temperature. Here we examined 525 individuals, with a width between 77 mm and 178
mm, sampled between February 2021 and February 2022. The measurements made it
possible to study the overall allometric relationships linking the different metric and
mass characters (total carapace length CL, total wet weight W).
Results
Of the 525 individuals examined, 312 were females and 213 were males. The specimens
analysed have an average CL of 70.01 mm and an average W of 173.80 g. Carapace
length (CL) distribution frequencies indicated 5 different cohorts with the following
mean lengths: 4.4 cm, 5.5 cm, 6.8 cm, 7.8 cm, 8.3 cm of CL). The mean annual sex
ratio is in favour of females (SR = 0.68, chi-square = 18.66). The latter numerically
dominated during all seasons, except in Summer when the population is numerically
balanced (SRwinter = 0.21, ²w = 38.22; SRspring = 0.44, ²s = 9.61; SRautumn = 0.43, ²a =
15.36; SRsummer = 1.18, ²s = 1.93). The first ovigerous females appeared in May and
became the majority in July (63.8%). The relative growth of length in relation to weight
shows that the value of the allometry coefficient b (7.22) differed significantly from 3 at
the 5% threshold. The relation established is allometric majorant.
Conclusion
This study provided the first information on the biology of C. sapidus in North Africa,
providing original data on the status of the population studied. Future studies can
contribute investigating impact on the environment and its interactions with resident
species.
Bibliography
BENABDI M, BELMAHI A E, GRIMES S. (2019) - First record of the Atlantic blue crab
Callinectes sapidus Rathbun, 1896 (Decapoda: Brachyura: Portunidae) in Algerian coastal
waters (southwestern Mediterranean), BioInvasions Rec., 8(1) : 119‑122, doi:
10.3391/bir.2019.8.1.13.
BOUVIER E. (1901) - Sur un Callinectes sapidus M. Rathbun trouvé à Rochefort. Bull. Mus.
Hist. Nat. 7, 16.
HAMIDA C, KARA M H (2021) - First documented record of the Atlantic blue crab
Callinectes sapidus Rathbun, 1896, from the southwestern Mediterranean coasts, DOI:
10.1163/15685403-BJA10051.
KARA M. H., CHAOUI L. (2021) - Strong invasion of Mellah lagoon (South-Western
Mediterranean) by the American blue crab Callinectes sapidus Rathbun, 1896. Marine
Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2021.112089
MIZZAN L. (1993) - Presence of swimming crabs of the genus Callinectes (Stimpson)
(Decapoda, Portunidae) in the Venice Lagoon (North Adriatic Sea, Italy). Bull. Nat. Hist.
Mus. Venice 42, 31–43.
MILLIKIN M R, WILLIAMS A B. (1984) - Synopsis of biological data on the blue crab,
Callinectes sapidus Rathbun. NOAA Tech. Rep. NMFS 1 (4) (39 pp).
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
84
mm, sampled between February 2021 and February 2022. The measurements made it
possible to study the overall allometric relationships linking the different metric and
mass characters (total carapace length CL, total wet weight W).
Results
Of the 525 individuals examined, 312 were females and 213 were males. The specimens
analysed have an average CL of 70.01 mm and an average W of 173.80 g. Carapace
length (CL) distribution frequencies indicated 5 different cohorts with the following
mean lengths: 4.4 cm, 5.5 cm, 6.8 cm, 7.8 cm, 8.3 cm of CL). The mean annual sex
ratio is in favour of females (SR = 0.68, chi-square = 18.66). The latter numerically
dominated during all seasons, except in Summer when the population is numerically
balanced (SRwinter = 0.21, ²w = 38.22; SRspring = 0.44, ²s = 9.61; SRautumn = 0.43, ²a =
15.36; SRsummer = 1.18, ²s = 1.93). The first ovigerous females appeared in May and
became the majority in July (63.8%). The relative growth of length in relation to weight
shows that the value of the allometry coefficient b (7.22) differed significantly from 3 at
the 5% threshold. The relation established is allometric majorant.
Conclusion
This study provided the first information on the biology of C. sapidus in North Africa,
providing original data on the status of the population studied. Future studies can
contribute investigating impact on the environment and its interactions with resident
species.
Bibliography
BENABDI M, BELMAHI A E, GRIMES S. (2019) - First record of the Atlantic blue crab
Callinectes sapidus Rathbun, 1896 (Decapoda: Brachyura: Portunidae) in Algerian coastal
waters (southwestern Mediterranean), BioInvasions Rec., 8(1) : 119‑122, doi:
10.3391/bir.2019.8.1.13.
BOUVIER E. (1901) - Sur un Callinectes sapidus M. Rathbun trouvé à Rochefort. Bull. Mus.
Hist. Nat. 7, 16.
HAMIDA C, KARA M H (2021) - First documented record of the Atlantic blue crab
Callinectes sapidus Rathbun, 1896, from the southwestern Mediterranean coasts, DOI:
10.1163/15685403-BJA10051.
KARA M. H., CHAOUI L. (2021) - Strong invasion of Mellah lagoon (South-Western
Mediterranean) by the American blue crab Callinectes sapidus Rathbun, 1896. Marine
Pollution Bulletin. https://doi.org/10.1016/j.marpolbul.2021.112089
MIZZAN L. (1993) - Presence of swimming crabs of the genus Callinectes (Stimpson)
(Decapoda, Portunidae) in the Venice Lagoon (North Adriatic Sea, Italy). Bull. Nat. Hist.
Mus. Venice 42, 31–43.
MILLIKIN M R, WILLIAMS A B. (1984) - Synopsis of biological data on the blue crab,
Callinectes sapidus Rathbun. NOAA Tech. Rep. NMFS 1 (4) (39 pp).
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
84