Peer Review #2 of "Thermal conditions and age structure determine the spawning regularities and condition of Baltic herring (Clupea harengus membras) in the NE of the Baltic Sea (v0.2)"

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.

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Change in growth rate of Baltic herring (Clupea harengus membras L.) in Lithuanian Exclusive Economic Zone (LEEZ) of the Baltic Sea

2012 IEEE/OES Baltic International Symposium (BALTIC) ◽

10.1109/baltic.2012.6249196 ◽

2012 ◽

Author(s):

J. Fedotova

Keyword(s):

Growth Rate ◽

Baltic Sea ◽

Clupea Harengus ◽

Exclusive Economic Zone ◽

The Baltic Sea ◽

Baltic Herring ◽

Economic Zone ◽

The Baltic

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A retrospective study of fatty acid composition in Baltic herring (Clupea harengus membras) caught at three locations in the Baltic Sea (1973–2009)

ICES Journal of Marine Science ◽

10.1093/icesjms/fsx127 ◽

2017 ◽

Vol 75 (1) ◽

pp. 330-339 ◽

Cited By ~ 6

Author(s):

Ylva Lind ◽

Tiina Huovila ◽

Reijo Käkelä

Keyword(s):

Fatty Acids ◽

Baltic Sea ◽

Principal Component ◽

Clupea Harengus ◽

The Baltic Sea ◽

Baltic Herring ◽

Spatial Changes ◽

Environmental Specimen ◽

The One ◽

The Baltic

Abstract Fatty acids (FAs) were analysed in Baltic herring (Clupea harengus membras) stored in the Swedish Environmental Specimen Bank for up to 40 years. The purpose was to evaluate the retrospective use of FA signatures to detect temporal and spatial changes in the Baltic ecosystem. Fish from northern and central Baltic captured in the 1970s, the 1980s, in 1990, 2000, and 2009 and stored at − 25 °C were analysed. From the 1980s and onward herring from the south Baltic were included. A total of 55 FA and 4 alkenyl chains (detected as dimethyl acetals) were identified, and 28 of these (present at > 0.5% by weight) were used in evaluation of the data. The amount of some 20–22 carbon polyunsaturated fatty acids (PUFA) was related to time with lower amounts in older samples while other PUFAs were not related to time. Principal component analysis with saturated FAs and monounsaturated FAs showed similar sample groupings as the one obtained by including the PUFAs. The differences found in herring FA in this longitudinal study could be attributed to location of sampling, year of collection and storage time. However, the clearly distinguishable pattern in the FA composition in herrings from different locations in the Baltic Sea seen at all decades indicate that this technique can be used retrospectively.

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Some Speculations about the Baltic Herring (Clupea harengus membras) in Connection with the Eutrophication of the Baltic Sea

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f85-264 ◽

1985 ◽

Vol 42 (S1) ◽

pp. s83-s90 ◽

Cited By ~ 29

Author(s):

G. Aneer

Keyword(s):

Baltic Sea ◽

Clupea Harengus ◽

Filamentous Algae ◽

The Baltic Sea ◽

Baltic Herring ◽

Significant Difference ◽

Spawning Time ◽

Low Levels ◽

The Baltic

In this paper the hypothesis is put forward that Baltic herring (Clupea harengus membras) spawning time, spring or autumn, is determined by feeding conditions during the adult phase and thus not genetically fixed. The present "absence" of autumn spawners is thought to be the result of improved feeding conditions during the latest decades as a result of the eutrophication of the Baltic Sea. During two spawning ground studies carried out in 1978 and 1982 unusually high mortality rates were noted for eggs in situ. In 1982, during 4 wk close to peak of spawning, the mortality increased substantially, especially for eggs among filamentous algae. A significant difference was noted between eggs on coarser algae and those among filamentous algae (p < 0.001). During this period the average mortalities were 33 and 75%, respectively. Very low levels of oxygen were measured at night among the filamentous algae. An increase in the amounts of this type of algae as a response to the eutrophication might constitute a new hazard to the reproductive success of the Baltic herring.

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Peer Review #1 of "Size matters: relationships between body size and body mass of common coastal, aquatic invertebrates in the Baltic Sea (v0.1)"

10.7287/peerj.2906v0.1/reviews/1 ◽

2017 ◽

Keyword(s):

Body Size ◽

Baltic Sea ◽

Peer Review ◽

Body Mass ◽

Aquatic Invertebrates ◽

The Baltic Sea ◽

The Baltic

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An ecosystem model of food web and fisheries interactions in the Baltic Sea

ICES Journal of Marine Science ◽

10.1016/s1054-3139(03)00098-5 ◽

2003 ◽

Vol 60 (5) ◽

pp. 939-950 ◽

Cited By ~ 89

Author(s):

Chris J Harvey ◽

Sean P Cox ◽

Timothy E Essington ◽

Sture Hansson ◽

James F Kitchell

Keyword(s):

Baltic Sea ◽

Food Web ◽

Species Interactions ◽

Gadus Morhua ◽

Population Analysis ◽

Clupea Harengus ◽

Trophic Relationships ◽

The Baltic Sea ◽

Management Actions ◽

The Baltic

Abstract Because fisheries operate within a complex array of species interactions, scientists increasingly recommend multispecies approaches to fisheries management. We created a food web model for the Baltic Sea proper, using the Ecopath with Ecosim software, to evaluate interactions between fisheries and the food web from 1974 to 2000. The model was based largely on values generated by multispecies virtual population analysis (MSVPA). Ecosim outputs closely reproduced MSVPA biomass estimates and catch data for sprat (Sprattus sprattus), herring (Clupea harengus), and cod (Gadus morhua), but only after making adjustments to cod recruitment, to vulnerability to predation of specific species, and to foraging times. Among the necessary adjustments were divergent trophic relationships between cod and clupeids: cod exhibited top-down control on sprat biomass, but had little influence on herring. Fishing, the chief source of mortality for cod and herring, and cod reproduction, as driven by oceanographic conditions as well as unexplained variability, were also key structuring forces. The model generated many hypotheses about relationships between key biota in the Baltic Sea food web and may ultimately provide a basis for estimating community responses to management actions.

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