Olfa BEN ABDALLAH, BEN HADJ HAMIDA N., LABNI M.A., MISSAOUI H.
Institut National des Sciences et Technologies de la Mer, Tunisia
E-mail: olfa.benabdallah@instm.rnrt.tn
STATUS OF THE ATLANTIC BLUE CRAB CALLINECTES
SAPIDUS RATHBUN, 1896 IN TUNISIAN WATERS
(CENTRAL MEDITERRANEAN)
Abstract
The Atlantic blue crab Callinectes sapidus is listed among the “worst invasive” species in the
Mediterranean, with reported impacts on both biodiversity and socioeconomics. This decapod
was recently recorded in the northern Tunisian coasts, when few specimens were caught by nets
in the Gulf of Tunis, then in Ariana and Bizerte. In spring 2020, the abundance of this invasive
species increased, especially in the coastal areas in northern Tunisia. Very recently, C. sapidus
was recorded in the Gulf of Gabès in April 2020 and in the Bay of Monastir in August 2020.
The abundance of C. sapidus is resulted to be higher on the northern coasts, and a little less on
the eastern coasts. In these two areas, a fishing activity targeting the species seems to be taking
hold. The quantities caught are more abundant during the hot season and are sold on local
markets. In southern Tunisia, the presence of C. sapidus is still sporadic.
Key words: Callinectes sapidus, Central Mediterranean, Tunisia, fisheries, status.
Introduction
The blue crab Callinectes sapidus Rathbun, 1896 (Crustacea: Decapoda: Portunidae) is
a commercially important species, widely distributed in estuaries and lagoons along the
entire Western Atlantic coast from southern Nova Scotia, Canada, to Argentina
(Nehring 2011). It is an euryhaline crustacean commonly found on muddy and sandy
bottoms, generally at depths < 35 m (Hill et al., 1989). The earliest confirmed record in
the Mediterranean was in 1948, when two specimens were found in the Northern
Adriatic (Giordani, 1951), although its presence in the Aegean Sea was suspected as
early as 1935 (Nehring 2011). Since then, C. sapidus has been widely recorded in
Mediterranean coastal waters (Galil et al., 2008; Galil 2011; Daban et al., 2016). This
American blue crab was recently reported in the northern Tunisian coasts (Bdioui et al.,
2019; Ben Abdallah-Ben Hadj Hamida et al., 2019), when few specimens were caught
in the Gulf of Tunis, then in Ariana and Bizerte and by nets. Very recently, C. sapidus
was recorded in the Gulf of Gabès in July 2020 and in the Bay of Monastir in August
2020.
The present study aims to detect the status of this invasive species in Tunisian waters
and to assess trends in its abundance to predict its impact on local resources and
fisheries.
Material and methods
In order to collect information on the spread and the status of the American blue crab C.
sapidus in Tunisia, surveys based on the Local Ecological Knowledge (LEK) were
conducted in the main ports and landing points of fishery products in the area.
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
18
Institut National des Sciences et Technologies de la Mer, Tunisia
E-mail: olfa.benabdallah@instm.rnrt.tn
STATUS OF THE ATLANTIC BLUE CRAB CALLINECTES
SAPIDUS RATHBUN, 1896 IN TUNISIAN WATERS
(CENTRAL MEDITERRANEAN)
Abstract
The Atlantic blue crab Callinectes sapidus is listed among the “worst invasive” species in the
Mediterranean, with reported impacts on both biodiversity and socioeconomics. This decapod
was recently recorded in the northern Tunisian coasts, when few specimens were caught by nets
in the Gulf of Tunis, then in Ariana and Bizerte. In spring 2020, the abundance of this invasive
species increased, especially in the coastal areas in northern Tunisia. Very recently, C. sapidus
was recorded in the Gulf of Gabès in April 2020 and in the Bay of Monastir in August 2020.
The abundance of C. sapidus is resulted to be higher on the northern coasts, and a little less on
the eastern coasts. In these two areas, a fishing activity targeting the species seems to be taking
hold. The quantities caught are more abundant during the hot season and are sold on local
markets. In southern Tunisia, the presence of C. sapidus is still sporadic.
Key words: Callinectes sapidus, Central Mediterranean, Tunisia, fisheries, status.
Introduction
The blue crab Callinectes sapidus Rathbun, 1896 (Crustacea: Decapoda: Portunidae) is
a commercially important species, widely distributed in estuaries and lagoons along the
entire Western Atlantic coast from southern Nova Scotia, Canada, to Argentina
(Nehring 2011). It is an euryhaline crustacean commonly found on muddy and sandy
bottoms, generally at depths < 35 m (Hill et al., 1989). The earliest confirmed record in
the Mediterranean was in 1948, when two specimens were found in the Northern
Adriatic (Giordani, 1951), although its presence in the Aegean Sea was suspected as
early as 1935 (Nehring 2011). Since then, C. sapidus has been widely recorded in
Mediterranean coastal waters (Galil et al., 2008; Galil 2011; Daban et al., 2016). This
American blue crab was recently reported in the northern Tunisian coasts (Bdioui et al.,
2019; Ben Abdallah-Ben Hadj Hamida et al., 2019), when few specimens were caught
in the Gulf of Tunis, then in Ariana and Bizerte and by nets. Very recently, C. sapidus
was recorded in the Gulf of Gabès in July 2020 and in the Bay of Monastir in August
2020.
The present study aims to detect the status of this invasive species in Tunisian waters
and to assess trends in its abundance to predict its impact on local resources and
fisheries.
Material and methods
In order to collect information on the spread and the status of the American blue crab C.
sapidus in Tunisia, surveys based on the Local Ecological Knowledge (LEK) were
conducted in the main ports and landing points of fishery products in the area.
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
18