14 research outputs found
Das Potential von Tauchklubs bei der Verringerung von Abfall im Meer, der jetzige Zustand und die Perspektive in Kroatien
Morski otpad je veliki globalni ekoloÅ”ki problem danaÅ”njice uglavnom kao posljedica sve veÄe upotrebe plastike i neodgovarajuÄeg gospodarenja otpadom na kopnu. Prilikom dospijevanja u more veÄina otpada potone na dno u priobalnim podruÄjima gdje se može godinama nakupljati. Otpad s morskog dna u plitkom priobalju može se jednostavno uklanjati organiziranjem ronilaÄkih ekoloÅ”kih akcija. RonilaÄki klubovi imaju veliki potencijal u takvim akcijama Äime se mogu ukloniti znaÄajne koliÄine otpada, meÄutim one se provode bez usklaÄene metodologije i koordinacije. Na taj naÄin ostaju nam nepoznati podaci o podruÄjima, koliÄinama i sastavu prikupljenog otpada, koji inaÄe imaju važnost za razvoj strategija za smanjivanje morskog otpada. Razvoj uÄinkovitih mjera za smanjivanje morskog otpada nužan za oÄuvanje bioloÅ”ke i gospodarske kvalitete morskog i priobalnog okoliÅ”a. U ovom je radu predstavljen potencijal ronilaÄkih akcija ÄiÅ”Äenja plitkog podmorja u smanjivanju koliÄina morskog otpada u Hrvatskoj. Posebno je istaknuta potreba za suradnjom ronilaÄkih klubova i znanstvenih institucija u cilju dobivanja Å”to kvalitetnijih podataka o prikupljenom morskom otpadu, te važnosti provoÄenja usklaÄenog naÄina prikupljanja podataka Äime se može znaÄajno doprinijeti razvijanju spoznaja o sadaÅ”njoj situaciji i trendovima te donoÅ”enju odgovarajuÄih preporuka i zakonodavnih mjera zaÅ”tite. Ukoliko se ova inicijativa bude sustavno organizirala i provodila mogla bi djelovati kao znaÄajan program i mjera za smanjivanje koliÄina morskog otpada.Marine waste is a huge environmental problem in the world today, mostly as a consequence of a growing use of plastics and inadequate waste management on the land. When it reaches the sea, most waste sinks to the bottom of coastal areas where it may accumulate for years. Waste from the sea bottom in shallow coastal waters can be easily removed by organising diving environmental activities. Diving clubs have a great potential in such activities to remove significant waste quantities. However, these activities cannot be carried out without a harmonised methodology and coordination, in which case we remain without data on the areas, quantities and compostion of the collected waste that play a significant role in the development of marine waste reduction strategies. A development of efficient measures for marine waste reduction is necessary for preserving biological and economic quality of marine and coastal environments. The paper presents a potential of diving activities in the cleanup of shallow coastal waters and reduction of marine waste quantities in Croatia. A need for cooperation between diving clubs and scientific institutions is particularly emphasized as a manner to obtain high quality data on the collected marine waste, and the importance of a harmonised manner of data collection that could significantly contribute to new insights into the current situation and trends, including adoption of adequate recommendations and legal protection measures. If this initiative is systemically organised and implemented, it could act as an importan programme and a meaasure for reducing the quantity of marine waste.Abfall im Meer ist ein groĆes globales ƶkologisches Problem der Gegenwart, der grƶĆtenteils als Auswirkung der immer grƶĆeren Nutzung von Kunststoffen und einer unangemessenen MĆ¼llentsorgung auf dem Land entstanden ist. Beim Gelangen des Abfalls ins Meer sinkt es auf den Grund an der KĆ¼ste, wo es sich jahrelang ansammelt. Der Abfall vom Meeresgrund kann an seichten KĆ¼sten mithilfe von organisierten ƶkologischen Tauchaktionen einfach entfernt werden. Tauchklubs haben ein groĆes Potential bei solchen Aktionen, bei denen bedeutende Mengen von Abfall entfernt werden kƶnnen, doch sie werden ohne abgestimmte Methodologie und Koordination durchgefĆ¼hrt. So bleiben uns Informationen/Daten Ć¼ber Gebiete, Mengen und Zusammensetzungen des gesammelten Abfalls unbekannt, die eigentlich wichtig zur Entwicklung von Strategien zur Verminderung von Abfall im Meer sind. Die Entwicklung wirksamer Methoden zur Verminderung von Abfall im Meer ist notwendig fĆ¼r den Schutz der biologischen und wirtschaftlichen QualitƤt der Umwelt im Meer und an der KĆ¼ste. In dieser Arbeit ist das Potential von Tauchaktionen zur SƤuberung der seichten Unterwassergebiete bei der Minderung der QuantitƤt von Abfall im Meer in Kroatien vorgestellt. Besonders hervorgehoben ist die Notwendigkeit der Zusammenarbeit zwischen Tauchklubs und wissenschaftlichen Institutionen, mit dem Ziel umso hochwertiger Daten Ć¼ber den gesammelten Abfall zu erhalten sowie die Wichtigkeit einer angepassten Art der Datensammlung. Dabei kƶnnen bedeutende Erkentnisse Ć¼ber die heutige Situation und Trends erhalten werden sowie die entsprechenden Empfehlungen und rechtlichen Schutzmittel erlassen werden. Falls diese Initiative systematisch organisiert und durchgefĆ¼hrt wird, kƶnnte sie als bedeutsames Programm und Mitter zur Verminderung von Abfall am Meeresgrund wirken
