Results and discussion
The main morphological and anatomic characteristics of the specimens collected in this study
were comparable to the existing data on S. schimperi (Verlaque & Boudouresque, 1991;
Verlaque et al., 2015). Additionally, the specimens obtained were large (several specimens up
to 40 cm) and approximately twice the size of those recorded previously. The sequences of the
Adriatic specimens showed high similarity (96.65% rbcL, 99.78% psbA and 99.7% psaA) to
the S. schimperi sequences obtained from GenBank. Stypopodium schimperi was observed on
a rocky bottom, primarily between 5 m and 15 m, whereas non-attached thalli were detected at
35 m. The number of thalli increased from a total of 20 in five transects in 2020 to several
thousand in 2021. Regarding the reproductive organs, only sporophytes with tetrasporangia
were recorded. Further sampling and examination are required to verify the development of a
gametophyte. In more than 50% of the photoquadrats, S. schimperi covered >75% of the
photoquadrat surface, with an average coverage of approximately 70% in the 100 m transect.
Coverage of 100% results in the entire displacement of native erect algal species. Other algal
species with significant coverage in the area were Dictyota spp., Taonia spp., Padina pavonica
and Halopteris scoparia, whereas those with negligible coverage were Caulerpa cylindracea,
Acetabularia acetabulum, Laurencia spp. and Amphiroa rigida. This study demonstrated a
distinct shift from native infralittoral erect algae to the dominance of S. schimperi. Based on the
recorded spreading dynamics, we believe further expansion of this species will occur. The
population of S. schimperi examined herein represents the northernmost record for the
Mediterranean Sea, and the results suggest a high potential for further dispersion within the
Adriatic Sea. Additionally, due to the sea temperature similarity and its presence in the Central
Mediterranean (Shakman et al. 2019), S. schimperi may also spread to the northwestern
Mediterranean.
Acknowledgments
We are thankful to Dr. M. Mucko for the help with phylogenetic analysis. This work was
supported by the Croatian Science Foundation under the project HRZZ-IP -2019-04-6702 and
project HIDROLAB, funded by the European Union through the European Structural and
Investment Funds 2014-2020 under contract number KK.01.1.1.04.0053.
Bibliography
BIANCHI C.N., PRONZATO R., CATTANEO-VIETTI R., BENEDETTI-CECCHI L., MORRI,
C. et. al. (2004) - Chapter 6: Hard bottoms. P. 185–215. In: Mediterranean marine benthos: A
manual of methods for its sampling and study, Vol. 11 (Suppl. 1). Gambi, M. C., Dappiano,
M. (Eds.). Biologia Marina. Mediterranea, Genova.
BITAR G., RAMOS-ESPLA A.A., OCAÑA O., SGHAIER Y.R., FORCADA A., VALLE C.,
EL SHAER H., VERLAQUE M. (2017) - The introduced marine macroflora of Lebanon and
its distribution on the Levantine coast. Mediterr. Mar. Sci. 18 (1): 138-155.
BOUDOURESQUE C. F., VERLAQUE M. (2002) - Biological pollution in the Mediterranean
Sea: invasive versus introduced macrophytes. Mar. Pollut. Bull. 44 (1): 32-38.
SHAKMAN E., ETEAYB K., TABONI I., ABDALHA, A. B. (2019) - Status of marine alien
species along the Libyan coast. J. Black Sea/Mediterranean Environment, 25 (2): 188-209.
VERLAQUE M., BOUDOURESQUE C. F. (1991) - Stypopodium schimperi (Buchinger ex
Kützing) Verlaque et Boudouresque comb. nov. (Dictyotales, Fucophyceae), algue de mer
Rouge récemment apparue en Méditerranée. Cryptogam. Algol., 12 (3): 195-211.
VERLAQUE M., RUITTON S., MINEUR F., BOUDOURESQUE C. F. (2015) - CIESM Atlas
of Exotic Species in the Mediterranean. Vol. 4 Macrophytes: 364 pp.
