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Western Lake Ontario Fisheries Acoustic Surveys (Hamilton Harbour, Toronto Harbour, Bronte Harbour and Rouge River) and Bay of Quinte Surveys.

The purpose of this project is to provide hydroacoustic data processing and fisheries assessment services in support of the “Western Lake Ontario Fisheries Acoustic Survey” program. The program was a multi-year study (2006, 2009, 2010, 2013 and 2016) aimed at assessing changes in the spatial distribution and density of fish in response to a suite of environmental variables (water temperature, dissolved oxygen, seiche events etc.)

Services provided for: Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada

Field technology utilized for this project:
• BioSonics DTX split-beam echosounder (120 kHz, 200 kHz, and 410 kHz)
• Fish sampling equipment including suspended gill nets and pelagic trawls

Products delivered by Milne Technologies:
• Acoustic estimates of pelagic fish abundance and biomass.
• Fish schooling behaviour analysis in relation to turbidity.
• Analysis of the spatial distribution of pelagic fish in relation dissolved oxygen.

Reports:
DFO GLLFAS. 2009. 2006 Hamilton Harbour Offshore Acoustic Surveys, Appendix I: Summary of Results. PowerPoint presentation. Prepared by Milne Technologies. 66 slides.

DFO GLLFAS. 2010. 2009 Toronto Harbour Hydroacoustic Survey Report: Methodology and Summary of Results. Report prepared by Milne Technologies. 57 pgs.

DFO GLLFAS. 2011. 2010 Toronto & Bronte Harbour Hydroacoustic Survey Report: Methodology and Summary of Results. Report prepared by Milne Technologies. 69 pgs.

DFO GLLFAS. 2012. 2011 Bay of Quinte at Conway Hydroacoustic Survey Report: Methodology and Summary of Results. Report prepared by Milne Technologies.

DFO GLLFAS. 2012. 2006-2011 Lake Ontario Nearshore Acoustic Data Review, LO-ERI: Depth Distribution of Fish Density and Biomass. Report prepared by Milne Technologies. 18 pgs.

DFO GLLFAS. 2017. 2016 Hamilton and Toronto Harbour Trawling and Acoustic Surveys: Methodology and Summary of Results. Report prepared by Milne Technologies. 127 pgs.


Fisheries Acoustic Surveys of Lake Simcoe, Ontario.

In 2011-2016, the Ontario Ministry of Natural Resources and Forestry (OMNRF) Aquatic Research & Development Section (ARDS) completed hydroacoustic surveys of Lake Simcoe to test the feasibility of developing acoustic technology into a long-term pelagic fish population monitoring and assessment program.

The objectives of the surveys were to; 1. test the feasibility and value of using hydroacoustic technology as a tool to assess pelagic fish populations in Lake Simcoe, and 2. calculate estimates of pelagic fish density and quantify the sampling variability. Defining the expected survey variability is critical for estimating the survey effort required to generate reliable “whole-lake” fish density estimates from future surveys.

Services provided for: ARDS, Ontario Ministry of Natural Resources and Forestry

Field technology utilized for this project:
• BioSonics DTX split-beam echosounder (70 kHz)
• Simrad EK60 Multi-frequency Echosounder System (38 kHz, 120 kHz, 333 kHz)
• Fish sampling equipment including suspended gill nets and pelagic trawls

Products delivered by Milne Technologies:
• Acoustic estimates of pelagic fish abundance and biomass with emphasis on Cisco.
• Analysis of the variability in the spatial distribution of pelagic fish between survey replicates.

Reports:
OMNRF. 2012. 2011 Lake Simcoe Hydroacoustic Survey Report: Methodology and Summary of Results. Report prepared by Milne Technologies.

OMNRF. 2013. 2012 Lake Simcoe Hydroacoustic Survey Report: Methodology and Summary of Results. Report prepared by Milne Technologies.

OMNRF. 2014. 2013 Lake Simcoe Hydroacoustic Survey Report: Methodology and Summary of Results. Report prepared by Milne Technologies.

OMNRF. 2015. 2014 Lake Simcoe Hydroacoustic Survey Report: Methodology and Summary of Results. Report prepared by Milne Technologies.

OMNRF. 2016. 2015 Lake Simcoe Hydroacoustic Survey Report: Methodology and Summary of Results. Report prepared by Milne Technologies.

OMNRF. 2017. 2016 Lake Simcoe Hydroacoustic Survey Report: Methodology and Summary of Results. Report prepared by Milne Technologies.


