What is the state of coral cover around Saba and St Eustatius
Coral cover is very low around Saba and St Eustatius and was at 2 and 3 percent in 2023. Around Bonaire, coral cover is higher at 15 percent. However, Bonaire’s coral cover also showed clear signs of decline between 2020 and 2023.
Coral cover is the percentage of the seabed that is covered by live coral on a reef. Coral cover has been monitored at the Karpata site on Bonaire since 1974. Monitoring around the whole of Bonaire began relatively recently, in 2014. Around Saba and St Eustatius coral cover monitoring began between 1990 and 2000.
Bonaire: decline between 2020 and 2023
In the waters around Bonaire, average coral cover has remained relatively stable since 2014 and it is currently regarded as fair (15 percent), although a noticeable decline was recorded between 2020 and 2023. Karpata’s long-term monitoring at ten meters depth began with 67 percent coral cover in 1974 but this had dwindled to 26 percent by 2023, despite some temporary recoveries.
| Year | Cover |
|---|---|
| 2014 | 18.7 |
| 2017 | 17.3 |
| 2020 | 19.6 |
| 2023 | 15.4 |
| Source: E. Meesters, Wageningen Marine Research, Dutch Caribbean Biodiversity Database | |
Saba and St Eustatius: rapid decline
Saba’s average coral cover has declined from around 24 percent in the early 1990s to 3 percent in 2023. This is most likely due to erosion-driven runoffnoot1, coral bleaching due to climate change, coral diseases, and coastal eutrophication.noot2 St Eustatius has also seen a decline in coral cover from an average of 22 percent in 1999 to just 2 percent in 2023.
| Year | Cover | Margin of error |
|---|---|---|
| 1999 | 22 | 22,00-22,00 |
| 2000 | ||
| 2001 | ||
| 2002 | ||
| 2003 | ||
| 2004 | ||
| 2005 | 27 | 27,00-27,00 |
| 2006 | ||
| 2007 | 26 | 26,00-26,00 |
| 2008 | 6,5 | 6,50-6,50 |
| 2009 | ||
| 2010 | ||
| 2011 | ||
| 2012 | ||
| 2013 | ||
| 2014 | ||
| 2015 | 5 | 5,00-5,00 |
| 2016 | 5 | 5,00-5,00 |
| 2017 | 2,85 | 2,06-3,64 |
| 2018 | 3,29 | 2,43-4,14 |
| 2019 | 3,91 | 2,94-4,88 |
| 2020 | 2,12 | 1,51-2,73 |
| 2021 | 2,31 | 1,66-2,96 |
| 2022 | 2,17 | 1,39-2,95 |
| 2023 | 1,5 | 0,80-2,20 |
| Year | Cover | Margin of error |
|---|---|---|
| 1991 | 24,35 | 23,50-25,20 |
| 1992 | ||
| 1993 | 29,35 | 24,10-34,60 |
| 1994 | 33,79 | 25,17-42,40 |
| 1995 | 31,05 | 24,17-37,92 |
| 1996 | ||
| 1997 | ||
| 1998 | ||
| 1999 | 15,21 | 11,71-18,71 |
| 2000 | ||
| 2001 | ||
| 2002 | ||
| 2003 | ||
| 2004 | ||
| 2005 | ||
| 2006 | ||
| 2007 | ||
| 2008 | ||
| 2009 | ||
| 2010 | ||
| 2011 | ||
| 2012 | ||
| 2013 | ||
| 2014 | ||
| 2015 | 5,15 | 3,90-6,40 |
| 2016 | 6,09 | 4,68-7,50 |
| 2017 | ||
| 2018 | ||
| 2019 | 7,7 | 6,21-9,19 |
| 20120 | ||
| 2021 | 5,19 | 4,06-6,32 |
| 2022 | 3,51 | 2,68-4,34 |
| 2023 | ||
| 2024 | 2,45 | 1,68-3,22 |
Source
Noten
Erosion-driven runoff
Caused when rainwater washes loose soil away and carries it into the sea, often polluting the water and harming ecosystems.
Coastal eutrophication
When too many nutrients get into the sea, causing too much algae to grow, which overgrows and kills coral and reduces coral recruitment.