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Reported checklist of marine macroalgae combined all available data for the Montenegro as a whole and open coastal waters without the Boka Kotorska Bay. Number of taxa reported here is 367, including 73 green algae (Chlorophyta), 77 brown algae (Heteroconthophyta) and 217 red algae (Rhodophyta). There is no doubt that additional surveys and analysis by algal taxonomist are needed in order to raise this number to the expected level and also to resolve some taxonomical issues. In the meanwhile we should not underestimate negative trends that are impacting marina algal assemblages, and first of all habitat destruction.

Lithophaga lithophaga is one of the commonest bivalves in the Mediterranean Sea and is present in almost every subtidal calcareous rock. Its reproductive cycle is known only from laboratory studies. Herein, we present data on the species reproductive activities based on localised but mass synchronized spawning events. The species reproduces at the end of the northern hemisphere summer and the majority of significant spawning events occur during the period between full moon and its last quarter. Calm seas are an important pre-requisite for the development of such co-ordinated mass spawning events. ‘Gamete to gamete’ induction seems to be the most likely proximate cue in synchronising gamete release. Spawning begins with a few individuals but spreads progressively along the coastline. In observed situations, reproductive waves finally affect between 10 and >400 m of coastline from 0 to 10 m depth and last longer than three days. In the reproductive zone, dense gamete clouds reduce visibility to zero over tens of metres along the shallow sea bed. No spawning events of such dimensions have been reported upon before for any bivalve.

One of the objectives of the BALMAS project was to conduct Port Baseline Biological Surveys of native and non-indigenous benthic flora in 12 Adriatic ports. Samples of macroalgae growing on vertical artificial substrates were collected in spring and autumn 2014 and/or 2015. A total number of 248 taxa, 152 Rhodophyta, 62 Chlorophyta, and 34 Ochrophyta, were identified. Of these, 13 were non-indigenous seaweeds, mainly filamentous macroalgae, that were probably introduced through hull fouling. Some of these taxa had already been described in the study areas, others were recorded for the first time, a few were no longer detected at sites where they had previously been recorded (e.g. Sargassum muticum). Some other NISS reported for the Adriatic Sea, were not collected at any sampling site (i.e. Caulerpa cylindracea, Codium fragile). Possible reasons for the absence of these species are discussed.

7 páginas, 6 figuras, 4 tablas., Littoral cartography is a valuable tool which uses shallow water macroalgal communities for monitoring ecosystem health and water quality. Cartography of littoral rocky-shore communities (CARLIT) is a European Union Water Framework Directive-compliant monitoring method widely used in the Western Mediterranean Sea. This non-destructive method is based on a visual observation of the type and length of coast occupied by rocky-shore communities in the upper-sublittoral zone. Here we present the first wide-scale application of CARLIT in the Adriatic Sea. The reference values calculated specifically for the Croatian coast (Eastern Adriatic Sea) ensure accurate calculation of the ecological status. The measured ecological quality ratio values (EQR) show a good linear relation with the Land Uses Simplified Index (LUSI) and appropriately reflect an increase in nutrient concentrations. The results suggest that this method can be used as a reliable biomonitoring tool in the Eastern Adriatic Sea. This study highlighted that Cystoseira forests thrive in 39% of the surveyed coastline and 23% of the coastline seems to be subjected to overgrazing by sea urchins. Our results provide a spatially accurate information on the abundance of different upper-sublittoral communities and the associated ecological status, which can be used in future management plans for improving water quality, This study has been supported by funds from the Croatian Water Agency and the project “Biodiversity of benthos in the changing environment of the middle Adriatic Sea” (Ministry of Science, Education and Sports of the Republic of Croatia, contract no. 001-0000000-3203).

Coralline red algae are significant components of sea bottom and up to now considered as exclusively marine species. Here we present the first coralline alga from a freshwater environment, found in the Cetina River (Adriatic Sea watershed). The alga is fully adapted to freshwater, as attested by reproductive structures, sporelings and an inability to survive brackish conditions. Morphological and molecular phylogenetic analyses reveal the species belongs to Pneophyllum and is described as P. cetinaensis sp. nov. The marine-freshwater transition most probably occurred during the last glaciation. The brackish-water ancestor was preadapted to osmotic stress and rapid changes in water salinity and temperature. The particular characteristics of the karst Cetina River, such as hard water enriched with dissolved calcium carbonate and a pH similar to the marine environment, favoured colonization of the river by a marine species. The upstream advance and dispersal is facilitated by exceptionally pronounced zoochory by freshwater gastropods. Pneophyllum cetinaensis defies the paradigm of Corallinales as an exclusively marine group.

