This study was conducted to evaluate nutritional composition and heavy metals
concentration of smoked and raw edible fish species from Ologe lagoon (freshwater) and Lagos
lagoon (marine). The fish species from Ologe include:
Chrysichthys nigrodigitatus
(Catfish),
Monodactylus sebae
(African moony),
Pomadasys jubelini
(Buro),
Sphyraena barracuda
(Great
barracuda), and
Pseudotolithus elongatus
(Croaker), while that of Lagos lagoon include
Chrysichthys nigrodigitatus (Catfish),
Caranx hippos
(Crevalle jack),
Liza falcipinnis
(Sicklefin
mullet),
Pomadasys jubelini (Buro), and
Monodactylus sebae (African moony). The nutritional
composition ranged in the following trend moisture (43.24 - 76.79 %) > carbohydrate (3.16 –
63.45 %) > protein (0.80 - 31.55 %) > fibre (1.07 – 2.8 %) > ash (0.81 – 1.88 %) > fat (0.40 –
1.30 %). In this study, these fishes are generally low in fats (lean fish), and fish smoking tend to
reduces their nutritional composition. Heavy metals concentration trend thus Zn (2.4 – 7.75
mg/kg) > Ni (0.80 – 1.925 mg/kg) > Cr (0.20 – 0.550 mg/kg) > Pb (0.025 – 0.50 mg/kg). In all
the samples, all the metals of interest were detected except cadmium which was not found in any
of the samples analysed. Pb (0.025 - 0.5 mg/kg) values in the fishes were lower than the maximum
standard level reported to be 0.5 mg/kg dry weight by FAO except in the raw
Pomadasys jubelini
where the value is 0.5mg/kg. The fresh water fishes showed higher concentration of heavy metals
than marine water fishes but not statistically significant (p>0.05). Although, smoked fishes
showed higher concentration of heavy metals than the raw fishes, it was only significant for zinc
(p<0.05). In view of this study and the importance of fish in human diet, it is recommended that
biological monitoring of fishes meant for consumption from these two water bodies be carried out
regularly to ensure human safety.