Advances in Fisheries Bioengineering

2008 ◽  
Keyword(s):  
Atlantic Salmon ◽  
Cumulative Effect ◽  
Fish Passage ◽  
Suitable Habitat ◽  
Upstream Migration ◽  
Spawning Period ◽  
Poor Water Quality ◽  
The Mean ◽  
Pass Through ◽  
The Impact

<em>Abstract.</em>—A 2-year radio-tracking study of Atlantic salmon <em>Salmo salar </em>upstream migrants was conducted on the Aulne River in France. The objective was to survey upstream migration in the river, of which 70 km are channeled. The behavior of 126 salmon was studied at 26 weirs (approximately 2 m high) from the beginning of July 1999 to the middle of December 2000. The mean percentage of fish able to pass upstream of weirs fitted with older fish passage facilities was less than for more recent fishways installed since 1994. An evaluation of the cumulative effect of the weirs indicates that only 2–3% of returning adults are likely to pass through the channeled part of the river and reach upstream areas with suitable habitat for spawning. The most obvious blockages occurred at weirs in the lowermost portion of the channeled river. Environmental conditions such as low flows and poor water quality may also make it difficult for salmon entering the river to progress upstream. Moreover, salmon appear to exhibit nontypical migration behaviors in this environment, which is heavily influenced by human activities. More than 26% of returning adults migrated downstream during the study, leaving the Aulne before the spawning period began and entering and migrating upstream through other neighboring rivers. We also estimated the impact of fishing on upstream migrants, which appeared far greater for spring salmon than for grilse. This study provides fisheries managers with a tool to assess restoration plans for Atlantic salmon and better define the actions needed to reach restoration goals.

scholarly journals Analysis of an Ecological Flow Regime during the Ctenopharyngodon Idella Spawning Period Based on Reservoir Operations

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2034 ◽  
Author(s):  
Jie Li ◽  
Hui Qin ◽  
Shaoqian Pei ◽  
Liqiang Yao ◽  
Wei Wen ◽  
...  
Keyword(s):  
Hydrodynamic Model ◽  
Habitat Suitability ◽  
Habitat Model ◽  
Ctenopharyngodon Idella ◽  
Suitable Habitat ◽  
Two Dimensional ◽  
Inference System ◽  
Spawning Period ◽  
Ecological Flow ◽  
The Impact

The study of fish habitats is important for us to better understand the impact of reservoir construction on river ecosystems. Many habitat models have been developed in the past few decades. In this study, a fuzzy logic-based habitat model, which couples fuzzy inference system, two-dimensional laterally averaged hydrodynamic model, and two-dimensional shallow water hydrodynamic model, is proposed to identify the baseline condition of suitable habitat for fish spawning activities. The proposed model considers the reservoir and the downstream river channel, and explores the comprehensive effects of water temperature, velocity, and water depth on habitat suitability. A real-world case that considers the Ctenopharyngodon idella in the Xuanwei Reservoir of Qingshui River is studied to investigate the effect of in- and outflow of reservoir on fish habitat and the best integrative management measure of the model. There were 64 simulations with different reservoir in- and outflows employed to calculate the weighted usable area and hydraulic habitat suitability. The experimental results show that the ecological flow for Ctenopharyngodon idella spawning can satisfy the basic demand when the reservoir inflow is greater than 60 m3/s and the reservoir outflow is greater than 100 m3/s. The habitat ecological suitability is the best when the reservoir outflow is 120 m3/s. A more reasonable and reliable ecological flow range can be obtained based on the habitat model in this paper, which provides the best scenario for water resources planning and management in the Qingshui River Basin.

Adult Atlantic salmon (Salmo salar) spawning migration and behaviour in the lower Skienselva

2021 ◽  
Author(s):  
Sheryl Schwert
Keyword(s):  
Power Plant ◽  
Atlantic Salmon ◽  
Low Flow ◽  
Upstream Migration ◽  
Hydroelectric Power ◽  
Negative Consequences ◽  
Spawning Period ◽  
Fish Ladder ◽  
Spawning Areas ◽  
Spawning Sites

