672 research outputs found
Automated artemia length measurement using U-shaped fully convolutional networks and second-order anisotropic Gaussian kernels
The brine shrimp Artemia, a small crustacean zooplankton organism, is universally used as live prey for larval fish and shrimps in aquaculture. In Artemia studies, it would be highly desired to have access to automated techniques to obtain the length information from Anemia images. However, this problem has so far not been addressed in literature. Moreover, conventional image-based length measurement approaches cannot be readily transferred to measure the Artemia length, due to the distortion of non-rigid bodies, the variation over growth stages and the interference from the antennae and other appendages. To address this problem, we compile a dataset containing 250 images as well as the corresponding label maps of length measuring lines. We propose an automated Anemia length measurement method using U-shaped fully convolutional networks (UNet) and second-order anisotropic Gaussian kernels. For a given Artemia image, the designed UNet model is used to extract a length measuring line structure, and, subsequently, the second-order Gaussian kernels are employed to transform the length measuring line structure into a thin measuring line. For comparison, we also follow conventional fish length measurement approaches and develop a non-learning-based method using mathematical morphology and polynomial curve fitting. We evaluate the proposed method and the competing methods on 100 test images taken from the dataset compiled. Experimental results show that the proposed method can accurately measure the length of Artemia objects in images, obtaining a mean absolute percentage error of 1.16%
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Fish Passage Engineering Design Criteria
Anthropogenic activities in rivers may introduce undue hazards to many aquatic organisms and contribute to overall habitat fragmentation. Fragmentation may negatively alter the structure and diversity of both diadromous and resident fish populations. These adverse impacts can be mitigated through dam removal, and a variety of technical and nature-like fish passage and protection technologies. Fish passage and protection (hereafter simply āfish passageā) requires the integration of numerous scientific and engineering disciplines including fish behavior, ichthyomechanics, hydraulics, hydrology, geomorphology, and hydropower. This document is intended to: 1) establish Engineeringās ābaselineā design criteria for fishways, dam removals, road crossings and other fish passage related technologies; 2) serve as a resource for training in these disciplines; and 3) support the implementation of the Serviceās statutory authorities related to the conservation and protection of aquatic resources (e.g., Section 18 of the Federal Power Act, Endangered Species Act, Fish and Wildlife Coordination Act, and the Anadromous Fish Conservation Act)
Nonintrusive methods for biomass estimation in aquaculture with emphasis on fish: a review
Fish biomass estimation is one of the most common and important practices in aquaculture. The regular acquisition of fish biomass information has been identified as an urgent need for managers to optimize daily feeding, control stocking densities and ultimately determine the optimal time for harvesting. However, it is difficult to estimate fish biomass without human intervention because fishes are sensitive and move freely in an environment where visibility, lighting and stability are uncontrollable. Until now, fish biomass estimation has been mostly based on manual sampling, which is usually invasive, timeāconsuming and laborious. Therefore, it is imperative and highly desirable to develop a noninvasive, rapid and costāeffective means. Machine vision, acoustics, environmental DNA and resistivity counter provide the possibility of developing nonintrusive, faster and cheaper methods forĀ in situĀ estimation of fish biomass. This article summarizes the development of these nonintrusive methods for fish biomass estimation over the past three decades and presents their basic concepts and principles. The strengths and weaknesses of each method are analysed and future research directions are also presented. Studies show that the applications of information technology such as advanced sensors and communication technologies have great significance to accelerate the development of new means and techniques for more effective biomass estimation. However, the accuracy and intelligence still need to be improved to meet intensive aquaculture requirements. Through close cooperation between fisheries experts and engineers, the precision and the level of intelligence for fish biomass estimation will be further improved based on the above methods
USCID water management conference
Presented at Emerging challenges and opportunities for irrigation managers: energy, efficiency and infrastructure: a USCID water management conference held on April 26-29, 2011 in Albuquerque, New Mexico.Includes bibliographical references.Verifying conservation estimates for on-farm agricultural water conservation programs -- Improving irrigation system performance in the Middle Rio Grande through scheduled water delivery -- Urbanization of irrigation districts in the Texas Rio Grande River Basin -- Urbanization issues in the Middle Rio Grande Conservancy District -- From canyons to canals: applying regulated river research to canal bank analysis -- Water for irrigation, streams and economy: evaluating past and future climate change to secure a reliable water supply for multiple needs -- Flow measurement capabilities of diversion works in the Rio Grande Project area -- Open-channel and pipe flow measurement at Mohave Valley Irrigation and Drainage District using Venturi technology with bubbler sensors -- Using an ADCP to determine canal seepage losses in the Middle Rio Grande Conservancy District -- Venturi meters constructed with pipe fittings: an under-appreciated option for measuring agricultural water -- Improving crop water use determination using adjusted eddy covariance heat fluxes -- Performance evaluation of TDT soil water content and Watermark soil water potential sensors -- Meeting water challenges in Idaho through water banking -- Water transfers in California: 20 years of progress, view to the future
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TRā2014 ā01 Fish Passage Workshop Training Manual (8/8/2014)
This Technical Report was assembled for, and disturbed during, the U.S. Fish and Wildlife Service (USFWS) Fish Passage Workshop (Workshop) held in Hadley, Massachusetts on August 5 and 6, 2014. The Workshop, a two-day training course for engineers, biologists, hydrologists, environmental scientists, and practitioners involved in the design, operation and oversight of fish passage projects, was developed in partnership with the U.S. Geological Surveyās (USGS) S.O. Conte Anadromous Fish Research Center (Conte) and the University of Massachusetts Amherstās Department of Civil and Environmental Engineering (CEE)
Modelling Braided River Morphodynamics Using a Particle Travel Length Framework
Numerical models that predict channel evolution are an essential tool for investigating processes that occur over timescales which render field observation intractable. The current generation of morphodynamic models, however, either oversimplify the relevant physical processes or, in the case of more physically complete codes based on computational fluid dynamics (CFD), have computational overheads that severely restrict the spaceātime scope of their application. Here we present a new, open-source, hybrid approach that seeks to reconcile these modelling philosophies. This framework combines steady-state, two-dimensional CFD hydraulics with a rule-based sediment transport algorithm to predict particle mobility and transport paths which are used to route sediment and evolve the bed topography. Data from two contrasting natural braided rivers (Rees, New Zealand, and Feshie, United Kingdom) were used for model verification, incorporating reach-scale quantitative morphological change budgets and volumetric assessment of different braiding mechanisms. The model was able to simulate 8 of the 10 empirically observed braiding mechanisms from the parameterized bed erosion, sediment transport, and deposition. Representation of bank erosion and bar edge trimming necessitated the inclusion of a lateral channel migration algorithm. Comparisons between simulations based on steady effective discharge versus event hydrographs discretized into a series of model runs were found to only marginally increase the predicted volumetric change, with greater deposition offsetting erosion. A decadal-scale simulation indicates that accurate prediction of event-scale scour depth and subsequent deposition present a methodological challenge because the predicted pattern of deposition may never ācatch upā to erosion if a simple path-length distribution is employed, thus resulting in channel over-scouring. It may thus be necessary to augment path-length distributions to preferentially deposit material in certain geomorphic units. We anticipate that the model presented here will be used as a modular framework to explore the effect of different process representations, and as a learning tool designed to reveal the relative importance of geomorphic transport processes in rivers at multiple timescales
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