scholarly journals Thermal conditions and age structure determine the spawning regularities and condition of Baltic herring (Clupea harengus membras) in the NE of the Baltic Sea

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7345 ◽  
Author(s):  
Timo Arula ◽  
Heli Shpilev ◽  
Tiit Raid ◽  
Elor Sepp
Keyword(s):  
Age Structure ◽  
Thermal Conditions ◽  
Climatic Conditions ◽  
Clupea Harengus ◽  
Spawning Season ◽  
Older Individuals ◽  
Spawning Period ◽  
Baltic Herring ◽  
The Baltic ◽  
Preceding Winter

Baltic herring (Clupea harengus membras) is a total spawner with a group-synchronous ovarian organization. Age polymodality in total spawners is considered an important factor in assuring that a strong population is sustainable under an intensive harvesting regime and different climatic conditions. In the present study, we investigated the seasonal and inter-annual variation in spawner age structure and the effect of preceding winter thermal conditions on the start of the herring spawning and larvae retention period. Herring spawning season in the Gulf of Riga starts up to six weeks later after colder winters compared to milder winters. Significantly older individuals dominated at the beginning of the spawning season, and thus herring mean age gradually decreased towards the end of the spawning season from 1999–2015. On an annual scale, this pattern was obvious after cold winters, while after mild winters the pattern did not continue, indicating a more homogenous maturation cycle and spawning period, despite the age and size of the herring population in mild winters. Further, herring condition factor was studied in relation to age and spawning season following different winter thermal conditions. Young, 2- and 3- year old first-spawning herring experienced significantly lower conditions after cold winters compared to older ages, indicating an age-dependent effect of preceding winter on herring maturation cycle, condition and spawning time.

Influence of environmental conditions, population density, and prey type on the lipid content in Baltic herring (Clupea harengus membras) from the northern Baltic Sea

2019 ◽  
Vol 76 (4) ◽  
pp. 576-585 ◽  
Author(s):  
Marjut Rajasilta ◽  
Jari Hänninen ◽  
Lea Laaksonen ◽  
Päivi Laine ◽  
Jukka-Pekka Suomela ◽  
...  
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Lipid Content ◽  
Sea Water ◽  
Energy Content ◽  
Global Climate ◽  
Clupea Harengus ◽  
Composition Analysis ◽  
Baltic Herring ◽  
The Baltic

Global climate change can affect the energy content of fish by altering their lipid physiology and consumption. We investigated the effects of different environmental stressors on the lipid content of the Baltic herring (Clupea harengus membras) from spawning ground samples that were collected annually in the northern Baltic Sea. During 1987–2014, the average lipid content of herring muscle decreased from 5%–6% (wet mass) to 1.5% (wet mass). Generalized linear mixed models indicated that sea water salinity and the size of the herring stock explained best the declining trend of lipid content. We estimated that the amount of the lipid storage incorporated in the spawning stock decreased by approximately 45% during the study, with respective energy content decreases. Fatty acid composition analysis revealed that herring lipids contained a high proportion of EPA (eicosapentaenoic acid; 20:5n-3) and DHA (docosahexaenoic acid; 22:6n-3), which likely originated from its main summertime prey, Limnocalanus macrurus. The results illustrate various climate change-induced processes leading to changes in the lipid content of the Baltic herring and, consequently, to changes in the energy flows of the northern Baltic ecosystem.

scholarly journals Decreasing salinity improves the feeding conditions of the Baltic herring (Clupea harengus membras) during spring in the Bothnian Sea, northern Baltic

2014 ◽  
Vol 71 (5) ◽  
pp. 1148-1152 ◽  
Author(s):  
M. Rajasilta ◽  
J. Hänninen ◽  
I. Vuorinen
Keyword(s):  
Stomach Contents ◽  
Clupea Harengus ◽  
Trophic Levels ◽  
Baltic Herring ◽  
Important Link ◽  
Limnocalanus Macrurus ◽  
The Baltic ◽  
Bothnian Sea

