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The microbial assemblage and occurrence in the gut, flesh and shell of Cardisoma armatum, from the tropical mangrove swamp of Lagos Lagoon, Nigeria, was analysed using standard microbiological techniques. The crab gut had the highest total heterotrophic bacteria count and total coliform count with respective significant (p flesh > shell and shell > flesh > guts for bacterial and fungi infestation respectively. The results of this study showed that the gercacinid crab, C. armatum in the tropical mangrove of Lagos harbours microorganisms including those that are pathogenic

Mangrove crabs are active burrowers in intertidal sediments of wetland, living beneath drifts and high-tide marks in lagoon shores in many parts of the world. The occurrence, distribution and burrow depths and diameters of the mangrove crabs, Cardisoma armatum and Goniopsis pelii collected from a mangrove wetland of the Lagos Lagoon were investigated between February and July, 2017. Burrows were counted biweekly on permanent square plots marked out in the six stations, while the appearance of new burrows as well as disappearance of old burrows, depths and diameters were recorded. C. armatum was present in all the study sites with a total of 848 specimens and occurred throughout the study period, while G. pelli with a total of 115 specimens occurred in two study sites and during the wet season only. Species ratio was 1: 0.37 while the Chisquared value at 1 d.f and 5 % significant level was 557.93. The depth of the crab burrows across the stations ranged from 16.65 – 33.47 cm with diameter ranging between 4.0 – 6.40 cm. Crab burrows, its occurrence and distribution were observed to be affected by natural and anthropogenic factors. There was a rapid decline in burrows in the month of April when rainfall seized and anthropogenic factors like noise, refuse dumping and construction works also played major roles in determining the dispersion of burrows. Therefore, mangrove crabs and their burrows are greatly influenced by both abiotic and biotic factors.Keywords: Cardisoma armatum, Goniopsis pelii, Mangrove wetland, Burrow, Depth and width, Occurrence, Distribution

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