Wabush Lake NL. fisheries acoustic survey program.

In 2002, 2005, 2010 and 2013 acoustic surveys of Wabush Lake were completed to assess the density and abundance of fish within the lake. Under the “Wabush Lake Fish Habitat Compensation Agreement Monitoring Program”, the Iron Ore Company of Canada (IOC) is required to monitor the relative abundance of four indicator fish species using an integrated hydroacoustic program that includes a biological sampling component (i.e. gill netting).

Services provided for: EcoMetrix Inc. (2013) and Sikumiut Environmental Management Ltd. (2016)

Field technology utilized for this project:
• Simrad EK60 Echosounder System (120 kHz vertical and horizontal)
• Fish sampling equipment including benthic and suspended gill nets.

Products delivered by Milne Technologies:
• Size stratified acoustic estimates of pelagic fish abundance and biomass.
• Analysis of the spatial distribution of pelagic fish as it relates to the IOC tailings area.

Reports:
Milne, S.W. 2014. 2013 Wabush Lake Hydroacoustic Survey Report: Methodology and Summary of Results. Prepared for EcoMetrix Inc., Mississauga, ON. 101 pages + app.

Milne, S.W. 2017. 2016 Wabush Lake Hydroacoustic Survey Report: Methodology and Summary of Results. Prepared for Sikumiut Environmental Management Ltd., St. John’s, NL. 117 pages + app.


Natural Sciences and Engineering Research Council of Canada (NSERC) Canadian Network for Aquatic Ecosystem Services (CNAES) Fisheries and Fish Habitat Acoustic Surveys of Oligotrophic Lakes (Experimental Lakes Area, Algonquin Park and Haliburton Highlands).

This was a multi-year project (2013-2017) with the aim of developing size-spectrum curves using acoustic estimates of particle size and abundance to provide a measure of aquatic ecosystem “health” (Project 3.3). This project also saw the development of integrated multibeam sonar and biotelemetry tools used for “tracking” tagged fish with a multibeam echosounder system.

Services provided for: University of Toronto and funded by Natural Sciences and Engineering Research Council of Canada (NSERC)

Field technology utilized for this project:
• Simrad EK60 Echosounder System (120 kHz vertical and horizontal, 333 kHz and 710 kHz).
• Kongsberg-Mesotech M3 Multibeam Echosounder System (500 kHz).
• Kongsberg-Mesotech M3 Tag Activator system.
• Sonotronics Transponder (200/500 kHz) Fish Tags
• Fish and zooplankton sampling equipment.


2016 Eastman Chemical Cooling Water Intake Structures (CWIS’s) Acoustic Monitoring and Acoustic Doppler Current Profiler (ADCP) velocity mapping.

In accordance with Clean Water Act § 316(b), the Environmental Protection Agency (EPA) issues regulations on the design and operation of cooling water intake structures (CWISs) in order to minimize adverse impacts on fish and other aquatic organisms. Rules introduced in 2014 requires the location, design, construction, and capacity of existing CWISs reflect the Best Technology Available (BTA) for minimizing adverse environmental impact associated with impingement and entrainment of fish through industrial sector cooling systems.

Eastman Chemical Company in Kingsport, Tennessee, draws water from three cooling water intake structure facilities within the South Fork Holston River. These existing CWISs are subject to Clean Water Act § 316(b) requirements and therefore methods for determining their potential effects (if any) on fish populations were developed and implemented.

Acoustic imaging technologies were accepted and implemented as a suitable non-destructive fisheries assessment tool for continuously monitoring and describing the relative fish abundance within the immediate vicinity of the CWISs and to also describe the general activity and behavioral response of fish to flow regimes adjacent to the CWISs. Alternative available acoustic methods were also used to describe the physical habitat (i.e. bathymetry, substrate and flow velocity) within the immediate vicinity of the CWISs.

Services provided for: Arcadis Canada, Inc.

Field technology utilized for this project:
• Kongsberg-Mesotech M3 Multibeam Echosounder System (500 kHz).
• Sound Metrics Corp., Adaptive Resolution Imaging System (ARIS) Model 1800
• SonTek RiverSurveyor M9 ADCP
• SonTek CastAway CTD
• Hach Model FH950.1 electro-magnetic velocity meter

Products delivered by Milne Technologies:
• Size stratified acoustic estimates of relative fish density and behaviour within the vicinity of 3 cooling water intake structures.
• Spatial (vertical and horizontal) analyses of river flow velocity and vectors.
• Multibeam sonar bathymetry/submerged macrophyte maps and bottom habitat mosaics.