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
104
The main morphological and anatomic characteristics of the specimens collected in this study
were comparable to the existing data on S. schimperi (Verlaque & Boudouresque, 1991;
Verlaque et al., 2015). Additionally, the specimens obtained were large (several specimens up
to 40 cm) and approximately twice the size of those recorded previously. The sequences of the
Adriatic specimens showed high similarity (96.65% rbcL, 99.78% psbA and 99.7% psaA) to
the S. schimperi sequences obtained from GenBank. Stypopodium schimperi was observed on
a rocky bottom, primarily between 5 m and 15 m, whereas non-attached thalli were detected at
35 m. The number of thalli increased from a total of 20 in five transects in 2020 to several
thousand in 2021. Regarding the reproductive organs, only sporophytes with tetrasporangia
were recorded. Further sampling and examination are required to verify the development of a
gametophyte. In more than 50% of the photoquadrats, S. schimperi covered >75% of the
photoquadrat surface, with an average coverage of approximately 70% in the 100 m transect.
Coverage of 100% results in the entire displacement of native erect algal species. Other algal
species with significant coverage in the area were Dictyota spp., Taonia spp., Padina pavonica
and Halopteris scoparia, whereas those with negligible coverage were Caulerpa cylindracea,
Acetabularia acetabulum, Laurencia spp. and Amphiroa rigida. This study demonstrated a
distinct shift from native infralittoral erect algae to the dominance of S. schimperi. Based on the
recorded spreading dynamics, we believe further expansion of this species will occur. The
population of S. schimperi examined herein represents the northernmost record for the
Mediterranean Sea, and the results suggest a high potential for further dispersion within the
Adriatic Sea. Additionally, due to the sea temperature similarity and its presence in the Central
Mediterranean (Shakman et al. 2019), S. schimperi may also spread to the northwestern
Mediterranean.
Acknowledgments
We are thankful to Dr. M. Mucko for the help with phylogenetic analysis. This work was
supported by the Croatian Science Foundation under the project HRZZ-IP -2019-04-6702 and
project HIDROLAB, funded by the European Union through the European Structural and
Investment Funds 2014-2020 under contract number KK.01.1.1.04.0053.
Bibliography
BIANCHI C.N., PRONZATO R., CATTANEO-VIETTI R., BENEDETTI-CECCHI L., MORRI,
C. et. al. (2004) - Chapter 6: Hard bottoms. P. 185–215. In: Mediterranean marine benthos: A
manual of methods for its sampling and study, Vol. 11 (Suppl. 1). Gambi, M. C., Dappiano,
M. (Eds.). Biologia Marina. Mediterranea, Genova.
BITAR G., RAMOS-ESPLA A.A., OCAÑA O., SGHAIER Y.R., FORCADA A., VALLE C.,
EL SHAER H., VERLAQUE M. (2017) - The introduced marine macroflora of Lebanon and
its distribution on the Levantine coast. Mediterr. Mar. Sci. 18 (1): 138-155.
BOUDOURESQUE C. F., VERLAQUE M. (2002) - Biological pollution in the Mediterranean
Sea: invasive versus introduced macrophytes. Mar. Pollut. Bull. 44 (1): 32-38.
SHAKMAN E., ETEAYB K., TABONI I., ABDALHA, A. B. (2019) - Status of marine alien
species along the Libyan coast. J. Black Sea/Mediterranean Environment, 25 (2): 188-209.
VERLAQUE M., BOUDOURESQUE C. F. (1991) - Stypopodium schimperi (Buchinger ex
Kützing) Verlaque et Boudouresque comb. nov. (Dictyotales, Fucophyceae), algue de mer
Rouge récemment apparue en Méditerranée. Cryptogam. Algol., 12 (3): 195-211.
VERLAQUE M., RUITTON S., MINEUR F., BOUDOURESQUE C. F. (2015) - CIESM Atlas
of Exotic Species in the Mediterranean. Vol. 4 Macrophytes: 364 pp.
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
104