Deep-water kelps are little-known large brown algae occurring close to the lower limit of photosynthetic life in the sea. This study compares historical and recent records of the deep-water Mediterranean kelp Laminaria rodriguezii in the Adriatic Sea. Historical records include data from herbarium collections and trawling fishery expeditions in the mid-twentieth century, while recent data comprise records of the last 17 years from MEDITS expeditions, ROV surveys of historical kelp locations, benthic surveys and records by fishermen. Altogether, these findings demonstrate that the Adriatic population of L. rodriguezii has suffered a decline of more than 85 % of its historical range and is now present only around the small offshore island of Palagruža. Bottom trawling activities are presumably responsible for the disappearance elsewhere. We propose to classify L. rodriguezii as “Endangered” in the Adriatic Sea under IUCN criteria B1ab(i,iii,iv), ver 3.1. Oceanographic characteristics of the habitat suggest that besides high water transparency, presence of North Adriatic Dense Water with both strong currents and stable low temperatures of around 14 °C are essential oceanographic factors for the development of L. rodriguezii in the Central Adriatic. The origin of cold water thus differs from that at upwelling sites permitting populations of tropical deep-water kelps. The phylogenetic position of L. rodriguezii is so far unknown. DNA sequences from nuclear and cytoplasmic markers of two thalli from Croatia and the western Mediterranean confirmed that L. rodriguezii is a member of the Laminariaceae and most closely related to L. ochroleuca, L. pallida and the Brazilian deep-water kelp L. abyssalis. Electronic supplementary material The online version of this article (doi:10.1007/s00227-016-2821-2) contains supplementary material, which is available to authorized users.

This study presents the first extensive investigation of echinoderm distribution in the area of mobile bottoms in the open part of the northern and middle Adriatic Sea. Five hundred and eighteen bottom trawl hauls were performed at 56 predetermined permanent stations along ten transects over different sediment types, at depths of 10 to 430 m. A total of 34 species of Echinodermata were identified (9 from the class Holothuroidea, 12 from the class Asteroidea, 4 from the class Ophiuroidea and 9 from the class Echinoidea). The list of the species, together with data on depth and sediment distribution, and the stations where individual species were found, are presented.

Changes of both macroalgal diversity and vegetational characteristics of the epiphytic macroalgal assemblage on Posidonia oceanica rhizomes of a meadow occurring at Marinkovac Island (central Adriatic Sea), following the invasion of Caulerpa racemosa var. cylindracea are reported. The study was based on the comparison between epiphytic macroalgae collected on rhizomes in an invaded and a reference P. oceanica meadow. Samples were collected in autumn 2002, during the annual maximum development of the C. racemosa var. cylindracea in order to assess its maximum impact. A significant reduction in both the number of epiphytic algal taxa and their cover was observed. A total of 71 epiphytic macroalgal taxa were found on the P. oceanica rhizomes within the reference area unaffected by C. racemosa var. cylindracea (Rhodophyta 55, Ochrophyta 5, Chlorophyta 11), compared with 20 taxa on rhizomes in the invaded area (Rhodophyta 18, Ochrophyta 1, Chlorophyta 1). The number of Rhodophyta, Ochrophyta and Chlorophyta were 3.1, 5 and 11 times lower, respectively, while the mean number of taxa per rhizome decreased by 6 times. The greatest decrease of the mean total percentage cover of macrolagal epiphytes (mRt%) in the invaded area was in Ochrophyta, ecological group D and calcareous encrusting algae, and was by 11.6, 17.4 and 13.3 times, respectively. The results give additional information on the extremely invasive behaviour of C. racemosa var. cylindracea in the Mediterranean Sea.

