Evaluation of the haematology and biochemistry of the silver catfish, Chrysichthys nigrodigitatus as biomarker of environmental pollution in a tropical lagoon

The objective of the present study was to examine the haematological and biochemical parameters of the silver catfish, Chrysichthys nigrodigitatus, from the Makoko area of a polluted tropical lagoon such as Lagos Lagoon, to serve as a baseline data for the assessment of the health status of the fish and as reference point for future studies. The mean values of the haematological parameters analyzed were: blood haemoglobin, Hb (97.29±4.35g/L); pack cell volume, PCV (29.28±1.23%); red blood cell/total erythrocyte count, RBC (2.97±0.12T/L); white blood cell count, WBC (10.69±0.37g/L); mean cell volume, MCV (95.19±2.28fl); mean corpuscular haemoglobin, MCH (30.53±0.67pg), mean corpuscular haemoglobin concentration, MCHC (33.32±0.38g/dl), and the differential leucocytes. While the mean values of the biochemical parameters were: aspartate transaminase, AST (66.06±6.12 IU/L); alanine transaminase, ALT (12.98±1.10 IU/L), and alkaline phosphatase, ALP (88.01±8.60 IU/L). The findings from this study gave an indication of stress on the health status of the fishes in this lagoon and there is need for proper management strategies to be adopted in monitoring the conditions of the faunal communities in the lagoon. The lagoon indeed showed signs of environmental stress, which eventually pose devastating effect on the health status of the fishes. These have an indirect effect on the coastal communities. There is therefore the need for periodic monitoring and enforcement of environmental laws by respective organisations to ensure health safety of the people especially in the coastal communities

Levels and patterns of genetic diversity in wild Chrysichthys nigrodigitatus in the Lagos Lagoon complex

Mitochondrial DNA control region sequences were used to investigate the genetic diversity of populations of Chrysichthys nigrodigitatus and Chrysichthys walkeri in the Lagos Lagoon complex. A total of 34 haplotypes were detected. The genetic diversity among C. nigrodigitatus as determined by haplotype and nucleotide diversities were 0.879 ± 0.033 and 0.0131 ± 0.003, respectively and the values were 0.93 ± 0.04 and 0.010 ± 0.0020 for a population of C. walkeri. The largest genetic distance was 7.01% between C. walkeri from Lagos Lagoon (WAK) and control region sequences of Chrysichthys nigrodigitatus samples obtained from different parts of the lagoon complex in 2008 (PRE). Within population differences accounted for 80.41% of total genetic variance in C. nigrodigitatus. There was no evidence of decreased genetic diversity in the populations. The mismatch distribution and neutrality test suggest that the effective size of C. nigrodigitatus population has been large and stable for a long period.Key words: Chrysichthys nigrodigitatus, Chrysichthys walkeri, Lagos Lagoon complex, mtDNA control region

Aspects of the biology and preliminary assessment of DNA quality and quantity of two cichlids from Lagos Lagoon, Nigeria

Aspects of the growth pattern, reproductive biology, and molecular characteristics of two cichlids, Sarotherodon melanotheron and Coptodon zillii were investigated in Lagos Lagoon. A total of twenty-nine individual species were collected from the Lagos Lagoon. Blood samples were obtained for DNA extraction and analysis from 9 specimens of each species. The morphometric data of S. melanotheron varied from 2.5-4.5cm (head length), 13.5-18.0cm (total length) and 35.00-135.00g (body weight), while that of C. zillii were 2.0-4.5cm, 12.0-21.5cm and 39.00-228.00g respectively. The growth pattern of S. melanotheron showed a positive allometric, b= 3.324, while that of C. zillii showed a negative allometric pattern with b= 2.715. The condition factors of S. melanotheron and C. zillii ranged from 4.15-4.55 and 4.12-5.07 respectively. The sex ratio for S. melanotheron was 1: 0.18, while C. zillii had a sex ratio of 1:0.33, and these were statistically significant (p 0.05). From the molecular characterization analysis, the DNA concentration ranged from 48-1265ng/µl and DNA purity ranged from 1.49-1.82. These findings form baseline information for conducting further investigations on the taxonomy, ecology, conservation of the genetic purity of these fisheries resources in Lagos Lagoon

Molecular Analysis of the Mangrove Oysters (Mollusca: Bivalvia) in Lagos Lagoon, Nigeria Based on Mitochondrial Genome