Kljunasta konÄarica Nemichthys scolopaceus Richardson, 1848 (Pisces: Nemichthydae), novi pripadnik ihtiofaune Jadranskog mora
The paper reports the first record of Nemichthys scolopaceus leptocephalus in the Adriatic Sea,
including a detailed description of the specimen with morphometric measurements and meristic
counts. A single leptocephalus specimen was caught on 18th September 2016 in south Adriatic with
a small mid-water trawl at a depth of approx. 120 meters. Further research is needed to reveal more
information about the distribution and potential spawning and nursery areas of slender snipe eel as
well as the mechanism of retention and dispersion of their larvae in the Adriatic.U radu je prikazan prvi nalaz vrste kljunasta konÄarica Nemichthys scolopaceus, ulovljen 18.
rujna 2016. godine u južnom Jadranu pelagiÄkom koÄom na dubini od cca. 120 metara. Nalaz se
odnosi na liÄinku leptocefala te ukljuÄuje detaljan opis jedinke s morfometrijskim i meristiÄkim oso-
binama. Svakako su potrebna daljnja istraživanja kako bi se otkrilo viŔe o rasprostranjenosti i poten-
cijalnim podruÄjima mrijesta i hraniliÅ”tima ove vrste, kao i o mehanizmu rasprÅ”ivanja i zadržavanja
njihovih liÄinki u Jadranu
El gallano, Labrus mixtus (Pisces: Labridae): Ćndices biolĆ³gicos para documentar la historia vital de la especie y contribuir a su conservaciĆ³n
The cuckoo wrasse, Labrus mixtus, is widely distributed in the moderate warm waters of the Atlantic Ocean, including the Mediterranean and Adriatic Seas. Generally, labrids are small inshore coastal species susceptible to anthropogenic habitat degradation and, although without commercial importance, they make up a significant part of the by-catch and discard. Also, these fishes are intensively caught in recreational and subsistence fisheries. Basic biological information is required for their stock assessment and conservation. Studies of the age, growth, reproduction and feeding of L. mixtus have not been undertaken previously in the Adriatic Sea. The observed maximum age of the cuckoo wrasse was 10 years, although most of the sampled fish were 7 years old. The estimated parameters of the von Bertalanffy growth model suggested that the growth of L. mixtus was relatively fast in the first four years of life. L. mixtus is a protogynous hermaphrodite and sex change occurred at 26 cm, while the greatest increase in gonadosomatic index in April confirmed spring as the spawning period. The cuckoo wrasse is an opportunistic predator, feeding primarily on crustaceans, gastropods and fishes. The information provided on biological indices is necessary for life history pathways and future conservation measures of this population in the Adriatic Sea.El gallano, Labrus mixtus, se halla ampliamente distribuido en las zonas templadas del OcĆ©ano AtlĆ”ntico, incluyendo el MediterrĆ”neo y el Mar Negro. En general, los lĆ”bridos son especies de pequeƱo tamaƱo que habitan en aguas costeras, siendo vulnerables a la degradaciĆ³n antrĆ³pica del hĆ”bitat y, a pesar de ser comercialmente poco importantes, forman una parte importante de los descartes de la pesca profesional. Estos peces tambiĆ©n son intensamente capturados por la pesca recreativa o de subsistencia. Se requiere, pues, una informaciĆ³n biolĆ³gica bĆ”sica para conocer el estado de los stocks y asegurar su conservaciĆ³n. Los estudios sobre la edad, el crecimiento, la reproducciĆ³n y la alimentaciĆ³n de L. mixtus no se han realizado hasta ahora en el AdriĆ”tico. La edad mĆ”xima observada en esta especie ha sido de 10 aƱos, si bien la mayorĆa de los peces capturados se situaba en los 7 aƱos. Los parĆ”metros estimados a partir de la ecuaciĆ³n de crecimiento de Von Bertalanffy sugieren que el crecimiento de L. mixtus es rĆ”pido durante los primeros aƱos de vida. L. mixtus es una especie hermafrodita proterogĆnica y el cambio de sexo se produce a los 26 cm de longitud, mientras que el gran incremento del Ćndice gonadosomĆ”tico en el mes de abril confirma que el periodo de reproducciĆ³n se produce durante la primavera. El gallano es un depredador oportunista que se alimenta preferentemente de crustĆ”ceos, gasterĆ³podos y peces. La informaciĆ³n que se da en este artĆculo sobre los Ćndices biolĆ³gicos es necesaria para conocer las caracterĆsticas vitales de esta especie y para adoptar futuras medidas de conservaciĆ³n de su poblaciĆ³n en el AdriĆ”tico
Characterization of Microplastics in Prapratno Beach Sediment