Background and purpose: Multiple studies have shown that Cystoseira species are sensitive to anthropogenic impact, and a decrease in their populations was observed, especially close to urban areas. To better understand status of such endangered and protected species, we studied the distribution of six rare Cystoseira species along the Montenegro coast: C. compressa subsp. pustulata, C. crinita, C. crinitophylla, C. sauvageauana, C. sqarrosa and C. tamariscifolia.Materials and methods: The study is based on field researches conducted through snorkelling and scuba diving along the Montenegrin coast during the period 1998-2009. In addition to the field work, we examined the published data for these species and the unpublished data from prof. Boris Antolić’s field diary.Results: Based on our 12-year-long investigations, we concluded that C. compressa subsp. pustulata, C. crinita, C. crinitophylla and C. sqarrosa are rare and endangered species along the Montenegro coast.Conclusions: The published data for C. sauvageauana is likely mistaken due to incomplete and poorly conserved algal material, while regarding the reference for C. tamariscifolia should be checked if the collected sample was preserved. Furthermore, we noted that the habitat destruction and the proliferation of sea urchin populations have the most dramatic negative impact on the biocenosis formed by such rare and endangered Cystoseira species.

A new geographic record of the oomycete Olpidiopsis feldmanni infecting the tetrasporophytic stage of the red alga Asparagopsis sp. from the Adriatic Sea, confirmed through morphological identification, allowed us to expand previous observations of this organism. Ultra- structural investigations of environmental material showed a large central vacuole and a cell wall thicker than previously reported from other basal oomycete pathogens of algae. Phylogenetic analysis closely associates O. feldmanni to O. bostrychiae concurrent with structural observations. This constitutes the first genetic characterisation of an Olpidiopsis species that was initially described before 1960, adding to the genetic data of 3 other marine Olpidiopsis species estab- lished and genetically characterised in the last 2 decades. The paper discusses concurrences of the ultrastructural observations made here and in previous studies of the marine Olpidiopsis species with those made on the freshwater species.

Three colonies of warm-water coral Astroides calycularis were found at the eastern part of the middle Adriatic Sea during the 1990–2001 period. For each specimen, depth distribution and habitat were recorded. Previous and recent knowledge of this species in the Adriatic Sea and in the Mediterranean Sea was discussed in relation to climatic changes. Occurrence of A. calycularis in the Adriatic Sea was related to the increased temperatures of the surface marine layer. Variable temperature conditions were connected to the climatic changes on the hemispheric scale through the North Atlantic Oscillation index. The prevailing sea current system together with the coastal configuration and bottom type favours the presence of the studied warm-water coral on the eastern Adriatic coast.

The tropical green alga Caulerpa taxifolia in the Mediterranean has spread steadily since its introduction in 1984. At the end of 2000, approximately 131 km2 of benthos had been colonized in 103 independent areas along 191 km of coastline in six countries (Spain, France, Monaco, Italy, Croatia and Tunisia). Large regions neighboring the invaded areas appear favorable to further colonization, and there is thus no reason to believe that spreading will slow down in the years to come.

In this paper we present a one-year investigation on the fluorescence characteristics of released products of selected Adriatic seaweeds. The technique chosen was UV-fluorescence spectroscopy with the synchronous mode, which involves the stepping of the excitation and emission monochromators. The five species, of representative macrophytes, Cystoseira compressa, Dictyopreris polypodioides, Gracilaria bursapastoris, Pterocladia capillacea, and Ulva rigida, were chosen on the basis of their dominance in the plant communities typical for the area near Split - Central Adriatic. Our results suggest that macroalgal-related dissolved fluorescent matter can be categorized into two distinct groups of fluorescing compounds with the following excitation wavelengths: one from 320–360 nm, probably for compounds with 2 fused aromatic rings, and another from 360–420 nm, corresponding with 3 & 4 fused rings. The contribution of aromatics with 2 and with 3 & 4 rings was very similar in the brown algae Cysroseira compressa and Dictyopteris polypodioides, while in the red algae Gracilaria bursapastoris and Pterocludia capillacea as well in the green alga Ulva rigida the group with 2 rings dominated.

Žuljevic A., Antolic B., Nikolic V., Despalatovic M. and Cvitkovic I. 2012. Absence of successful sexual reproduction of Caulerpa racemosa var. cylindracea in the Adriatic Sea. Phycologia 51: 283–286. DOI: 10.2216/11-22.1 Gamete formation and release in Caulerpa racemosa var. cylindracea from the Croatian part of the Adriatic Sea was followed in field and laboratory conditions. During the ten years of research only female gametes were observed. Gamete formation occurred when seawater temperature was above 20°C. Gametes had a distinct eyespot and were 9.3 ± 0.6 µm (mean ± SD, n = 140) long and 3.3 ± 0.3 µm (mean ± SD, n = 135) wide. In situ gamete release started 12–18 min before the sunrise. In Caulerpa, a typically monoecious genus, the production of only one gamete phase in the same thallus is a rare exception. Our observation also differs with previous research of C. racemosa var cylindracea reproduction in Greece where both gametes were found.

