In-situ observations of Baltic herring (Clupea harengus membras) spawning behaviour in the Ask�-Landsort area, northern Baltic proper

1983 ◽  
Vol 74 (2) ◽  
pp. 105-110 ◽  
Author(s):  
G. Aneer ◽  
G. Florell ◽  
U. Kautsky ◽  
S. Nellbring ◽  
L. Sj�stedt
Keyword(s):  
Clupea Harengus ◽  
Baltic Herring ◽  
Spawning Behaviour ◽  
Baltic Proper ◽  
In Situ Observations

Planktivorous Baltic Herring (Clupea harengus) Prey Selectively on Reproducing Copepods and Cladocerans

1992 ◽  
Vol 49 (1) ◽  
pp. 73-77 ◽  
Author(s):  
Juha Flinkman ◽  
Ilppo Vuorinen ◽  
Eero Aro
Keyword(s):  
Large Body ◽  
Stomach Contents ◽  
Clupea Harengus ◽  
Large Body Size ◽  
Food Items ◽  
Baltic Herring ◽  
Gulf Of Bothnia ◽  
Baltic Proper ◽  
The Baltic ◽  
Plankton Species

Plankton and Baltic herring (Clupea harengus) were sampled simultaneously at nine sites in the northern Baltic Sea and Gulf of Bothnia. The stomachs from 45 herring and 54 plankton samples were analysed. The prey consisted mainly of adult mesozooplankters: copepods and cladocerans. Larger zooplankters (mysids and amphipods) were very rare in the stomachs as were the younger stages (copepodids) of copepods. The stomach contents of the fish changed from brackish water and neritic plankton species in the northern Baltic Proper to limnic species in the northern part of the Bothnian Sea. The diversity of plankton species decreased along with the salinity from south to north. Comparison of the plankton samples and herring stomach contents showed that prey with a large body size was selected as food. Generally this resulted in female copepods being chosen, since they are larger than males of the same species. Especially preferred food items were species and stages which carried conspicuous egg sacs (Eurytemora affinis females) or pigmented eggs and embryos (Bosmina longispina, Podon spp). Our results suggest that the Baltic herring is capable of exerting a regulative effect on the prey population comparable with that found in freshwater planktivores.

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

1985 ◽  
Vol 42 (S1) ◽  
pp. s83-s90 ◽  
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.

In situ observations of electromigration induced void behavior

1995 ◽  
Vol 53 ◽  
pp. 244-245
Author(s):  
T. Marieb ◽  
J. C. Bravman ◽  
P. Flinn ◽  
D. Gardner ◽  
M. Madden
Keyword(s):  
Electron Microscopy ◽  
Void Nucleation ◽  
Plan View ◽  
Transmission Electron ◽  
Nucleation Sites ◽  
Microelectronics Industry ◽  
In Situ Observations ◽  
Backscatter Electron Detector ◽  
Voltage Scanning

Electromigration and stress voiding have been active areas of research in the microelectronics industry for many years. While accelerated testing of these phenomena has been performed for the last 25 years[1-2], only recently has the introduction of high voltage scanning electron microscopy (HVSEM) made possible in situ testing of realistic, passivated, full thickness samples at high resolution.With a combination of in situ HVSEM and post-testing transmission electron microscopy (TEM) , electromigration void nucleation sites in both normal polycrystalline and near-bamboo pure Al were investigated. The effect of the microstructure of the lines on the void motion was also studied.The HVSEM used was a slightly modified JEOL 1200 EX II scanning TEM with a backscatter electron detector placed above the sample[3]. To observe electromigration in situ the sample was heated and the line had current supplied to it to accelerate the voiding process. After testing lines were prepared for TEM by employing the plan-view wedge technique [6].

EFFECT OF SODIUM LACTATE ON QUALITY OF LIGHTLY SALTED FISH IN OXYGEN FREE PACKAGING

2017 ◽  
pp. 128-137
Author(s):  
Elena Yuryevna Porotikova ◽  
Boris Lazarevich Nekhamkin ◽  
Mikhail Pavlovich Andreev
Keyword(s):  
Modified Atmosphere Packaging ◽  
Storage Period ◽  
Sodium Lactate ◽  
Vacuum Packaging ◽  
Storage Life ◽  
Clupea Harengus ◽  
Modified Atmosphere ◽  
Salted Fish ◽  
Baltic Herring ◽  
Organoleptic Characteristics

The present article investigates the effect of sodium lactate on microbiological, physico-chemical and sensory characteristics of lightly salted Pacific herring ( Clupea pallasii ) and Baltic herring ( Clupea harengus membras ) during refrigerated storage 5 ± 0.3°C. There have been analyzed different processing methods of lightly salted samples of Pacific and Baltic herring: control (without sodium lactate), and experiment (3% sodium lactate), both in vacuum packaging and modified atmosphere packaging (MAP - 40% CO2/60% N2). For vacuum and MAP there were used bags with low oxygen permeability (3 cm3/m2/day). It was found that 3% sodium lactate keeps firmness of the texture of salted fish muscle and reduces the release of water into the package during storage. Adding 3% sodium lactate reduces the value of the water activity in lightly salted Pacific and Baltic herring by 0.01-0,012 units. The lowest pH (0.02 units) was registered in samples without sodium lactate packed in MAP. Organoleptic signs of spoilage in fish without sodium lactate appeared much earlier, and using 3% sodium lactate both in vacuum and in MAP helped protect and improve organoleptic characteristics of the product during storage. Total biological semination of experimental samples packed in MAP kept at the very low level during the whole storage period, i.e. combined effect of using 3% sodium lactate and MAP inhibited microbial growth. This combination allows to reduce twice the rate of accumulation nitrogen in terminal amino-groups and to increase 1.5-2 times storage life of lightly salted Pacific and Baltic herring, compared to their storage life in vacuum packaging without sodium lactate. The results obtained allow us to recommend using sodium lactate in production of lightly salted fish in oxygen-free packaging, especially in modified atmosphere packaging (40% CO2/60% N2).

