Brachidontes pharaonis
Information
The rayed Erythrean mussel is found in shallow and sheltered marine areas and in hypersaline waters (> 45 PSU). It can live in polluted waters such as those close to municipal waste-water pipes. It can reach very dense populations of up to 11,000 individuals per square metre. It can also tolerate high water temperatures of up to 31 °C.
It reproduces all year around and has a short development cycle that results in young bivalves in about 10-20 days. Adults live for up to five years.
Mytilaster minimus, Gregariella petagnae and Mytilaster lineatus. Major differences are that in M. minimus: 1) the shell surface is smooth and only concentric growth lines with no ribs are evident; and 2) the internal shell margin is smooth. Gregariella petagnae has a hairy shell and Mytilaster lineatus, an endemic species from the Adriatic, is very similar in shape but has numerous rib lines on the shell surface.
Brachidontes pharaonis is a classic example of an introduced species from the Red Sea and Indian Ocean that was introduced into the Mediterranean after the opening of the Suez Canal in 1869. It was first recorded in 1876 in Egypt. Since then it has been recorded in Lebanon, Israel, Italy (Sicily), Malta, Greece, Syria, Cyprus and Croatia. The latest record was in 2007 from Izmir in Turkey. These bivalves can also be easily spread by boat fouling (in the communities encrusting a ship’s hull).
This species can deplete the phytoplankton concentration in the water column, constraining the growth of other filter-feeding animals such as Mytilaster minimus. It is a preferred prey of the gastropod Stramonita haemastoma.
The economic impact of this species has not yet been quantified anywhere; however, dense mats of these bivalve populations in industrial facilities and salt works might result in high energy consumption and economic losses.