In the attempt to identify an appropriate molecular marker which will enable genetic distinction between different Cystoseira species from the Adriatic Sea, two mitochondrial molecular markers were tested: the mt 23S rDNA and the mt23S-tRNAVal spacer. Two species were studied: Cystoseira spinosa and Cystoseira squarrosa. Sequence analyses showed no variation in the mt 23S rDNA among all individuals analyzed. But the analysis of the mt23S-tRNAVal spacer showed a differentiation between three haplotypes named A, B and C. The most abundant haplotype A was found in equal number in both species, while haplotype B was found only in C. spinosa and haplotype C was found only in C. squarrosa. However, when comparing to sequences available for several selected Mediterranean Cystoseira species, the mt23S-tRNAVal spacer failed to discriminate between species. Although these results indicate a limited use of the mitochondrial mt23S-tRNAVal intergenic spacer for discrimination among Adriatic Cystoseira species, they could also be interpreted as a sign of conspecificity of the investigated species or the reflection of a recent radiation. Further analysis will be necessary to improve molecular identification of these brown algae., U cilju odabira odgovarajućeg molekularnog biljega koji bi omogućio genetičko razlikovanje među različitim vrstama roda Cystoseira u Jadranskom moru, analizirana su DVA molekularna biljega: mitohondrijska 23S rDNA i mitohondrijska razmaknica (mt23S-tRNAVal). U istraživanju su bile korištene dvije vrste Cystoseira spinosa i Cystoseira squarrosa. Sekvenciranje i usporedba tih fragmenata pokazali su da je regija mt23S rDNA viskoko konzervirana, jer u svih analiziranih jedinki te sekvence nisu pokazivale varijablinost. U strukturi mitohondrijske razmaknice (mt23StRNAVal) uočene su dvije mutacije i tri haplotipa; A, B i C. Dok je haplotip B nađen samo u vrste C. spinosa, a haplotip C u vrste C. squarrosa, najdominatniji haplotip A nađen je kod podjednakog broja jedinki obiju vrsta. U usporedbi s nekoliko odabranih vrsta roda Cystoseira, podrijetlom iz drugih dijelova Mediteranskog mora, taj molekularni biljeg mt23S-tRNAVal ipak nije pokazao vrsnu specifičnost. Iako ti preliminarni rezultati pokazuju ograničenu mogućnost mitohondrijske razmaknice (mt23S-tRNAVal) za razlikovanje među jadranskim vrstama roda Cystoseira, oni mogu ukazivati i na konspecifičnost istraživanih vrsta odnosno odražavati njihovu relativno nedavnu divergenciju. Daljnja istraživanja će biti potrebna kako bi se poboljšala molekularna identifikacija vrsta ovih smeđih alga.

Here we present the first observation of 11 the impact of the invasive Caulerpa racemosa var. cylindracea on native photophilic sponge species in the Adriatic Sea, with special focus on Sarcotragus spinosulus. Caulerpa racemosa var. cylindracea is able to completely overgrow the sponge, developing an exceptionally thick canopy with a maximum measured density of 1, 887 m of stolons m-2 and 40, 561 fronds m-2. Necrosis of the sponge surface was significantly correlated with the algal dry biomass, frond number and stolon length. Dense algal canopy, penetration of the algal stolon and rhizoids into the sponge oscula and covering of the ostiae probably diminishes the seawater circulation through the sponge and consequently results in its smothering and even death. We suggest that chemotropism is the reason why C. racemosa penetrates the sponge oscula and establishes such dense canopy on the sponge.

The first part of the checklist of red algae (Rhodophyta: Ceramiales) from the eastern Adriatic coast, based on records published from 1948 to 2009, is presented. For geographic analysis the coast is divided into three parts: northern, central, and southern. A total of 187 macroalgal taxa at specific and infraspecific levels are recognized., U ovom radu se iznosi popis svojti morskih bentoskih makroalgi iz jednog dijela sistematskog odjeljka crvenih alga (Rhodophyta: Ceramiales) koji se temelji na podacima objavljenim između 1948. i 2009. godine. Zemljopisno je istočna obala Jadranskog mora podijeljena na tri dijela: sjeverni, srednji i južni. Ukupno je navedeno 187 vrsta i nižih taksonomskih kategorija crvenih algi. Najviše ih je zabilježeno u sjevernom (163), manje u srednjem (142), a najmanje (107) u južnom dijelu Jadranu.