The commercial and economic importance of the mangrove oysters in the Lagos Lagoon provokes a great deal of biotic investigation, which provides a convincing justification for sequencing an oyster genome. Differentiating oysters based on their morphological characteristics for species identification and taxonomy is highly challenging because of the high intensity of phenotypic changes they exhibit. The genomic resources available for the mangrove oysters are incomparable to resources for any other bivalve invertebrates.  In this study, unidentified mangrove oysters were collected from three different mangrove swamps off the Lagos Lagoon, Nigeria. Molecular procedures were used to identify the oysters genetically while pairwise and multiple alignments of mitochondrial DNA gene sequences of representative oyster strains within the clusters were used to relate them phenotypically to other oysters from various locations. Genetic diversity present in the selected mangrove oyster samples based on cytochrome oxidase I (COI) gene sequences reveals that the unidentified species at the three locations are Crassostrea gasar (Adanson, 1757) and were shown to be more like Brazilian oysters (Crassostrea brasiliana) with 99.55% similarity but clustered in a different clade of mangrove oysters in the GenBank. Similarities in the genetic makeup can principally be accredited to high levels of constant gene flow that are aftermaths of dispersal facilitated by a relatively long pelagic larval stage while the morphological differences can be primarily attributed to ontogeny with environmental conditions. A phylogenetic tree was constructed. The significance of these existing resources for a broad range of evolutionary and environmental sciences will be critically leveraged by having a recent or current genome sequence. The information obtained from this report is crucial to the understanding of diversity, systematics, and population genetics of mangrove oyster species of the Lagos Lagoon

Seasonal distribution and richness of fish species in the Badagry Lagoon, south-west Nigeria

Abstract. We recorded 37 fish species representing 21 families in the Badagry Lagoon, south-west Nigeria. Adult stages of 13 (35.14%) of them were freshwater, 7 (13.51%) estuarine, and 19 (51.35%) near-shore marine species. The seasonal variation in the fish catch composition of the lagoon was attributed to the seasonal fluctuation in salinity. Availability of food organisms was also noted to affect the seasonal distribution of the fish fauna. Other physical features such as temperature and pH varied slightly, while the concentration of dissolved oxygen was higher in the dry season than in the rainy season. The highest species richness was observed in September with 11 species, while the lowest with the smallest abundance was observed in February with 5 species. The most abundant species during their occurrence were Cynoglossus senegalensis (7.92%), Tilapia mariae (7.17%), and Ilisha africana (6.04%). Species richness and total abundance were found to increase during the rainy season

Exposure To Effluent From Pharmaceutical Industry Induced Cytogenotoxicity, Hematological And Histopathological Alterations In Clarias Gariepinus (Burchell, 1822)

Pharmaceutical effluents contain toxic xenobiotics capable of contaminating aquatic environments. Untreated effluents are illegally discharged into aquatic environment in most developing countries. Pharmaceutical effluent induced alterations in biomarkers of genetic and systemic damage on rodents. However, information is relatively scarce on the possible cytogenotoxicity and systemic toxicity of this effluent on aquatic vertebrates. The study herein assessed the cytogenotoxic, hematological and histopathological alterations induced by pharmaceutical effluent in Clarias gariepinus. 96 h acute toxicity of the effluent was determined after C. gariepinus was exposed to six different concentrations (10 - 60 %) of the effluent. Subsequently, fish was exposed to sub-lethal concen-trations (2.18 - 17.41 %) obtained from the 96 h LC50 for 7 and 14 days after which micronucleus (MN) and nu-clear abnormalities (NAs) in peripheral erythrocytes were assessed as cytogenotoxic biomarkers, alterations in hematological indices and histopathological lesions were also examined. Fish, concurrently exposed to dechlo-rinated tap water and benzene (0.01 mL/L), served as negative and positive controls respectively. The derived 96 h LC50 of 17.41 % which was 1.89 times more toxic than the 24 h LC50 (32.95 %) showed that the effluent induced concentration-dependent mortality according to exposure duration. The effluent caused significant (p<0.05) time-dependent increase in the frequency of MN and abnormal nuclear erythrocytes compared to the negative control. Also, there was decrease in total erythrocyte counts, hemoglobin and hematocrit concentrations and increase in leucocyte and lymphocyte counts. The effluent induced pathological lesions on gills, liver and kidneys of treated fish. Higher physicochemical parameters than standard permissible limits in the effluent are capable of inducing genomic instability and systemic damage in fish. Pharmaceutical effluent can increase micropollutants in aquatic environmental and health risks to aquatic biota. There is need to promulgate stringent laws against illegal discharge of effluents into aquatic environment

