Samples of sediments were collected at several sites.Credit: François Le Loc’h
Heavy metal pollution and traditional shellfish harvesting methods have unintended effects on coastal ecosystems in Senegal, a study suggests.
The study led by a doctoral researcher at Åbo Akademi University in Finland showed for the first time, the impact of humans and environmental variables on Senegalese mangroves, underlining the importance of local conservation and management.
Samples of sediments were collected at several sites.Credit: François Le Loc’h
The study was part of the project, Femmes et Coquillages, (Women and Shellfish), seeking to understand traditional knowledge and practices in order to contribute to sustainably harvesting shellfish resources.
The team investigated the main mangrove areas in Senegal: the Sine Saloum and the Petite Cote, to evaluate the influence of environment and human activities (i.e. shellfish harvesting and heavy metal pollution) on key coastal animals. Based on collected data of invertebrates living in the sediments of the seabed from 2007 to 2008, the researchers established a conditions report for the mangrove areas to understand the factors influencing aquatic animals that live in the substrate of a body of water and which are especially common in soft sediments, known as infaunal.
The results are important because "there have not been any published data on these infaunal communities since 1985. So our study serves as an important reference point for future research," says Maïté Jacquot, the lead author.
The researchers found that in places where shellfish harvesting happened, invertebrates were less abundant and weighed less. Heavy metal pollution affects the diversity of invertebrates, which leads to less presence of species on the polluted sites. Furthermore, in places located further from human settlements, and less affected by harvesting and pollution, invertebrate diversity and abundance were affected by natural changes in the environment, such as water temperature and salinity.
