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Seasonal patterns in human fisheries resource utilisation and the capture characteristics of fish, swimming crabs and land crabs harvested from four coastal lagoons in Ghana between September 2005 and August 2007 are described. These are discussed in relation to sustainable management of the lagoons' fisheries for both human and waterbird use. With the exception of small pelagic foraging fish-eating birds, human fishing practices in the lagoons were in direct competition with crab- and fish-eating birds, because of the overlap of same-sized fish and crabs, and also in indirect competition because many of the exploited fish and crabs were immature. Fishing practices were also in direct competition with food foraging by invertebrate-eating birds. Intense exploitation of swimming crabs was linked to the use of drag nets, in comparison to the exclusive use of cast nets in some lagoons. In order to reduce the incidence of waterbird-human interactions and conflict during the energy-demanding phase of the birds' non-breeding season, it is recommended that the practice of closed seasons be extended to include crab fisheries and be strictly enforced at all Ramsar sites on the Ghanaian coast. [ABSTRACT FROM AUTHOR]

The present study investigated the levels of Manganese (Mn), Cadmium (Cd), Copper (Cu), Zinc (Zn), Lead (Pb) and Iron (Fe) in the tissues of a benthic fish (Clarias gariepinus) and a pelagic fish (Oreochromis niloticus), which are highly consumed in Ghana. The fish were collected from the Weija reservoir, which is an important source of fishery and potable water in Accra, Ghana. The results indicate heavy metal accumulation in all the tissues (gills, liver and muscles) analyzed. The bioaccumulation of all the metals was lowest in the muscles compared to the liver and gills in both species. The bioaccumulation of the metals was generally higher in the tissues of the catfish, except for Fe and Zn. Fe was higher in the gills and liver of the tilapia, and Zn was higher in the liver of the tilapia. The analysis of relationships between metal levels in the different tissues and the size of the fish showed a few significant correlations. The results also showed that all metals showed no potential health risk to consumers, as THQs and TTHQs in tilapia and catfish were less than one, and the metal levels in both species were all below the FAO/WHO maximum permissible limits., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

This study compared Lead (Pb), Chromium (Cr), Copper (Cu), Zinc (Zn), Mercury (Hg), Arsenic (As) and Cadmium (Cd) concentrations in sediment, water, and biota at Vaughan Dam which receives limited sewage effluent discharge from residential areas, and Korle Lagoon which receives industrial effluents, electronic waste, garages-spill oil and a host of others in addition to residential sewage effluent discharge. Samples were analyzed with Atomic Absorption Spectrometer. The results showed that concentrations of trace metals were generally higher in the sediment, water, and plants from the Korle Lagoon but only Cu in the sediment of Korle Lagoon showed a significantly high concentration. The similarities in the rank orders of the metal concentrations together with the dominance of Zn and Pb in most compartments of the wetlands indicated major differences did not exist in the contaminant input to the two wetlands except electronic waste recycling and disposal that resulted in significantly high copper concentrations in the sediment of Korle Lagoon. No evidence of biomagnification was determined along the food chains of the Vaughan Dam and the Korle Lagoon for all the metals studied.The Tilapia zilli from Vaughan Dam, the only biota that is regularly consumed from the wetlands, had Cr, Cu, Pb, Cd, Hg, and As concentrations above FAO/WHO permissible limits and therefore pose a health risk to consumers., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Baseline data on plastic landing by fishers and monitoring of this is important in evaluating the success of plastic waste management efforts. This study investigated plastic and fish landed by beach seine fishers in Ghana together with the rate of plastic deposition on an adjoining beach. Plastic constituted 31.6% of the total catch and 41.7% of the fish landed by weight. There were significant differences between the average weight of fish (139.58 ± 53.6 kg) and plastic (65.73 ± 14.6 kg) landed per fishing session and the catch per unit effort of fish (183.4 ± 76.7 kg/day) and plastic (88.4 ± 35.2 kg/day). The mean weight of plastic landed per fishing session was higher than the mean weight of each of the 26 species of fisheries. The rate of plastic deposition on the beach was 8.1 ± 2.5 plastic items per m 2 per tidal cycle or 0.35 ± 0.11 kg plastic per m 2 per tidal cycle with food packs and tableware dominating the deposited plastic. The results suggested ongoing water sachets and plastic bottle recycling in Ghana are yielding results and calls for targeted efforts in plastic food packs and tableware management., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Urban riverine systems serve as conduits for the transport of plastic waste from the terrestrial dumpsites to marine repositories. This study presented data on the occurrence of microplastics in water, sediment, Bagrid Catfish (Chrysichthys nigrodigitatus) and Black-chinned Tilapia (Sarotherodon melanotheron) from the Densu River, an urban riverine system in Ghana. Microplastics were extracted from the samples collected from both the lentic and lotic sections of the river. The results indicated widespread pollution of the Densu River with microplastics in all the compartments studied. The average numbers of microplastic particles deposited in the Dam (2.0 ± 0.58) and Delta (2.50 ± 0.48) sections of the river were not affected by the differences in their hydrology. However, the stagnant water system of the Dam promoted the floating of larger-sized microplastics while the flowing waters of the Delta did not show any selectivity in the deposition of microplastics between sediment and the water column. The number of microplastics ingestions by the Bagrid Catfish (2.88 ± 2.11) was similar to the Black-chinned Tilapia (2.38 ± 1.66) but both species ingested lower numbers of microplastics than reported for marine fish species in coastal Ghana., Competing Interests: The authors have declared that no competing interests exist.

