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The killer shrimp Dikerogammarus villosus (Crustacea, Amphipoda) invades Lithuanian waters, South-Eastern Baltic Sea

Šidagytė E., Solovjova S., Šniaukštaitė V., Šiaulys A., Olenin S., Arbačiauskas K.

Oceanologia

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2017

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No. 59 (1)

85--91

EN

The killer shrimp Dikerogammarus villosus was recorded for the first time in Lithuanian waters in 2015. The species was detected in three sites in the Curonian Lagoon (on two buoys in the lagoon strait and the harbour, and one littoral sampling site) and in the mouth of the Šventoji River. The species presence in the buoy fouling suggests the involvement of shipping in species introduction. Most likely D. villosus has arrived to the Curonian Lagoon with commercial ships, while the invasion into the mouth of the Šventoji River may be associated with leisure shipping as the port situated therein is not currently functioning. Further northward expansion of the killer shrimp in the Baltic Sea basin seems very probable. As the species is highly aggressive, alterations of local macroinvertebrate assemblages can also be predicted.

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Baltic herring (Clupea harengus membras) spawning grounds on the Lithuanian coast: current status and shaping factors

Šaškov A., Šiaulys A., Bučas M., Daunys D.

Oceanologia

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2014

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No. 56 (4)

789--804

EN

During the 2009 and 2010 seasons Baltic herring (Clupea harengus membras L.) spawning grounds were investigated by SCUBA divers off the Lithuanian Baltic Sea coast. The most important spawning substrate was a hard bottom overgrown with red algae Furcellaria lumbricalis, but only 32.8% of potentially suitable spawning locations had herring eggs. Bottom geomorphological analysis using multibeam bathymetry revealed that the distribution of spawning beds is not random, but is determined rather by small-scale geomorphological features. The majority of the detected spawning locations were on local elevations characterised by 2.4±1.1 m depth differences and 4.8±1.8 slopes.

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Mapping an ecosystem service: A quantitative approach to derive fish feeding ground maps

Šiaulys A., Daunys D., Bučas M., Bacevičius E.

Oceanologia

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2012

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No. 54 (3)

491-505

EN

This study presents a quantitative approach to mapping benthophagous fish feeding grounds. This approach combines the spatial biomass distribution of benthic prey items and their importance for the diets of predators. A point based biomass data of macrozoobenthos together with a set of environmental factors was used to develop Random Forests models that produce continuous biomass distribution layers for individual prey species. Depending on the diet composition and the importance of prey for fish feeding, these layers are overlaid and an integrated GIS map of the seabed showing the quality of feeding grounds is generated. These maps provide a useful basis for conservation and marine spatial planning. In addition, this method could be applied to the mapping of resources used by other benthophagous organisms. The method is presented using the example of three common Baltic fish species: cod, flounder and viviparous eelpout.