scholarly journals MODERN BIOLOGICAL CHARACTERISTICS OF WHITEFISH COREGONUS LAVARETUS, EUROPEAN VENDACE C. ALBULA AND EUROPEAN SMELT OSMERUS EPERLANUS FROM THE IMANDRA LAKE

2020 ◽  
pp. 210-226
Author(s):  
E. M. Zubova ◽  
◽  
N. A. Kashulin ◽  
P. M. Terentyev ◽  
◽  
...  
Keyword(s):  
Fish Species ◽  
Breeding Strategy ◽  
Biological Characteristics ◽  
Coregonus Lavaretus ◽  
Short Cycle ◽  
The Past ◽  
Negative Change ◽  
Osmerus Eperlanus ◽  
Imandra Lake

The modern biological characteristics of numerous fish species from the Imandra Lake reaches – white-fish, european vendace and european smelt was investigated. It was shown that under the conditions of the ongoing negative change in the hydrological and hydrochemical regimes of the lake over the past 20 years, there have been multidirectional changes in the population’s structures of these species. If in short-cycle species (smelt, vendace) there is a positive dynamics of a number of indicators, then in whitefish these changes are negative. Euryphagia of smelt from the Imandra Lake, including the transition to preda-tion when reaching a length of 150 mm, combined with an effective breeding strategy and the virtual ab-sence of a predator press, provide him high numbers and successful competition with other species.

Non-Lethal Sampling Methods for Assessing Environmental Impacts Using a Small-Bodied Sentinel Fish Species

2002 ◽  
Vol 37 (1) ◽  
pp. 195-211 ◽  
Author(s):  
Michelle A. Gray ◽  
Allen R. Curry ◽  
Kelly R. Munkittrick
Keyword(s):  
Fish Species ◽  
Environmental Effects ◽  
Monitoring Program ◽  
Survey Study ◽  
Paper Mills ◽  
The Past ◽  
Slimy Sculpin ◽  
Receiving Waters ◽  
Study Designs ◽  
Fisheries Act

Abstract Under the Canadian Fisheries Act, pulp and paper mills and metal mines must conduct a cyclical monitoring program for potential environmental effects that includes a fish survey. Study designs for the fish survey have been evolving over the past few years, and there has been increased emphasis on the use of small-bodied fish species. Increasing concerns about the potential impacts of sampling programs on the fish populations in smaller receiving waters have led us to develop non-lethal sampling methodologies that will satisfy the information requirements for the environmental effects monitoring program. This manuscript outlines the use of a non-lethal sampling program to collect information on age distributions, growth rates, reproductive performance and fish condition in populations of slimy sculpin inhabiting forested and agricultural sections of a small New Brunswick river.

Returns to education in Russia: Nowhere below?

2021 ◽  
pp. 37-68
Author(s):  
R. I. Kapeliushnikov
Keyword(s):  
Returns To Education ◽  
Tertiary Education ◽  
Economic Value ◽  
Short Cycle ◽  
The Past ◽  
Monitoring Survey ◽  
Low Levels ◽  
Alternative Sources ◽  
Using Data ◽  
Russian Education

The paper presents a wide set of estimates for returns to education in Russia, introducing a number of new sources of microdata that previosly remained unused by both Russian and foreign researchers. Until now virtually all available estimates for Russia were based on data from a single source — The Russia Longitudinal Monitoring Survey — Higher School of Economics (RLMS-HSE). According to these data, since the mid-2000s returns to education rapidly declined and have dropped to abnormally low levels. The paper tests the thesis of ultra-low economic value of Russian education using data from three alternative representative surveys regularly conducted by Rosstat. The analysis shows that currently returns to education in Russia reach 12—13%, which is much higher than the standard RLMS estimates. University-type tertiary education almost doubles earnings (its premium approaches to 100%), and even short-cycle tertiary education provides a premium of about 20—30%. Alternative sources also indicate that over the past 15 years, returns to education in Russia remained stable and, therefore, no decreasing trend in the economic value of education has been observed. This makes it possible to reject the currently popular thesis about abnormally low returns to education in Russia.

