Factors driving life-histories in brown trout Salmo trutta exhibiting partial migration behaviours

The behaviors of some partially migratory salmonids, at both the among- and within-species levels, can be established early - on during their respective lives. For those species that have a plastic early life history in these regards, a variety of biological and environmental factors can result in some juvenile fish in a population to either stay resident within their natal streams or become migratory. This study examines the role of intraspecific competition as a trigger, either to remain resident or emigrate, for YoY (young-of-the-year) non-native (introduced) brown trout Salmo trutta found in a number of populations of selected natal streams in a large catchment in South Island, New Zealand. Brown trout are known to have the genetically-mediated flexibility leading to the potential establishment of a variety of within-population alternatives for migratory life-history outcomes (e.g., stay put, move out of the immediate area, become anadromous). The role of positive feedback loops generated by parents that either stay to live out their whole lives within their natal stream, or leave either to go to other freshwater environments (other streams, lakes) or the ocean, before spawning and producing viable offspring is examined in this study. This thesis provides strong evidence for the role of competition in initiating downstream movement of YoY brown trout populations. These are mechanisms leading to the establishment of feedback loops between the migratory or resident life-histories of adults and the density of juvenile fish while they are stream rearing. Competition amongst juveniles was assessed by estimating and comparing the demands for energy and space of a number of rearing populations of YoY fish and the capacity of study stream to provide food and space. Stream-carrying capacity was estimated using data on fish-habitat suitability, invertebrate drift, energetic demand and the trophic selectivity of YoY trout. In the lowland reaches of my study catchment the population densities of YoY fish in their natal streams were generally high. I found the intensity of competition within this category of natal streams, amongst the high-density populations of the offspring of migratory trout, to also be high. Anadromy was the dominant life-history strategy for adult brown trout in these low-gradient, lowland streams. Along the lowland reaches, positive associations between YoY loss rate (driven by both emigration and mortality) and intra-cohort competition, were observed. The intensity of competition amongst YoY cohorts was primarily determined by temperature-mediated energy restrictions rather than territorial limitations. In contrast, in the headwater streams which are inhabited by resident trout, the abundance of YoY juvenile fish was relatively low, and there was no evidence to indicate that competition influenced the loss rate of these fish. Hence, based on the densities, competition and self-thinning of YoY brown trout, this suggests that the majority of the recruitment across the catchment was driven by the high reproductive inputs into lowland spawning grounds from adults with migratory life-history traits. However, an analysis of the recruitment sources of fish using otolith microchemistry indicated that a high proportion of adults reproducing in the coastal part of the catchment originated from the upland part of the catchment. This indicates that populations of anadromous and potamodromous brown trout are likely comprised of individuals originated from throughout the entire catchment. Most notably, the geomorphology of the landscape limits the upstream migration and spawning distribution of large fecund migratory trout due to physical barriers. These results highlight the genetically-mediated life-history flexibility of brown trout and their ability to shift between either migratory or resident phenotypes at early life stages. This flexibility is sustained even in populations that have originated from a likely-narrow genetic pool of introduced lineages of brown trout. Considering current changes in global-climates, the findings of temperature-driven energetic restrictions on species distributions may be highly important for brown trout management and conservation in New Zealand and elsewhere. The observed flexibility in life-history traits and high straying from natal streams contributes to their ability to utilize a wide range of opportunities across catchments

Principios de optimización para los diseños de portales de entrada de salidas de peces por gravedad de estructuras de protección de peces de instalaciones de toma de agua

