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Integrated multi-trophic aquaculture of the European flat oyster (Ostrea edulis Linnaeus, 1758) : A case study from Boka Kotorska Bay (Montenegro)

Nikolić Slađana, Mandić Milica, Pešić Vladimir, Ikica Zdravko, Peraš Ines

Oceanological and Hydrobiological Studies

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2024

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Vol. 53, No. 1

31--39

EN

Although integrated multi-trophic aquaculture (IMTA) is recognized as a strategy to control and minimize the impact of fish farming on the marine environment, there are still many unknowns when it comes to this type of farming. This paper presents the results of research on the growth of European flat oysters in IMTA and monoculture systems. Growth was monitored at three different sites: near fish cages, 100 m from fish cages, and in a monoculture system, during an 18-month experiment. The highest mortality occurred at the site near the fish cages. At the end of the experiment, all monitored individuals reach commercial size, except for four individuals at the site near the fish cages. There were statistically significant differences in oyster growth with respect to site and period. At the site near the fish cages, oyster growth was significantly lower compared to the growth at the two other sites. The most intense growth of oysters occurred during the spring and early summer period. Our results indicate that the production cycle of oysters in integrated aquaculture and monoculture is quite similar and that sites directly adjacent to fish cages should be avoided for oyster farming.

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First record of blister pearls in the oyster Hyotissa hyotis (Linné, 1758) from Pliocene deposits at Sidi Brahim, Lower Chelif Basin (north-west Algeria)

Khalili Rachid, Vinn Olev

Geologos

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2023

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Vol. 29, No. 3

167--172

EN

Fossil pearls are rare but important palaeoecological indicators in proving the former presence of parasites. A single right valve of Hyotissa hyotis from the Pliocene of Sidi Brahim shows numerous blister pearls inside the adductor muscle imprint. At the same locality, numerous shells with smooth adductor scars and without any blisters, have been collected. The structures in the studied valve can be assigned to blister pearls with high confidence due to their similarity to other Cenozoic pearls from Austria. The blister pearls likely formed as a reaction to parasite infestation. It is possible that some parasites especially targeted areas associated with the adductor muscles in the oyster genus Hyotissa, because similar blister pearls have previously been described in a congeneric species, H. squarrosa, from the Miocene of Austria.

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Palaeoenvironmental changes recorded in the oxygen and carbon isotope composition of Kimmeridgian (Upper Jurassic) carbonates from central Poland

Wierzbowski Henryk

Geological Quarterly

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2019

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Vol. 63, No. 2

359--374

EN

Oxygen and carbon isotope ratios of well-preserved calcitic bivalves from the Lower-lowermost Upper Kimmeridgian of Central Poland (SW margin of the Holy Cross Mountains) have been studied to reconstruct palaeoenvironmental conditions and variations in ancient water chemistry. Low and scattered δ18O and δ13C values of bivalve shells from shallow carbonate deposits of the Hypselocyclum and the Hypselocyclum-Divisum zone boundary (-3.5 to -1.5, and 2.6 to 4.0‰, respectively) are a result of salinity changes, and local variations in the composition of dissolved inorganic carbon (DIC) in conditions of restricted water circulation. A slight increase in bivalve δ13C values and more densely clustering of δ18O values is observed after the marine transgression at the Divisum-Mutabilis zone boundary. A global decrease of δ13C values of marine carbonates is partly recorded in Lower-lowermost Upper Kimmeridgian bulk carbonates from central Poland (from the Radomsko Elevation and the Wieluń Upland). Local negative shifts and the data scatter are, however, observed in rocks deposited in a very shallow environment of carbonate platforms during the Platynota and Hypselocyclum chrons. This interval corresponds to the uppermost part of the lowstand systems track of a major regressive trend, which had started already in the Late Oxfordian.

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The late Cenomanian oyster Lopha staufferi (Bergquist, 1944) – the oldest ribbed oyster in the Upper Cretaceous of the Western Interior of the United States

Hook S. C., Cobban W. A.

Acta Geologica Polonica

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2016

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Vol. 66, no. 4

609--626

EN

Lopha staufferi (Bergquist, 1944) is a medium-sized, ribbed, Late Cretaceous oyster with a slightly curved axis and a zigzag commissure; it appears suddenly and conspicuously in upper Cenomanian rocks in the Western Interior Basin of the United States. At maturity, the ribs on both valves thicken into steep flanks that allow the oyster to increase interior volume without increasing its exterior footprint on the seafloor. Lopha staufferi is the first (earliest) ribbed oyster in the Late Cretaceous of the Western Interior, but has no ancestor in the basin. It disappears from the rock record as suddenly as it appeared, leaving no direct descendent in the basin. In the southern part of the basin where it is well constrained, L. staufferi is restricted stratigraphically to the upper Cenomanian Metoicoceras mosbyense Zone (= Dunveganoceras conditum Zone in the north). Lopha staufferi has an unusual paleogeographic distribution, occurring in only two, widely scattered areas in the basin. It has been found at several localities near the western shoreline of the Late Cretaceous Seaway in west-central New Mexico and adjacent Arizona, and in localities 1,900 km (1,200 mi) to the northeast near the eastern shoreline in northeastern Minnesota, but nowhere in between. In west-central New Mexico and adjacent Arizona, L. staufferi is a guide fossil to the Twowells Tongue of the Dakota Sandstone.

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Oyster-bioimmured ammonites from the Upper Albian of Annopol, Poland: stratigraphic and palaeobiogeographic implications

Machalski M., Kennedy W. J.

