Understanding Complex Data: Coastal Monitoring


The Province of Nova Scotia recognizes the importance of coastal waters, which are critical to the prosperity and sustainability of rural and coastal communities. To bridge the gap between science and decision making, the Nova Scotia Department of Fisheries and Aquaculture (NSDFA) partners with the Centre for Marine Applied Research (CMAR) to measure the environmental conditions of Nova Scotia’s coastal waters.
The data derived from coastal ocean monitoring is useful to many stakeholders, including:
  • Scientists studying coastal species, coastal ecosystems, and climate change;
  • Engineers and operators in the fisheries, aquaculture, and renewable energy industries seeking to minimize environmental impacts while maximizing economic development;
  • Governments taking a data-driven approach to policy and decision making; and
  • Individuals and community groups engaged in conservation or recreation.
Photo of workers deploying an acoustic doppler current profiler (ADCP) off the side of a Department of Fisheries and Aquaculture boat.

Monitoring Nova Scotia’s Coastal Waters   

The Centre for Marine Applied Research collects two main types of coastal ocean data at stations throughout Nova Scotia:
  • Long-term water quality data
  • Current speed and direction data
The following sections give insight into how these datasets are collected, and their application to the aquaculture industry in Nova Scotia.

Long-Term Water Quality Data

Detailed environmental data is vital to decision making in the aquaculture industry. Water quality data can be used by government and industry to improve and adapt ongoing operations as well as to inform the identification and selection of suitable farming areas for future fish and shellfish aquaculture.
Data are collected from sampling stations located across most counties in Nova Scotia. Approximate station coordinates may be viewed or downloaded from the Nova Scotia Water Quality Data: Station Locations dataset and associated map (see below) on the portal. The exact station coordinates may change slightly as instruments are periodically retrieved, serviced, and re-deployed.

Nova Scotia Water Quality Data: Station Locations Map

The three main types of data collected at the long-term water quality monitoring stations are:
  • Temperature (degrees Celsius);
  • Dissolved oxygen (percent saturation or milligrams per liter); and
  • Salinity (practical salinity units).
These measured variables strongly influence growth, physiology, and mortality of aquatic organisms and animals.

Sensors designed to measure temperature, dissolved oxygen, and salinity data are deployed at targeted depths in the water. The sensors are attached at fixed intervals to lines also referred to as sensor strings. The sensor strings are moored with a heavy anchor weight and suspended through the water column using a sub-surface buoy.
To ensure easy sensor string retrieval, the deepest sensor is equipped with an acoustically-triggered release mechanism. When triggered by a hydrophone onboard a nearby research vessel, these acoustic release mechanisms detach from the anchor, allowing the sensor string to rise to the surface.
Each deployment may last from 6 months to a year and data is measured by each sensor every 1 to 60 minutes. The resulting datasets are very large, containing tens or hundreds of thousands of data points. Datasets from some locations span over 7 years of continuous monitoring.
Illustration depicting a submerged buoy and rigging with sensors attached, anchored to ocean floor.
Temperature sensors secured at specific locations along a sensor string in preparation for deployment
Photo of a buoy with a sensor string and sensors attached laid out on a boat with a rocky shore in view.
Recovering data from a retrieved temperature sensor using a data shuttle
Photo of a worker on a boat retrieving a data shuttle from a sensor string.

Long-Term Water Quality Data on the Open Data Portal

The Nova Scotia Department of Fisheries and Aquaculture has released long-term water quality datasets on the portal, grouped by county. The table below contains data collected at one of the Guysborough County monitoring stations and is just a small sample of the data released on the Open Data Portal. The associated charts depict daily average temperature values for individual stations within Guysborough, Shelburne, Yarmouth, and Richmond counties. The charts are interactive and can be changed to show temperature at selected waterbodies, stations, depths, and timeframes. Links to all of the long-term water quality datasets and visualizations on the Open Data Portal are available here.
Guysborough County Water Quality Data
Guysborough County Water Quality Data – Daily Average Temperature
Shelburne County Water Quality Data – Daily Average Temperature
Yarmouth County Water Quality Data – Daily Average Temperature
Richmond County Water Quality Data – Daily Average Temperature

Current Speed and Direction Data

Ocean current speed and direction data provide valuable insight for a variety of engineering and environmental applications. Characterization of localized water currents is essential for assessing and modelling mechanical stresses and the potential for infrastructure damage associated with both existing and proposed aquaculture facilities. Researchers also depend on this data when creating ecological simulation models to predict factors such as: the biomass that a waterbody could sustainably support; the amount and location of fallen organic matter potentially produced by an operation; and the amount of phytoplankton available to feed shellfish aquaculture operations in a given area.
Acoustic doppler current profilers (ADCPs) are deployed at stations in the coastal waters of several counties across Nova Scotia. The Nova Scotia Current Data: Deployment Information dataset and its associated map (see below) contain details on current meter deployments conducted by NSDFA and CMAR between 2007 and 2024.

Nova Scotia Current Data: Deployment Information Map

The two main types of data are collected by the ADCPs are:
  • Current speed (metres/second, captured through multiple readings); and
  • Water direction (degrees relative to true north).
Current speed and water direction data is collected from several depths through the water column using acoustic doppler current profilers (ADCPs). ADCPs rely on a phenomenon known as the Doppler effect. The ADCP transmits ultrasonic “pings” of sound at a constant frequency into the water. As these acoustic beams travel, sound waves ricochet off particles suspended in the moving water and are reflected back to the instrument. Due to the Doppler effect, sound waves bounced back from a particle moving away from the profiler have a slightly lower frequency when they return, while a particle moving toward the instrument sends back higher frequency waves. The difference in frequency between these two sound waves is called the Doppler shift. The instrument uses the Doppler shift to calculate how fast the particle and the water around it are moving.
Illustration of an acoustic doppler current profiler (ADCP) on the ocean floor showing the acoustic beams coming from the ADCP to the surface of the water and an arrow indicating current direction.
Once deployed, the instrument is left to collect data for a minimum of 30 days, though instruments may collect data for 120 days or more, depending on battery capacity and recording configuration. A typical configuration will have the ADCP recording water speed and direction parameters at 10-minute intervals. The data points recorded by the instrument are the averaged result of many individual measurements taken over the course of the recording interval.
1000 kHz, shallow-water ADCP in a bottom mounted tripod frame prior to deployment
600 kHz ADCP in a tripod frame being deployed from a small vessel
ADCP recovered following a 90 day deployment
Photo of an acoustic doppler current profiler on the floor of a boat with a worker leaning over to attach a rope to it.
Photo of workers deploying an acoustic doppler current profiler off the side of a boat.
Photo of an acoustic doppler current profiler on the floor of a boat after being pulled out of the water.

Current Speed and Direction Data on the Open Data Portal

The Nova Scotia Department of Fisheries and Aquaculture has released current data from deployments for several counties across Nova Scotia. The table below contains an example of data collected from Shelburne County. The charts below depict daily average current speed at stations in Shelburne, Digby, Queens, and Pictou counties. Links to all current speed and direction datasets and visualizations on the Open Data Portal are available here.
Shelburne County Current Data
Shelburne County Current Data – Daily Average Current Speed
Digby County Current Data – Daily Average Current Speed
Queens County Current Data – Daily Average Current Speed
Pictou County Current Data – Daily Average Current Speed

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