La prevención de la entrada de peces juveniles en las tomas de agua para diversos fines económicos mediante el diseño de una estructura de protección de peces está asociada a la necesidad de desviar los peces juveniles protegidos (salida de peces) a un lugar seguro de una fuente de agua manteniendo su viabilidad. El desarrollo de principios para la selección de elementos estructurales de salida de peces se basa en los requisitos hidráulicos y biológicos existentes para garantizar el movimiento efectivo de los peces fuera de la influencia de la toma de agua. Para las condiciones de una salida de peces por gravedad abierta, se consideran las características de funcionamiento y las posibles formas de optimización de su elemento central: la parte de entrada, la sección de recepción y la sección de transición. Con base en el análisis de las características más características de la formación del flujo en la zona de influencia de la toma de agua, se determinan las condiciones para el diseño de la parte de entrada de la salida de peces. La solución técnica de la sección de recepción se basa en las características de diseño y el cálculo de los parámetros hidráulicos de las boquillas de presión. Además, los elementos estructurales de la sección de recepción deben ser una combinación secuencial de boquillas desde el aspecto funcional: un confusor cónico - una boquilla cilíndrica - difusor cónico, y las condiciones hidráulicas deben corresponder a los requisitos biológicos y garantizar una corriente de flujo que sea segura para los peces; se presenta el análisis de las condiciones hidráulicas y técnicas de la salida de peces. Desde el punto de vista de los requisitos hidráulicos y biológicos modernos y el conocimiento de los patrones de comportamiento de los peces, se propone el diseño óptimo para el diseño del portal de entrada de una salida de peces por gravedad abierta de la estructura de protección de peces de la instalación de toma de agua

Comparative analysis of the performance of selective and group repeat transmission modes in a transport protocol

We propose a model of a virtual connection controlled by a transport protocol in the selective and group failure modes as a Markov chain with discrete time that accounts for the influence of protocol parameters of window size and timeout duration for waiting for acknowledgements, probabilities of distorting segments in individual links of the data transmission path on the throughput of a transport connection. We have analyzed how the throughput of the control procedure depends on protocol parameters, level of errors in communication channels, and round-trip delay. We have proposed a method for choosing protocol parameters

Kinematical features of locomotion -basis of fish control management in zones of influence of hydrotechnical structures

The structural analysis of the locomotion of various fish species presented in this work opens the possibility to take a fresh look at the solution of the problem of controlling fish behavior in a stream - through the prism of the kinematic structure of vortex structures generated by fish in the course of their swimming by different styles. In the locomotion of fish, there is an analogy with the phenomenon of the superimposition of two "antagonistic" forms of the jet stream - the wakeful (behind the streamlined object) and the flooded turbulent stream

IMPROVING THE EFFICIENCY OF MASTERING DISTRIBUTED INFORMATION SYSTEMS IN A VIRTUAL COMPUTER LAB BASED ON THE USE OF CONTAINERIZATION AND CONTAINER ORCHESTRATION TECHNOLOGIES

This article discusses issues surrounding the training of specialists in distributed information systems using innovative methods and technologies in a virtual computer lab environment with an integrated knowledge management system. The article clearly shows how complex knowledge, skills, and professional competencies should be taught to IT specialists. It provides a detailed exploration of the architecture of the Virtual Computer Lab (VCL) and describes the successful experience of using the VCL in classes taught by the Department of Systems Analysis and Control at the Dubna State University. The new practice with containers is different compared to hardware virtualization case and effectively complements it for a wide range of practical educational tasks dedicated to the mastering distributed information systems in a virtual computer lab. For the underlying operating system kernel can be used for all containers and improves payload on the north of a similar configuration. The article provides a detailed description of containerization technology to improve the efficiency of IT-training and features of container management in a distributed environment

Оркестрация жизненного цикла многопользовательской виртуальной сетевой функции

Network function virtualization (NFV) is a promising technique of high quality, flexible and scalable service for telecommunication companies clients and for enterprise data center clients. One of the important capabilities of this technique is providing a virtual service as a combination of multiple virtual functions. There are two types of virtual functions: those intended for a single customer (su-VF) and those that can serve multiple users (mu-VF). In case when output of mu-VF is chained with inputs of several different su-VFs, there is a need for a mechanism of identification and separation of users network flows passing through mu-VF to allocate them correctly between inputs of su-VFs in the NFV infrastructure. In the cloud environment, it is not always possible to use VLAN tags, IP and MAC addresses for that. In this paper, we consider the problem of identification of network traffic coming from a certain user inside an NFV platform and present a solution implemented in C2 MANO-platform.Виртуализация сетевых функций (NFV) – перспективная технология предоставления качественного, гибкого и масштабируемого сервиса для клиентов телекоммуникационных компаний и операторов центров обработки данных. Одной из важных возможностей этой технологии является предоставление “сложного” (состоящего из нескольких виртуальных функций) сервиса. Есть два типа виртуальных функций: те, которые ориентированы на работу с конкретным пользователем (далее su-VF); и те, которые используют разные пользователи (далее mu-VF). Если выход mu-VF соединен с входами нескольких su-VF, то возникает необходимость в механизме идентификации и разделения трафика разных пользователей в NFV-инфраструктуре. В облачной среде идентификация пользователей традиционными способами через VLAN теги, IP и MAC-адреса не всегда возможна. В статье рассматривается описанная выше проблема идентификации трафика конкретного пользователя NFV-инфраструктуры, и представлено ее решение, реализованное на MANO-платформе С2