Abstract The stomach contents of the herring (Clupea harengus membras L.) from the Bothnian Sea, northern Baltic, were analysed during spring 2011 and 2013. The stomachs were full of Limnocalanus macrurus in May and June, and an improvement in the condition of herring was observed when fish started to feed on this prey. The analyses showed that Limnocalanus is currently an important link between lower trophic levels and Baltic herring in the Bothnian Sea.

scholarly journals Structure and Characterization of Phosphoglucomutase 5 from Atlantic and Baltic Herring—An Inactive Enzyme with Intact Substrate Binding

Biomolecules ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1631
Author(s):  
Robert Gustafsson ◽  
Ulrich Eckhard ◽  
Weihua Ye ◽  
Erik D. Enbody ◽  
Mats Pettersson ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Active Site ◽  
Muscle Protein ◽  
Substrate Binding ◽  
Clupea Harengus ◽  
Metabolic Enzyme ◽  
Structure Comparison ◽  
Baltic Herring ◽  
The Baltic

Phosphoglucomutase 5 (PGM5) in humans is known as a structural muscle protein without enzymatic activity, but detailed understanding of its function is lacking. PGM5 belongs to the alpha-D-phosphohexomutase family and is closely related to the enzymatically active metabolic enzyme PGM1. In the Atlantic herring, Clupea harengus, PGM5 is one of the genes strongly associated with ecological adaptation to the brackish Baltic Sea. We here present the first crystal structures of PGM5, from the Atlantic and Baltic herring, differing by a single substitution Ala330Val. The structure of PGM5 is overall highly similar to structures of PGM1. The structure of the Baltic herring PGM5 in complex with the substrate glucose-1-phosphate shows conserved substrate binding and active site compared to human PGM1, but both PGM5 variants lack phosphoglucomutase activity under the tested conditions. Structure comparison and sequence analysis of PGM5 and PGM1 from fish and mammals suggest that the lacking enzymatic activity of PGM5 is related to differences in active-site loops that are important for flipping of the reaction intermediate. The Ala330Val substitution does not alter structure or biophysical properties of PGM5 but, due to its surface-exposed location, could affect interactions with protein-binding partners.

scholarly journals Discrimination of western Baltic spring-spawning and central Baltic herring (Clupea harengus L.) based on growth vs. natural tag information

2013 ◽  
Vol 70 (6) ◽  
pp. 1108-1117 ◽  
Author(s):  
Tomas Gröhsler ◽  
Rainer Oeberst ◽  
Matthias Schaber ◽  
Niklas Larson ◽  
Georgs Kornilovs
Keyword(s):  
Age Groups ◽  
Clupea Harengus ◽  
Commercial Fisheries ◽  
Survey Area ◽  
Separation Function ◽  
The Baltic Sea ◽  
Quick Method ◽  
Baltic Herring ◽  
Abundance Indices ◽  
The Baltic

Abstract Gröhsler, T., Oeberst, R., Schaber, M., Larson, N., and Kornilovs, G. 2013. Discrimination of western Baltic spring-spawning and central Baltic herring (Clupea harengus L.) based on growth vs. natural tag information. – ICES Journal of Marine Science, 70: 1108–1117. In the Baltic Sea, several stocks of herring (Clupea harengus L.) are surveyed and managed separately. For assessment purposes, a spatial stock separation based on ICES subdivisions is implemented. However, especially in the western Baltic, the distribution areas of two stocks, the western Baltic spring-spawning herring and the central Baltic herring, overlap. Results of regularly conducted surveys for assessment purposes indicated variable degrees of mixing of both stocks in the survey area, based on conspicuous differences in weights/lengths within certain age groups, especially in an area known for overlapping distribution of both stocks. At present, varying fractions of the central Baltic herring stock have not been taken into account during regular surveys conducted in the western Baltic, leading to possible undetected biases in assessment indices derived from these surveys. Additionally, methods otherwise applied for stock separation of Baltic herring so far are based on parameters that cannot readily be derived during regular surveys. In this paper, we present a simple and quick method to reliably allocate herring to either stock based on a separation function derived from survey-based length-at-age data, thus facilitating a more precise estimate of biomass and abundance indices from regular surveys and commercial fisheries.

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