Consumption and trade in bushmeat are entrenched in sub-Saharan Africa amid growing land degradation and environmental pollution that raise safety concerns, yet sustainability of bushmeat extraction and zoonoses considerations have been the focus of bushmeat research. Here, we evaluated the health risk of trace metals in the skeletal muscle, bone, liver, and skin of the black duiker (Cephalophus niger), brush-tailed porcupine (Atherurus africanus), bushbuck (Tragelaphus scriptus), cane rat (Thryonomys swinderianus), and Maxwell's duiker (Cephalophus maxwelli) being the five most hunted and consumed species of bushmeat in Ghana. Sample tissues of the five species were analyzed for Cu, Zn, Se, Cd, As, Pb, and Hg. Targeted hazard quotient (THQ) of Se for black duiker, bushback, and Maxwell's duiker as well as that of Pb for black duiker, Brush-tailed porcupine, and Maxwell's duiker were concerning (> 1) for individuals foraging daily on bushmeat. Thus, cane rat was the only species that recorded both estimated daily intake (EDI) and THQ of Se and Pb within safe limits for daily consumption. In respect of Cu, Zn, Cd, As, and Hg, EDI and THQ values indicated no perceived risk to consumers for all five species. Lifetime cancer risk (CR) of As was negligible for all species. At the rate of bushmeat consumption in sub-Saharan Africa (0.104 kg per day), the cane rat was the only species considered safe for daily consumption among the five species.

The use of optical microscope remains the most commonly used technique for microplastic identification and quantification despite major limitations with misidentifications and biases. We evaluated the use of the 1% Rose Bengal stain in improving the identification of microplastics after a standard microplastic isolation process. The stain discriminated organic materials from potential microplastics with significant differences between numbers observed before (6.65 ± 5.73) and after staining (2.91 ± 3.43). Numbers of potential microplastics observed under the conventional method (without staining) in sediment, feacal matter of shorebirds and the lagoon water were respectively 3.55 g -1 , 0.8 g -1 and 0.13 ml -1 but reduced to 1.85 g -1 of sediment, 0.35 g -1 of feacal material and 0.09 ml -1 of water after staining. Colour composition of potential microplastics under the conventional method was brown (31.0%), black (26.5%), white (20.2%), translucent (16.7%) and red (5.6%). After staining, brown (49,2%), black (30.5%) white (2.3%) and translucent (18.0%) were retained but distinction could not be made between stained organic items and red-coloured microplastics. It was clear that the stain has the potential in improving microplastic identification but requires further investigations.