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Reviewing evidence of marine ecosystem change off South Africa
journal contribution
posted on 2013-09-01, 00:00 authored by C L Moloney, S T Fennessy, M J Gibbons, A Roychoudhury, F A Shillington, B P von der Heyden, Kate WatermeyerKate WatermeyerRecent 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.
History
Journal
African journal of marine scienceVolume
35Issue
3Pagination
427 - 448Publisher
Taylor & FrancisLocation
Abingdon, Eng.Publisher DOI
ISSN
1814-232XeISSN
1814-2338Language
engPublication classification
C Journal article; C1.1 Refereed article in a scholarly journalCopyright notice
2013, NISC (Pty) LtdUsage metrics
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