Pseudotolithus Typus Research Articles

Bioaccumulation dynamics, noncarcinogenic and carcinogenic risks of heavy metals in commercially valuable shellfish and finfish species from the world largest floating slum, Makoko, Nigeria

This study examined ten heavy metals in five species: Macrobrachium vollenhovenii, Penaeus monodon, P. notialis, Chloroscombrus chrysurus, and Pseudotolithus typus, from Makoko floating slum, Lagos Lagoon to discern their bioaccumulation potentials, sources of origin, and health implications. The concentrations were in this order: Fe (4.172–10.176) > Zn (1.310–5.754) > Mn (0.475–2.330) > Cu (0.238–1.735) > Pb (0.121–0.391) > Cd (0.055–0.283) > Co (0.056–0.144) > Ni (0.039–0.121) > Cr (0.022–0.095) > As (0.003–0.031) mg/kg. The MPDI denotes “low toxicity,” and the BAF/BSAF revealed that benthic species had higher bioconcentration potentials. Multivariate analyses revealed that heavy metals exhibited mutual relationships during chemical transport, and their sources were both geogenic and human-induced. The HI values were below 1, and the TCR values were below the threshold of 1 × 10−4. This suggests that the probabilities of noncancer and carcinogenic risks in human populations due to long-term consumption of the evaluated species are unlikely.

Microbial diversity, heavy metals and hydrocarbons concentration in some fish species from Qua Iboe River Estuary, Akwa Ibom State, Nigeria

The diversity of fish gut microflora, heavy metals and hydrocarbon concentration of two fish species (Pseudotolithus typus and Chrysichthys nigrodigitatus) from Qua Iboe River Estuary was investigated. The total heterotrophic bacteria and fungi as well as hydrocarbon utilizing bacteria and fungi in the fish guts were abundant and ranged from 6.87 to 7.57logcfu/g, 5.68 to 5.80logcfu/g, 5.42 to 5.48 logcfu/g and 2.76 to 3.40logcfu/g respectively. The microbial counts varied among the fish species. Proteus, Bacillus, Staphylococcus, Salmonella, Vibrio, Escherichia, Lactobacillus, Micrococcus and Enterobacter were the different bacterial genera encountered in the study while Penicillium sp., Aspergillus niger., Fusarium sp. and Mucor sp were the fungal species identified. The analysis of the metals showed that Zn, Cu and Fe with concentrations ranging from 0.51 to 4.20mg/kg, 3.51 to 4.11 and 1.19 to 2.04mg/kg respectively were the most abundant and were higher than the maximum permissible limits set by FEPA/WHO. The total mean PAHs and BTEX concentrations were 62.18±4.72 ng/g and 43.67±4.06 ng/g for C. nigrodigitatus, 123.52±3.11 ng/g and 211.68±3.53 ng/g for P. typus respectively which were higher than acceptable limits. Findings from this study shows poor microbiological quality thus the need for continuous monitoring of our natural waters and proper processing of aquatic foods as the present situation portends a potential concern for ecological risk.

Trace metal concentration in common fishes from the Lagos lagoon, Southwestern Nigeria

Due to trace metals’ toxicity, accumulative tendency, and non-biodegradability, we assessed their levels in six fish species: Chrysichthys nigrodigitatus (Silver Catfish), Sarotherodon melanotheron (Blackchin Tilapia), Scomber scombrus (Atlantic Mackerel, locally known as Titus), Sardinella maderensis (Sardine), Dentex canariensis (Canary dentex), and Pseudotolithus typus (Croaker) commonly available in the Lagos lagoon. Samples of various sizes and maturity were selected, and their tissues (fillets, gills, and intestines) were examined for trace metal concentrations. Fe was the most concentrated metal in all the tissues (1.64–8.61 mg/kg), albeit below the WHO permissible limits (100 mg/kg). Others were Pb (0.05–8.2 mg/kg), Zn (0.48–4.88 mg/kg), Cu (0.08–2.51 mg/kg), and Cd (0.03–1.95 mg/kg), with only Zn and Cu entirely below WHO permissible limits of 100 and 30 mg/kg, respectively. Specifically, the toxic metals were more concentrated in the intestines (mean = 4.36 ± 1.02 mg/kg), reaching 8.61 mg/kg, followed by the gills (mean = 1.50 ± 0.77 mg/kg; max = 3.17 mg/kg), while the fillet was the least toxic metal-laden (mean = 0.55 ± 0.08 mg/kg; max = 2.01 mg/kg). Further, Fulton condition factor assessment (body weight–length relationship) identified Sarotherodon melanotheron as “good” (1.74) and Dentex canariensis as “moderately good” (1.33), while others were “poor” Overall, Scomber Scrombus, Psuedotolithus typus, and Dentex canariensis exhibited the least toxic metal accumulations. Therefore, having considered WHO’s permissible limits for the metals in edible fishes, these three species seem suitable for human consumption, provided other environmental and human conditions are favorable.

