Age and growth of Pecten jacobaeus in the eastern Adriatic Sea – why location matters?

Contrasting shell growth strategies in two Mediterranean bivalves revealed by oxygen-isotope ratio geochemistry: The case of Pecten jacobaeus and Glycymeris pilosa

A survey of fresh great Mediterranean scallops (Pecten jacobaeus) and frozen queen scallops (Aequipecten opercularis) collected from the northern Adriatic Sea demonstrated the presence of nematode larvae that were morphologically and molecularly identified as Sulcascaris sulcata. The presence of this nematode in the northern Adriatic Sea has been described in the logger head sea turtle, which is the final host, but it was only recently described in the intermediate molluscan host. Affected scallops present rust-brown lesions in the adductor muscle. In this study, necroscopic and histopathological lesions are described in affected scallops. Furthermore, the detrimental effects of this parasite on the commercialization of scallops under the current European legislation concerning the hygiene of seafood products are evaluated.

Simple SummaryLepidorhombus boscii is a flatfish of high commercial value. However, the existing knowledge about the biology and ecology of this species is scarce. The aim of this study is to describe the reproductive cycle of L. boscii in the eastern Adriatic Sea. The sex ratio of L. boscii was 1:0.89 (female:male), and the size at first sexual maturity was 19.2 cm for females and 20.3 cm for males. Previtellogenic and vitellogenic oocytes are present in the ovaries throughout the year. L. boscii has a prolonged spawning season in the Adriatic Sea with the main spawning season between November and March.This study presents data on the seasonal changes in population structure, maturation, fecundity and reproduction of the Lepidorhombus boscii from the central-eastern Adriatic Sea. This species is a commercially valuable fish in the Adriatic Sea; still, knowledge about its reproductive biology is very scarce. The analyses are based on the data collected between July 2020 and June 2021 by bottom trawls. In total, 963 individuals were collected out of which 508 were females (47.24%) and 455 were males (52.75%). Throughout the year, oocytes in the previtellogenic and vitellogenic stages were present in the ovaries, and the development of the ovaries followed the values of the gonadosomatic index. L. boscii has asynchronous ovarian development and a prolonged spawning season in the Adriatic Sea with the main spawning season between November and March. The oocyte diameter ranged from 34.01 to 562.72 μm (178.49 ± 129.83 μm). This study presents the first information on the reproductive cycle of L. boscii in the eastern Adriatic Sea and contributes to the understanding of the biology of this species necessary for its sustainable management.

Growth and longevity of Glycymeris nummaria were determined from samples of shells, collected monthly by scuba divers between January 2010 and December 2010 from Mali Ston Bay, eastern Adriatic Sea. Acetate peel replicas of the shell margin (marginal increment analysis) and hinge region of the shell were used to validate an annual periodicity of growth lines and to determine shell age, respectively. Results indicate that G. nummaria forms a narrow growth line after February, when seawater temperatures are at a minimum. Growth lines, visible in the hinge region of all the shells, were used to estimate the age of 76 G. nummaria and provided an estimate of maximum longevity of the species at 20 y. Construction of a von Bertalanffy curve using shell length at age data produced a value of L∞ = 71 mm, a growth parameter (K) of 0.11/y, and time at length 0 was -3.74 y. The growth performance index was 2.74.