Acta Geologica Polonica

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2013

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Vol. 63, no. 4

545--554

EN

Ammonites Mortoniceras (Subschloenbachia) sp. are preserved as attachment scars on the oyster shells from the topmost portion of the Albian succession at Annopol, Poland. These oyster-bioimmured ammonites show a closest affinity to the representatives of Mortoniceras (Subschloenbachia) characteristic of the upper Upper Albian Mortoniceras perinflatum Zone. No ammonites indicative of the uppermost Albian–lowermost Cenomanian Praeschloenbachia briacensis Zone are recorded. Thus, the hiatus at the Albian–Cenomanian boundary at Annopol embraces the latter zone. The presence (and dominance) of Mortoniceras in the upper Upper Albian ammonite assemblage of Annopol suggests that the representatives of this Tethyan genus could migrate into the epicratonic areas of Poland directly from the Tethyan Realm, via the Lwów (Lviv) region.

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The carbon and oxygen isotope records of Upper Bajocian-Bathonian calcareous fossils from the Polish Jura Chain

Wierzbowski H., Joachimski M.

Volumina Jurassica

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2006

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Vol. 4, no. 1

220-222

EN

A collection of stratigraphically well-dated calcitic and aragonitic fossils (belemnites, ammonites, nautiloids and oysters), derived from Upper Bajocian - Upper Bathonian clays from the Polish Jura Chain (central Poland), were studied for oxygen and carbon isotopes. The preservation state of the shell material was investigated by means of cathodoluminescence microscopy, trace element geochemistry and X-ray diffraction. Palaeotemperatures calculated from the oxygen isotope composition of calcitic shells (belemnites and oysters) are similar to each other despite the significant spread in 18O values (Fig. 1). The 18O values of calcitic fossils generally vary from -0.1 to +1.1‰ VPDB for the studied interval, which corresponds to palaeotemperatures between +7.9 and +12.4°C (calculated with the equation of Anderson & Arthur 1983). The palaeotemperatures derived from the oxygen isotope composition of aragonitic ammonoid and nautiloid shells are distinctly higher (Fig. 1) with most of the estimates ranging from 15 to 23°C (calculated with the equation of Grossman & Ku 1986). The observed temperature difference may have resulted from different depth habitats of the organisms. The ammonites and nautiloids might have lived in surface waters and the temperature contrast might represent a palaeotemperature gradient between thermally stratified surface and deep waters of the Late Bajocian - Late Bathonian sea in the Polish Jura Chain. The ?13C values for the Upper Bajocian - Upper Bathonian belemnite rostra do not indicate major secular variations (Fig. 1). However, the data show a significant scatter of about 1.5‰. Several oyster shells show considerable higher 13C values (around +3‰ VPDB) compared to coeval belemnite rostra (between 0 and +1.5‰ VPDB). This may point to a metabolic fractionation effect that resulted in disequilibrium fractionation of carbon isotopes within belemnite skeletons (cf. Wierzbowski 2002). The aragonitic ammonite and nautiloid shells show a significant variation in 13C with values ranging from -3.7 to +2.2‰ VPDB. The carbon isotope composition of the oysters and the belemnites may suggest that the ?13C value of ancient seawater bicarbonate (HCO3-) averaged +3‰ VPDB.

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Oyster and brachiopod stable isotopes across the Triassic/Jurassic boundary and in the Early Jurassic

Korte C., Hesselbo S., Jenkyns H., Dietl G., Dulai A., Vörös A.

Volumina Jurassica

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2006

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Vol. 4, no. 1

289-289

EN

Oxygen and carbon isotope values have been obtained from oysters for the Triassic/Jurassic boundary section at Lavernock Point (Wales), and from brachiopods and oysters for different Hettangian, Sinemurian and Pliensbachian localities of South Germany and Hungary. Low-Mg-calcite brachiopods and oysters are particularly suitable for such studies because this carbonate phase is the most resistant to diagenetic alteration. Nevertheless, all fossils have been screened by chemical and optical techniques (optical microscope, scanning electron microscopy, trace element analyses) to evaluate the isotope data for diagenetic change, and only samples with Mn content less than 250 ppm and Sr content more than 400 ppm, complemented by well preserved textures under SEM, were considered in this study. For the Triassic/Jurassic boundary (TJB) the carbon isotope values are at about 2.5‰ in the lower Langport Member, increase to 4.5‰ in the lowest Blue Lias and decrease subsequently to 1.5‰ just below the Planorbis Zone. The data remain low with variations between 1.5 and 2.5‰ up to the Liassicus Zone. These results correspond to the organic carbon isotope trend for the Triassic/Jurassic boundary section at St Audrie's Bay (Hesselbo et al. 2002). Oxygen isotope values increase from -0.5‰ in lower Langport Member to 0‰ at the base of the Blue Lias, decrease in the Blue Lias down to -1.5‰ just below the Planorbis Zone and change in parallel with the organic and inorganic carbon-isotope trends. The δ ¹ ⁸O values indicate decreasing seawater temperature with increasing δ ¹ ³C in the Langport Member and increasing water temperatures of about 6°C in the lower Blue Lias. The distinct warming trend occurred during the "main" TJB negative excursion. Carbon and oxygen isotope values from Hettangian, Sinemurian and Pliensbachian brachiopods and oysters, as well as from some complementary belemnites, show similar values and trends compared to the data compilation by Jenkyns et al. (2002). Carbon isotope values are between 1 and 2‰ in the Hettangian and Early Sinemurian followed by an increase of about 1‰ during the Sinemurian, a nearly 3‰ decrease in the Early Pliensbachian and higher δ ¹ ³C values (˜2.5‰) in the later Pliensbachian.