Evaluating the sustainability of fishery resources and fishing gears: Case study of Ngoyè and Elabè, Kribi, South Cameroon

Evaluating fishing methods and associated gears over the time is one key to understanding the sustainability of fisheries resources. Well-managed fishery is expected to use gear that catch most of the available species at sizes that do not undermine sustainability. This study investigates effects of two fishing gears used in two landing sites of Kribi and sustainable exploitation of fishery resources. The semi-direct survey included questionnaire interview from fishermen and direct observation of fishing gears at the time of operation was chosen to collect information. A total of 299 bottom-set gillnets with mesh sizes ranging from 15 mm to 100 mm and 17 beach seines were listed at both landing sites. Beach seine catches combined as well as pelagic, demersal or benthic species. Among the species caught, Ilisha africana was the dominant species followed by Pseudotolithus senegalensis, Pseudotolithus typus. Cath profile of bottom-set gillnet showed that Pseudotolithus typus, Pseudolithus senegalensis, and Cynoglossus sp. were the three dominant species. No growing stage is spared by the beach seine catches and the minimum size obtained was 4 cm for Selenne dorsalis and Pseudotolithus senegalensis. The reduction in size and relative high number of landed species result from pressure on fishery resources, non-compliance with regulations in terms of gear and fishing techniques.

Ichthyological composition of fishing gear types from marine artisanal fishery of grand-lahou (Ivory Coast)

In Côte d'Ivoire, fishing in Grand-Lahou locality provides 20% of national artisanal catches. From August 2016 to February 2017, fishing units and the ichthyological composition of their fishing gears were characterised on Lahou-Kpanda site. One unit using the beach seine, eleven the purse seines and seven the gillnets were involved. Twenty-two fish species have been identified. Twenty-one of them were caught by purse seines, eleven by the beach seine and six by gillnets. Purse seines and the beach seine preferentially catch Clupeidae, 80.95% and 88.12% respectively. According to species, Sardinella maderensis (55.76%) and Ethmalosa fimbriata (13.73%) dominate purse seines catches and Sardinella maderensis (37.68%), Ethmalosa fimbriata (28.16%) and Sardinella aurita (20.12%) those of the beach seine. The gillnets catch more Sciaenidae (59.10%), Sphyraenidae (16.20%) and Cynoglossidae (15.39%) with Pseudotolithus typus (30.14%) as well as Pseudotolithus elongatus, Sphyraena afra and Cynoglossus canariensis as dominant species.

Local Ecological Knowledge and Trend of Catches on Pseudotolithus typus, Lutjanus goreensis and Sphyraena afra from Lagos Coastal Waters, Lagos State, Nigeria