Factors driving life-histories in brown trout Salmo trutta exhibiting partial migration behaviours

The behaviors of some partially migratory salmonids, at both the among- and within-species levels, can be established early - on during their respective lives. For those species that have a plastic early life history in these regards, a variety of biological and environmental factors can result in some juvenile fish in a population to either stay resident within their natal streams or become migratory. This study examines the role of intraspecific competition as a trigger, either to remain resident or emigrate, for YoY (young-of-the-year) non-native (introduced) brown trout Salmo trutta found in a number of populations of selected natal streams in a large catchment in South Island, New Zealand. Brown trout are known to have the genetically-mediated flexibility leading to the potential establishment of a variety of within-population alternatives for migratory life-history outcomes (e.g., stay put, move out of the immediate area, become anadromous). The role of positive feedback loops generated by parents that either stay to live out their whole lives within their natal stream, or leave either to go to other freshwater environments (other streams, lakes) or the ocean, before spawning and producing viable offspring is examined in this study. This thesis provides strong evidence for the role of competition in initiating downstream movement of YoY brown trout populations. These are mechanisms leading to the establishment of feedback loops between the migratory or resident life-histories of adults and the density of juvenile fish while they are stream rearing. Competition amongst juveniles was assessed by estimating and comparing the demands for energy and space of a number of rearing populations of YoY fish and the capacity of study stream to provide food and space. Stream-carrying capacity was estimated using data on fish-habitat suitability, invertebrate drift, energetic demand and the trophic selectivity of YoY trout. In the lowland reaches of my study catchment the population densities of YoY fish in their natal streams were generally high. I found the intensity of competition within this category of natal streams, amongst the high-density populations of the offspring of migratory trout, to also be high. Anadromy was the dominant life-history strategy for adult brown trout in these low-gradient, lowland streams. Along the lowland reaches, positive associations between YoY loss rate (driven by both emigration and mortality) and intra-cohort competition, were observed. The intensity of competition amongst YoY cohorts was primarily determined by temperature-mediated energy restrictions rather than territorial limitations. In contrast, in the headwater streams which are inhabited by resident trout, the abundance of YoY juvenile fish was relatively low, and there was no evidence to indicate that competition influenced the loss rate of these fish. Hence, based on the densities, competition and self-thinning of YoY brown trout, this suggests that the majority of the recruitment across the catchment was driven by the high reproductive inputs into lowland spawning grounds from adults with migratory life-history traits. However, an analysis of the recruitment sources of fish using otolith microchemistry indicated that a high proportion of adults reproducing in the coastal part of the catchment originated from the upland part of the catchment. This indicates that populations of anadromous and potamodromous brown trout are likely comprised of individuals originated from throughout the entire catchment. Most notably, the geomorphology of the landscape limits the upstream migration and spawning distribution of large fecund migratory trout due to physical barriers. These results highlight the genetically-mediated life-history flexibility of brown trout and their ability to shift between either migratory or resident phenotypes at early life stages. This flexibility is sustained even in populations that have originated from a likely-narrow genetic pool of introduced lineages of brown trout. Considering current changes in global-climates, the findings of temperature-driven energetic restrictions on species distributions may be highly important for brown trout management and conservation in New Zealand and elsewhere. The observed flexibility in life-history traits and high straying from natal streams contributes to their ability to utilize a wide range of opportunities across catchments