Due to human activities and demands, oyster reefs are at risk. Due to the proximity to sea and the economic benefits that it garnered from selling of seafood, many harbours, ports and business centres have been built around the coastal areas. Undeveloped coastal areas are suffering from exploitation of overfishing, and the coastal lands are being converted for aquaculture and agriculture purposes. All of these results in environmental degradation, pollution, and it affects the marine biodiversity. Sadly, the list of causes and consequences is non exhaustive, and many of the coastal areas and marine life are still suffering.
Approximately 85% of oyster habitats around the world have been destroyed, and the remaining populations are in poor conditions (Beck et al. 2011).
Condition of oyster reefs around the world. The ones highlighted in red are in poor condition. (cr: vims.edu)
A study found that in Bangkok alone, overfishing and coastal development had resulted in the disappearance of 85% of oyster reefs. And, in Hiroshima Bay, Japan, due to oxidative stress, the mass mortality of oysters caused a tremendous economic loss of about 3 to 4 billion yen (USD$2 to 2.7 million) (Matsuyama 2003).
There are many natural and human threats that oysters are vulnerable to such as:
- Over-harvesting
- Predators
- Flattened reefs
- Pollutions
- Land reclamation
- Oyster shells being removed from oyster reefs
- Diseases
- Competition from non-native species
However, in this blog, I am to going to focus more on the threats of ocean acidification, harmful algae blooms and plastic pollution.