Review Papers

Reviewing evidence of marine ecosystem change off South Africa

Published in: African Journal of Marine Science
Volume 35, issue 3, 2013 , pages: 427–448
DOI: 10.2989/1814232X.2013.836135
Author(s): C L MoloneyDepartment of Biological Sciences, South Africa, S T FennessyOceanographic Research Institute, South Africa, M J GibbonsDepartment of Biodiversity and Conservation Biology, South Africa, A RoychoudhuryDepartment of Earth Sciences, South Africa, F A ShillingtonMarine Research Institute, South Africa, B P von der HeydenDepartment of Earth Sciences, South Africa, K WatermeyerDepartment of Biological Sciences, South Africa

Abstract

Recent changes have been observed in South African marine ecosystems. The main pressures on these ecosystems are fishing, climate change, pollution, ocean acidification and mining. The best long-term datasets are for trends in fishing pressures but there are many gaps, especially for non-commercial species. Fishing pressures have varied over time, depending on the species being caught. Little information exists for trends in other anthropogenic pressures. Field observations of environmental variables are limited in time and space. Remotely sensed satellite data have improved spatial and temporal coverage but the time-series are still too short to distinguish long-term trends from interannual and decadal variability. There are indications of recent cooling on the West and South coasts and warming on the East Coast over a period of 20–30 years. Oxygen concentrations on the West Coast have decreased over this period. Observed changes in offshore marine communities include southward and eastward changes in species distributions, changes in abundance of species, and probable alterations in foodweb dynamics. Causes of observed changes are difficult to attribute. Full understanding of marine ecosystem change requires ongoing and effective data collection, management and archiving, and coordination in carrying out ecosystem research.

Get new issue alerts for African Journal of Marine Science