Parasites of Clarias gariepinus obtained from culture and wild specimens of Onitsha urban stretch of River Niger. Amambra State, Nigeria

Parasites recovered from randomly-selected specimens of Clarias gariepinus, obtained from artisanal fishery landings of River Niger at Onitsha Urban were studied. They were compared with pooled C. gariepinus specimens from two private fish farms at Onitsha Urban, Anambra State, Nigeria. The total number of fish host dissected during this investigation was one hundred and sixty. Eighty specimens were drawn from the wild and culture systems, respectively, at fortnightly interval between April to August, 2006 of the one hundred and sixty fish hosts examined, eight specimens each were studied from the wild and culture respectively. Similarly, thirty-two males and forty-six females were selected respectively for the two group studies. From the culture milieu, fifty-two were infected with one or more parasite species. The wild population presented with twenty four cases of various parasites were recovered from the liver, mouth, brain, gills, stomach and fins. Seventy-nine parasites were recovered from the wild affecting the same body areas, except that Ergasillus sp. and Argulus sp. respectively affected the fills and fins more. No significant difference was recorded in the level of parasitic infection among the two groups (P>0.05) and amongst the host males and female fish hosts. The parasite burden showed no significant differences across the selected age groups of the wild study. However, notable difference was recorded between adults, sub-adults and juveniles of the culture and wild sets studied. The economic implication of these parasites to aquaculture is noted.Key word: Parasites, Clarias gariepinus, wild culture Onitsha Urban, River Niger

Traditional methods of fish smoking and drying in reducing loss to spoilage in selected fishing communities of Anambra State, Nigeria

The preservation and processing of fish by smoking / drying are methods used by artisanal fishermen to avoid spoilage of their catches. In Anambra State, these methods of fish handling were investigated in four fishing communities (Isiokwe Otu, Nmiata Anam, Iyi Ora and Enugu Otu) out of about 17 fishing communities in Anambra West Local Government Area of the State. Average fish production in the communities ranged between 20kg/day to 50kg/day per boat, producing an income of between N6,000.00 to N15,000 per day. The preference of the consumers of these catches tilted towards preferring a properly-smoked product in all seasons especially during the rainy season. Two drying methods - sun drying with or without salting and use of natural air (sun-drying) were not highly embraced during the rainy periods as it is for smoking methods. Their average catch (kg/day) was 20 for community A, 30 for community B, 50 for community C and 45 for community D. The estimated losses to spoilage and its implication to fish preservation and availability in the wild are herein discussed. Key Words: Traditional methods, spoilage, fish loss

Copepods of Jamieson River, Nigeria

No Abstract

Baseline limnological investigation of the Utor River in Esan Southeast, Edo State, Southern Nigeria: I. Physical and chemical hydrology

The Utor River is a pristine ecosystem remote from the current wave of urbanization and industrialization. This baseline study of a 2.5km stretch of the river describes its physical and chemical environment. The Utor River is oligotrophic, relatively acidic, well oxygenated, and low in solids, conductivity, cations and heavy metals. All the physical and chemical conditions except water level and iron (Pb) were significantly similar in the four sampling stations. The environmental conditions studied have been discussed in relation to the drainage characteristics, rainfall regime, potability, equivalent ecosystems and general water quality standards.Keywords: Utor River, water quality, seasonal dynamicsTropical Freshwater Biology 2003/2004 Vol. 12/13: 45-6

The Physical and Chemical Hydrology of a Niger Deltan tidal creek, Nigeria

The physical and chemical conditions of the Buguma Creek, Niger Delta, Nigeria were investigated between November, 2004 and October, 2006. Five stations, made up of two (4 and 5) from the main channel and three (1,2 and 3) from the associated interconnecting creeks were sampled. From the salinity record of 0-21%0, the creek ranges from limnetic/oligohaline to polyhaline condition. Of the twenty-five physical and chemical parameters determined, only water temperature, transparency, water level and total suspended solids were significantly different (P< 0.05) among the stations. The a posteriori DMR test showed that stations 1 and 2 which were still fairly well covered by mangrove had water temperature significantly lower (P< 0.05) than those of stations 3 to 5. Stations 2 and 4 had higher transparency than station 1. Station 4 had significantly higher water levels than stations 1 and 2 which were significantly different, while station 1 had significantly higher water level than stations 3 and 5 which were not significantly different. Stations 2 to 5 which were not significantly different from each other had significantly different total suspended solids than station 1. Most of the parameters were observed to exhibit temporal variations, due to high influx of run-off in the wet months, high incursion of seawater, and evaporation during the dry months. The generally low biochemical oxygen demand (0 – 4.50 mg/l), chemical oxygen demand (2.05 – 46.8 mg/l), and extremely low total hydrocarbon content (THC) (0.01 mg/l) indicate that the water was not polluted

The impact of bitumen exploration on the physical and chemical quality of the Benin river, Nigeria