Womersleyella setacea (Hollenberg) R.E. Norris (Rhodophyta, Ceramiales) is an invasive macrophyte in the Mediterranean Sea, first recorded from the coast of Italy in 1986. This is a review of the geographic distribution and depth limits of W. setacea invasion in the Adriatic Sea since its first record in 1997. Algal turfs were collected and examined from different locations in the Croatian part of the Adriatic Sea from 2005 to 2009 by SCUBA diving and grab sampling. A total of 50 sites invaded by W. setacea were recorded in the Adriatic Sea; 40 new sites in this research and 10 from the literature records. Womersleyella setacea was recorded from 7 to 72 meters depth. Only sterile specimens without any reproductive structures were found. The magnitude of the invasion is discussed., Womersleyella setacea (Hollenberg) R.E. Norris (Rhodophyta, Ceramiales) je invazivna crvena alga, koja je u Sredozemnom moru prvi put zabilježena u Italiji 1986. godine. U ovom radu prikazana je geografska i dubinska rasprostranjenost ove invazivne vrste u Jadranskom moru od prvog nalaza na području sjevernog Jadrana 1997. godine. Uzorci zajednica alga su sakupljeni na različitim postajama u hrvatskom dijelu Jadranskog mora u razdoblju od 2005. do 2009. godine autonomnim ronjenjem i grabilom. Ukupno je zabilježeno 50 lokaliteta s vrstom W. setacea, 40 tijekom ovog istraživanja i 10 iz literaturnih podataka. Womersleyella setacea je pronađena na dubinama od 7 do 72 metra. Zabilježeni su samo sterilni primjerci bez prisutnih reproduktivnih struktura. U radu se raspravlja o razmjerima invazije.

A checklist of brown algae (Heterokontophyta: Phaeophyceae) from the eastern Adriatic coast, based on records published from 1948 to 1997, is presented. For geographic analysis the coast is divided into three parts: northern, middle, and southern. A total of 180 macroalgal taxa at specific and infraspecific levels are recognized, in which 12 new combinations are proposed., U ovom radu iznosimo popis svojti morskih bentoskih makroalgi iz odjeljka smeđih alga (Heterokontophytata: Phaeophyceae) koji se temelji na podacima objavljenim između 1948. i 1997. godine. Zemljopisno smo istočnu obalu Jadranskog mora podijelili na tri dijela: sjeverni, srednji i južni. Navedeno je ukupno 180 vrsta i nižih taksonomskih kategorija smeđih algi među kojima je predloženo 12 novih sistematskih kombinacija. Najviše ih je zabilježeno u srednjem (153), manju u srednjem (129), a najmanje u južnom (75) Jadranu.

The sand star Astropecten irregularis (Pennant, 1777) is a very common species in the Adriatic Sea. This study establishes the distribution, biomass and abundance of that species on the continental shelf of the open waters in the northern and middle Adriatic Sea based on experimental sampling by bottom trawl during 11 cruises of the “Pipeta” Expedition (1985-1994). Five hundred and eighteen bottom trawl hauls were performed at 56 predetermined permanent stations along ten transects, over different sediment types at depths of 10 to 430 m. Astropecten irregularis was recorded in 82.2% of the hauls, with the highest biomass and abundance indices at depths from 10 to 50 m. The deepest record was in a haul from 313.5 to 412.5 m depth. Even though it was recorded all over the investigated area, it was most abundant in some areas of the northernmost part of the Adriatic, and very abundant in the areas along the western coast. The highest average biomass and abundance indices were recorded on sand-silt-clay sediment, on silty sand and sandy silt and on the clayey silt and silty clay., Morska zvijezda Astropecten irregularis (Pennant, 1777) je uobičajena vrsta u Jadranskom moru. Glavni ciljevi ovog istraživanja su bili ustanoviti njezinu distribuciju, biomasu i abundanciju na kontinentskoj podini otvorenih voda sjevernog i srednjeg Jadrana na osnovi eksperimentalnog uzorkovanja pridnenom kočom za vrijeme 11 putovanja ekspedicije Pipeta (1985.-1994.). Obavljeno je 518 potega pridnenom kočom na 56 unaprijed određenih stalnih postaja uzduž deset transekata, na različitim tipovima sedimenta na dubinama od 10 do 430 m. Vrsta A. irregularis je zabilježena u 82,2% potega, s najvećim vrijednostima indeksa biomase i abundancije na dubinama od 10 do 50 m. Najdublje je zabilježena tijekom potega od 313,5 do 412,5 m. Iako je vrsta zabilježena na cijelom istraživanom području, najabundantnija je bila na nekim područjima najsjevernijeg dijela Jadrana, te vrlo abundantna na područjima uzduž zapadne obale. Najveće srednje vrijednosti indeksa biomase i abundancije su zabilježene na pijesku-siltu-glini, siltoznom pijesku i pjeskovitom siltu te na glinovitom siltu i siltoznoj glini.