Event Abstract Back to Event Spatial distribution of sardine and anchovy early life stages along the eastern Adriatic Sea Barbara Zorica1, Vanja Cikes Kec1*, Goran Brzulja1 and Viktor Kraljević1 1 Institute of Oceanography and Fisheries, Croatia Despite long-term investigations of the Adriatic Sea in general and extensive research on sardine and anchovy as ecologically and economically important fish species, knowledge concerning their spawning ecology, precisely their possible spawning grounds, is still incomplete. Therefore, two scientific surveys (January, July 2012) were performed, as target species spawn during different periods of the year (sardine - October to April (Sinovčić et al., 2007) and anchovy - April to September (Zorica et al., 2013)). Throughout these surveys, standard vertical plankton tows were made during the daylight at 72 stations in January and 60 stations in July using a WP2 sampler (mouth opening, 0.255 m2; mesh size, 0.200 mm). WP2 net was put vertically down during the calm sea to a depth of 100 m or to 5 m above the seabed in relatively shallow marine area (less than 100 m). Plankton samples were preserved in 4% buffered formalin and transported to the laboratory where they were analysed. Throughout ichtyoplankton analysis of samples collected during the winter survey a total of 506 sardine eggs and 348 larvae were sorted out. The mean sardine egg and larval abundance in the analysed period at positive stations was 57.8 +/- 77.4 eggs/m2 and 29 +/- 25.85 larvae/m2, with peaks of 396 eggs/m2 and 108 larvae/m2 at positive sampling stations. Concerning the summer survey and anchovy early life stages from obtained samples 1489 anchovy eggs and 1036 larvae were isolated. Average abundance of anchovy eggs and larvae was 145.26 +/- 201.27eggs/m2 and 115.11+/- 162.32 larvae/m2, respectively. The highest values of mentioned parameters at positive stations were 800 eggs/m2 and 952 larvae/m2. According to obtained results and their processing within Ocean Data View (odv.awi.de), revile that both species during 2012 spawn above the whole continental shelf and the areas of higher early life stages abundance overlap. Acknowledgements This study was supported by the Ministry of Agriculture of the Republic of Croatia, as a part of the research project “Defining the spatial and temporal periods of sardine and anchovy spawning in the Adriatic Sea". References Sinovčić, G., Zorica, B. and ČIKEŠ KEČ, V. (2007). Abundance and some biological characteristics of sardine, Sardina pilchardus (Walb.,1792), in the coastal and open sea waters of the Adriatic Sea (Croatia). In: I. Rožanić (Editor). Proceedings, Second Conference on Marine Technology, Rijeka, pp. 155-174. Zorica, B., Vilibić, I., Čikeš Keč, V. and Šepić, J. (2013). Environmental conditions conducive to anchovy spawning in the Adriatic Sea. Fish. Oceanogr. 22(1): 32-40. Keywords: Small pelagic, Eggs, Larvae, Adriatic sea, Mediterranean Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Poster Presentation Topic: Life Cycles, Migration and Connectivity Citation: Zorica B, Cikes Kec V, Brzulja G and Kraljević V (2015). Spatial distribution of sardine and anchovy early life stages along the eastern Adriatic Sea. Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.fmars.2015.03.00009 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Oct 2015; Published Online: 04 Nov 2015. * Correspondence: PhD. Vanja Cikes Kec, Institute of Oceanography and Fisheries, Split, Croatia, cikes@izor.hr Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Barbara Zorica Vanja Cikes Kec Goran Brzulja Viktor Kraljević Google Barbara Zorica Vanja Cikes Kec Goran Brzulja Viktor Kraljević Google Scholar Barbara Zorica Vanja Cikes Kec Goran Brzulja Viktor Kraljević PubMed Barbara Zorica Vanja Cikes Kec Goran Brzulja Viktor Kraljević Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 509:193-202 (2014) - DOI: https://doi.org/10.3354/meps10962 Impact of bleaching on the coral Cladocora caespitosa in the eastern Adriatic Sea Petar Kružić1,*, Lovrenc Lipej2, Borut Mavrič2, Petra Rodić3 1Laboratory for Marine Biology, Department of Zoology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia 2Marine Biological Station Piran, National Institute of Biology, Fornaˇce 41, 6330 Piran, Slovenia 3State Institute for Nature Protection, Trg Mažurani΄ca 5, 10000 Zagreb, Croatia *Corresponding author: pkruzic@zg.biol.pmf.hr ABSTRACT: Thermal anomalies during the last 15 yr caused bleaching in the zooxanthellate scleractinian coral Cladocora caespitosa (Linnaeus, 1767) in the eastern part of the Adriatic Sea. In this study, we assessed the long-term response of this temperate coral to warming seawater in the Adriatic Sea and described, for the first time, the relationship between recurrent coral bleaching events and local seawater temperature regimes. These were also the first coral bleaching events reported for the Mediterranean Sea. Coral bleaching was recorded in the period from 1997 to 2012 in Veliko Jezero within Mljet National Park (NP), Croatia. The most severe bleaching in Veliko Jezero was observed during the summer of 2003, when C. caespitosa colonies were exposed to temperatures >29°C for 46 d. A total of 426 colonies experienced partial bleaching and 133 colonies died due to complete bleaching. Bleaching results during 2011 were compared with bleaching events in the Piran area (Slovenia) over this same temporal interval. The highest seawater temperatures were recorded in the period from August to October of 2011 (28.8°C in Piran, 30.3°C at Mljet NP). Severe bleaching was observed on 54 (29.3%) colonies within the Mljet coral bank, while 39 colonies with complete bleaching died. In the Piran area, severe bleaching was observed on 26 (34.7%) colonies, while complete bleaching occurred in 8 (10.6%) colonies. Under the present climate-warming trend, the coral bleaching reported here could lead to a severe decline in the abundance of the surveyed populations of C. caespitosa. KEY WORDS: Cladocora caespitosa · Coral bleaching · Coral mortality · Adriatic Sea Full text in pdf format PreviousNextCite this article as: Kružić P, Lipej L, Mavrič B, Rodić P (2014) Impact of bleaching on the coral Cladocora caespitosa in the eastern Adriatic Sea. Mar Ecol Prog Ser 509:193-202. https://doi.org/10.3354/meps10962 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 509. Online publication date: August 27, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Cartography of littoral rocky-shore communities (CARLIT) as a tool for ecological quality assessment of coastal waters in the Eastern Adriatic Sea

Semi-enclosed bays are generally considered important environmental resources for mariculture. This study was conducted within cage fish farms in two semi-enclosed bays of the Eastern Adriatic Sea, at Boka Kotorska Bay (Montenegro), and at Mali Ston Bay (Croatia). A total of 16 sea water samples, and 46 swabs from the gills and skin of European seabass were collected from two sea bass farms during two samplings in autumn and spring. The aim of this study was to determine the health status of European seabass in Montenegro and Croatia, to evaluate the environmental conditions in both farming areas, and to assess the presence of Vibrio and its impact on fish health. Most of the isolated bacteria from the samples were Gram-negative and comprised of Vibrio, Photobacterium and Pseudomonas genera. Assessment of fish health status showed that fish were clinically healthy and results present a bacterial community associated with healthy farmed European seabass. At the same time, some of the isolated bacterial strains are known to be pathogenic (V. alginolyticus, V. harveyi, V. anguillarum, P. damselae), and present a potential reservoir of infection. Simultaneous survey confirmed microbial impact in both bays due to an anthropogenic influence. The approach presented in this study is valuable in the assessment of farming conditions in semi-enclosed aquatic environments and is easily applicable to other similar locations worldwide.

