Milne Technologies

Keene, Canada

Milne Technologies

Keene, Canada
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Patrick P.H.,Arcadis | Mason E.,Arcadis | Powell J.,Arcadis | Milne S.,Milne Technologies | Poulton J.S.,Ontario Power Generation
North American Journal of Fisheries Management | Year: 2014

Barrier nets can be an effective alternative for reducing impingement mortality of fish at power plant intakes. In 2010, a paired, split-beam hydroacoustic method was used as the primary assessment tool for comparing relative fish density between the lake ("outside") and station ("inside") side of the Pickering Nuclear Generating Station fish diversion system (FDS) barrier net while it was in place. Behavioral information was also collected using a DIDSON acoustic camera and underwater video camera to determine fish responses to the FDS. Verification monitoring was completed using conventional gill netting. The DIDSON provided useful and valuable information on relative fish densities, relative school sizes, and behavior of fish as individuals, small groups, or schools on both the outside and inside of the FDS, as well as general behavior of fish approaching the FDS. There was no evidence of passage through the net based on DIDSON evaluation; however, fish passage occurred when the FDS net was considered to be in a degraded condition (from biofouling or storm events, or both) and passage occurred over the net, not through it. Analysis of the hydroacoustic data based on the weighted average biomass indicated that FDS effectiveness was 75, 98, and 100% for the spring, summer, and fall periods, respectively, and 98% for the three seasons combined. The summer and fall estimates were based on net performance under optimal net-deployment conditions and if the net degrades, effectiveness is reduced significantly as observed in the spring data. Our study results were supported by impingement monitoring at the station whereby impingement biomass was reduced by greater than 80% for each of the first 3 years after installation compared with before installation of the barrier net. Overall, the FDS was demonstrated to offer significant fish protection from potential impingement at the Pickering Nuclear Generating Station.Received July 21, 2013; accepted December 6, 2013. © 2014 Copyright © Taylor & Francis Group, LLC.

Cott P.A.,Natural Resources Canada | Guzzo M.M.,University of Manitoba | Chapelsky A.J.,University of Manitoba | Milne S.W.,Milne Technologies | And 2 more authors.
Hydrobiologia | Year: 2015

Determining the habitat use and movements by fish is critical to our understanding of aquatic ecosystem function. The objective of this study was to assess the diel movements of Burbot (Lota lota) over the open water season. We employed a high-resolution acoustic telemetry positioning system to track the movements and activity of four Burbot during the ice-free season (between June and September) in a sub-Arctic lake. Burbot underwent diel bank migration (DBM), a benthic form of diel vertical migration, where depths are transitioned in close association with the bottom rather than through the water column. During daytime, Burbot occupied deeper water, at the transition of soft, low complexity substrates and ascended along the rocky bottom lake banks to shallower water habitats at night. Increased activity rates during shallow water forays suggest active feeding events. DBM was low at the start of summer with nearly 24 h of daylight, but increased towards the mid-summer with a more pronounced night cycle, coalescing towards the fall. The DBM of Burbot is dynamic, with proximate triggers of light and temperature, and ultimate causes likely being foraging opportunities, bioenergetics gain and predator avoidance. © 2015 Springer International Publishing Switzerland

Dunlop E.S.,Ontario Ministry of Natural Resources | Milne S.W.,Milne Technologies | Ridgway M.S.,Ontario Ministry of Natural Resources | Condiotty J.,Kongsberg Simrad United States | Higginbottom I.,Myriax Software Pty Ltd
Transactions of the American Fisheries Society | Year: 2010

Multibeam echo sounder systems allow the in situ observation of swimming and foraging behavior and give insights into the ecology of fish at the individual level. In Lake Opeongo, Ontario, 16 adult lake trout Salvelinus namaycush were surgically implanted with ultrasonic tags, released, and studied by means of mobile fisheries acoustics. The transmitted pulses from the ultrasonic tags could be detected and displayed within the multibeam echogram in real time. Tagged lake trout were relocated on 131 occasions over 12 d, for a total of 11.7 h of echogram observations. From these events we observed and quantified the spatial relationships of individual lake trout to other fish targets, schools of cisco Coregonus artedi, and the surrounding habitat. We found that all but one tagged lake trout spent at least a portion of their time close to the lake's bottom, but interestingly, many made rapid vertical swimming movements into the water column. These burst vertical movements were sometimes targeted at schools of cisco, such attacks always occurring from below the schools. During such interactions, the lake trout showed distinct peaks in swimming speed when they were between 2.4 and 6.4 m from the schools; we interpret this as the range of their reactive distance in the field. Some of the lake trout were also found to travel alongside of or to actively swim toward other fish targets, whereas others were more solitary. This type of information, made possible by the integration of fisheries acoustics and biotelemetry technology, gives us a fuller understanding of the ecology of aquatic predators and their prey and provides the direct measurements needed to quantify the bioenergetics of lake trout in their natural environment. © Copyright by the American Fisheries Society 2010.

de Kerckhove D.T.,University of Toronto | Milne S.,Milne Technologies | Shuter B.J.,University of Toronto
Fisheries Research | Year: 2015