The reproductive cycle of a local population the aspidochirote Holothuria tubulosa in Kaštela Bay (Adriatic Sea) was analysed from July 1994 to August 1995 by histological examination and observations of macroscopic features of the gonads. Five gonadal stages were described: recovery stage, growing stage, mature stage, spawning stage, and post-spawning stage. The distinguishing features used to describe gonad stages in both sexes included the main features of reproductive cells and gonad wall. The reproductive cycle showed a clear annual pattern and was synchronous in both sexes. Spawning occurred during the warm season, from July to September, when the surface water temperature ranged from about 22°C to 26°C. From October to January individuals were in resting phase and had no gonads. In both sexes, variations in maturity indices were related to the seasonal changes in temperature.

Fifteen years after the first report of the presence of the tropical green alga Caulerpa taxifolia (Chlorophyta) in the Medi-terranean Sea off the shores of Monaco, this alga is now present in the waters of five Mediterranean countries. This rapid, broad dissemination is believed to have occurred solely by thallus fragmentation, because sexual reproduction, common in tropical Caulerpa species, has not been demonstrated in Mediterranean C. taxifolia. Here, we report field observations of the synchronous formation and release of male gametes by the Mediterranean strain of C. taxifolia. As in related species living in tropical regions, gamete release was synchronized by light intensity. Despite the prolific release of male gametes, sexual reproduction apparently does not occur, because female gametes are absent.

Fourteen years after the first observation of Caulerpa taxifolia (Valh) C. Agardh in the northwestern Mediterranean Sea, this green alga of tropical origin is now present in five countries (Spain, France, Monaco, Italy and Croatia). By the end of 1997, more than 46 km(2), at depths of between 0 and 50 m, were found to be affected by this expansion. A standardization of the cartographic procedure is proposed here. Such a standardization is necessary to compare maps produced by various organizations from different countries. For a given independent station, it is based on the definition of three levels of colonization:Level I refers to a station where one or several colonies less than 100 m apart cover a total surface area inferior to 1000 m(2):Level II refers to a station where several colonies less than 250 m apart totally cover more than 1000 m(2) with fragments and small colonies dispersed over a surface area inferior to 10 ha;Level III is attained when several large colonies are dispersed over a surface area superior to 10 ha, with a total covered surface of more than 1000 m(2), impossible to map with precision due to its size.For each of these colonization levels, descriptive parameters can be used to precisely describe the situation: covered surface area, dispersion surface (i.e. "affected" zone), estimation of very large affected zones (i.e. "concerned" zones) and the portions of the coastline along which an affected or concerned zone can be found., Quatorze années après la première observation de Caulerpa taxifolia en Méditerranée nord-occidentale, cette algue d'origine tropicale est présente dans cinq pays (Espagne, France, Monaco, Italie et Croatie). À la fin de l'année 1997, plus de 46 km2 de fonds, situés essentiellement entre 0 et 50 m de profondeur, sont concernés à divers degrés par cette invasion. Une standardisation de la représentation cartographique est proposée. L'objectif de cette normalisation est de pouvoir comparer les cartes produites par divers organismes appartenant à plusieurs pays. Elle est basée sur la définition, pour une station donnée, de trois niveaux de colonisation : ¿ - Le niveau I correspond à une station où se développent une ou plusieurs colonies (réparties à moins de 100 m les unes des autres) et couvrant au total une surface inférieure à 1000 m2 ; ¿ - Le niveau II correspond à une station où de nombreuses colonies (réparties à moins de 250 m les unes des autres) couvrent au total plus de 1000 m2 et sont dispersées dans une surface inférieure à 10 ha ; ¿ - Le niveau III correspond à une station où les colonies sont disséminées dans une zone supérieure à 10 ha et pour lesquelles la surface totale couverte (très supérieure à 1000 m2) n'est plus cartographiable avec précision. Pour chaque niveau un ensemble de paramètres descriptifs permet de préciser la situation : surface totale couverte, surface atteinte, estimation des larges surfaces atteintes (ou surface concernée), linéaire de côte devant lequel on trouve des surfaces atteintes ou concernées.