&lt;p&gt;Atlantic salmon swim upstream from the North sea through Frierfjorden to spawn in the Skien watershed, the third largest in Norway. There are two hydroelectric power plants in the lower reaches of the Skienselva: Klosterfoss and Skotfoss. Salmon caught swimming up the fish ladder at the downstream power plant (Klosterfoss) were tagged, released, and at the downstream power plant tracked from the beginning of the upstream migration to the end of the spawning period in the entire anadromous watershed. Salmon spent unequal amounts of time at the four spawning areas in the main river and a tributary between Klosterfoss and Skotfoss. Salmon spent less time at the larger spawning site, Vadrette, compared to the smaller Fossum and Gr&amp;#248;tsund spawning sites. 26% of tagged salmon which swam upstream to the Skotfoss hydroelectric power plant ascended the fish ladder. Further, 16% of all salmon ascended the fish ladder at Skotfoss and continued to upstream spawning sites, indicating that they were homing to sites in the upper watershed. This is much smaller than the what is expected based on the fry populations in the rivers of the Skien watershed, which are augmented by yearly stocking in some of the rivers. Salmon which ascended the Klosterfoss ladder relatively early, swam upstream to Skotfoss more quickly than salmon that arrived relatively late at the Klosterfoss ladder. Short and repeated movements upstream to Skotfoss, and downstream to areas in the Farelva, and back again to Skotfoss were observed in the majority of tagged salmon that approached Skotfoss. The &amp;#8220;yo-yo&amp;#8221; migration of salmon in the Farelva is for the most part unexplained, but the movement costs the salmon valuable energy before and during the spawning season and may have negative consequences. Overall, these results indicate that salmon find the entrance to the fish ladder and do not remain stuck at the tunnel outlet, but most do not successfully ascend it. This could be the result of poor ladder construction, too low flow from the ladder, low survival of fry from upstream of Skotfoss reducing the number of salmon that are homing to upstream spawning areas, or that not all salmon which approach Skotfoss are homing to areas above the ladder. The possibility exists that salmon which will eventually spawn in areas downstream of the ladder engage in searching behavior near the fish ladder. If efforts to restore the populations in the upper watershed are to continue, issues salmon have with ascending the Skotfoss fish ladder must be addressed first.&lt;/p&gt;

scholarly journals The impact of a small-scale riverine obstacle on the upstream migration of Atlantic Salmon

Hydrobiologia ◽  
2017 ◽  
Vol 806 (1) ◽  
pp. 251-264 ◽  
Author(s):  
M. Newton ◽  
J. A. Dodd ◽  
J. Barry ◽  
P. Boylan ◽  
C. E. Adams
Keyword(s):  
Atlantic Salmon ◽  
Small Scale ◽  
Upstream Migration ◽  
The Impact

scholarly journals The Potential Distribution of Juniperus rigida Sieb. et Zucc. Vary Diversely in China under the Stringent and High GHG Emission Scenarios Combined Bioclimatic, Soil, and Topographic Factors

Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1140
Author(s):  
Zhenjiang Lv ◽  
Dengwu Li
Keyword(s):  
Climate Change ◽  
Potential Distribution ◽  
Changbai Mountain ◽  
Suitable Habitat ◽  
Mongolian Plateau ◽  
Plateau Region ◽  
Potential Habitats ◽  
Rcp 8.5 ◽  
The Mean ◽  
The Impact

Global warming poses an enormous threat to particular species with shifts to their suitable habitat. Juniperus rigida Sieb. et Zucc., an endemic species to East Asia and a pioneer species in the Loess plateau region, is endangered because of the shrinking and scattered habitat threatened by climate change. For the sake of analyzing the impact of climate warming on its possible habitat, we herein projected the current and future potential habitats of J. rigida in China and comparatively analyzed the ecological habitat changes in three main distribution regions. There were 110 specimen records of J. rigida collected across China and 22 environmental datasets, including bioclimatic variables and soil and topographical factors, selected by the Pearson Correlation Coefficient. The MaxEnt model based on specimen presence and environmental factors was used for projecting the potential habitats of J. rigida in China in the 2050s and the 2070s of RCP 2.6 and RCP 8.5 scenarios. The results indicated an excellence model performance with the average value of the area under curve (AUC) is 0.928. The mean temperature of the driest quarter (MTDq) and the temperature annual range (TAR) provided important contributions to the potential distribution of J. rigida. There were three main distribution areas in China, the Xinjiang region, the Loess-Inner Mongolian Plateau region, and the Changbai Mountain region. The distribution increased overall in area under RCP 2.6 and decreased for RCP 8.5. The mean altitude of the core distribution shifted upward in general under both scenarios. The Loess–Inner Mongolian Plateau region is the biggest distribution, encompassing ca. 61.39 × 104 km2 (86.87 × 104 km2 in China). The region threatened most by climate change is located in the Changbai Mountain distribution, with the centroid of the cord suitable habitat migrating southwest about 227.47 and 260.32 km under RCP 2.6 and RCP 8.5 by the 2070s. In summary, these findings provided a well-grounded understanding of the effect of climate change on ecological distribution and furnished theory evidence for the protection, management, and sustainable use of J. rigida.

Asteroid and Comet Impact Speeds upon Mars: Significance for Panspermia and the Supply of Organics

1997 ◽  
Vol 161 ◽  
pp. 197-201 ◽  
Author(s):  
Duncan Steel
Keyword(s):  
Probability Distributions ◽  
Regions Of Interest ◽  
Significant Fraction ◽  
Organic Chemicals ◽  
Impact Speed ◽  
The Mean ◽  
The Impact

AbstractWhilst lithopanspermia depends upon massive impacts occurring at a speed above some limit, the intact delivery of organic chemicals or other volatiles to a planet requires the impact speed to be below some other limit such that a significant fraction of that material escapes destruction. Thus the two opposite ends of the impact speed distributions are the regions of interest in the bioastronomical context, whereas much modelling work on impacts delivers, or makes use of, only the mean speed. Here the probability distributions of impact speeds upon Mars are calculated for (i) the orbital distribution of known asteroids; and (ii) the expected distribution of near-parabolic cometary orbits. It is found that cometary impacts are far more likely to eject rocks from Mars (over 99 percent of the cometary impacts are at speeds above 20 km/sec, but at most 5 percent of the asteroidal impacts); paradoxically, the objects impacting at speeds low enough to make organic/volatile survival possible (the asteroids) are those which are depleted in such species.

Sound Production Treatment for Acquired Apraxia of Speech: An Examination of Dosage in Relation to Probe Performance

2020 ◽  
pp. 1-16
Author(s):  
Julie L. Wambaugh ◽  
Lydia Kallhoff ◽  
Christina Nessler
Keyword(s):  
Retrospective Analysis ◽  
Sound Production ◽  
Apraxia Of Speech ◽  
Practice Schedule ◽  
Practice Schedules ◽  
Baseline Performance ◽  
The Mean ◽  
Number Of Treatment ◽  
The Impact

Purpose This study was designed to examine the association of dosage and effects of Sound Production Treatment (SPT) for acquired apraxia of speech. Method Treatment logs and probe data from 20 speakers with apraxia of speech and aphasia were submitted to a retrospective analysis. The number of treatment sessions and teaching episodes was examined relative to (a) change in articulation accuracy above baseline performance, (b) mastery of production, and (c) maintenance. The impact of practice schedule (SPT-Blocked vs. SPT-Random) was also examined. Results The average number of treatment sessions conducted prior to change was 5.4 for SPT-Blocked and 3.9 for SPT-Random. The mean number of teaching episodes preceding change was 334 for SPT-Blocked and 179 for SPT-Random. Mastery occurred within an average of 13.7 sessions (1,252 teaching episodes) and 12.4 sessions (1,082 teaching episodes) for SPT-Blocked and SPT-Random, respectively. Comparisons of dosage metric values across practice schedules did not reveal substantial differences. Significant negative correlations were found between follow-up probe performance and the dosage metrics. Conclusions Only a few treatment sessions were needed to achieve initial positive changes in articulation, with mastery occurring within 12–14 sessions for the majority of participants. Earlier occurrence of change or mastery was associated with better follow-up performance. Supplemental Material https://doi.org/10.23641/asha.12592190

The influence of inflation targeting on the pass-through effect of the exchange rate

2018 ◽  
pp. 70-84
Author(s):  
Ph. S. Kartaev ◽  
Yu. I. Yakimova
Keyword(s):  
Developing Countries ◽  
Monetary Policy ◽  
Exchange Rate ◽  
Inflation Targeting ◽  
Policy Regime ◽  
Short And Long Term ◽  
The Exchange Rate ◽  
Pass Through ◽  
The Impact

The paper studies the impact of the transition to the inflation targeting regime on the magnitude of the pass-through effect of the exchange rate to prices. We analyze cross-country panel data on developed and developing countries. It is shown that the transition to this regime of monetary policy contributes to a significant reduction in both the short- and long-term pass-through effects. This decline is stronger in developing countries. We identify the main channels that ensure the influence of the monetary policy regime on the pass-through effect, and examine their performance. In addition, we analyze the data of time series for Russia. It was concluded that even there the transition to inflation targeting led to a decrease in the dependence of the level of inflation on fluctuations in the ruble exchange rate.

Global Food Commodity Prices and Domestic Food Inflation: Some Insights from Morocco

New Medit ◽  
2020 ◽  
Vol 19 (3) ◽  
Author(s):  
Ahmed EL GHIN ◽  
Mounir EL-KARIMI
Keyword(s):  
Exchange Rate Regime ◽  
Commodity Prices ◽  
Food Prices ◽  
Consumer Prices ◽  
Floating Exchange Rate ◽  
Pass Through ◽  
The Impact ◽  
Food Inflation ◽  
Global Food ◽  
Domestic Food

This paper examines the world commodity prices pass-through to food inflation in Morocco, over the period 2004-2018, by using Structural Vector Autoregression (SVAR) model on monthly data. Several interesting results are found from this study. First, the impact of global food prices on domestic food inflation is shown significant, which reflects the large imported component in the domestic food consumption basket. Second, the transmission effect is found to vary across commodities. Consumer prices of cereals and oils significantly and positively respond to external price shocks, while those of dairy and beverages are weakly influenced. Third, there is evidence of asymmetries in the pass-through from world to domestic food prices, where external positive shocks generate a stronger local prices response than negative ones. This situation is indicative of policy and market distortions, namely the subsidies, price controls, and weak competitive market structures. Our findings suggest that food price movements should require much attention in monetary policymaking, especially that the country has taken preliminary steps towards the adoption of floating exchange rate regime.

Impact of changing rainfall conditions on surface and groundwater resources in an experimental watershed in Greece

2013 ◽  
Vol 12 (2) ◽  
pp. 119-125
Keyword(s):  
Groundwater Resources ◽  
Annual Runoff ◽  
Annual Rainfall ◽  
Rainfall Regime ◽  
Winter Rainfall ◽  
Rainfall Depth ◽  
Rainfall Volume ◽  
The Mean ◽  
Groundwater Reserves ◽  
The Impact

The present study concerns the impact of a change in the rainfall regime on surface and groundwater resources in an experimental watershed. The research is conducted in a gauged mountainous watershed (15.18 km2) that is located on the eastern side of Penteli Mountain, in the prefecture of Attica, Greece and the study period concerns the years from 2003 to 2008. The decrease in the annual rainfall depth during the last two hydrological years 2006-2007, 2007-2008 is 10% and 35%, respectively, in relation to the average of the previous years. In addition, the monthly distribution of rainfall is characterized by a distinct decrease in winter rainfall volume. The field measurements show that this change in rainfall conditions has a direct impact on the surface runoff of the watershed, as well as on the groundwater reserves. The mean annual runoff in the last two hydrological years has decreased by 56% and 75% in relation to the average of the previous years. Moreover, the groundwater level follows a declining trend and has dropped significantly in the last two years.

Implementasi Probability Impact Matriks (PIM) Untuk Mengidentifikasi Kemungkinan dan Dampak Risiko Proyek

2017 ◽  
Vol 8 (1) ◽  
pp. 43-47
Author(s):  
Sufa'atin Sufa'atin
Keyword(s):  
Risk Assessment ◽  
Cumulative Effect ◽  
Project Risk ◽  
Project Construction ◽  
Index Terms ◽  
Project Objectives ◽  
The Impact

One of the obstacles in project construction is that the project is experiencing delays. The delay is influenced by several factors including the absence of risk recording, the unavoidability of the opportunities and the impact of risks that arise in the project and its handling, and the neglected risks that may disrupt the project. Project risk is the cumulative effect of an uncertain event opportunity, which affects the project objectives. Several methods can be used to handle the occurrence of project risk, one of the methods used to perform a risk assessment is the Probability Impact Matrix (PIM). PIM is a method that can be used to analyze risk qualitatively based on probability and its impact. By using the PIM method, some of the opportunities and impacts of risks that may arise in the project can be identified. In addition, the PIM method can minimize the risks that arise in the project and quickly resolve the risks. Index Terms— Project, Risk, PIM, Possibility, Impact

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