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Effects of seasonal changes and depth on growth parameters of the Mediterranean mussel (Mytilus galloprovincialis) on a shipwreck in the Eastern Mediterranean Sea

Şensurat-Genç Tuğçe, Karadal Onur, Oruç Adnan Çağlar, Özgül Aytaç, Aytaç Altan

Oceanological and Hydrobiological Studies

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2021

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Vol. 50, No. 4

441--454

EN

The study was conducted between July 2018 and May 2020 to compare seasonal changes in growth parameters of the Mediterranean mussel (Mytilus galloprovincialis) at different depths in two different areas of the Northeastern Mediterranean Sea (Aegean Sea). In a preliminary study, mussels were placed in cages at different depths of an artificial reef (AR – shipwreck) and natural reef (NR). Temperature, salinity, pH, and dissolved oxygen were determined seasonally at both sites at a depth of 37 m (deepwater) and 25 m (midwater). Linear increases in length and width of mussels at the AR site were recorded, while no consistent changes were observed for mussels at the NR. There was negative correlation between the specific growth rate (SGR) and salinity (r2 = 0.5098) and temperature (r2 = 0.1470) at the AR site. Negative correlations were also recorded between pH and the commercial condition index (CCI) at both the AR (r2= 0.3869) and NR (r2 = 0.3600) sites. Our findings show that depth had a significant effect (p < 0.05) on the CCI of mussels at the NR site, while its effect was insignificant for this index at the AR site (p > 0.05). This study indicates that natural reefs provide more suitable conditions for the growth of Mediterranean mussels than shipwrecks used as artificial reefs.

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Recruitment patterns of the solitary ascidian Phallusia nigra Savigny, 1816 on artificial substrates submerged in the central Red Sea, Saudi Arabia

Al-Sofyani Abdul Mohsin A, Satheesh Sathianeson

Oceanological and Hydrobiological Studies

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2019

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Vol. 48, No. 3

262--269

EN

The solitary ascidian Phallusia nigra is commonly found on hard substrates along the Jeddah coastal waters of the central Red Sea. In this study, the recruitment pattern of P. nigra on artificial substrates was assessed in relation to their type, surface color and orientation. The results showed a higher recruitment rate of the ascidian species on concrete and dark panels. The abundance of the ascidian on test panels varied between the four seasons. The orientation (vertical or horizontal) of the panels did not show any major difference in the recruitment. Significant effects of light intensityon the recruitment of P. nigra were observed on test panels, with higher abundance on panels submerged in the shade. In conclusion, this study clearly indicates the importance of the type and color of substrates in the recruitment of ascidians on artificial materials.

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Sediment transport modifications induced by submerged artificial reef systems : a case study for the Gulf of Venice

Bonaldo D., Benetazzo A., Bergamasco A., Falcieri F. M., Carniel S., Aurighi M., Sclavo M.

Oceanological and Hydrobiological Studies

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2014

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Vol. 43, No. 1

7--20

EN

The shallow, gently sloping, sandy-silty seabed of the Venetian coast (Italy) is studded by a number of outcropping rocky systems of different size encouraging the development of peculiar zoobenthic biocenoses with considerably higher biodiversity indexes compared to neighbouring areas. In order to protect and enhance the growth of settling communities, artificial monolithic reefs were deployed close to the most important formations, providing further nesting sites and mechanical hindrance to illegal trawl fishing. In this framework, a multi-step and multi-scale numerical modelling activity was carried out to predict the perturbations induced by the presence of artificial structures on sediment transport over the outcroppings and their implications on turbidity and water quality. After having characterized wave and current circulation climate at the sub-basin scale over a reference year, a set of small scale simulations was carried out to describe the effects of a single monolith under different geometries and hydrodynamic forcings, encompassing the conditions likely occurring at the study sites. A dedicated tool was then developed to compose the information contained in the small-scale database into realistic deployment configurations, and applied in four protected outcroppings identified as test sites. With reference to these cases, under current meteomarine climate the application highlighted a small and localised increase in suspended sediment concentration, suggesting that the implemented deployment strategy is not likely to produce harmful effects on turbidity close to the outcroppings. In a broader context, the activity is oriented at the tuning of a flexible instrument for supporting the decision-making process in benthic environments of outstanding environmental relevance, especially in the Integrated Coastal Zone Management or Maritime Spatial Planning applications. The dissemination of sub-basin scale modelling results via the THREDDS Data Server, together with an user-friendly software for composing single-monolith runs and a graphical interface for exploring the available data, significantly improves the quantitative information collection and sharing among scientists, stakeholders and policy-makers.

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Sztuczne rafy jako innowacyjna biotechnologia wykorzystywana w procesie rewitalizacji środowiska morskiego

Chojnacki J., Raczyńska M., Grzeszczyk-Kowalska A., Zamkowski T.

Ekologia i Technika

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2013

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R. 21, nr 4

141--149

PL

W pracy przedstawiono inicjatywy ekologiczne dotyczące wykorzystania sztucznych podłoży w środowisku strefy przybrzeżnej Zatoki Pomorskiej (południowy Bałtyk) na przykładzie sztucznych raf. Pierwsza z nich została zrealizowana w 1990 r. i miała na celu rewitalizację środowiska morskiego w Południowym Bałtyku, natomiast druga została wstrzymana w fazie projektowej i w głównej mierze miała służyć zwiększeniu bioróżnorodności hydrobiontów oraz stworzeniu miejsc tarliskowych dla ryb. W 1990 r. sztuczne podłoże okazało się doskonałym siedliskiem dla zespołu omułka Mytilusedulis, w rejonie sztucznej rafy stwierdzono również duże koncentracje ryb i ich larw. W pracy zawarto również problemy związane z przygotowaniem i wypełnieniem wymaganych procedur zarówno w fazie przygotowania i realizacji tego typu projektów.

EN

Ecological initiatives concerning the use of artificial surfaces placed in the littoral zone of the PomeranianBay (southern Baltic) as exemplified by construction of artificial reefs are presented. First was realized in 1990 and aimed at revitalization of the Baltic environment: the other one is in a project phase, referring chiefly to an increase of aquatic species diversity and the creation of spawning grounds for fish. In 1990 such artificial substratum showed that it is an excellent habitat for Myiilusedulis, huge concentration of fishes and its larvae were noted as well. Problems connected with the preparation and fulfilment of required procedures, both in the preparatory phase and during realization of these types of projects, are also discussed.