Zoology-Scholarly Publications

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Browsing Zoology-Scholarly Publications by Subject "Aquatic ecosystems"

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  • Item
    Open Access
    Adverse Impact of Human Activities on Aquatic Ecosystems: Investigating the Environmental Sustainability Perception of Stakeholders in Lagos and Ogun States, Nigeria
    (Springer Nature, 2021-02) Sogbanmu, Temitope O.; Ogunkoya, O.A.; Olaniran, E.I.; Lasisi, A.K.; Seiler, T.-B.
    Environmental risk perception of stakeholders for various human activities is germane to the sustainable development of a society. In urban Africa, rising population rates pose environmental challenges for the management of aquatic resources. Examples of two metropolitan cities in urban Africa are Lagos and Ogun states, Nigeria, with their teeming populations. The proximity of the Lagos lagoon and Ogun River to human settlements predisposes their use as sinks for disposal of wastewaters from potentially polluting activities such as sawmills and livestock processing (abattoirs). This chapter evaluates the environmental risk perception of specific stakeholders in the states whose activities result in potential adverse impact on aquatic ecosystems and associated ecosystem services. Copies of a structured questionnaire were administered to stakeholders at selected anthropogenic sites, i.e. Okobaba Sawmills and Kara Cow Market, in Lagos and Ogun states respectively. At the Okobaba sawmills adjoining the Lagos lagoon, respondents stated that sawdust is the major (84%) waste generated, most (90%) of which is burnt. Over half (51–90%) of the respondents noted that air quality, water quality and aquatic animals are adversely impacted by the sawmill activities. At Kara Cow Market, which adjoins Ogun River, respondents reported that they utilise the river for domestic activities, such as source of drinking water and for washing of cows. Most respondents (70–82%) acknowledged that the river is polluted, wastes are deliberately disposed into the river and wastewater from the abattoir is never treated. It is suggested that stakeholder environmental education, advocacy, risk communication, as well as demand for, and implementation of, evidence-based policies for the management of these ecosystems are crucial steps to be taken in addressing the situation. Further, the planning of human settlements near aquatic ecosystems should be considered alongside the sustainability of aquatic resources and ecosystem services in urban Africa, given the need to support life below water (UN SDG 14).
  • Item
    Open Access
    Embryotoxic, Developmental and Genotoxic Evaluations of a Endosulfan and Deltamethrin Mixture on the African Sharptooth Catfish (Clarias gariepinus)
    (West African Journal of Applied Ecology, 2018-07) Mumuni, Abdulmujib A.; Sogbanmu, Temitope O.
    The evaluation of pesticides using early life stages of fish yields high throughput results that can inform one about the developmental effects of these toxicants. The effects of sublethal concentrations of a commercial mixture of endosulfan and deltamethrin (ratio 280:2) were evaluated in the embryos and juveniles of Clarias gariepinus. Embryotoxic and developmental evaluations were conducted in the embryos from 0 - 26 hours post fertilization. Genotoxic effects were assessed in the erythrocytes of the juveniles using the micronucleus assay over a period of 28 days. The acute toxicity studies revealed that the 24 hLC50 and 26 hEC50 (non-hatching) values for embryos were 25.25 μg/L and 12.96 μg/L respectively while the 96 hLC50 value for fingerlings was 12.67 μg/L. Hatching success was lower in the exposed embryos compared to the control. The percentage developmental abnormalities and number of heartbeats per minute were statistically higher (p<0.05) in the exposed embryos compared to the control. Developmental abnormalities observed included pericardial and yolk sac oedema, scoliosis and tail curvature. The genotoxicity studies showed that there was a significant increase (p<0.05) in micronuclei in the erythrocytes of the exposed juveniles by days 14 and 28 compared to the control animals. These results imply that the pesticide mixture can cause a decline in the population of non-target organisms such as fish at sub-lethal or environmentally realistic concentrations. A review of the use of this pesticide formulation and development of environmentally friendly methods for pest management are recommended to safeguard non-target organisms such as the African sharptooth catfish.