Cramic Tiles from Tahong Shell Background Study

Submitted by: Submitted by

Views: 89

Words: 305

Pages: 2

Category: Science and Technology

Date Submitted: 07/07/2014 07:04 PM

Report This Essay

Perna viridis

The Asian green mussel (Perna viridis), is an economically important mussel, a bivalve belonging to the family Mytilidae. It is harvested for food but is also known to harbor toxins and cause damage to submerged structures such as drainage pipes. It is native in the Asia-Pacific region but has been introduced in the Caribbean, and in the waters around Japan, North America, and South America.

Perna viridis ranges from 80 to 100 millimeters in length and may occasionally reach 165 mm. Its shell ends in a downward-pointing beak. The smooth periostracum is dark green, becoming increasingly brownish towards its point of attachment (umbo), where it is lighter. Younger mussels are bright green and that becomes darker as it ages.[2] The shell’s interior has a pale-blue sheen.[3] The mussel has a large mobile foot which it uses to climb vertically should it be covered by sediments. It also produce byssus to help it attach to its substrate.

The Asian green mussel is found in the coastal waters of the Indo-Pacific region. However the mussels are introduced to other areas as invasive species via boat hulls and water ballasts.[1]

The mussel inhabits estuarine habitats and is found in densities as high as 35,000 individuals per square meter in any submerged marine object. Although vivid green in appearance, the mussels are shrouded with overgrowth and are often hard to find. The mussels live in waters that are 11-32°C with a wide-ranging salinity of about 18-33 ppt.[3] P. viridis grows fastest at 2 meters below the surface, in high salinity and high concentration ofphytoplankton although it can tolerate a range of salinity and turbid water.[5]

The Asian green mussel has separate sexes and fertilizes externally. There are a very few functional hermaphrodites (