Living Planet Index
Living Blue Planet Report
This is a special marine edition of WWF’s Living Planet Report. This report uses the Living Planet Index to provide a global picture of the status of marine biodiversity using data from 7,829 populations of 1,234 species of marine birds, mammals, reptiles and fishes. Download the full report here
The main statistic from the report is the global marine LPI which shows a 49% decline between 1970 and 2012. This means that the average population size of these monitored species is roughly half what it was 42 years ago.
Figure 1: The marine LPI shows a 49% decline between 1970 and 2012. The white line shows the index values and the shaded areas represent the 95% confidence intervals surrounding the trend. WWF/ZSL (2015).
Threats to marine populations
Over-exploitation is one of the main drivers behind the decline, particularly for highly commercial species. For example the average decline in Scombridae populations – species of tuna, mackerel and bonito – was 74%.
Important marine habitats are also under threat from climate change, pollution and coastal development. A reduction in the coverage of coral reefs, seagrass habitat and mangrove forests were reported along with an accompanying decline in fish populations in coral reefs and seagrass.
Coral reefs support 25% of marine species; seagrass habitat is an important carbon sink and provides nursery areas for fish; mangroves offer coastal protection from storm surges and are a key spawning and nursery ground for many species. Safeguarding these habitats is vital for the conservation of marine biodiversity, the protection of coastline and the support of people’s livelihoods and food security across the globe.
An index of 17 species of tunas, mackerels and bonitos from the Scombridae family of fish declined by 74% between 1970 and 2010, a trend that shows no sign yet of recovery. These species are important for regional economies, livelihoods and food.
The LPI for reef-associated fish shows a decline of 34% from 1979 to 2010. These are species that live or feed on or near coral reefs. This index is based on 2,501 populations from 352 species. There has been an observed decline in coral reef cover in many areas, particularly the Caribbean and Indo-Pacific. Project levels of warming mean that climate change could cause the loss of reefs by 2050.
Fish populations that are found in seagrass habitat suffered more than a 70% drop in size between 1970 and 2010. This is based on 350 populations of 232 species. Research suggests that 29% of seagrass area has been lost since the end of the 19th century. This important habitat is a carbon sink and provides nursery areas for many marine species.