The measurement of school swimming speeds across an acoustic beam from a fixed-platform split-beam transducer is difficult because it is impossible to accurately discern individual fish within a school, or track the displacement of the leading edge of the school over time. However, with two acoustic transducers the swimming speed of schools can be estimated as long as the school swims through both beams, and the detection angle when the school first interacts with the beam is known. Here we present a methodology for (1) measuring school swimming speeds with two 120. kHz elliptical (4°. ×. 10°) split-beam acoustic transducers, and (2) estimating the detection angle of the school using Angular Position data within the school region. We verify the use of Angular Position data by comparing our derived detection angle with Diner's Attack Angle algorithm for a set of mobile vertical surveys on the same lake. Our derived detection angle methodology may also provide a method for fisheries biologists to correct school dimensions under conditions for which Diner's Attack Angle is not appropriate (i.e. when schools are smaller than the beam width), which should be common in lake surveys or generally when using elliptical acoustic beams. © 2015 Elsevier B.V.

De Kerckhove D.T.,University of Toronto | Milne S.,Milne Technologies | Shuter B.J.,University of Toronto | Abrams P.A.,University of Toronto
Behavioral Ecology | Year: 2015

Movement is a fundamental aspect of the population and community ecology of many organisms, yet, until recently, it has been difficult to measure in the wild. Consequently, simple assumptions are often used to represent movement; a key assumption found in many classic theoretical ecological models (e.g., predator-prey interactions) is that organisms move like ideal gas particles. Here, we test whether this assumption adequately describes the movement of the Cisco (Coregonus artedi) and its schools using fisheries acoustic surveys and mathematical models. We find that several of the individual components of an ideal gas model (IGM) have some inconsistencies with Cisco behavior, yet overall patterns of school formation are close to IGM expectations. For both individual fish and schools: 1) the spatial distributions were random or slightly clumped; 2) the swimming speed distributions were unimodal but significantly different from normal; 3) horizontal movement was more frequent than depth changes; and 4) movement trajectories across the acoustic beam sometimes deviated from straight lines. However, including the average individual and school swimming speeds and known nighttime densities in an IGM generated values that were similar to the observed values for: 1) the time required for schools to form in the morning and 2) school encounter rates. © The Author 2015. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved.

Petreman I.C.,Ontario Ministry of Natural Resources | Jones N.E.,Ontario Ministry of Natural Resources | Milne S.W.,Milne Technologies
Fisheries Research | Year: 2014

Fixed-location, side-looking, multibeam, sonar techniques offer a practical approach to estimate the numbers of migrating fish in rivers that are too large or occluded for traditional sampling methods, such as weir trapping, visual observation techniques, and netting. While this technology has been used to enumerate salmonid escapement in coastal river systems of western North America, little use and evaluation has occurred in inland waters such as the Great Lakes, where rivers and runs of fish are considerably smaller than those along the Pacific coast. We use a "Dual-frequency IDentification SONar" ("DIDSON") imaging sonar system to investigate the error and variability among nine people performing fish counts. There was no significant difference found among observers' estimates of fish abundance per DIDSON file however, the total count of all fish differed from the benchmark value by as much as 26%. Post-processing simple fish counts from DIDSON raw data is labour-intensive and costly. Three subsampling methods of fish passage estimations were developed and evaluated for their accuracy and precision for daily and seasonal time frames. The random and systematic subsampling methods had similar seasonal and daily accuracy and precision with few exceptions. Automation-assisted counting was much more accurate and efficient for seasonal estimates. A ratio of approximately 2:1 was found for the automated to manual fish counts and this varied little among years. The DIDSON multibeam sonar unit is useful in estimating potamodromous fish migrations for large tributaries of the Great Lakes. DIDSON image processing costs can be minimized through suitable subsampling approaches. The automation-assisted method is the most cost-effective means of estimating moderate levels of fish passage over longer study periods. Multiple individuals can be used interchangeably for the manual post-processing of DIDSON data. © 2014.

Dunlop E.S.,Ontario Ministry of Natural Resources | Milne S.W.,Milne Technologies | Ridgway M.S.,Ontario Ministry of Natural Resources
Journal of Great Lakes Research | Year: 2010

We used hydroacoustics to characterize temporal dynamics of fish schools in Georgian Bay and the North Channel of Lake Huron from 2000 to 2004. Dramatic changes in fish school numbers and characteristics were observed over the 5-year period. In 2000, fish schools had an average trace length of 18.2 m and an average height of 2.7 m. Between 2000 and 2004, there was then an increase in the distance of schools from bottom and a drop in the number of schools per kilometer of transect, in the number and proportion of benthic schools, and in the depth, length, height, area, and volume of schools. Netting data confirm that there was a reduction in alewife (Alosa pseudoharengus) that could explain the declines in the number of schools and the changes in fish school characteristics. There was also evidence that the alewife schools were replaced, to a degree, by lake herring schools in Georgian Bay and rainbow smelt schools in the North Channel. Our work provides an example of how fisheries acoustics can be used to study the spatial and behavioural dynamics of fish schools in the Great Lakes. © 2009 Elsevier B.V. All rights reserved.

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