Results
A total of 10 NIS was identified belonging to Bryozoan, Ascidian and Polychaeta (Tab.1).
Five species are reported for the first time in the marinas of Tunisia (Bugula stolonifera,
Watersipora subtorquata, Watersipora arcuata, Botrylloides violaceus, Ciona robusta).
The result of the ANOVA test showed no differences among seasons and zones in NIS
abundance (F=14.008, p=1.91). The highest number of NIS observed during September
(37.29%) compared to the other period of monitoring. W. subtorquata and Hydroides
elegans were the most abundant species in our samples. Some species have been absent
during December such as Clavelina lepadiformis, W. arcuata. C. robusta and appear in
September. The abundance of this last species grows up in the next period of sampling.
However, Botryllus schlosseri and Ecteinascidia turbinata have been detected only
during September (Tab.1).
Tab. 1: Abundance variation and status of NIS found during monitoring period in marina
of Gammarth
Status
March
June
September
December
Bryozoan
Bugula stolonifera
Cryptogenic
20
10
25
4
Bugula neritina
Cryptogenic
6
3
3
11
Watersipora
subtorquata
Cryptogenic
127
148
235
92
Watersipora arcuata
Non indigenious
3
61
32
Ascidian
Clavelina lepadiformis Cryptogenic
60
38
62
Botrylloides violaceus
non indigenious
3
1
42
Botryllus schlosseri
Cryptogenic
36
Ecteinascidia turbinate Non indigenious
4
Ciona robusta
Non indigenious
1
4
Polychaeta
Hydroides elegans
Non indigenious
144
210
248
103
Total
363
(20.92%)
470
(27.09%)
647
(37.29%)
255
(14.70%)
Conclusion
Seasonal sampling and monitoring of NIS showed the similar phenomenon of abundance
of one or two species in all plates (Watersipora subtorquata and Hydroides elegans). This
result was observed in the study of Tamburini et al. (2021) in Italy. This could be related
to the ecology of species. SERC protocol seems like a good method for sampling NIS.
It’s rapid for early detection, quantitative and specific techniques.
Bibliography
JIMENEZ H., KEPPEL E., CHANG A.L., RUIZ G.M. (2018) - Invasions in marine communities:
contrasting species richness and community composition across habitats and salinity. Estuar.
Coasts., 41 (2): 484-494.
TAMBURINI M., KEPPEL E., MARCHINI A., REPETTO M.F., RUIZ G.M. et al. (2021) -
Monitoring Non-indigenous Species in Port Habitats: First Application of a Standardized
North American Protocol in the Mediterranean Sea. Front. Mar. Sci., 8: 700-730.
ULMAN A., FERRARIO J., FORCADA A., SEEBENS H., ARVANITIDIS C.,
OCCHIPINTI−AMBROGI A., et al. (2019) - Alien species spreading via biofouling on
recreational vessels in the Mediterranean Sea. J. Appl. Ecol., 56: 2620–2629.
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
110
A total of 10 NIS was identified belonging to Bryozoan, Ascidian and Polychaeta (Tab.1).
Five species are reported for the first time in the marinas of Tunisia (Bugula stolonifera,
Watersipora subtorquata, Watersipora arcuata, Botrylloides violaceus, Ciona robusta).
The result of the ANOVA test showed no differences among seasons and zones in NIS
abundance (F=14.008, p=1.91). The highest number of NIS observed during September
(37.29%) compared to the other period of monitoring. W. subtorquata and Hydroides
elegans were the most abundant species in our samples. Some species have been absent
during December such as Clavelina lepadiformis, W. arcuata. C. robusta and appear in
September. The abundance of this last species grows up in the next period of sampling.
However, Botryllus schlosseri and Ecteinascidia turbinata have been detected only
during September (Tab.1).
Tab. 1: Abundance variation and status of NIS found during monitoring period in marina
of Gammarth
Status
March
June
September
December
Bryozoan
Bugula stolonifera
Cryptogenic
20
10
25
4
Bugula neritina
Cryptogenic
6
3
3
11
Watersipora
subtorquata
Cryptogenic
127
148
235
92
Watersipora arcuata
Non indigenious
3
61
32
Ascidian
Clavelina lepadiformis Cryptogenic
60
38
62
Botrylloides violaceus
non indigenious
3
1
42
Botryllus schlosseri
Cryptogenic
36
Ecteinascidia turbinate Non indigenious
4
Ciona robusta
Non indigenious
1
4
Polychaeta
Hydroides elegans
Non indigenious
144
210
248
103
Total
363
(20.92%)
470
(27.09%)
647
(37.29%)
255
(14.70%)
Conclusion
Seasonal sampling and monitoring of NIS showed the similar phenomenon of abundance
of one or two species in all plates (Watersipora subtorquata and Hydroides elegans). This
result was observed in the study of Tamburini et al. (2021) in Italy. This could be related
to the ecology of species. SERC protocol seems like a good method for sampling NIS.
It’s rapid for early detection, quantitative and specific techniques.
Bibliography
JIMENEZ H., KEPPEL E., CHANG A.L., RUIZ G.M. (2018) - Invasions in marine communities:
contrasting species richness and community composition across habitats and salinity. Estuar.
Coasts., 41 (2): 484-494.
TAMBURINI M., KEPPEL E., MARCHINI A., REPETTO M.F., RUIZ G.M. et al. (2021) -
Monitoring Non-indigenous Species in Port Habitats: First Application of a Standardized
North American Protocol in the Mediterranean Sea. Front. Mar. Sci., 8: 700-730.
ULMAN A., FERRARIO J., FORCADA A., SEEBENS H., ARVANITIDIS C.,
OCCHIPINTI−AMBROGI A., et al. (2019) - Alien species spreading via biofouling on
recreational vessels in the Mediterranean Sea. J. Appl. Ecol., 56: 2620–2629.
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
110