Exposure to effluent from pharmaceutical industry induced cytogenotoxicity, hematological and histopathological alterations in Clarias gariepinus (Burchell, 1822)

Pharmaceutical effluents contain toxic xenobiotics capable of contaminating aquatic environments. Untreated effluents are illegally discharged into aquatic environment in most developing countries. Pharmaceutical effluent induced alterations in biomarkers of genetic and systemic damage on rodents. However, information is relatively scarce on the possible cytogenotoxicity and systemic toxicity of this effluent on aquatic ertebrates. The study herein assessed the cytogenotoxic, hematological and histopathological alterations induced by pharmaceutical effluent in Clarias gariepinus. 96 h acute toxicity of the effluent was determined after C. gariepinus was exposed to six different concentrations (10 - 60 %) of the effluent. Subsequently, fish was exposed to sub-lethal concentrations (2.18 - 17.41 %) obtained from the 96 h LC50 for 7 and 14 days after which micronucleus (MN) and nuclear abnormalities (NAs) in peripheral erythrocytes were assessed as cytogenotoxic biomarkers, alterations in hematological indices and histopathological lesions were also examined. Fish, concurrently exposed to dechlorinated tap water and benzene (0.01 mL/L), served as negative and positive controls respectively. The derived 96 h LC50 of 17.41 % which was 1.89 times more toxic than the 24 h LC50 (32.95 %) showed that the effluent induced concentration-dependent mortality according to exposure duration. The effluent caused significant (p<0.05) time-dependent increase in the frequency of MN and abnormal nuclear erythrocytes compared to the negative control. Also, there was decrease in total erythrocyte counts, hemoglobin and hematocrit concentrations and increase in leucocyte and lymphocyte counts. The effluent induced pathological lesions on gills, liver and kidneys of treated fish. Higher physicochemical parameters than standard permissible limits in the effluent are capable of inducing genomic instability and systemic damage in fish. Pharmaceutical effluent can increase micropollutants in aquatic environmental and health risks to aquatic biota. There is need to promulgate stringent laws against illegal discharge of effluents into aquatic environment

Short communication: Length-frequency distribution, length-weight relationship and condition factor of two grey mullets from Lagos Lagoon

There is a growing interest in examining of economically important fish species with excellent mariculture potentials in lagoons of coastal states. Members of the family Mugilidae, which are permanent residents in Lagos Lagoon form a mainstay of fish protein source and are potential candidates for such investigations. Length-frequency distribution, length-weight relationship, condition factor and molecular characteristics of two grey mullets, Mugil cephalus and Liza falcipinniswere investigated in Lagos Lagoon. A total of 52 samples (26 specimens of each species) of the fish were collected from the Lagos Lagoon. The standard length ranged from 10.0 – 19.2 cm and 12.0 – 18.2 cm for M. cephalus and L. falcipinnis respectively, with corresponding weights of 13.90 – 105.00 g and 36.00-129.00 g respectively. The growth pattern of the species showed negative allometric, b = 0.32 and 0.65 respectively. The condition factors were 1.81 and 2.16 respectively and this meant both species were in good condition

Assessing smart infrastructure for sustainable urban development in the Lagos metropolis

The challenges of sustainable urban development increases daily and the usual planning approaches to ameliorate these challenges are ineffective. This study assesses the applicability of ‘smart infrastructure’ to achieve sustainable urban development in Lagos metropolis. The study theoretical framework is based on ‘smart’ principles. The study adopts a mixed method of data collection and analysis with multi-stage sampling techniques of 460 households in six communities of Eti-Osa and Ikeja local government areas of Lagos metropolis. The objectives of the study were to examine the socioeconomic characteristics of the residents and assess the infrastructure, the building uses and the environmental conditions of the study areas in relation to smart principles and smart infrastructure application in the study areas. The data were analyzed using inferential statistics and the findings reflect that the building use is sprawl development in nature with the informal settlement and infrastructure inadequacy as the major challenges. Smart infrastructure approaches are identified as applicable for achieving sustainable development in the study areas with smart interventions in socioeconomic status of the residents, the environment, the building uses and the basic facilities and services in the study areas