The present study examined the fishers’ knowledge and a ten-year (2009 -2018) trend analysis of prices and catches on Pseudotolithus typus, Lutjanus goreensis and Sphyraena afra from Lagos coastal waters. While data for local ecological knowledge (LEK) were obtained with the aid of a semi-structured questionnaire, secondary data collected from both the field and the Federal Department of Fisheries were used to estimate the trend analysis of prices and catch composition respectively. The results showed that prices of all the fish species changed annually, with an annual average increase of 10.85%, 9.25% and 12.03% for P. typus, L. goreensis and S. afra respectively. L. goreensis and S. afra had an annual average increase of fish catch landed of 5.39% and 2.77%, while P. typus had -8.98% annual average decrease of fish landed. All the fishers were males and their modal age group was 41-60years (92.31%), while the least was 21-24years (7.69%). Sixty-nine percent (69%) and 31% of the fishers had secondary and primary school education respectively. Most fishers (69%) had a fishing experience of 21-25 years while the least fishing experience was 6-10 years. Most of the fishers had vast knowledge of the habitat of the fish species, morphological identification, causes of declined fish catches, conservation strategy, seasons of catch and problems of overfishing. In conclusion, this study showed a high level of agreement of fishers' ecological knowledge with the scientific literature, and such synergy could provide important additional biological information that could be used in the process of participative and sustainable management of marine resources.

Length–weight relationships of four fish species from Fatala estuary, Guinea, West Africa

This study provides length-weight relationships (LWR) that had not yet been reported for four fish species belonging to four different families: Chrysichthys johnelsi Daget, 1959, Cynoglossus senegalensis (Kaup, 1858), Citharichthys stampflii (Steindachner, 1894) and Pseudotolithus typus, Bleeker, 1863. Data were collected in the Fatala estuary, republic of Guinea, each month between January 1993 and March 1994, using alternately a purse seine net (length 250 m, height 20 m, 14 mm side mesh) and gillnets (side mesh sizes of 10, 12.5, 15, 15.5, 20, 22.5, 25, 30, 35 and 40 mm). For each fish specimen, fork or total length and total weight were measured with precision to 0.1 cm and 0.1 g respectively. A wider size range, compared to the size range available in FishBase, was obtained for Pseudotolithus typus. The present study also provides a new maximum total length for Citharichthys stampflii. The determination coefficient (r²) between length and total body weight ranged between 0.958 in Citharichthys stampflii and 0.989 in Cynoglossus senegalensis. The allometric coefficient b varied from 2.9552 (Chrysichthys johnelsi) to 3.7288 (Citharichthys stampflii). The value of LWRs for the four fish species should assist fisheries scientists and managers to complement their further studies of population parameters to improve management decisions in Fatala estuary and, more widely, in West Africa.

Trace Metals in Selected Fish Species from Five Cowries Creek, Southwest Nigeria: Consumer Safety Assessment

This study aims to examine trace metals (Pb, Cd, Cr, Zn, and Cu) concentration in muscle tissues of four fish species from Five Cowries Creek and assess the safety risks posed by consuming these fish species. For this purpose, fish species such as Cynoglossus senegalensis, Mugil cephalus, Chrysichthys nigrodigitatus and Pseudotolithus typus were procured monthly from anglers in Five Cowries Creek, Lagos, from February to May, 2019. The fish muscle tissues were digested according to the international standards, and the trace metals were measured using an atomic absorption spectrophotometer (AAS). Results revealed that the ranking order of trace element concentrations followed this sequence: Pb > Cr > Zn > Cu > Cd. There were significant differences (P < 0.05) in Pb and Cr among the fish species. Consumer health risk was evaluated using non-carcinogenic and carcinogenic risk indices. The results showed that EDI and target hazard quotient (THQ) of Cr, Zn, Cu and Cd suggested that fish species consumption did not pose risk to consumer health. Nevertheless, the estimated daily intake (EDI) along with THQ of Pb indicated potential health risks to consumers (children and adult) of Chrysichthys nigrodigitatus. The target hazard index (THI) of trace elements in all investigated fish species exceeded the guideline value of 1, indicating an adverse health risk for exposed consumers. However, the carcinogenic risk of Pb was negligible for children and adult consumers of fish species. The results are anticipated to create alertness among the public on the safety risks as a result of consuming metal-contaminated fish. Authorised regulatory agencies should control the unregulated uses of Five Cowries Creek, Lagos and associated water bodies through the enforcement of various regulations, policies and laws.