Whitefish (Coregonus lavaretus (L.)) landings in the Baltic Sea during the past 100 years: combining official datasets and grey literature

2013 ◽  
Vol 64 ◽  
pp. 133-152 ◽  
Author(s):  
Aare Verliin ◽  
Lauri Saks ◽  
Roland Svirgsden ◽  
Markus Vetemaa ◽  
Mehis Rohtla ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Grey Literature ◽  
Coregonus Lavaretus ◽  
The Baltic Sea ◽  
The Past ◽  
The Baltic

scholarly journals Mitigation of seal-induced damage in salmon and whitefish trapnet fisheries by modification of the fish bag

2004 ◽  
Vol 61 (7) ◽  
pp. 1195-1200 ◽  
Author(s):  
Esa Lehtonen ◽  
Petri Suuronen
Keyword(s):  
Halichoerus Grypus ◽  
Coregonus Lavaretus ◽  
Wire Grid ◽  
The Past ◽  
Steel Wires ◽  
Bag Experiments ◽  
The Wire ◽  
The Difference ◽  
The Baltic ◽  
The Gulf Of Finland

Abstract During the past decade, seal-induced gear and catch damage has increased dramatically in the Baltic Sea. The problems are most severe in the coastal trapnet fisheries for salmon (Salmo salar) and whitefish (Coregonus lavaretus), where grey seals (Halichoerus grypus) in particular frequently visit the traps. There is an acute need for gear modifications and other solutions that can prevent seals from entering the fish bag of the traps. Modifications that have been tested in Finland include a wire grid installed in the funnel of the trap and a fish bag made of extra-strong netting material. In comparative fishing experiments conducted in 2001 in the Gulf of Finland the grid was made of 2-mm steel wires with 175-mm spacing. The average undamaged salmon catch per haul in the fish bag of modified trapnets was significantly higher (70%) than that of traditional traps (Mann–Whitney, p < 0.01). In the whitefish experiments, the average undamaged catch of whitefish per haul was 16% higher in modified trapnets than in traditional traps, but the difference was not significant (Mann–Whitney, p > 0.05). These results indicate that the wire grid did not prevent fish from swimming into the fish bag. Experiments also suggest that the wire grid and the extra-strong netting prevented seals from entering the bag. However, on some occasions seals were able to tear the fish through the netting. Underwater observations confirmed that the wire grid kept adult seals outside the bag while salmon and whitefish could be seen entering through the grid into the bag.

The Strange Case of Relative Gratification and Potential for Political Violence: The V-Curve Hypothesis

1973 ◽  
Vol 67 (2) ◽  
pp. 514-539 ◽  
Author(s):  
Bernard N. Grofman ◽  
Edward N. Muller
Keyword(s):  
Political Violence ◽  
Additive Model ◽  
Absolute Magnitude ◽  
Political Regime ◽  
Collective Violence ◽  
Optimum Level ◽  
Moderate Degree ◽  
The Past ◽  
Negative Change ◽  
Degree Of Association

Perception of discrepancy between optimum level of achievement with respect to desired values and actual level of achievement is a concept that has figured importantly in explanations of collective violence and its subset, political violence (approval of and readiness to engage in behaviors which constitute progressively greater challenge to a political regime). Hypotheses about relationships between a number of static and dynamic achievement discrepancy constructs (labeled “relative gratification,” and built from a variant of the Cantril Self-Anchoring scale) are tested. The achievement discrepancy constructs generally show only a weak degree of association with potential for political violence. However, measures of shift over time in discrepancy show an unexpected and intriguing relationship with potential for political violence: individuals who perceive negative change and individuals who perceive positive change show the highest potential for political violence, while individuals who perceive no change show the lowest potential for political violence; and this V-Curve relationship persists in the presence of various control variables. Moreover, absolute magnitude of shift in discrepancy from present to future shows a moderate degree of correlation with potential for political violence, and makes an independent contribution to a linear additive model. The data base is a sample of a population in which instances of political violence have been relatively frequent in the past.