Scallop settlements were examined over a 16 month period using collectors placed in the sea at 28 day intervals near Torre la Sal Beach, Castellon, Eastern Spain in the western Mediterranean. Collectors were set over depths of 20 m and five species, Flexopecten flexuosus, Chlamys varia, Aequipecten opercularis, Pecten jacobaeus and Palliolum incomparabile, were collected. The most frequent species, F. flexuosus, had peak settlements in August 1992 and in July 1993. C. varia had peaks in April and July 1992 and in June 1993. Both of these species settled throughout the year, except in winter. A. opercularis settled predominantly from February to June and in October, but with a few settlements during the rest of the year. Pecten jacobaeus had a small peak in February and another peak from April to July. P. incomparabile spat were rare. Settlements were studied in relation to chlorophyll a, suspended particulate and sea temperature data in the area of study.

Susceptibility to oxyradical toxocity in Antarctic, Arctic, and Mediterranean scallops

Spatio-temporal reproducibility of the microbial food web structure associated with the change in temperature: Long-term observations in the Adriatic Sea

Adriatic Sea is a diverse marine ecosystem that supports a rich biodiversity of polychaete species on soft and hard-bottoms, with 764 recorded species in the latest inventory list. Benthic surveys conducted in 2018 in the hard-bottom infralittoral zone on the east coast of the central Adriatic Sea revealed one previously unreported species for the Adriatic Sea, Syllis kabilica Ben-Eliahu, 1977 (Syllidae), as well as two species reported for the first time in the eastern Adriatic Sea, Syllis tyrrhena (Licher and Kuper, 1998) (Syllidae), and Streblosoma nogueirai Lezzi and Giangrande, 2019 (Terebellidae). Furthermore, one alien species was identified, Lysidice collaris Grube, 1868 (Eunicidae). These findings provide new insights into the distribution and diversity of polychaete fauna in the Adriatic Sea.

ABSTRACTGeometric morphometry is effective in distinguishing bivalve species and populations, including the economically and environmentally important Mediterranean mussel, Mytilus galloprovincialis. Although widely distributed, shell shape variation in M. galloprovincialis along the eastern Adriatic Sea has been infrequently studied. Farming practices and environmental conditions may affect the development of shell shape, as has been reported in the Mytilus genus from numerous locations globally. Building on earlier genetic analyses of mussels collected along a natural environmental gradient, this study aimed to identify shell landmark differentiation between wild and cultured populations and among northern, middle, and southern populations of the eastern Adriatic Sea using a geometric morphometric approach. Samples from 12 sites in Croatia, Montenegro, and Albania, including 4 aquaculture farms, were examined for variation in 9 internal shell landmarks. Wild populations exhibited a more extended posterior adductor muscle scar and a more elongated shape compared to farmed populations. Mussels from low salinity environments in the north and south exhibited an elongated shell shape compared to high salinity environments. Southern populations exhibited an extended posterior adductor muscle scar, along with an elongation of the lateral ligament and ventral umbo orientation that caused a concave shape of the ventral shell border compared to northern populations. The differences in environmental conditions in the Adriatic Sea, such as reduced salinity in Boka Kotorska Bay (Montenegro) in the south and Limski Bay (Croatia) in the north, likely play a role in influencing the variability of shell landmarks. These results may be applied to farming practices so that high‐quality spat are collected from source sites with environmental conditions that match the farm site to which the spat are transferred. Overall, these results provide valuable insight into how M. galloprovincialis shell landmarks respond to environmental variation at large (hundreds of kilometres) spatial scale.

Although extensive studies have been made on Posidonia oceanica ecosystems, in terms of their phenological characteristics, shoot density, biomass, and associated faunal assemblages, little attention has been given to the depth distribution of this species in the Adriatic Sea. The depth limits of the Mediterranean endemic seagrass P. oceanica growing along the eastern coast of the Croatian Adriatic Sea were examined by the use of SCUBA diving. Fifty-two independent measurements show that the lower depth limit of P. oceanica in the Croatian Adriatic Sea ranges from 24 m in the north to 36 m in the south, with a strong latitudinal gradient. The information on maximum depth distribution is an important asset when the increased human pressure and rapid environmental changes pose a threat to the survival of this slow-growing marine species.

Competitive feeding interactions between native Ostrea edulis and non-native Crassostrea gigas with implications of introducing C. gigas into commercial aquaculture in the eastern Adriatic Sea