The complete mitochondrial genome of the longneck croaker, pseudotolithus typus Bleeker, 1863 from Sierra Leone

The complete mitochondrial DNA information of Pseudotolithus typus Bleeker, 1863, collected from Sierra Leone was determined using next-generation sequencing (NGS) and bioinfromatic analysis. Its mitogenome (16,504 bp) encoded the typical 13 protein-coding genes (PCGs), 2 ribosomal RNAs (12S & 16S), and 22 tRNAs. All 13 PCGs showed a standard start codon (ATG) but an unusual stop codon (AGA) was identified in COX1 gene. Except for ND6, all 12 PCGs were encoded on the light strand. Except for tRNASer-GCT, 21 tRNAs formed the typical clover-leaf structures. Phylogenetic analysis showed three mitochondrial genomes in the genus Pseudotolithus formed a clade distinct from the other species in the same family. The mitogenome of P. typus identified in this study exhibited 96.27% and 88.86% identity to T. typus in the Guinean water and P. elongatus, respectively. Additional mitogenome sequences of Pseudotolithus species will provide useful information for their scientific management in western African countries.

Stomach and gut content of Long Neck Croacker–Pseudotolithus typus (Bleeker,1863) from Lagos Lagoon, Nigera

<em>Pseudotolithus typus</em> has been considered to hold great promise for fish farming in Africa, the fish having a wide geographical spread, a high growth rate, resistance to handling stress and well appreciated in a wide number of African countries.

Length –weight relationship and condition factor of long neck croaker –Pseudotolithus typus (Bleeker, 1863) from Lagos Lagoon, Nigeria

The length-weight relationship and condition factor of Pseudotolithus typus from makoko lagoon, Lagos state was evaluated over a period of 24 weeks in September 2018 to February, 2019 from fishermen catches at Makoko landing point. A total of 93 specimens were collected and transported in ice-packed container to the wet laboratory of the Department of Biological Oceanography, Nigerian Institute for Oceanography and Marine Research (NIOMR) for further examination. These specimens were usually collected during early hour of the morning. The sampling methods were season stratified.Total length and Standard lengths of each fish sample were measured to the nearest 0.50cm using a measuring board. Specimens were weighed with Camry model EK5350 of 5kg capacity to the nearest 0.10 g after blotting dry with filter paper. The total weight ranged from 129.00cm-261.00cm with a mean value of 200.01cm.The degree of association between the total length and weight was computed from linear regression analysis. The overall exponential equations for the length weight relationship are; LogW = -2.37 + 2.208logL. The highest correlation coefficient value recorded in December with a value of 0.87. Condition factors were significantly for both wet and dry season (P>0.05). Pseudotolithus typus in this study exhibited a negative allometric growth (b < 3) with a mean b value of 2.21.The It has been established that when K value is greater than one, this indicates that the fish species is living well in the concerned habitat (Ikongbeh et al., 2012); the ‘K’ value in this experiment, which has varied values suggests that the wellbeing of Pseudotolithus typus varies with season.

Aspects of the reproductive biology of &lt;i&gt;Pseudotolithus typus&lt;/i&gt; (Bleeker, 1863) from qua Iboe River Estuary, Nigeria

The study was conducted to assess the reproductive biology and condition index of Pseudotolithus typus in Qua Iboe Estuary using standard methods. A total of 580 fish specimen were sampled over a period of 8 months (January – August, 2018). Condition index was generally low with the highest value of 1.03 recorded in the month of April. The overall mean condition index significantly deviated (p&lt;0.05) from the expected value of 1.0. Male-female ratio of the species showed female dominance. Significant variation (p&lt;0.05) were observed in condition and gonadosomatic indices with peak values in the months of March and July for females. Male fish showed no seasonality in gonadosomatic index. The average fecundity ranged from 2140 eggs to 8560 eggs with mean value of 4891±641 eggs. Positive correlation was observed between fecundity and total length, body weight, standard length and gonad weight of the fish. Thus, it could be concluded that P. typus is a dual seasonal spawner having spawning periods early in the year (March) and in the peak of wet season (July).&#x0D; Keywords: Pseudotolithus typus, condition index, gonadosomatic index, fecundity, estuary.

