Mediterranean invasive species factsheet www.iucn-medmis.org
Species report Brachidontes pharaonis (Rayed
Erythrean mussel) AFFILIATION MOLLUSCS
SCIENTIFIC NAME AND COMMON NAME REPORTS Brachidontes pharaonis 11
Key Identifying Features
The shell is formed of two elongated, trapezoidal valves that are equal in shape and size. The shell surface is characterized by distinctly sculpted ribs radiating from the hinge of the two valves towards the shell margin. The ribs are coarser towards the margin. The internal shell margin is serrated. The outside of the shell is dark brown, while the interior is violet. Adult shells can reach up to 4 cm in length.
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Other species that look similar
Identification and Habitat
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.
Reproduction
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.
Similar Species
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.
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History and Route of Further Reading Introduction http://www.europe-aliens.org/pdf/Brachidontes_pharaonis.pdf Brachidontes pharaonis is a classic example of an introduced species from the Red Sea and http://www.ciesm.org/atlas/Brachidontespharaonis.html Indian Ocean that was introduced into the Mediterranean after the opening of the Suez http://convittofoscarini.it/didattic/conchiglie/bivalvi/specie/MytilasterLineatus.htm 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).
Ecological Impacts
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.
Economic Impacts
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.
Management Options
Suggested prevention actions are: a) to conduct local public awareness campaigns combined with monitoring; and b) to identify and remove rayed Erythrean mussels from the hull fouling assemblages on vessels. Control actions to eradicate this species from the environment are not feasible due to the small size and large number of individuals forming new populations. If MPA managers or port authorities plan to check the hulls of boats entering marine reserves, B. pharaonis should be a target species to look for and scrape off the keel once the boat is out of the water.
2013-2021 © IUCN Centre for Mediterranean Cooperation. More info: www.iucn-medmis.org Pag. 3/5 Mediterranean invasive species factsheet www.iucn-medmis.org
Legend
Algae Angiosperm Cnidarians Centre for Mediterranean Molluscs Crustaceans Ascidians Cooperation Combjellies / Fishes Ctenophores
More Information: Guide and reports platform for Marine Protected Areas (MPAs) in the Mediterranean. www.iucn-medmis.org
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MPAs, Country Date Density Measure
Hof Dor and Ma'Agan Michael Islands, Israel Before 2013 -- --
Rosh Hanikra - Akhziv, Israel Before 2013 -- --
Yam Evtah, Israel Before 2013 -- --
Shiqma, Israel Before 2013 -- --
Shiqmona, Israel Before 2013 -- --
Rosh Hanikra islands, Israel Before 2013 -- --
Yam Dor Habonim, Israel Before 2013 -- --
Yam Gador, Israel Before 2013 -- --
Marine Area in the Northeast Malta, Malta 28/06/2011 -- --
Marine Between Rdum Majjiesa u Ras ir-Raheb, 28/06/2011 -- -- Malta
Marine Area in the limits of Dwejra, Malta 01/09/2011 -- --
How to cite this tab: Brachidontes pharaonis - Invasive Alien Species Fact Sheet for Mediterranean Network of MPAs. From Online Database MedMIS (IUCN Center for Mediterranean Cooperation, Download date 28/09/2021.
More information about this species from: Otero, M., Cebrian, E., Francour, P., Galil, B., Savini, D. 2013. Monitoring Marine Invasive Species in Mediterranean Marine Protected Areas (MPAs): A strategy and practical guide for managers. Malaga, Spain: IUCN. 136 pages www.iucn.org/dbtw-wpd/edocs/2013-008-Es.pdf .
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