Content of metals in flounder, Platichthys flesus L., and Baltic herring, Clupea harengus membras L., from the southern Baltic Sea

AbstractDiet composition of two commercial fish species, herring and cod, were studied in some regions (mainly Gda’nsk and Bornholm Basins, and the Polish coast) of the southern Baltic Sea in 2007 and 2008. Herring is the dominant zooplanktivorous species in the ecosystem of the Baltic Sea, but apart from mesoplanktonic organisms it also eats macroplanktonic and benthic species in considerable amount. The diet of cod consists of fish and crustaceans from pelagic, hyperbenthic and benthic habitats. The feeding preferences of fish indirectly reflect changes in the whole food chain in the Baltic Sea. This research focuses specifically on these invertebrate species, which are eliminated from the environment by most of the ichthyofauna of this region. The aim of this research is to examine the role of invertebrate organisms belonging to Crustacea in the diet of herring and adult cod to supply updated results about feeding of these fish as little data have been collected since the 1990s. The present study is a preliminary survey and results can not be considered conclusive. The restricted numbers of analyzed stomachs of fish and selected seasons of the year addressed in this paper are a starting point for further studies with a larger scope. In this study, 20 to 90% of herring had empty stomachs. Mesozooplankton dominated the diets of small and large herring. Mysidacea, which were historically important prey for herring, are now scarce and have been replaced by planktonic Amphipoda. In the case of cod, consumption of Mysidacea has never been as low as in this study. As for other invertebrate prey, the benthic isopod Saduria and Crangon shrimp achieved the highest amount by number and weight. These results show distinct changes in diet when compared to previous investigations and require verification at a larger spatial scale.

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Bioaccumulation of polybrominated diphenyl ethers (PBDEs) in flounder (Platichthys flesus) in the southern Baltic Sea

Marine Environmental Research ◽

10.1016/j.marenvres.2012.06.006 ◽

2012 ◽

Vol 79 ◽

pp. 132-141 ◽

Cited By ~ 19

Author(s):

Ilona Waszak ◽

Henryka Dabrowska ◽

Agnieszka Góra

Keyword(s):

Baltic Sea ◽

Polybrominated Diphenyl Ethers ◽

Southern Baltic Sea ◽

Platichthys Flesus ◽

Diphenyl Ethers ◽

Southern Baltic

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Reference organisms for assessing the impact of ionizing radiation on the environment of the southern Baltic Sea

Oceanological and Hydrobiological Studies ◽

10.2478/s13545-012-0033-z ◽

2012 ◽

Vol 41 (4) ◽

pp. 1-7 ◽

Cited By ~ 4

Author(s):

Tamara Zalewska ◽

Maria Suplińska

Keyword(s):

Ionizing Radiation ◽

Baltic Sea ◽

Benthic Fauna ◽

Clupea Harengus ◽

Assessment System ◽

Ecological Niches ◽

Hediste Diversicolor ◽

Southern Baltic Sea ◽

Southern Baltic ◽

The Impact

AbstractAssessing the impact of ionizing radiation on the marine environment requires a well-defined methodology, which includes, among other elements, the analysis of exposure and effects. One of the most important components of the assessment system is the choice of reference organisms specific for the assessed area that fulfill requirements such as radioecological sensitivity, widespread distribution, and amenability to research and monitoring. The following species specific to the southern Baltic Sea that represent diversified ecological niches were proposed as reference organisms. Polysiphonia fucoides was proposed as a representative of macroalgae. Pelagic and benthic fauna were represented by Crangon crangon (crustacean), Saduria entomon (crustacean), Hediste diversicolor (polychaete), and Mytilus trossulus (mollusc). Fish were represented by Clupea harengus (pelagic planctotrophic fish), Gadus morhua (pelagic carnivorous fish), and Platichthys flesus (benthic fish). Activity concentrations of 137Cs were determined in reference biota as well as in seawater, as required for the total dose-rate evaluation, and relevant concentration factors were calculated.

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Assessing the performance of statistical classifiers to discriminate fish stocks using Fourier analysis of otolith shape

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2019-0251 ◽

2020 ◽

Vol 77 (4) ◽

pp. 674-683 ◽

Cited By ~ 2

Author(s):

Szymon Smoliński ◽

Franziska Maria Schade ◽

Florian Berg

Keyword(s):

Machine Learning ◽

Fourier Analysis ◽

Baltic Sea ◽

Clupea Harengus ◽

Fish Stock ◽

Fish Stocks ◽

Otolith Shape ◽

Southern Baltic Sea ◽

Statistical Classifiers ◽

Southern Baltic

The assignment of individual fish to its stock of origin is important for reliable stock assessment and fisheries management. Otolith shape is commonly used as the marker of distinct stocks in discrimination studies. Our literature review showed that the application and comparison of alternative statistical classifiers to discriminate fish stocks based on otolith shape is limited. Therefore, we compared the performance of two traditional and four machine learning classifiers based on Fourier analysis of otolith shape using selected stocks of Atlantic cod (Gadus morhua) in the southern Baltic Sea and Atlantic herring (Clupea harengus) in the western Norwegian Sea, Skagerrak, and the southern Baltic Sea. Our results showed that the stocks can be successfully discriminated based on their otolith shapes. We observed significant differences in the accuracy obtained by the tested classifiers. For both species, support vector machines (SVM) resulted in the highest classification accuracy. These findings suggest that modern machine learning algorithms, like SVM, can help to improve the accuracy of fish stock discrimination systems based on the otolith shape.

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