Characterization of the complete mitochondrial genome of longneck croaker Pseudotolithus typus (Perciformes: Sciaenidae)

The complete mitogenome of Pseudotolithus typus (Perciformes: Sciaenidae) is analyzed by high-throughput sequencing. The 16,502 nucleotides of assembled mitogenome has 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and the 1 putative control region. Incomplete stop codons were found in seven genes (ND2, ND3, ND4, COII, COIII, CytB, ATPase6). The phylogenetic analysis indicated that P. typus is closely related to P. elongatus. This study will provide useful information to understand the evolutionary and phylogenetic exploration of the family Sciaenidae.

Assessment of heavy metal content in imported and local fish and crustacean species obtained within Lagos Metropolis

Fishes are known for their abilities to concentrate heavy metals in their muscles and since they play important role in human nutrition, they need to be carefully screened to ensure that unnecessary high level of some toxic trace metals are not being transfer to man through their consumption. The study was to evaluate heavy metals (chromium, lead, iron and cadmium) in imported and local species of shrimps, crabs and fish using Atomic Absorption Spectroscopy. The selected imported species were horse mackerelkote fish (Trachurus trachurus), mackerel - titus (Scomber scrombus), croaker (Pseudotolithus typus), smooth swim crab (Portunus validus) and pink shrimp (Farfantepenaeus notialis) while the local species used were; Sole fish (Cynoglossus senegalensis), Tilapia (Oreochromis niloticus), brackish water catfish (Chrysichthys nigrodigitatus), freshwater catfish (Clarias gariepinus), lagoon crab (Callinectes amnicola) and freshwater prawn (Macrobrachium macrobrachion). It was observed that there was no significant difference in the metals (Cd, Pb and Cr) between the imported and local fish species and between imported and local crustacean species. However, these metals concentrated more in the local fish species, O. niloticus (1.846 ± 1.00 mg/100g). The mean heavy metals concentration occurred in the following decreasing order: Fe > Cd > Pb > Cr for all the samples. The mean concentrations of the analyzed heavy metals in the samples were below the maximum permissible limits as recommended by the International Atomic Energy Agency (IAEA), United Nations Environment Program (UNEP) and Federal Environmental Protection Agency (FEPA) for heavy metals in fish.Keywords: Fish, Shrimp, Crab, Heavy metal, Chromium, Lead, Iron

Population Dynamics of Pseudotolithus Senegalensis and Pseudotolithus Typus and Their Implications for Management and Conservation within the Coastal Waters of Liberia

The study evaluated some aspect of population parameters of Pseudotolithus senegalensis and Pseudotolithus typus within Liberia’s coastal waters. A total of 177 and 152 samples of P. senegalensis and P. typus respectively were collected from July to December, 2016. Individual fish samples was measured for standard length and analysed using FiSAT II software. From the results, P. senegalensis growth parameter were estimated at asymptotic length (L∞)=66.68 cm, growth rate (K)=0.13 yr-1, the longevity (tmax)=21.49 years, theoretical age at birth (t0)=-1.586 years and growth performance index (φ')=2.762. While P. typus growth parameters asymptotic length (L∞)=66.68 cm, growth rate (K)=0.14 yr-1, the longevity (tmax)=19.3 years, theoretical age at birth (t0)=-2.126 years and growth performance index (φ')=2.294. Mortality parameters for P. senegalensis and P. typus were calculated as total mortality rate (Z)=0.93 yr-1 and 0.70 yr-1, natural mortality rate (M)=0.37 yr-1and 0.39 yr-1 and fishing mortality rate (F)=0.56 yr-1 and 0.31 yr-1 respectively. The calculated fishing mortality rates (F) compared to Fopt=0.4M were beyond the limit for sustainable fishing. The exploitation rate (E) of P. senegalensis (E=0.60) was higher than the Eopt=0.5 criterion. It implies that P. senegalensis is overexploited while P. typus was at the peak of exploitation (E=0.45). Results from the study revealed that the P. senegalensis fishery in Liberia is slightly overexploited while P. typus is at the optimal level of exploitation; as well as the presence of growth overfishing within the two species population within Liberian coastal waters. Thus, to avert the consequences of growth overfishing, sustainable fisheries measures including monitoring of fishing efforts, and increase in mesh size should be implemented and enforced.