scholarly journals Enzyme-Assisted Extraction of Fish Oil from Whole Fish and by-Products of Baltic Herring (Clupea harengus membras)

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1811
Author(s):  
Ella Aitta ◽  
Alexis Marsol-Vall ◽  
Annelie Damerau ◽  
Baoru Yang
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fish Oil ◽  
Crude Oil ◽  
Proteolytic Enzymes ◽  
Clupea Harengus ◽  
Omega 3 Fatty Acids ◽  
Omega 3 ◽  
Baltic Herring ◽  
By Products

Baltic herring (Clupea harengus membras) is one of the most abundant commercially caught fish species from the Baltic Sea. Despite the high content of fat and omega-3 fatty acids, the consumption of Baltic herring has decreased dramatically over the last four decades, mostly due to the small sizes and difficulty in processing. At the same time there is an increasing global demand for fish and fish oil rich in omega-3 fatty acids. This study aimed to investigate enzyme-assisted oil extraction as an environmentally friendly process for valorizing the underutilized fish species and by-products to high quality fish oil for human consumption. Three different commercially available proteolytic enzymes (Alcalase®, Neutrase® and Protamex®) and two treatment times (35 and 70 min) were investigated in the extraction of fish oil from whole fish and by-products from filleting of Baltic herring. The oil quality and stability were studied with peroxide- and p-anisidine value analyses, fatty acid analysis with GC-FID, and volatile compounds with HS-SPME-GC-MS. Overall, longer extraction times led to better oil yields but also increased oxidation of the oil. For whole fish, the highest oil yields were from the 70-min extractions with Neutrase and Protamex. Protamex extraction with 35 min resulted in the best fatty acid composition with the highest content of eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) but also increased oxidation compared to treatment with other enzymes. For by-products, the highest oil yield was obtained from the 70-min extraction with Protamex without significant differences in EPA and DHA contents among the oils extracted with different enzymes. Oxidation was lowest in the oil produced with 35-min treatment using Neutrase and Protamex. This study showed the potential of using proteolytic enzymes in the extraction of crude oil from Baltic herring and its by-products. However, further research is needed to optimize enzymatic processing of Baltic herring and its by-products to improve yield and quality of crude oil.

scholarly journals In situ observations of coral spawning and spawn slick at Lankayan Island, Sabah, Malaysia

2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Sze Hoon Gan ◽  
Zarinah Waheed ◽  
Fung Chen Chung ◽  
Davies Austin Spiji ◽  
Leony Sikim ◽  
...  
Keyword(s):  
Coral Spawning ◽  
In Situ Observations

scholarly journals Snow Depth Fusion Based on Machine Learning Methods for the Northern Hemisphere

2021 ◽  
Vol 13 (7) ◽  
pp. 1250
Author(s):  
Yanxing Hu ◽  
Tao Che ◽  
Liyun Dai ◽  
Lin Xiao
Keyword(s):  
Machine Learning ◽  
Northern Hemisphere ◽  
Snow Depth ◽  
Learning Algorithm ◽  
Random Forest Regression ◽  
Machine Learning Methods ◽  
Long Time ◽  
In Situ Observations ◽  
Input Variables

In this study, a machine learning algorithm was introduced to fuse gridded snow depth datasets. The input variables of the machine learning method included geolocation (latitude and longitude), topographic data (elevation), gridded snow depth datasets and in situ observations. A total of 29,565 in situ observations were used to train and optimize the machine learning algorithm. A total of five gridded snow depth datasets—Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) snow depth, Global Snow Monitoring for Climate Research (GlobSnow) snow depth, Long time series of daily snow depth over the Northern Hemisphere (NHSD) snow depth, ERA-Interim snow depth and Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) snow depth—were used as input variables. The first three snow depth datasets are retrieved from passive microwave brightness temperature or assimilation with in situ observations, while the last two are snow depth datasets obtained from meteorological reanalysis data with a land surface model and data assimilation system. Then, three machine learning methods, i.e., Artificial Neural Networks (ANN), Support Vector Regression (SVR), and Random Forest Regression (RFR), were used to produce a fused snow depth dataset from 2002 to 2004. The RFR model performed best and was thus used to produce a new snow depth product from the fusion of the five snow depth datasets and auxiliary data over the Northern Hemisphere from 2002 to 2011. The fused snow-depth product was verified at five well-known snow observation sites. The R2 of Sodankylä, Old Aspen, and Reynolds Mountains East were 0.88, 0.69, and 0.63, respectively. At the Swamp Angel Study Plot and Weissfluhjoch observation sites, which have an average snow depth exceeding 200 cm, the fused snow depth did not perform well. The spatial patterns of the average snow depth were analyzed seasonally, and the average snow depths of autumn, winter, and spring were 5.7, 25.8, and 21.5 cm, respectively. In the future, random forest regression will be used to produce a long time series of a fused snow depth dataset over the Northern Hemisphere or other specific regions.

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