Non-indigenous macrozoobenthic species on hard substrata of selected harbours in the Adriatic Sea

Abstract

The intense shipping traffic characterising the Adriatic Sea favours the spread of marine organisms. Yet, a study of 12 Adriatic ports (4 on the western side and 8 on the eastern side of the basin) found that non-indigenous species (NIS) accounted for only 4% of the benthic communities settled on hard substrates. The cirripeds Amphibalanus amphitrite and Balanus trigonus, found in 8 harbours, were the most common invaders followed by Amphibalanus eburneus, the ascidian Styela plicata, and the bivalve Magallana gigas. The highest percentage of NIS was recorded in Venice and Ploče, the harbours with the least rich native communities; the lowest percentage was retrieved in Trieste, Koper, Pula, and Rijeka, the harbours hosting the highest species diversity. In contrast, the ports of Bari and Ancona showed both high NIS percentages and highly diversified communities.

Rasprostranjenost nezavičajne vrste kamenice Magallana gigas(Thunberg, 1793) duž istočne obale Jadrana

“…Our study detected wild populations of M. gigas along the entire west coast of Istria, which is neighbouring area of the above mentioned regions and further extension of the Eastern Adriatic southwards. Confirming the previous study by SPAGNOLO et al (2019) which assessed non-native macrozoobenthic species in twelve ports throughout the entire Adriatic basin during 2014, our study did also not record any M. gigas specimens in the CE and SE Adriatic, except at one location that was not included in their study (i.e., Biograd na Moru). SPAGNOLO et al (2019) did not record the species neither in ports in Montenegro nor Albania.…”

“…Confirming the previous study by SPAGNOLO et al (2019) which assessed non-native macrozoobenthic species in twelve ports throughout the entire Adriatic basin during 2014, our study did also not record any M. gigas specimens in the CE and SE Adriatic, except at one location that was not included in their study (i.e., Biograd na Moru). SPAGNOLO et al (2019) did not record the species neither in ports in Montenegro nor Albania. However, the authors reported the presence of the species in all Italian and Slovenian ports surveyed, as well as in the Port of Pula in Croatia.…”

“…At all locations on the west coast of Istria (NE Adriatic), the species was ubiquitous and commonly formed very dense colonies (Fig 3). In No *Short description of substrata type: harbour structuresteep rock and/or concrete wall; natural rocky shorerocky shore with different stope (from gentle slope to steep rocks); aquaculture facilitieswooden pillars coastal region of Istria peninsula, the occurrence of M. gigas was previously reported in the Lim Bay, Medulin Bay, Port of Pula and Budava Bay (ŠEGVIĆ-BUBIĆ et al, 2016;ŠPELIĆ et al, 2018;SPAGNOLO et al 2019). Magallana gigas was also recorded in the National Park "Brijuni".…”

“…Then, PEČAREVIĆ et al (2013) provided a review on introduced marine species, including M. gigas, and suggested that anthropogenic activities might be the vector of the species introduction to the Eastern Adriatic Sea. In the last few years, M. gigas has become a focus of several studies dealing only with its occurance, mostly using molecular methods for species determination (ŠEGVIĆ-BUBIĆ et al, 2016;ŠPELIĆ et al, 2018;SPAGNOLO et al, 2019), but thorough assesment of the species distribution and establishemnt has not been conducted yet. The aim of this research was to summarize existing and novel data on the distribution of M. gigas in coastal areas of the Eastern Adriatic, and to ŠEGVIĆ-BUBIĆ et al 2016 provide a baseline for the future monitoring and assessment program of this species.…”

New Mediterranean Biodiversity Records (November 2018)

“…Numerous specimens of the species were also observed in the same area attached to hard substrata in the 2018 surveys (February, May, August). This is first finding from Montenegrin waters, although the species was expected (Karachle et al, 2017) since the species has been long established in the Adriatic Sea: Italy: (Heller, 1877); Croatia, Slovenia and Albania (Spagnolo et al, 2018).…”