Mikroplastika predstavlja ozbiljan problem u morskom i priobalnom okoliÅ”u. Analiziran je uzorak mikroplastike iz sedimenta plaže Prapratno na poluotoku PeljeÅ”cu, Hrvatska. Uzorkovanje i laboratorijsko odvajanje provedeni su prema DeFishGear protokolu. Svaki ispitak svrstan je u odreÄenu kategoriju te je svakom odreÄena masa, boja, prozirnost, maksimalna dimenzija i povrÅ”ina. Identifikacija je provedena infracrvenom spektroskopijom (FTIR) ā HATR tehnikom. Otpad s plaže Prapratno sastoji se uglavnom od polietilena te, u manjem udjelu, od polistirena i polipropilena.
Ovo djelo je dano na koriÅ”tenje pod licencom Creative Commons Imenovanje 4.0 meÄunarodna.Microplastics represent a major problem in the marine and coastal environment. In this work, microplastics from the sediment of Prapratno beach on the PeljeÅ”ac Peninsula (Croatia) were analysed. Sampling and laboratory separation were performed according to the DeFishGear protocol (Derelict Fishing Gear Management System in the Adriatic Region). The microplastic waste from Prapratno beach sediment consisted of 116 specimens, which could be classified into 6 micro litter categories according to EU TG ML Master List (Fig. 1). Fragments were found to be the predominant category of microplastic waste from the sediment of Prapratno beach, followed by granules, films, pellets and foams, which were present in approximately the same number, while filaments were the least represented category (Fig. 2). The most important categories by mass were granules and fragments, followed by pellets, while films, foams and filaments made up a very small content of the total sample mass (Fig. 3). The numerical contents (Fig. 4), did not correspond to the mass contents (Fig. 3) of individual categories due to the different densities and thicknesses of the specimens in each category. Almost all the base colours were present in the analysed samples (Fig. 5), while 90.52 % of specimens were opaque (Fig. 6). The maximum dimension and surface area of each specimen was determined by Digimizer Image Analysis Software. Maximum dimensions in the range of 1ā5 mm were observed in 52.59 % of the specimens, thus belonging to large microplastics (LMP), while 47.41 % of the specimens had maximum dimensions in the range of 5ā20 mm, thus belonging to so-called mezzo litter. The distribution of specimen dimensions within LMP is shown in Fig. 8, and within mezzo litter in Fig. 9. The fraction of each category in the total sample surface area is shown in Fig. 10. These results are similar to the numerical fractions of categories, since the samples were generally in the narrow range of maximum dimensions, and thus their numerical fractions corresponded to their fraction in the total surface of the sample. Identification of plastic material was performed by infrared spectroscopy, HATR technique. The obtained spectra were compared with the spectra in the database (Fig. 11ā13). The results showed (Fig. 14) that the microplastic waste from Prapratno beach was made of polyethylene (82.46 %), polystyrene (11.40 %) and polypropylene (6.14 %). These polymers came from plastic packaging since polyethylene, polystyrene and polypropylene are the most used polymers for plastic packaging.
This work is licensed under a Creative Commons Attribution 4.0 International License
Reproductive cycle of a non-native oyster, Crassostrea gigas, in the Adriatic Sea
The Pacific oyster Crassostrea gigas was introduced for the aquaculture purposes in many different parts of the world. However, the species has never been officially introduced for commercial farming in the Croatian part of the Adriatic Sea. Interestingly, in the 1970s, the Pacific oyster has been reported in the natural habitats of the Lim Bay, in northern Adriatic Sea. Although the species was recorded there, there is a lack of knowledge about its biology and ecology in this region, including a reproductive cycle. Information on the reproductive biology of non-indigenous species in new areas is crucial for prediction of their future survival and possible spread in invaded habitats. In this study, we provide the first data on the reproductive biology of the Pacific oyster in the Adriatic Sea, the northernmost part of the Mediterranean Sea. Quantitative and qualitative methods of gonad tissue analysis were conducted, and effects of environmental conditions on the gametogenesis were evaluated during two reproductive cycles. Our study confirmed that environmental conditions in the Lim Bay were favourable for the reproduction of the species. The Pacific oyster reproduced once per year and had a prolonged spawning period. Water temperature was the main factor affecting gonad development and oocyte size, while chlorophyll a concentration had an impact on the oocyte development in terms of their size.
