Dyspanopeus sayi (Smith, 1869) is a marine crustacean decapod species. It was collected for the first time on mussel culture of Mytilus galloprovincialis from Mar the Piccolo of Taranto. A total of 14 specimens were recorded in September 2011 (11 individuals) and May 2012 (3 ovigerous females). The data suggest a slow spread of this invasive species northwards to the Central Mediterranean Sea, however it is necessary to maintain high vigilance in order to prevent its spread to the mussel-culture of the Mar Piccolo. The first reporting of Caprella scaura (Crustacea, Amphipoda) in the Mar Piccolo of Taranto was noticed on 2008. C. scaura was collected during one year, from January 2008 to December 2008, on seaweed beds and on the algal cover of rocky substrates, at depths of 0.5 m, using a square metal box (50 x 50 cm). The results suggest that the population had successfully established at this location, albeit with great density fluctuations. It is highly probable that C. scaura has been introduced, either from eastern Mediterranean or Indo-Pacific populations, by a combination of vectors including independent natural dispersal and attachment. During a visual survey in August 2018, several specimens of Malleus regula (Mollusca, Bivalvia) were noticed on the poles of mussel farms and rocky substrata at about 2 m depth in the first inlet of the Mar Piccolo. The absence of earlier records of this newcomer may be attributed to a very recent introduction or to the fact that it may have been overlooked until now.

Floristic list of seaweeds collected in 21 stations in the Mar Piccolo of Taranto in July 2001. In July 2001, sampling activities were carried out throughout the Mar Piccolo of Taranto, to evaluate the biodiversity in terms of phytobenthic species. Twenty-one stations were monitored, 11 in the First Inlet and 10 in the Second Inlet. A total of 45 taxa were recorded: 8 Chlorophyta, 5 Ochrophyta, 32 Rhodophyta. No Tracheophyta was recorded. 5 species were non-indigenous (NIS). Updating of the current species nomenclature was performed according to Algaebase (https://www.algaebase.org) and the original taxonomic binomial was reported

Floristic list of macrophytes (seaweeds and phanerogams) collected in the Mar Piccolo in the years 1987-1988. For each species the location in the basin, the month of collection and the phenology was reported. A qualitative study was performed in 1987-1988 to assess the composition in species of the macrophytobenthos of the Mar Piccolo of Taranto. Forty-eight stations were bi-monthly monitored, 20 in the First Inlet (10 in the Intertidal and 10 in the sublittoral) and 28 in the Second Inlet (16 in the Intertidal and 12 in the sublittoral). A total of 86 taxa were recorded: 24 Chlorophyta, 10 Ochrophyta, 51 Rhodophyta, 1 Tracheophyta. 4 species were non-indigenous (NIS). For the location of the stations see [Cecere E., Cormaci M., Furnari G. 1991. The marine algae of Mar Piccolo, Taranto (Southern-Italy): A re-assessment. Botanica Marina 34: 221-227]

Undaria pinnatifida was observed for the first time in the Mar Piccolo in April 1998, settled on the docks near the small fishing boat harbour. A systematic campaign of measurements was carried out from December 2000 to November 2002 and from December 2006 to November 2007 to follow the development of this non-indigenous species population

Biomass data (g fw m-2) of macrophytes collected in 5 stations in the Mar Piccolo in the period spring 2011-winter 2019. Presence of species is indicated by 0,01 value This data set includes biomass values of phytobenthic species, mainly seaweeds, recorded in the Mar Piccolo of Taranto in the years 2011-2019. Seasonal collection campaigns have been carried out in four stations and three replicates were collected for each station. Starting from 2016 a fifth station was analyzed (40°30'03.15"N; 17°18'30.99"E) . For station 1-4 location see (Petrocelli A., Cecere E., Rubino F. 2019. Successions of phytobenthos species in a Mediterranean transitional water system: the importance of long term observations. Nature Conservation 34: 217-246).

Biomass data (g fw m-2) of macrophytes collected in four stations in the Mar Piccolo in the period October 2007-September 2008. Presence of species is indicated by 0,01 value In the period October 2007-September 2008, a sampling campaign was carried out in the Mar Piccolo of Taranto, to assess the biodiversity of macrophyte populations. Four coastal stations were monthly monitored, two in the First Inlet (A 40°29'30.50"N 17°14'08.29"E) (B 40°30'03.86"N 17°15'20.52"E) and two in the Second Inlet (C 40°29'38.99"N 17°19'22.87"E) (D 40°28'22.17"N 17°18'35.79"E). A total of 79 taxa were recorded: 18 Chlorophyta, 5 Ochrophyta, 54 Rhodophyta, 2 Tracheophyta. 4 species were non-indigenous (NIS). The Tracheophyta Ruppia cirrhosa was recorded for the first time in the basin.

Long-term studies allow to evaluate all the significant changes which an ecosystem encounters with time. In this respect, the Mar Piccolo of Taranto represents a good example for the studies on the phytobenthos. Indeed: in the Twenties the first researches were carried out; up to the Seventies they were occasionally performed; in the Eighties they became continuous and are still ongoing as such. Therefore, the presence of historical series of data gives the chance of assessing both qualitative and quantitative modifications, which occurred against the phytobenthic communities of the basin. Irma Pierpaoli was the first phycologist in Taranto. She was a young teacher of Natural Sciences from Ancona, who taught in Taranto in a secondary school from 1920 to 1925, dabbling in picking seaweeds along the Mar Piccolo shore before going to school in the morning. Of this activity, she left two published papers and an herbarium. Up to the second half of the Eighties’, no phycological information are available on the Mar Piccolo. But, in 1986, the Phycological Laboratory was set up at the Istituto Talassografico, now CNR-IRSA, and the orderly study of the Mar Piccolo phytobenthos began from both a floristic and a vegetational point of view. Also the collection of quantitative data started. From 1987 up today several series of different data became available.

The introduction of non-indigenous species (NIS), also known as alien species, is a pressing issue throughout the world nowadays, mostly linked to globalization. Transitional environments are particularly exposed to this threat due to the importation of seafood for either aquaculture or sale. According to the most recent observations, the Mar Piccolo of Taranto hosts 36 NIS positively identified, divided in 13 invertebrates, 15 macroalgae, and 8 planktonic species. This basin ranks third among the Mediterranean hot spots for seaweed introduction, after the Thau Lagoon (southern France) and the Venice Lagoon. Continuous monitoring activities are carried out to early identify new introductions and follow the fate of those already introduced.

Biomass data (g fw m-2) of macrophytes collected in 20 stations in the Mar Piccolo in the period February 1989-January 1990. Presence of species is indicated by 0,01 value In the period February 1989-January 1990, a sampling campaign was carried out in the Mar Piccolo of Taranto, to assess the biodiversity of unattached macrophyte populations. A stratified random sampling was performed in 20 stations variously distributed in the First and the Second Inlet. A total of 54 taxa were recorded: 15 Chlorophyta (included the rhizophytic Caulerpa prolifera), 5 Ochrophyta, 32 Rhodophyta, and unidentified colonial Bacillariophyta and Cyanobacteria. 3 species were non-indigenous (NIS). Considering the biogeographic element 2 species were Indo Pacific (IP), 18 species were Atlantic (A), 4 species were Mediterranean (M), 21 species were Cosmopolite (C), 4 species were Circum Tropical (CT) For the location of the stations see [Cecere E., Saracino O.D., Fanelli M., Petrocelli A. 1992 - Presence of a drifting algal bed in the Mar Piccolo basin, Taranto (Ionian Sea, Southern Italy). Journal of Applied Phycology 4: 323-327]