Ocean diversity and human impact: 49% decline in marine vertebrate populations between 1970 and 2012Thursday, September 17th, 2015
According to an emergency edition of the WWF Living Blue Planet Report, there has been a 49% decline in marine vertebrate populations between 1970 and 2012. These estimates are based on tracking 5829 populations of 1234 species. For some fish species, the decline has been almost 75%. Overfishing, habitat destruction and climate change are held to be responsible.
Concerning the importance of marine ecosystems more generally, a concise and up-to-date list of important aspects of ocean diversity and how it has been affected by human activities is given in the UNESCO report:
Some important points from this report:
- “By the year 2100, without significant changes, more than half of the world’s marine species may stand on the brink of extinction.
- Today 60% of the world’s major marine ecosystems that underpin livelihoods have been degraded or are being used unsustainably.
- If the concentration of atmospheric CO2 continues to increase at the current rate, the ocean will become corrosive to the shells of many marine organisms by the end of this century. How or if marine organisms may adapt is not known.
- Ocean acidification may render most regions of the ocean inhospitable to coral reefs, affecting tourism, food security, shoreline protection, and biodiversity.
- Commercial overexploitation of the world’s fish stocks is so severe that it has been estimated that up to 13 percent of global fisheries have ‘collapsed.’
- There are now close to 500 dead zones covering more than 245,000 km² globally, equivalent to the surface of the United Kingdom.
- Between 1980 and 2005, 35,000 square kilometers of mangroves were removed globally.
- Between 30 and 35 percent of the global extent of critical marine habitats such as seagrasses, mangroves and coral reefs are estimated to have been destroyed.”
Causes of losses in marine biodiversity are discussed here, with some references: