Initiation of migration and movement rates of Atlantic salmon smolts in fresh water

2015 ◽  
Vol 72 (9) ◽  
pp. 1339-1351 ◽  
Author(s):  
Daniel S. Stich ◽  
Michael T. Kinnison ◽  
John F. Kocik ◽  
Joseph D. Zydlewski
Keyword(s):  
Atlantic Salmon ◽  
Environmental Conditions ◽  
Management Practices ◽  
Movement Rate ◽  
Movement Rates ◽  
Trade Offs ◽  
Hydropower Dams ◽  
Before And After ◽  
Penobscot River ◽  
Migratory Period

Timing of ocean entry is critical for marine survival of both hatchery and wild Atlantic salmon (Salmo salar) smolts. Management practices and barriers to migration such as dams may constrain timing of smolt migrations resulting in suboptimal performance at saltwater entry. We modeled influences of stocking location, smolt development, and environmental conditions on (i) initiation of migration by hatchery-reared smolts and (ii) movement rate of hatchery- and wild-reared Atlantic salmon smolts in the Penobscot River, Maine, USA, from 2005 through 2014 using acoustic telemetry data. We also compared movement rates in free-flowing reaches with rates in reaches with hydropower dams and head ponds. We compared movement rates before and after (1) removal of two mainstem dams and (2) construction of new powerhouses. Initiation of movement by hatchery fish was influenced by smolt development, stocking location, and environmental conditions. Smolts with the greatest gill Na+, K+-ATPase (NKA) activity initiated migration 24 h sooner than fish with the lowest gill NKA activity. Fish with the greatest cumulative thermal experience initiated migration 5 days earlier than those with lowest cumulative thermal experience. Smolts released furthest from the ocean initiated migration earlier than those released downstream, but movement rate increased by fivefold closer to the ocean, indicating behavioral trade-offs between initiation and movement rate. Dams had a strong effect on movement rate. Movement rate increased from 2.8 to 5.4 km·h−1 in reaches where dams were removed, but decreased from 2.1 to 0.1 km·h−1 in reaches where new powerhouses were constructed. Movement rate varied throughout the migratory period and was inversely related to temperature. Fish moved slower at extreme high or low discharge. Responses in fish movement rates to dam removal indicate the potential scope of recovery for these activities.

scholarly journals Optimal Flow—A Pilot Study Balancing Sheep Movement and Welfare in Abattoirs

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 344
Author(s):  
Melissa J. Starling ◽  
Elyssa Payne ◽  
Paul McGreevy
Keyword(s):  
Pilot Study ◽  
Additional Source ◽  
Movement Rate ◽  
Optimal Outcomes ◽  
Optimal Flow ◽  
Livestock Movement ◽  
Trade Offs ◽  
Behavioural Interactions ◽  
Handling Practices ◽  
Rate Of Movement

Abattoirs are faced with the challenge of moving livestock efficiently through the plant, while also engaging in handling practices that assure good animal welfare. Achieving optimal outcomes for both of these goals can bring them into conflict. An additional source of conflict can arise from the design of the abattoir. These problems are compounded by the dearth of research available to inform how livestock should be handled to achieve all of these goals. We applied the concept of ‘Optimal Flow’ to describe conditions under which rate of movement is maximised while overt signs of distress in sheep are minimised. Effectively, this represents the point at which trade-offs between speed and welfare converge. The current pilot study examined the behavioural interactions between humans (n = 5), livestock herding dogs (n = 7), and sheep (n = 3235) in a large Australian abattoir to describe the factors associated with an increase or decrease in rate of sheep movement per minute. It revealed that distress behaviours in sheep were associated with dog presence and with a decrease in livestock movement rate. However, we found that as sheep density increased, there was increased livestock movement rate as well as an elevated incidence of distress behaviours. Optimal Flow at this abattoir was achieved by maintaining sheep at lower densities. Our report discusses the possible confounds in this interpretation.

scholarly journals Assessing demographic effects of dams on diadromous fish: a case study for Atlantic salmon in the Penobscot River, Maine

2015 ◽  
Vol 72 (8) ◽  
pp. 2423-2437 ◽  
Author(s):  
Julie L. Nieland ◽  
Timothy F. Sheehan ◽  
Rory Saunders
Keyword(s):  
Atlantic Salmon ◽  
Performance Metrics ◽  
Survival Rates ◽  
Population Viability Analysis ◽  
River System ◽  
Diadromous Fish ◽  
Viability Analysis ◽  
Penobscot River ◽  
Passage Efficiency ◽  
Demographic Effects

Abstract Dams are a major contributor to the historic decline and current low abundance of diadromous fish. We developed a population viability analysis to assess demographic effects of dams on diadromous fish within a river system and demonstrated an application of the model with Atlantic salmon in the Penobscot River, Maine. We used abundance and distribution of wild- and hatchery-origin adult salmon throughout the watershed as performance metrics. Salmon abundance, distribution to upper reaches of the Penobscot watershed, and the number and proportion of wild-origin fish in the upper reaches of the Penobscot watershed increased when dams, particularly mainstem dams, were removed or passage efficiency was increased. Salmon abundance decreased as indirect latent mortality per dam was increased. Salmon abundance increased as marine or freshwater survival rates were increased, but the increase in abundance was larger when marine survival was increased than when freshwater survival was increased. Without hatchery supplementation, salmon abundance equalled zero with low marine and freshwater survival but increased when marine and freshwater survival rates were increased. Models, such as this one, that incorporate biological, environmental, and functional parameters can be used to predict ecological responses of fish populations and can help evaluate and prioritize management and restoration actions for diadromous fish.

Short-term effects of timber harvest and forest edges on ground-layer mosses and liverworts

2005 ◽  
Vol 83 (6) ◽  
pp. 610-620 ◽  
Author(s):  
Cara R Nelson ◽  
Charles B Halpern
Keyword(s):  
Forest Management ◽  
Edge Effects ◽  
Management Practices ◽  
Timber Harvest ◽  
Ground Layer ◽  
Limited Information ◽  
Short Term ◽  
Before And After ◽  
Logging Effects ◽  
Structural Retention

Limited information exists on the effects of forest management practices on bryophytes, despite their importance to forest ecosystems. We examined short-term responses of ground-layer bryophytes to logging disturbance and creation of edges in mature Pseudotsuga forests of western Washington (USA). The abundance and richness of species were measured in four 1-ha forest aggregates (patches of intact forest) and in surrounding logged areas before and after structural retention harvests. One year after treatment, species richness, total cover, and frequency of most moss and liverwort taxa declined within harvest areas. Within forest aggregates, mosses did not show significant edge effects; however, richness and abundance of liverworts declined with proximity to the aggregate edge. Our results suggest that, over short time frames, 1-ha-sized aggregates are sufficient to maintain most common mosses through structural retention harvests but are not large enough to prevent declines or losses of liverworts. Thus, current standards for structural retention, which allow for aggregates as small as 0.2 ha, may be inadequate to retain the diversity and abundance of species found in mature, undisturbed forests.Key words: bryophyte, edge effects, forest borders, forest management, logging effects, structural retention harvest.

scholarly journals Estimation of mean movement rates for blue sharks in the northwestern Pacific Ocean

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Mikihiko Kai ◽  
Yuki Fujinami
Keyword(s):  
Pacific Ocean ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Movement Direction ◽  
Northwestern Pacific ◽  
Migratory Species ◽  
Northwestern Pacific Ocean ◽  
Movement Rate ◽  
Movement Rates ◽  
Wide Range

Abstract Background The blue shark Prionace glauca is a highly migratory species with a circumglobal distribution. Mean movement rate, defined by the horizontal tracking distance between two data points over the duration of time, is commonly used to understand the horizontal displacement of highly migratory species across a wide range. However, the estimation of mean movement rates for blue sharks has never been conducted using a statistical model. We therefore investigated the mean movement rates using a generalized linear mixed model with data from satellite tags to estimate the range of mean movement rates for 10 blue sharks in the northwestern Pacific Ocean and to reveal the interaction of mean movement rate with several factors. Results (1) Estimations of mean movement rates for the 10 blue sharks were significantly influenced by behavioral differences among individuals; (2) uncertainty in the estimation (i.e., predictive and confidence intervals) of mean movement rates for these blue sharks was larger over shorter time periods, and (3) the predictive intervals of mean movement rates for the sharks ranged widely from 0.33 to 5.02 km/h. Conclusion Blue sharks are considered to opportunistically change their mean movement rates regardless of differences in sex, movement direction, or season.

scholarly journals Identifying Sustainable Nitrogen Management Practices for Tea Plantations

Nitrogen ◽  
2022 ◽  
Vol 3 (1) ◽  
pp. 43-57
Author(s):  
Rhys Rebello ◽  
Paul J. Burgess ◽  
Nicholas T. Girkin
Keyword(s):  
Management Practices ◽  
Synergistic Effects ◽  
Soil Health ◽  
N Leaching ◽  
N2o Emissions ◽  
Nitrification Inhibitors ◽  
Financial Barriers ◽  
Trade Offs ◽  
High Yields ◽  
N Management

Tea (Camellia sinensis L.) is the most widely consumed beverage in the world. It is mostly grown in the tropics with a heavy dependence on mineral nitrogen (N) fertilisers to maintain high yields while minimising the areas under cultivation. However, N is often applied in excess of crop requirements, resulting in substantial adverse environmental impacts. We conducted a systematic literature review, synthesising the findings from 48 studies to assess the impacts of excessive N application on soil health, and identify sustainable, alternative forms of N management. High N applications lead to soil acidification, N leaching to surface and groundwater, and the emission of greenhouse gases including nitrous oxide (N2O). We identified a range of alternative N management practices, the use of organic fertilisers, a mixture of organic and inorganic fertilisers, controlled release fertilisers, nitrification inhibitors and soil amendments including biochar. While many practices result in reduced N loading or mitigate some adverse impacts, major trade-offs include lower yields, and in some instances increased N2O emissions. Practices are also frequently trialled in isolation, meaning there may be a missed opportunity from assessing synergistic effects. Moreover, adoption rates of alternatives are low due to a lack of knowledge amongst farmers, and/or financial barriers. The use of site-specific management practices which incorporate local factors (for example climate, tea variety, irrigation requirements, site slope, and fertiliser type) are therefore recommended to improve sustainable N management practices in the long term.

scholarly journals Missing Links in Predicting Berry Sunburn in Future Vineyards

2021 ◽  
Vol 12 ◽  
Author(s):  
Christopher Bahr ◽  
Dominik Schmidt ◽  
Katrin Kahlen
Keyword(s):  
Environmental Conditions ◽  
Management Practices ◽  
Developmental State ◽  
Local Heat ◽  
Mitigation Strategies ◽  
Plant Management ◽  
Modeling Framework ◽  
Promising Tool ◽  
Berry Quality ◽  
Open Issues

Sunburn in grapevine berries is known as a recurring disorder causing severe yield losses and a decline in berry quality. The transition from healthy to sunburnt along a temporal trajectory is not fully understood. It is driven by light-boosted local heat impact and modulated by, e.g., past environments of the berry and its developmental state. Events of berry sunburn are often associated with heatwaves, indicating a link to climate change. In addition, the sensitivity of grapevine architecture to changing environmental condition indicates an urgent need to investigate and adapt mitigation strategies of berry sunburn in future vineyards. In this perspective, we want to identify missing links in predicting berry sunburn in vineyards and propose a modeling framework that may help us to investigate berry sunburn in future vineyards. For this, we propose to address open issues in both developing a model of berry sunburn and considering dynamic canopy growth, and canopy interaction with the environment and plant management such as shoot positioning or leaf removal. Because local environmental conditions drive sunburn, we aim at showing that identifying sunburn-reducing strategies in a vineyard under future environmental conditions can be supported by a modeling approach that integrates effects of management practices over time and takes grapevine architecture explicitly into account. We argue that functional-structural plant models may address such complex tasks. Once open issues are solved, they might be a promising tool to advance our knowledge on reducing risks of berry sunburn in silico.

scholarly journals Rhythmic Clock Gene Expression in Atlantic Salmon Parr Brain

2021 ◽  
Vol 12 ◽  
Author(s):  
Charlotte M. Bolton ◽  
Michaël Bekaert ◽  
Mariann Eilertsen ◽  
Jon Vidar Helvik ◽  
Herve Migaud
Keyword(s):  
Atlantic Salmon ◽  
Clock Genes ◽  
Expression Patterns ◽  
Circadian Expression ◽  
Clock Gene Expression ◽  
Sister Clade ◽  
Before And After ◽  
Salmon Parr ◽  
Species Specific ◽  
Atlantic Salmon Parr

To better understand the complexity of clock genes in salmonids, a taxon with an additional whole genome duplication, an analysis was performed to identify and classify gene family members (clock, arntl, period, cryptochrome, nr1d, ror, and csnk1). The majority of clock genes, in zebrafish and Northern pike, appeared to be duplicated. In comparison to the 29 clock genes described in zebrafish, 48 clock genes were discovered in salmonid species. There was also evidence of species-specific reciprocal gene losses conserved to the Oncorhynchus sister clade. From the six period genes identified three were highly significantly rhythmic, and circadian in their expression patterns (per1a.1, per1a.2, per1b) and two was significantly rhythmically expressed (per2a, per2b). The transcriptomic study of juvenile Atlantic salmon (parr) brain tissues confirmed gene identification and revealed that there were 2,864 rhythmically expressed genes (p < 0.001), including 1,215 genes with a circadian expression pattern, of which 11 were clock genes. The majority of circadian expressed genes peaked 2 h before and after daylight. These findings provide a foundation for further research into the function of clock genes circadian rhythmicity and the role of an enriched number of clock genes relating to seasonal driven life history in salmonids.

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