The alga Caulerpa racemosa was found the first time in the Adriatic Sea in autumn 2000 offshore of Marinkovac Islet, located on the west side of Hvar Island (Middle Adriatic). The colonized area is oligotrophic, not affected by human activities and is exposed to strong waves. Caulerpa racemosa had formed 15 rounded colonies from 1 to 6 m in diameter, and from 5 and 15 m depth on sandy and rocky substrate.

A check list of the marine benthic flora of Kornati National Park (Kornati Archipelago, Middle Adriatic) was compiled on the basis of long-term personal collections and sparse bibliographical data. The list includes 352 specific and infraspecific taxa of algae (225 Rhodophyta, 75 Phaeophyta, 52 Chlorophyta) and 3 species of seagrasses, of which 255 are reported from the archipelago for the first time. The R/P ratio of 3 indicates a sub¬tropical flora . The flora is analyzed in terms of its phytogeographical components.

The specimens of Melibe fimbriata were found during October 2001 in Stari Grad Bay (Island of Hvar, Croatia) in Cymodocea nodosa and Posidonia oceanica beds on sandy and sandy–muddy bottoms at depths of 2 to 15 m. Presently, this is the northernmost record of this lessepsian immigrant in the Mediterranean basin.

UV-fluorescence spectrophotometry was used to investigate dissolved fluorescent matter in coastal seawater samples from Split. Conventional and synchronous scanning modes were employed. Concentrations of dissolved fluorescent matter were estimated using calibration curves constructed from known concentrations of quinine in sulphuric acid and additionally of Suwannee River fulvic acid in Copenhague standard seawater. The results obtained during a one-year survey showed a low variability except during a phytoplankton bloom, when values were much higher. In that period the presence of aromatic systems with 3 and 4, 5 and probably 7 fused rings was also detected by a synchronous technique. The fluorescence method using calibration curves of standard solutions of quinine in sulphuric acid and SuwanneeRiver fulvic acid in standard seawater allowed rapid and sensitive assessment of these substances in seawater.

The summer aspect of seaweed communities of the island of Lokrum and the opposite Dubrovnik coastline was studied by the technique of free diving. Algal specimens were collected in August—September 1960 and 1961, May 1962, and in July 1974 and 1979, along many vertical and horizontal profiles within the upper, middle, and lower infralittoral zones. Among the specimens collected 234 taxa of Thallophyta and 1 species of Angiospermae were determined, belonging to the following phylla: Rhodophyta 157 taxa, Phaeophyta 38 taxa, and Chlorophyta 39 taxa. On the ground of its geographic location, its vicinity to the coast, and the strong influence of the open sea, Lokrum seems to display transitional characteristics between the southern coastal facies and the facies of the open sea., Ljetni aspekt zajednica bentoskih algi otoka Lokruma i nasuprotnog dubrovačkog primorja ispitivan je tehnikom slobodnog ronjenja. Alge su skupljane od kolovoza do rujna 1960. i 1961. godine, u svibnju 1962. godine i u srpnju 1974. i 1979. godine, uz veći broj vertikalnih i horizontalnih profila unutar gornjeg, srednjeg i donjeg infralitorala. Među skupljenim uzorcima određena je 1 vrsta angiosperma i 234 vrsta talofita, i to Rhodophyta 157 vrsta, Phaeophyta 38 vrsta i Chlorophyta 39 vrsta. Svojim geografskim položajem, blizinom kopna, a unatoč tome pod jakim utjecajem otvorena mora, Lokrum svojom bentoskom florom pokazuje prijelazni oblik ozmeđu južnog priobalnog facijesa i facijesa otvorenog mora.