Physical, chemical and macrobenthic invertebrate fauna characteristics of swampy water bodies within University of Lagos, Nigeria

A comparative study conducted on three swampy water bodies draining through the University of Lagos into the Lagos Lagoon describes the physical, chemical and macrobenthic invertebrate characteristics of these water bodies at the study sites. Three stations, one at each water body were sampled fortnightly from June to December, 2000. Water temperature, total alkalinity and salinity were the only physical and chemical conditions significantly different at the study stations. The physical and chemical conditions at stations A and B were similar and significantly different from station C exposed to domestic effluent, thereby, reflecting the perturbational stress at that site. A total of 43 benthic invertebrate taxa belonging to five classes, 31 families and 2424 individuals were recorded at the study stations. The study stations can be ranked as B > A > C and B > C > A in terms of number of taxa and number of individuals, respectively. The low number of taxa and individuals in stations A and C is suggestive of habitat instability. The pattern of invertebrate distribution and abundance was influenced by the fluctuations in the abundance of Oligochaeta, Hemiptera and Diptera. The taxon richness (D), genera diversity (H) and evenness (E) estimated for the study sites supported the trends observed in the numbers of taxa occurring and their abundance. The low concentrated dominance (C) calculated for station B compared to stations A and C reflects an ecologically heterogenous and relatively stable site. Morisita-Horn index showed that station C was dissimilar to stations A and B. Jaccard’s coefficient indicated that all stations were dissimilar. In general, the faunal comparison showed that the level of exposure to urban discharges, inert pollutants and the presence of aquatic macrophytes influenced the differences in the abundance, occurrence and number of taxa at the three stations

Hydrobiological studies on Ibiekuma river at Ekpoma, Southern Nigeria, after impoundment: The faunal characteristics

A study of a 3 Km stretch of a perennial rainforest stream in southern Nigeria describes the macrobenthic faunal characteristics of pools (dam site stations) and runs. A total of 84 invertebrate taxa made up of 2,535 individuals were recorded. The overall faunal abundance was not significantly different at the study stretch. The abundance of the major taxonomic groups washowever significantly different (P < 0.05) at the study stations. Hemiptera and Diptera were the most abundant invertebrate groups recorded. The high number of benthic invertebrates observed is a reflection of the physical and chemical stability of the study stream

Food and Feeding Habits of the Guppy, Poecilia reticulata, from Drainage Canal Systems in Lagos, Southwestern Nigeria

The food and feeding habits of the Guppy, Poecilia reticulata, from drainage canal systems in Lagos Metropolis, Nigeria, was investigated over a period of 24 months. Fish samples were collected monthly from 15 study sites. A total of 2400 fish stomachs were analyzed using the numerical and frequency of occurrence methods. P. reticulata fed mainly on algae, organic detritus, diatoms, mosquito larvae parts, protozoan, zooplankton and fish parts while algae form the most abundant and important food item, constituting 79.03% of food items by numerical and 33.17% by occurrence of stomachs examined. Amongst the algae, Ulothrix sp. was the most preferred, constituting 33.17% by numerical and 20.82% by occurrence. The least eaten food item was fish parts constituting 4.46% by numerical and 1.19% by occurrence. There was a significant difference (P &lt; 0.05) in the number of algae and mosquito larvae consumed, while there was no significant difference (P &gt; 0.05) in the number of other food items consumed for both seasons. However, by occurrence method there was no significant difference (P &gt; 0.05) in food items consumed for both seasons. The three size classes of P. reticulata exhibited similar food habits with the presence of eight categories of food items in their stomachs. The largest size class ate more of algae, organic detritus and fish parts, followed by the medium size class while the small size class ate less of these food items. The species is an opportunistic benthopelagic omnivores, whose preference for food fluctuates with season, with a peak in diversity of food types occurring in the rainy season

Hydrochemistry and Community Structure of Benthic Macroinvertebrates of Lagos Lagoon, Nigeria

ABSTRACT The west of the Lagos lagoon, Nigeria has been subjected to lots of stress resulting from various anthropogenic activities around it. The sedentary nature of the benthic macrofauna makes them a very useful tool for assessing the health of this water body. Ecological study of these benthic organisms was conducted between January, 2007 and December, 2008 with the aim of using them to assess the pollution status of this part of the lagoon. Water and benthic samples were collected monthly and analysed in a standard laboratory. Results of the analysis of the physico-chemical parameters of water samples indicated that their temporal variation was controlled by the rainfall pattern while their spatial variation was controlled by proximity to sea and pollution sources. A total of 3,159 individuals comprising three phyla, five classes, nineteen families and twenty-three species were recorded. More individuals were recorded in the dry than in wet season. Iddo I, Iddo II, Ogudu and Agboiyi recorded very low individuals, but relatively high number of opportunistic species like the polychaetes. There was generally low biodiversity which indicates the stressed nature of the study area

Some aspects of the ecology of Macrobrachium macrobrachion Herklots, 1851 (Crustacea: Decapoda: Natantia) in the Brackish water zone of the Benin River at Koto, Southern Nigeria

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Observations on some aspects of the biology of Sudanonautes aubryi (H. Milne Edward,1886) (Crustacea: brachyura: potamoidea: potamonautidae) in Orogodo River, Niger Delta, Nigeria

Investigation into some aspects of the ecology of the amphibious freshwater crab, Sudanonautes aubryi (H. Milne Edwards, 1886) in Orogodo River at Abavo, Southern-Nigeria was carried out between March and August, 1995. The study revealed that the crab species is wide spread and abundant in the river. There was a seasonal trend in the level of abundance both in number and biomass. The crab showed more abundance at the peak of the rainy season (August). Both adults and juveniles showed a progressive increase from late dry season to mid-rainy season (August). The male–female ratio was 1:1.2. The fluctuation in the number and percentage of gravid females indicated that the crab spawned during the mid-rainy season (June–August). The crab attained a maximum total length and weight of 8.4cm and 89.09g respectively. Its growth pattern was isometric. The mean monthly condition factor (k) ranged from 17.15 to 23.52 and generally showed a monthly fluctuation with a peak in April. Keywords: sudanonautes aubryi, biomass, gravid, Orogodo River, condition factorTropical Freshwater Biology 2003/2004 Vol. 12/13: 105-11

Zooplankton of a temporary pond in a threatened Nigeria Forest Reserve, the Crustacea

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