stored. Fish were packaged in black polythene bags and kept in perforated plastic containers. The fish were left in the plastic baskets for 56 days at ambient temperature (25-32oC). Samples of fish were assessed weekly for physical attributes such as colour, fragmentation, odour, taste and texture. Proximate composition was assessed using changes in moisture content, crude protein, lipid and ash content. Biochemical indexes carried out were: Total Volatile Nitrogen (TVN), pH, Peroxide Value (PV) and Free Fatty Acid (FFA) levels. There was a general decline in physical attributes i.e. colour, fragments or cracks, odour, taste and texture of fish during storage. Fluffy woolly mat of moulds were noticed on the Clarias gariepinus from the 5th week of storage. There was a significant (P <0.05) colour change in most species as from the 6th week. During this study, the moisture content increased weekly in the five smoked fish species from the initial average of 10.41±0.02%. This could be attributed to the difference in the moisture of the smoked fish relative to the surroundings. Oreochromis niloticus and Heterotis niloticus had the best taste value. Apart from Parachanna obscura , the other fatty species, C. gariepinus and L. coubie became less firm as the weeks progressed. There were significant changes (P <0.05) in most of the physical and chemical characteristics except odour from the 6th week (42 days) of storage. There were also significant differences (P <0.05) between the initial and final values of the proximate and chemical constituents of the different species of fish. The study showed that keeping quality of smoked fish under ambient conditions decreases with increase in length of storage. Keywords : Freshwater fish, hot smoking, storage

English

This study assessed and monitored the concentrations of Cu, Mn, Zn, Cd, Cr, Ni and Pb in the gills, offal, muscle and liver of a commercially important mudfish (Parachanna obscura) from Ogba River, Benin City, Nigeria between January and December, 2005. The same metals were also determined in the water of the river. The results revealed that the concentrations of all the metals in the tissues (offal, gills, muscle and liver) were higher than the concentrations of the metals in water and indicated bioaccumulation. The concentrations of all the metals in water were below WHO and FEPA recommended limits and suggested that the water of Ogba River was suitable for drinking, but the concentrations of Cu, Mn, Cr, Ni and Pb in all fish tissues exceeded these limits and indicated that the fishes of Ogba River, as far as these metals were concerned, were unfit for human consumption. Consequently, close monitoring of metals pollution and the consumption of the fishes of Ogba River is recommended with a view to minimizing the risks to health of the population that depend on the river for their water and fish supply. &nbsp; Key words:&nbsp;Heavy metals, water, fish, Ogba River, Nigeria.

Normal Haematological Profile of Parachanna obscura as a Diagnostic Tool in Aquaculture

Normal Haematological Profile of Parachanna obscura as a Diagnostic Tool in Aquaculture

BIOMETRY AND COMPOSITION OF FISH SPECIES IN OWENA RESERVOIR, ONDO STATE, NIGERIA

A survey of fish species present in Owena reservoir was conducted between October 2004 and March 2005. Fish samples were taken from the catch of the fishermen operating in the reservoir. The results of the survey showed that 14 fish species belonging to seven families were recorded. Two families namely Characidae and Clariidae constituted the dominant fish families in the reservoir. Among the Characidae, Brycinus nurse (23.1%) and among the Clariidae family, Clarias gariepinus (22.8%) were dominant. Other fish species with significant abundance were Sarotherodon galilaeus (9.3%), Parachanna obscura (8.0%), Clarias anguillaris (7.7%) and Oreochromis niloticus (6.4%). The meristic features of the two most abundant fish species caught are as follows: Brycinus nurse had two dorsal spines with eight dorsal fins, two anal spines with eleven anal fins, 25 caudal fins, one pectoral spine and 13 pectoral fins and two ventral spines with seven ventral fins. Clarias gariepinus had 75 dorsal fins, 31 anal fins, 10 caudal fins, six pectoral fins and five ventral fins. The morphometric features of the two most abundant fish species are: Brycinus nurse: total length: 312mm, standard length: 255mm, head length: 60mm, body length: 90mm and body girth: 190mm. Clarias gariepinus: total length: 265mm, standard length: 240mm, head length: 62mm, body length: 62mm and body girth: 130mm.

Toxicity of cadmium to Parachanna obscura : As evidenced by alterations in hematology, histology, and behavior

Fish of species Parachanna obscura are exposed to four concentrations of cadmium (Cd) (0.02, 0.06, 0.18, or 0.54 mg L−1). Acute toxicity test results after 96 h showed marked hematological, histological, and behavioral changes. Quantitative blood analysis revealed that white blood cell (WBC), packed cell volume (PCV), and platelets counts were linearly correlated with increasing Cd concentrations; however, blood haemoglobin (Hb) showed an inverse relationship, with higher Hb levels at lower Cd concentrations. Histological changes of the liver showed hepatic separation, bloody appearance, and deposition of a brownish-yellow substance, which increased with rising concentrations of metal. Behavioral changes observed included reduced activity, avoidance response, and deposition of a slimy-whitish film on the body of the fish, which increased with concentration and exposure time.

Assessment of polynuclear aromatic hydrocarbon content in four species of fish in the Niger Delta by gas chromatography/mass spectrometry

Analysis for the presence of sixteen priority polynuclear aromatic hydrocarbons (PAHs) (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene, dibenz[a, h]anthracene and indeno[1,2,3-cd]pyrene) was carried out on four different species of fish found in the Niger Delta region of Nigeria. The fish species included Parachanna obscura, Pseudolithus elongatus, Liza dumerillii and Clarais gariepinnus. Individual PAHs were identified through both retention time match with authentic standards and simultaneous maximization of several major ions from gas chromatography/mass spectrometry (GC/MS) data. Four isotopically-labeled internal standards namely D10-acenaphtalene, D12-chrysene, D10-phenanthrene and D12-perylene, were used for quantitation. All four species of fish were found to contain high levels of PAHs ranging from 0.41 to 39.64 ug/kg. The high molecular weight PAHs such as benzo[ghi]perylene, dibenzo[a,h]anthracene and indeno[1,2,3-cd]pyrene were consistently present in much higher amount than other PAHs in all four species of fish studied, suggesting higher resistance of these compounds to degradation.

Haematological characteristics of the African snakehead, Parachanna obscura

The haematological characteristics of the African snakehead Parachanna obscura includes mean blood haemoglobin concentration of 5.70g/dl, mean haematocrit of 19.20%, mean red blood cell count of 1.67 x 10 12 /L, mean total white blood cell count of 19.07 x 10 3 mm -3 , mean erythrocytic haemoglobin concentration of 29.08%, mean erythrocytic haemoglobin of 39.86
g, mean erythrocytic volume of 132.84 μ 3 , mean total plasma protein of 4.45 g/dl and mean plasma glucose of 67.42 mg/dl. Correlations were found with certain blood parameters as function of the length, weight and condition factor.. African Journal of Biotechnology Vol. 4 (6), pp. 527-530, 2005