Reports:
Milne, S.W. 2016. 2016 Eastman Chemical Cooling Water Intake Structures Acoustic Monitoring Project (EPA 316B): Methodology and Summary of Results. Prepared for Arcadis Canada, Inc., Richmond Hill, ON. 155 pages + app.


USGS Great Lakes Coastal Wetlands DIDSON/ARIS monitoring program.

The USGS Great Lakes Science Center (GLSC) has implemented an experimental fish passage detection and enumeration methodology using a multi-beam Dual Frequency IDentification SONar (DIDSON) and Adaptive Resolution Imaging Sonar (ARIS) system. The sonar systems were deployed in the vicinity of a wetland water control structure that drains into Crane Creek, a tributary of Lake Erie, located within the U.S. Fish and Wildlife Service Ottawa National Wildlife Refuge. The objective of this work was to assess the activity and abundance of fishes that use the corridor between the riverine and wetland habitats.

From 2011 through 2014 a DIDSON or ARIS imaging system was installed in front of the Pool 2B fish passage structure. Continuous acoustic monitoring occurred over a few days, on a fortnightly schedule, during the spring, summer and fall of each year. From this effort, many TB’s of DIDSON/ARIS echogram data were recorded and an efficient data processing solution was required to extract meaningful ecological information for further analyses. In the past, USGS had relied on staff to manually work through all or a sub-sample of the echograms to provide a visual count of fish and to assess fish activity. This method is highly labour intensive and results in fish count estimates and assessments that may vary significantly between individual observers.

In 2013 and 2016, Milne Technologies successfully developed an automated data processing and fish detection software application that provided USGS the ability to generate timely, cost-effective and reproducible relative fish flux estimates from the 2011-2014 ARIS and DIDSON data.

Services provided for: USGS Great Lakes Science Center (GLSC)

Field technology utilized for this project:
• Sound Metrics Corp., Adaptive Resolution Imaging System (ARIS) Model 1800
• Sound Metrics Corp., Dual Frequency IDentification SONar (DIDSON) Model SR

Products delivered by Milne Technologies:
• User-friendly GUI and software application to work seamlessly with Echoview hydroacoustic processing software to automate ARIS and DIDSON data processing.

Reports:
Milne, S.W. 2016. USGS Crane Creek Automated Sonar Processing Application, AUTOMODV2: User Handbook. Prepared for USGS Great Lakes Science Center, Ann Arbor, MI. 50 pages.


Municipal Waste Water Lagoon multibeam sonar sludge mapping and waste water retention time analyses at the Municipality of Stratford, PEI.
As part of a larger sewage treatment system project, Terrapin Water in association with Milne Technologies carried out two hydroacoustic sonar sludge mapping surveys (one in 2014 and one in 2015) to produce sludge maps and sludge volume estimates for both of the two sewage treatment lagoons located at 10, Stratford Road, Stratford Prince Edward Island. One of the primary goals of the project was to assess the performance of the newly installed “Blue Frog System” as a means of digesting sewage sludge within the lagoons. The report summarizes the results of this project.

The high-resolution sludge maps revealed the formation of a pit or depression within the sludge layer near the effluent stand-pipe within Cell 2. Diver inspection of the stand-pipe showed that a 6 cm crack had formed in the pipe close to the lagoon liner and needed immediate repair. The crack was allowing sludge and solids to leave the lagoon before full biological decomposition was completed. The operator was not aware of the problem previous to the multibeam sludge mapping and was appreciative that we identified the damaged asset.

Services provided for: Terrapin Water and Town of Stratford

Field technology utilized for this project:
• Kongsberg-Mesotech M3 Multibeam Echosounder System (500 kHz).

Products delivered by Milne Technologies:
• High-resolution maps of the sludge layer within each lagoon.
• Estimates of sludge volume and water retention volumes.
• Identified and geo-located damaged lagoon assets

Reports:
TERRAPIN WATER & MILNE TECHNOLOGIES. 2015. 2014 & 2015 Stratford Sewage Lagoon Sludge Mapping. Prepared for the Town of Stratford, PEI. 38 pages.


Little Bear Creek Multi-beam bathymetry data collection, processing and production of high quality fish habitat and bathymetry maps.