Plankton diversity in Anthropocene: Shipping vs. aquaculture along the eastern Adriatic coast assessed through DNA metabarcoding
Coastal ecosystems globally are exposed to the most pervasive anthropogenic activities, caused by a suite of human infrastructure and enterprises such as shipping ports, aquaculture facilities, fishing, and tourism. These anthropogenic activities may lead to changes in ecosystem biodiversity, followed by loss of ecosystem functioning and services. Shipping industry and aquaculture have also been recognized as the main vectors for introduction of marine non-indigenous species (NIS) worldwide. In this study, we used DNA metabarcoding-based methods to investigate plankton biodiversity under varying anthropogenic pressures (shipping and bivalve aquaculture) along the eastern Adriatic coast (the northernmost part of the Mediterranean Sea). Our comparative assessment revealed similar community structures among investigated coastal locations (Northern, Central and Southern Adriatic). When the whole plankton communities were considered, they did not differ significantly between port and aquaculture sites. However, the proportion of the unique zOTUs in the port samples was remarkably higher than that in aquaculture sites (40.5% vs 8.2%), indicating that port areas may receive higher abundance and species richness of NIS than aquaculture sites. Further important difference between the two types of anthropogenically impacted habitats was a high abundance of three notorious invaders ā M. leidyi, M. gigas, and H. elegans in late summer at the aquaculture site in Northern Adriatic. Therefore, the plankton community of the area is under pressure not only from aquaculture activities, but also establishment of NIS. Port areas are probably under greater introduction pressure from NIS, but aquaculture sites may experience greater community changes due to their establishmen
Plankton biodiversity in Anthropocene: shipping vs. aquaculture along the eastern Adriatic coast
Although anthropogenic activities are widely recognized as a major threat to marine biodiversity, their impacts have not been fully assessed and there is an urge to improve the understanding of the magnitude and mechanisms of those impacts. In this study, we used DNA metabarcoding-based methods to investigate plankton biodiversity patterns under varying anthropogenic pressures (i.e., shipping and bivalve aquaculture) along the eastern Adriatic coast. Our study determined similar community structures among investigated coastal locations in three geographic regions in the Adriatic Sea, as well as between shipping ports and aquaculture sites
Distribution patterns of two co-existing oyster species in the northern Adriatic Sea: The native European flat oyster Ostrea edulis and the non-native Pacific oyster Magallana gigas
The Pacific oyster Magallana gigas, globally one of the most translocated marine species, has never been commercially farmed in any part of the Croatian eastern Adriatic Sea, where the native flat oyster Ostrea edulis is the only cultured oyster species. The Pacific oyster has, however, established populations on the west coast of the Istria peninsula, in the northeast Adriatic Sea. Current distribution, abundance and size structure of the flat and Pacific oysters were studied there along spatial and depth gradients in natural and artificial habitats to assess their potential for coexistence. This is the first quantitative assessment of native and non-native oyster populations on a Mediterranean-wide scale providing a baseline for determining future changes in their distribution. Both species were omnipresent, with the Pacific oyster displaying a more pronounced variability in abundance and size in relation to survey regions and depths. The population density of flat oysters was low, generally less than 1 individual/m(2), with no difference among regions. The density of the Pacific oyster was significantly higher, being on average 5 individuals/m(2). Dense, reef-forming aggregations of Pacific oysters were contained in Lim Bay, a nationally-important shellfish aquaculture area, where its mean density was 107 individuals/m(2). Along the open coastline its densities were considerably lower and followed a latitudinal gradient. The observed abundance and size distribution patterns of the Pacific oyster suggest that Lim Bay was the introduction point, with feral settlement likely originating from short-lived experimental aquaculture trials and subsequently dispersing by prevailing local currents. The flat oysters were larger in size and settled at different depths compared to the Pacific oysters. The vertical range of Pacific oysters was mostly contained in the tidal zone, while flat oysters were present in the subtidal exclusively. Such spatial partitioning likely resulted from introduced oysters occupying a vacant ecological niche and not due to interspecific competitive exclusion. Habitat type had a strong effect on proliferation of Pacific oysters. Artificial hard substrata harboured more abundant and larger Pacific oysters than the natural rocky shore habitat. The possibility of multiple local introduction pathways in ports and marinas is also discussed. Currently, there seems to be no spatial competition between the two oyster species, but as it is hard to predict future possible impacts of non-native species, we strongly suggest regular monitoring of the Pacific oyster, prioritising sensitive and protected areas as well as areas at the edge of its distribution