The impact of bitumen exploration on the physicochemical parameters of the Benin River in Delta State was assessed between May and November 2010. There was no statistically significant difference (P&gt;0.05) in the physico-chemical parameters of the study stations, except for total suspended solids (TSS), zinc and chromium which differed significantly (P&lt;0.05) across the stations. A posteriori Duncan Multiple Range (DMR) test showed that these significant parameters were higher around the bitumen processing plant than at the other stations. The mean ranking distribution pattern of the heavy metals in surface water was Fe&gt;Mn&gt;Ni=V&gt;Zn&gt;Cu&gt;Pb&gt;Cr&gt;Cd. The water quality parameters were within the Federal Ministry of Environment (FMEnv) and World Health Organization (WHO) minimum criteria for drinking waters, except TSS, TDS, iron, manganese, lead, nickel and vanadium which were not compliant. The sediment had higher concentrations of all the heavy metals and the rank profile of the metals was Fe&gt;Zn&gt;Mn&gt;Ni&gt;Cu&gt;V&gt;Cr&gt;Cd&gt;Pb. The distribution coefficient Kd, which is an indication of the adsorbing capacity of the substrate, varies within a wide range, from 11.097 (Pb) to 202.122 kg/l (Fe). Desorption of metals from the solid phase is thus small, indicating that the sediment matrix is significantly affecting the mobility of metals by modifying the bonding of pollutants to the sediment system. The dissolved oxygen, TSS and the levels of heavy metals indicate degradation of the Benin River. Apart from bitumen exploitation, the river and its adjoining creeks are exposed to intense anthropogenic activities which include industrial, boat transportation, agricultural and domestic sewage disposal. The need to regulate and closely monitor all such activities in the river and its catchment area becomes imperative for natural attenuation and restoration of the aquatic ecosystem.Keywords: bitumen, exploitation, impacts, water, sediment, quality, K

Assessment of nutrients and metals in sediments of Ogba river, Southern Nigeria

This study assesses the concentrations of nutrients and metals in river bed sediments of Ogba River, a fourth-order river in Southern Nigeria. Most rivers in this region are exposed to untreated industrial and domestic wastewater discharge, including atmospheric deposition from crude oil exploration activities. River bed sediment samples were collected from four sites located downstream of an urban sewage discharge and agro-allied industry wastewater release point. The results showed statistically significant differences in sediment particle size distribution, nutrient and metal concentrations across the sites. The sediment particle size distribution was dominated by sand (92%), with mean pH range of between 5.1 and 6.0. Concentrations of metals and nutrients were highest in sediments of Site 2 located in close proximity to refuse dump sites and arable land use. Total organic carbon (TOC) and nitrate (NO3--N) were negatively correlated with sand but positively related to clay (P&lt;0.01). No significant relationship was found between metals except for Ni and cadmium (Cd), and Fe and Ni. In addition, no significant relationship was found between TOC and metals (Fe, Zn, Cu, Cd, Pb and Ni), suggesting that in this fluvial system TOC may not be effective in the complexation of metals.Key Words: Sediment, metals, nutrients, freshwater, Nigeri

Some Aspects Of The Biology Of Papyrocranus Afer And Xenomystus Nigri (Family Notopteridae) In The River Osse, Southern Nigeria

Specimens of two notopterids, Papyrocranus Afer and Xenomystus Nigri were collected from Osse River at Ikoro between December 2002 and August 2003 and examined for morphometric features, condition factor and food and feeding habits. The standard length of P. Afer ranged from 13.7-38.1 cm and X. Nigri, 8.3-16 cm. The mean condition factor of P. Afer was 0.96 and X. Nigri was 1.18. Generally, specimens of higher standard length had lower condition factor than those of lower standard length. A significant negative regression (

The gastrointestinal helminth parasites of some scianid species (Croakers) in a Niger Delta mangrove creek, Nigeria

Sciaenid fishes (croakers), Argyrosomus regius, Pseudotolithus (Fonticulus) elongatus and Pseudotolithus (Pseudotolithus) senegalensis were isolated from fish samples collected monthly from November 2004 to June 2006 at flood tide in Buguma creek, Niger Delta, Nigeria. The fish samples were caught by the use of hooks and lines and cast nets. A total of seven hundred and eighty nine specimens comprising A. regius (12), P. (Fonticulus) elongatus (753) and P. (Pseudotolithus) senegalensis (24) were examined for gastrointestinal helminth parasites. All helminth parasites observed were nematodes. No infection was recorded in A. regius. P. (Pseudotolithus) senegalensis had the highest prevalence (41.7%), followed by P. (Fonticulus) elongatus (23.4%). A total of 57 helminth parasites were recorded, of which 54 were found in P. (Fonticulus) elongtus, and 20 in P. (Pseudololithus) senegalensis. Goezia sigalasi (Ascarididae) and Pseudanisakis sp. (Heterocheilidae) had the highest prevalence in both species of sciaenid fishes infected.Key words: Gastrointestinal helminth parasites, croakers, Sciaenidae, mangrove creek, Nigeria

Morphormetric Measurements Of Barbels, Head And Standard Length Of Catfish From Osse River, Nigeria

Measurement of sensory barbels of five catfish species from the Osse River was undertaken to ascertain the differences between the types of barbels. The five species showed the maxillary to have the largest proportion of SL. The differential rankings of the maxillary were Heterobranchus bidorsalis Geoffrey Saint Hilaire (41.58%), H. longifilis Valenciennes (36.05%), Malapterurus electricus (Gmelin) (23.60%), Synodontis nigrita Valenciennes (22.24%) and Chrysichthys furcatus Gunther (20.30%). The head – SL relationship was significant in all five species whereas the maxillary – SL relationship was significant in C. furatus, H. bidorsalis and M. electricus. It was the mandibulary – SL relationship that was significant in C. furcatus, H. longifilis and M. electricus, while the nasal – SL relationship was significant in C. furcatus and H. bidorsalis (