Little Bear Creek (LBC) is a small tributary that flows into the St. Clair River estuary approximately 10 km south of the town of Wallaceburg, Ontario. The lower reaches of LBC have been identified as an area where dredging and channel maintenance may be required to increase drainage and minimize the risk of upstream flooding.

The proposed dredging operation within LBC, and its potential impact on fish and fish habitat, is subject to approval by the Department of Fisheries and Oceans (DFO). As a result, DFO requires further knowledge about the pre-dredge status of the drainage channel including bathymetry, existing fish habitat and hydrology, to which the post-redging condition of LBC can be compared.

Milne Technologies provided multibeam bathymetry data collection and map production services in support of the Little Bear Creek fish habitat project.Services provided for: Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada

Field technology utilized for this project:
• Kongsberg-Mesotech M3 Multibeam Echosounder System (500 kHz).

Products delivered by Milne Technologies:
• High-resolution maps for the lower 11 km segment of Little Bear Creek.
• ArcGIS geodatabase

Reports:
Milne, S.W. 2015. 2015 Little Bear Creek multibeam bathymetry survey: field notes and data processing methodology. Prepared for Great Lakes Laboratory for Fisheries and Aquatic Sciences, DFO.


Habitat mapping and substrate classification of Lake Opeongo

In the summer of 2008, Milne Technologies conducted hydroacoustic surveys for the purpose of classifying the substrate of Lake Opeongo, Ontario. Echo integration of the primary and secondary bottom reflections was used to provide a measure of relative substrate roughness and hardness. Several substrate classes were statistically identified using Quester Tangent's Impact seabed classification software. Further assessment of the identified substrate classes was then done using an underwater camera and Ekman dredge. The association of fish targets, including lake trout, with certain types of substrate and habitat can further be analyzed from these and similar future surveys. Click here for more information on how hydroacoustics can be used for habitat mapping and substrate classification.

Services provided for: Harkness Laboratory of FIsheries Research and the Ontario Ministry of Natural Resources

Field technology utilized for this project:
   •  Simrad EY500 120 kHz Split-beam
   •  Splashcam Deep Blue underwater camera
   •  Ekman dredge

Products delivered by Milne Technologies:
   •  Detailed bathymetric and substrate maps
   •  Lake bottom substrate classification and analysis (QTC, E1 Roughness and E2 Hardness)
   •  Data on the distribution of pelagic fish targets in relation to specific habitat features


Lake Huron Double-crested Cormorant Experimental Management Program

The purpose of this project is to provide hydroacoustic data processing and fisheries assessment services in support of the “Lake Huron Double-crested Cormorant Experimental Management Program”. The program was a multi-year study (2000-2005) aimed at monitoring the potential effects of double-crested cormorants on the nearshore and pelagic fish communities in the coastal areas of Georgian Bay and the North Channel.

Services provided for: Ontario Ministry of Natural Resources

Field technology utilized for this project:
   •  Simrad EY500 120 kHz Split-beam
   •  Fish sampling equipment including suspended gill nets and trap nets

Products delivered by Milne Technologies:
   •  Acoustic estimates of pelagic fish abundance and biomass
   •  Fish schooling behaviour analysis in relation to cormorant abundance
   •  Analysis of the spatial distribution of pelagic fish in relation to cormorant abundance
   •  Near-shore index trap-netting data analysis
   •  Bathymetric and habitat mapping

Report:
   •  Double-Crested Cormorant and Coastal Fish Monitoring and Assessment in the North Channel and Georgian         Bay, Lake Huron: Field Methods, Site Descriptions and Analysis Information. Download Full Report.


Integrating Remote Sensing Technologies: A Method for Sampling from Multiple Trophic Levels in Lakes

The purpose of this project was to develop a “rapid resource assessment methodology” that provides the ability to simultaneously sample from multiple trophic levels and across a wide size spectrum of organisms. Five coldwater lakes in Southern Ontario were surveyed with a suite of remote sensing technology. The lakes surveyed were Lake Opeongo (Algonquin Park), Smoke Lake (Algonquin Park), Drag Lake (Haliburton County), Dickey Lake (Hastings County), and Harp Lake (District Municipality of Muskoka).

Services provided for: Aquatic Ecology Group at the University of Toronto.