scholarly journals eDNA as a tool for non-invasive monitoring of the fauna of a turbid, well-mixed system, the Elbe estuary in Germany

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250452
Author(s):  
Martin Schwentner ◽  
Reza Zahiri ◽  
Satoshi Yamamoto ◽  
Martin Husemann ◽  
Björn Kullmann ◽  
...  
Keyword(s):  
Inner City ◽  
Fish Species ◽  
High Tide ◽  
Mixed System ◽  
Invasive Monitoring ◽  
Elbe Estuary ◽  
Small Bodies ◽  
Non Invasive ◽  
The Past ◽  
Ncbi Blast

The Elbe is one of the longest European rivers and features a large, turbid and well-mixed estuary, which runs through the inner city of Hamburg. The Elbe has been closely monitored using classical catch techniques in the past. Here we tested a COI-based eDNA approach for assessing the biodiversity within the Elbe. We sampled three stations in the Elbe, included low and high tide events, as well as two adjoining lakes to compare the recovered faunas. To analyze the data, we employed two different pipelines: the automated mBRAVE pipeline utilizing the BOLD database and one including NCBI BLAST. The number of OTUs with species or higher-level identifications were similar between both approaches with 352 OTUs and 355 OTUs for BLAST and mBRAVE, respectively, however, BLAST searches recovered another 942 unidentified metazoan OTUs. Many taxa were well represented; however, fish species were poorly represented, especially in the Elbe estuary samples. This could be a result of the universal COI primers, which also yielded high read numbers for non-metazoan OTUs, and small-bodies taxa like Rotifera, which might have been sampled together with the eDNA. Our results show a strong tidal influence on the recovered taxa. During low tide, downstream stations resembled sites further upstream, but the former showed a very different OTU composition during high tide and early tide. Such differences might be due to varying impacts of upstream-originating eDNA during tide cycles. Such factors need to be considered when routinely employing eDNA for monitoring programs.

scholarly journals PLENTY OF FISH IN THIS SEA: SIFTING THE PAST IN THE NORTHEASTERN ADRIATIC

Traditiones ◽  
2020 ◽  
Vol 49 (3) ◽  
pp. 17-34
Author(s):  
Nataša Rogelja Caf ◽  
Alenka Janko Spreizer ◽  
Martina Bofulin
Keyword(s):  
Fish Species ◽  
The Past ◽  
North East ◽  
The North ◽  
Nodal Points

The paper discusses heritagization, remembering, and past presencing in the North East Adriatic through the four fish species that serve as nodal points in the interplay between the past and the present. Following the selected fish species, the paper explores the diversity of imaginaries that pertain to the mediation of the past in the present in the field of ethnological study in the North East Adriatic.

scholarly journals Delivering Food to Hungry Fish in the San Francisco Estuary

2021 ◽  
Vol 9 ◽  
Author(s):  
Laura Twardochleb ◽  
Leela Dixit ◽  
Mallory Bedwell ◽  
Brittany Davis ◽  
Jared Frantzich
Keyword(s):  
Invasive Species ◽  
San Francisco ◽  
Fish Species ◽  
San Francisco Estuary ◽  
Fish Food ◽  
Yolo Bypass ◽  
Delta Smelt ◽  
Endangered Fish ◽  
The Past

The San Francisco Estuary is home to an important endangered fish called delta smelt. Delta smelt eat small, nutritious animals called zooplankton to survive and grow. In turn, zooplankton grow by eating microscopic plant-like organisms called phytoplankton. In the past, the Estuary was full of plankton and delta smelt. Because people have removed water from the Estuary and invasive species now live there, the Estuary no longer has enough plankton to feed delta smelt, making it difficult for them to survive. Scientists have found a unique place in the Estuary, the Yolo Bypass, that has lots of fish food. The problem is that delta smelt do not live in the Yolo Bypass year-round. Scientists are working to solve this problem by sending river or farm water through the Yolo Bypass, to move fish food downstream to feed the hungry delta smelt and other fish species.

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