Proximate composition, mineral content and fatty acid profile of two marine fishes from Cameroonian coast: Pseudotolithus typus (Bleeker, 1863) and Pseudotolithus elongatus (Bowdich, 1825)

BackgroundKnowledge of chemical composition of fish from Cameroon is poor. The genera Pseudotolithus are nutritionally and economically important in Cameroon. Thus the knowledge on their chemical composition could help in functional food elaboration. PurposeIn this study, Proximate composition, fatty acid profiles and mineral composition were determined in two fish species, Pseudotolithus typus and Pseudotolithus elongatus from Cameroonian coasts. Basic procedureAOAC standard method was used. Fatty acids were identified by GC/MS as N-acylpyrolidides. Mineral compositions were determined by atomic absorption spectrophotometry for Ca, Na, K, Mg, Fe, Zn, Cu, Mn, and by UV spectrophotometry for phosphorus (P). Main findingResults indicated that chemical composition was not similar in the two fish species. Results also showed that water is the main constituent in the edible parts and in the bones with 76.17% to 78.24% and 51.21% to 55.28% respectively. Pseudotolithus typus and Pseudotolithus elongatus were good sources of proteins with 16.17% and 13.4% respectively. All the fish analyzed for fat were lean with fat contents less than 0.5%. These species of fish were poor in ω6PUFA and were rich in ω3PUFA with about one third of total fatty acids. The main ω3 fatty acids were eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The most abundant main elements were the potassium in the edible parts (1.39%) and calcium in the bones (18.26%). The most abundant trace elements were Zn and Fe in the edible parts and in the bones. Principal conclusionThe Na/K ratio values and ω3 fatty acids contents suggest that consumption of these two fish species could be recommended to prevent cardiovascular diseases.

시판 반염건 능성어(Epinephelus septemfasciatus)와 영상가이석태(Pseudotolithus typus)의 위생학적 품질 특성

This study investigated the sanitary characteristics of commercial salted semi-dried convict grouper Epinephelus septemfasciatus (SSD-CG) and longneck croaker Pseudotolithus typus (SSD-LC) and suggested standards for salted semi-dried fish (SSD-F), based on the domestic standards for salted mackerel (Scomber japonicus or kwamegi) and salted dried yellow corvenia (Pseudosciaena manchurica), and sanitary characteristics of commercial SSD-F. For the commercial SSD-CG and SSD-LC, respectively, the moisture content ranged from 64.6-76.1 and 65.7-77.5%, salinity from 2.7-8.2 and 1.5-4.9%, volatile basic nitrogen (VBN) from 22.1-88.2 and 13.5-87.4 mg/100 g, peroxide value (POV) from 17.2-195.0 and 28.5-190.2 mEq/kg, and viable cell counts from 6.1-8.4 and 5.4-7.2 log (CFU/g). No Escherichia coli was detected in six kinds of SSD-CG or three kinds of SSD-LC. The standard for controlling the quality of SSD-F is the moisture content (>68%), salinity (>3%), VBN content (>50 mg/100 g), POV (>60 mEq/kg), viable cell counts (> CFU/g), E. coli (>MPN/100 g), and others. Using the established standards, no commercial SSD-F passed. The chemical, microbial, and other results for commercial SSD-F suggest that provisions for controlling the quality of high-quality SSD-F should be established.