Field technology utilized for this project:
   •  120 kHz split-beam to assess the pelagic fish community
   •  710 kHz single beam acoustic system to determine the abundance and spatial distribution of zooplankton
   •  Optical plankton counter (OPC) to assess the abundance and size distribution of zooplankton at depth.
   •  SM2000 200 kHz multi-beam sonar was also deployed to observe and map the spatial distribution of lake herring
      schools.

Products delivered by Milne Technologies:
   •  lake trout density and biomass estimates
   •  analysis of the morphology and spatial distribution of lake herring schools
   •  model developed to estimate abundance and size distribution of zooplankton from high-frequency hydroacoustics       to compare with OPC estimates
   •  substrate analyses and classification
   •  bathymetric mapping products



Using Mulit-beam and Split-beam Hydroacoustic Technology to Detect and Track Ultrasonic Tagged Fish

The purpose of this project is to provide a method for directly measuring the in situ target strength of lake trout using integrated multibeam, split beam, and biotelemetry technologies. This work will also provide a unique opportunity to describe the spatial distribution and behavioural patterns of lake trout as they relate to the schooling behaviour of their prey. The field work is being conducted on Lake Opeongo in Algonquin Provincial Park, Ontario, Canada.

Partners: Ontario Ministry of Natural Resources, Kongsberg-Mesotech Simrad Ltd., SonarData Pty Ltd., and the University of Toronto at Mississauga.

Field technology utilized for this project:
   •  SM20 multibeam sonar
   •  EK60 multi-frequency echosounder system
   •  200 kHz pulse coded ultrasonic tags

Products delivered by Milne Technologies:
   •  methodology and results summary report
   •  in situ measurements of target strength of tagged lake trout
   •  lake trout behaviour manuscript
   •  combined frequency echogram analysis
   •  lake bottom substrate classification and analysis (QTC, E1 Roughness and E2 Hardness)

Report:
   •  Using Hydroacoustic Technology to Detect and Track Ultrasonic Tagged Fish: Methodology and Preliminary       Results. 
   •  Click here to see replays of a series of multibeam echogram movies that were recorded during the 2007
      tracking surveys. Go to our lake trout behaviour page.


Understanding the Impact of the Double-crested Cormorant Management Program and the Walleye Rehabilitation Program on the Prey Fish Community of Lac La Biche

The aquatic communities of lakes across Canada are impacted by a number of stresses including habitat degradation, introduction of exotic species, water diversion, climate change, and over-exploitation. Alberta's Lac La Biche has been impacted by the effects of hyper-eutrophication resulting in blooms of toxic blue-green algae, declines in water quality, and fluctuating water levels. Another concern is the observed declines in the commercial and sport fisheries that have been attributted to factors including the increase in piscivorous bird populations (pelicans and cormorants), over-exploitation, and larval fish bottlenecks as a result of increased planktivorous fish production. Recently, the Alberta Sustainble Resource Development introduced a series of management initiatives to return trophic stability to the system. Measures taken include the intensive reintroduction and rehabilitatation of walleye and northern pike within the system as well as intensive management and culling of double crested cormorant colonies. These management changes are expected to impact the species composition and abundance of the planktivorous fish community in the lake. 

The purpose of this project was to design and implement a long-term hydroacoustic survey program for assessing changes in the size, spatial distribution, and abundance of prey fish in Lac La Biche in response to management decisions. The time series of data provided by annual and biannual hydroacoustic surveys will allow the early detection of ecosystem changes and perturbations that will enable managers to respond using an adaptive management plan.

To detect and quantify the number of fish that might have been undersampled within the vertical surveys, a second 200 kHz transducer was used to sample the shallower (< 4 m) regions of the water column. With this method, the split beam transducer was mounted on the tow-body to point away from the survey vessel in a horizontal orientation thus insonifying a large volume of water just below the surface. 

Services provided for: Sustainable Resource Development, Government of Alberta

Field technology utilized for this project:
   •  BioSonics DTX 200 kHz split-beam

Products delivered by Milne Technologies:
   •  echo integration estimates of pelagic fish density and biomass
   •  spatial distribution of fish density and biomass
   •  lake bottom substrate classification and analysis (QTC, E1 Roughness and E2 Hardness)
   •  bathymetry, habitat and submerged macrophyte mapping

Reports:
   •  2006 Lac La Biche Hydroacoustic Survey Report: Methodology and Summary of Results.
   •  2007 Lac La Biche Hydroacoustic Survey Report: Methodology and Summary of Results.


