Emna DEROUICHE., CHEBAANE S., BEJAOUI T., SGHAIER Y.R.
TunSea, 33 rue de l’Irak, la Soukra. Tunisia.
E-mail: sahar.chebaane@mare-centre.pt
CONTINUED EXPANSION OF THE LESSEPSIAN INVADER MYTILID
BRACHIDONTES PHARAONIS ALONG THE TUNISIAN COAST
Abstract
The Red Sea mussel, Brachidontes pharaonis is an invasive species in the Mediterranean. This species
was observed for the first time in Tunisia (Zarzis, southern Tunisia) in August 2007. A monitoring
covering the entire shallow coastline of Tunisia was carried out to collect quantitative and qualitative
data on the mytilid between 2019 and 2022 by the authors and reinforced by recorded through citizen
science Since its first record, B. pharaonis has rapidly extended its geographical range to the lagoon of
Bougherara, then to almost Tunisian coast reaching more than 700 km from its initial area of first
detection. B. pharaonis is present in the Bizerte lagoon (northern Tunisia), most likely facilitated by a
combination of commercial and recreational boat traffic. Brachidontes pharaonis was found and
colonized both natural habitats and artificial hard structures such as, rocky shores, aquaculture cages,
harbours docks, with a high level of frequency and abundance, especially in lagoons (e.g., the lagoon
of Boughrara) where extensive beds of B. pharaonic were found with individual abundances exceeding
10 000 specimens per square meter. The continuing spreading of B. pharaonis indicates the species is
one of the most aggressive invaders and should be added to the list of invasive non-indigenous species
to be monitored by the National monitoring programme for biodiversity in Tunisia.
Key-words: B. pharaonis, invader, citizen science, Tunisia.
Introduction
Brachidontes pharaonis from Indian Ocean origin is widely spread throughout the Red Sea.
This bivalve was among the first non-indigenous species (NIS) introduced and noticed in the
Mediterranean Sea. The occurrence of B. pharaonis in Tunisia was first signed in August 2007
(Ounifi et al., 2016). This work aimed to study the new distribution of B. pharaonis along the
Tunisian coast and to assess its invasion rate by conducting targeted surveys and supporting
records through citizen science to collect quantitative and qualitative data on this NIS.
Material and methods
The authors conducted the targeted surveys in the following localities: Tunis Northern lagoon
la Goulette, Gammarth (Tunis), Fratelli Islands, Bizerte lagoon, Cani, Plane, Pilou Islands,
Rafraf, Sidi Ali Makki (Bizerte), Bir Jday, Haouaria, Hammam Ghzez, Sidi Mahrsi (Nabeul),
Chott Mariem, Marina Cap Monastir, Monastir touristic area, Kuriat Island, Hmem Island,
Teboulba (Monastir), Sidi Frej –Kerkennah (Sfax), Djerba Island (all the coast of the Djerba
Island), Boughrara port (Mednine). Along these locations, The intertidal zone and the rocky
beaches were targeted and surveyed by snorkeling or by visual assessing the coast. Densities
were classified as follow (low, medium, high, or very high. Additionally, a campaign was
launched via the social media Facebook using the citizen science group TunSea and some
naturalists were contacted to track the presence of B. pharaonis in other locations. Moreover,
Malloula (Tabarka), Sidi Mechreg, Ghar El Melh lagoon, the shellfish farming in the Bizerte
lagoon (Bizerte), aquaculture facilities in Bni Khiar, Kelibia, Kerkouene (Nabeul),
aquaculture facilities in Teboulba (Monastir), Sidi Mansour (Sfax) and Ghannouche (Gabes)
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
91
TunSea, 33 rue de l’Irak, la Soukra. Tunisia.
E-mail: sahar.chebaane@mare-centre.pt
CONTINUED EXPANSION OF THE LESSEPSIAN INVADER MYTILID
BRACHIDONTES PHARAONIS ALONG THE TUNISIAN COAST
Abstract
The Red Sea mussel, Brachidontes pharaonis is an invasive species in the Mediterranean. This species
was observed for the first time in Tunisia (Zarzis, southern Tunisia) in August 2007. A monitoring
covering the entire shallow coastline of Tunisia was carried out to collect quantitative and qualitative
data on the mytilid between 2019 and 2022 by the authors and reinforced by recorded through citizen
science Since its first record, B. pharaonis has rapidly extended its geographical range to the lagoon of
Bougherara, then to almost Tunisian coast reaching more than 700 km from its initial area of first
detection. B. pharaonis is present in the Bizerte lagoon (northern Tunisia), most likely facilitated by a
combination of commercial and recreational boat traffic. Brachidontes pharaonis was found and
colonized both natural habitats and artificial hard structures such as, rocky shores, aquaculture cages,
harbours docks, with a high level of frequency and abundance, especially in lagoons (e.g., the lagoon
of Boughrara) where extensive beds of B. pharaonic were found with individual abundances exceeding
10 000 specimens per square meter. The continuing spreading of B. pharaonis indicates the species is
one of the most aggressive invaders and should be added to the list of invasive non-indigenous species
to be monitored by the National monitoring programme for biodiversity in Tunisia.
Key-words: B. pharaonis, invader, citizen science, Tunisia.
Introduction
Brachidontes pharaonis from Indian Ocean origin is widely spread throughout the Red Sea.
This bivalve was among the first non-indigenous species (NIS) introduced and noticed in the
Mediterranean Sea. The occurrence of B. pharaonis in Tunisia was first signed in August 2007
(Ounifi et al., 2016). This work aimed to study the new distribution of B. pharaonis along the
Tunisian coast and to assess its invasion rate by conducting targeted surveys and supporting
records through citizen science to collect quantitative and qualitative data on this NIS.
Material and methods
The authors conducted the targeted surveys in the following localities: Tunis Northern lagoon
la Goulette, Gammarth (Tunis), Fratelli Islands, Bizerte lagoon, Cani, Plane, Pilou Islands,
Rafraf, Sidi Ali Makki (Bizerte), Bir Jday, Haouaria, Hammam Ghzez, Sidi Mahrsi (Nabeul),
Chott Mariem, Marina Cap Monastir, Monastir touristic area, Kuriat Island, Hmem Island,
Teboulba (Monastir), Sidi Frej –Kerkennah (Sfax), Djerba Island (all the coast of the Djerba
Island), Boughrara port (Mednine). Along these locations, The intertidal zone and the rocky
beaches were targeted and surveyed by snorkeling or by visual assessing the coast. Densities
were classified as follow (low, medium, high, or very high. Additionally, a campaign was
launched via the social media Facebook using the citizen science group TunSea and some
naturalists were contacted to track the presence of B. pharaonis in other locations. Moreover,
Malloula (Tabarka), Sidi Mechreg, Ghar El Melh lagoon, the shellfish farming in the Bizerte
lagoon (Bizerte), aquaculture facilities in Bni Khiar, Kelibia, Kerkouene (Nabeul),
aquaculture facilities in Teboulba (Monastir), Sidi Mansour (Sfax) and Ghannouche (Gabes)
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
91