Assessment of Heavy Metals in Some Marine Fish Species Relevant to their Concentration in Water and Sediment from Coastal Waters of Ondo State, Nigeria

Due to oil exploration activities and urbanization as well as continuous industrial and agricultural growth in Ondo State, Nigeria. The coastal water has been heavily impacted by a number of pollutants originating from different sources including heavy metals. This investigation assessed and monitored accumulation levels of ( Cr, Cd, Pb, Cu, Zn, and Ni ) in different organs ( Gill, Head, Bone, Muscle and Eye ) of five fish species (Pentanemus quinquarius, Pseudoltolithus senegalensis, Trichirus lepturus, Plectorhynchus meditarraneus and Pseudotolithus typus together with water and sediment collected from the ocean shoreline in the coastal waters of Ondo State, Nigeria. Heavy metals concentrations in fish tissues, water and sediment samples were analyzed after treatment using atomic absorption spectrophotometer. Dissolve total metal in water (in mg/l) Zn 0.12-0.22 , Cu 0.26-0.27 and Ni BDL-0.01 recorded in the water samples in this study were low and within the maximum permissible level (MPL) recommended by WHO and USEPA, while higher concentrations above the MPL were recorded for Cr 0.31-0.34 Cd 0.08 -0.21 and Pb 0.57-0.79. The concentrations of these metals in sediment in (mg/kg) were in the range Cr (0.16-4.19, Cd 0.35-0.38, Pb 0.9-1.00, Cu 0.24-1.44, Zn 2.12-3.11 and Ni BDL-0.01. They are all lower than their probable effect concentrations (PEC) in sediment. Mean Concentrations of the heavy metals in fish species were of the order: Zn>Cu>Cr>Cd>Pb>Ni. Levels of heavy metals varied depending on different tissues in the fish species. Correspondingly, high concentrations of the metals were found in gills and eye compared to other tissues. While the concentration of Zn (0.34 mg/kg-1.29 mg/kg), Cu (BDL-1.88 mg/kg), Ni (BDL-0.01 mg/kg) , and Cr (BDL-1.28) in the fish tissues were within the maximum allowable level (MAL) for a food source, the findings of this study shows higher value above the allowable limit for Cd(BDL-1.14 mg/kg) and Pb (BDL-0.71 mg/kg), thus constituting potential health hazard to consumers of these fish species.

Microbiological and biochemical spoilage of smoke-dried fishes sold in West African open markets

Proximate composition and microbiological characteristics of pre-dried Chrysichthys nigrodigitatus and Pseudotolithus typus were studied over a period of 4weeks to determine the health risks associated with delayed consumption. All analyses were conducted using standard microbiological and chemical methods. Results showed a general decline in microbiological safety and nutritive characteristics of both fish species over time, with an observed increase in microbial loads over time. Aspergillus flavus was also present on both species which makes consumption of the fishes hazardous to the health of consumers due to its ability to produce carcinogenic aflatoxins. In order to minimise the health risks to consumers, it is recommended that smoke-dried fishes be consumed with minimal delay and cooked properly before consumption. The findings of this study will prove important in the development of more stringent regulations regarding food safety in Nigeria.

English

The aim of the current study was to determine proximate composition (protein, lipid, ash and moisture), energy and microbiological spoilage in five fish species. The chemical analysis revealed that the protein content of&nbsp;Pseudotolithus typus&nbsp;was 19.19%,Pomadasys&nbsp;peroteti&nbsp;16.05%,&nbsp;Galeoides&nbsp;decadactylus&nbsp;17.15%,&nbsp;Carassius&nbsp;auratus20.78% and&nbsp;Pimelodus&nbsp;grosskopfii&nbsp;18.57% of the fresh weight, respectively. The lipid content, the ash, and carbohydrate ranged from 0.46 to 1.76, 1.01 to 1.40 and 0.20 to 0.49% of the fresh weight correspondingly. Microbiological analysis showed that the Total Viable Count (TVC) varied between 5.20 and 8.42 LogUFC/g. The results obtained on TVC were not within the acceptable limits set by the International Commission on Microbiological Specification for Foods.&nbsp;Staphylococcus&nbsp;sp. bacteria were observed in all five species and fecal coliforms in&nbsp;Carassius&nbsp;auratus&nbsp;and&nbsp;Pimelodus&nbsp;grosskopfii&nbsp;only.The bacteria isolated on each of the five fish species included&nbsp;Staphylococcus aureus,Staphylococcus xylosus,&nbsp;Enterobacter agglomerans&nbsp;and one unidentified species.However, fungi were not found in these five samples. Key words:&nbsp;Franceville, Gabon, proximate composition, microbiological quality, fish species.