The Potential Impacts of the 2005 Oil Spill on the Fish Community and Habitat of Wabamun Lake

Wabamun Lake recently received national attention when, in August 2005, a train derailment near the town of Whitewood, Alberta spilled 750,000 litres of heavy bunker oil into the lake. The short-term impacts were obvious (e.g., contaminated drinking and bathing water, beach closures, wildlife fouling, etc.), but the long-term ecological impacts of the spill on the lake are unknown. To further understand the ecological impacts of the oil spill and to effectively manage the fish communities within the lake, the Alberta Sustainable Resource Development (SRD) has initiated a long-term fisheries assessment and monitoring program. In consultation with Milne Technologies, the Alberta SRD has designed and implemented a hydroacoustic survey program to assess changes in the size and abundance of the lake whitefish population in the lake.

To detect and quantify the number of fish that might have been undersampled within the vertical surveys, a second 200 kHz transducer was used to sample the shallower (< 4 m) regions of the water column. With this method, the split beam transducer was mounted on the tow-body to point away from the survey vessel in a horizontal orientation thus insonifying a large volume of water just below the surface. 

Services provided for: Sustainable Resource Development, Government of Alberta

Field technology utilized for this project:
   •  BioSonics DTX 200 kHz split-beam

Products delivered by Milne Technologies:
   •  echo integration estimates of pelagic fish density and biomass
   •  spatial distribution of fish density and biomass
   •  lake bottom substrate classification and analysis (QTC, E1 Roughness and E2 Hardness)
   •  bathymetry, habitat and submerged macrophyte mapping

Reports:
   •  2006 Wabamun Lake Hydroacoustic Survey Report: Methodology and Summary of Results.
   •  2007 Wabamun Lake Hydroacoustic Survey Report: Methodology and Summary of Results.


Hydroacoustic Assessment of Lake Trout in Grist Lake and Cold Lake

Cold Lake and Grist Lake are two of only a handful of lakes in Alberta that provide suitable habitat for naturally reproducing populations of lake trout. There is increasing pressure on Alberta’s wetlands, lakes, and rivers from stresses including climate change, introduction of exotic species, over-exploitation, and loss of biodiversity. The effective management and conservation of lake trout populations throughout the province is critical to ensure protection of the resource for generations to come.

The purpose of this project was to design and implement a long-term hydroacoustic survey program to assess and monitor changes in the size, spatial distribution, and abundance of lake trout. This project also provided a direct comparison of abundance estimates generated from the hydroacoustic method and the Alberta standardized gill net index (SPIN) program. 

Services provided for: Sustainable Resource Development, Government of Alberta

Field technology utilized for this project:
   •  BioSonics DTX 200 kHz split-beam

Products delivered by Milne Technologies:
   •  echo integration estimates of pelagic fish density and biomass
   •  fish tracking analysis and echocounting estimates of lake trout density and biomass
   •  analysis of the morphology and spatial distribution of lake herring schools
   •  spatial distribution of fish density and biomass
   •  lake bottom substrate classification and analysis (QTC, E1 Roughness, and E2 Hardness)
   •  bathymetry, habitat and submerged macrophyte mapping

Reports:
   •  2006 Cold Lake Hydroacoustic Survey Report: Methodology and Summary of Results.
   •  2007 Cold & Grist Lake Hydroacoustic Survey Report: Methodology and Summary of Results.


The Response of Lake Trout Populations to Re-opened Winter Fisheries

In collaboration with Milne Technologies and the Ontario Ministry of Natural Resources, the Wildlife Conservation Society of Canada designed and implemented a hydroacoustic survey program in an effort to detect potential changes in the population abundance and size distribution of lake trout in Myrt and Hood Lakes (Thunder Bay district of Ontario). Both lakes were closed to ice fishing but in February 2008, the Ontario Ministry of Natural Resources re-opened the lakes to winter angling. This management change provided a unique opportunity to directly measure the response of the lake trout populations to the change in regulations and the increased level of fishing effort.

Services provided for: Wildlife Conservation Society

Field technology utilized for this project:
   •  BioSonics DTX 120 kHz split-beam
   •  OMNR standardized index gill nets

Products delivered by Milne Technologies:
   •  lake trout density and biomass estimates
   •  lake bottom substrate classification
   •  bathymetry and habitat mapping

Report:
   •  2007 Myrt and Hood Lakes Hydroacoustic Survey Report: Abundance and spatial distribution of lake trout
      (Salvelinus namaycush) in two Northern Ontario lakes.

 
 
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