Gliding into the Honguedo Strait: critical ocean monitoring for whales at risk

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Researchers from Canada and the United States have embarked on a study to evaluate the effectiveness of baleen whale monitoring systems in and around the Honguedo Strait, off the northern Gaspé Peninsula in the Gulf of St. Lawrence. The information gathered will help scientists and managers understand hazards for whales, and inform appropriate steps towards conserving one of the world’s most endangered species.

A Slocum glider prepped for deployment.
Photo: N. Beauchamp

There are 14 species of baleen whale, including blue, sei, fin, humpback and North Atlantic right whale. All have baleen instead of teeth, which they use to collect small, shrimp-like copepods. Baleen is made out of keratin, the same protein that makes up fingernails and hair. In 2018, the world’s population of right whales was estimated to be roughly 400 individuals.

In the last couple of years, the Canadian government announced a range of measures to protect right whales—including speed restrictions and fisheries closures—after an increased number of deaths caused by ship strikes and entanglement in fishing gear. The frequency of whale-ship interactions may also be linked to the fact that an increasing number of right whales are using the Gulf of St. Lawrence as their preferred feeding grounds due to changing availability of food. Copepods prefer colder water and the Gulf of St. Lawrence has become an area where they now thrive since warming waters south of Nova Scotia no longer provide an ideal habitat.

Gliders are the only operational and reliable real-time acoustic monitoring system used for right whales in Canadian waters. This technology has been used since 2014, principally by the Ocean Tracking Network (OTN) and the Marine Environmental Observation Prediction and Response-Whale Habitats and Listening Experiment, both at Dalhousie University, to successfully monitor the species on the Scotian Shelf and more recently the Gulf of St. Lawrence. Local environmental factors, like ocean currents, and engine and communications noise from boats can strongly influence glider “flight” as well as the ability to differentiate whale sounds from other noises. Improving the effectiveness of monitoring systems will help managers and policy-makes fine-tune regulatory responses to the presence of whales around busy shipping areas.

Latest Slocum glider positions in the Gulf of St. Lawrence (yellow icon) conducting multiple transects of the Honguedo Strait (between Gaspe and Anticosti Island) between September and November 2019.
Source: whalemap.ocean.dal.ca

The study, led by Prof. Kim Davies (University of New Brunswick), aims to identify optimal locations, technology and scientific approaches to maximize the effectiveness of whale monitoring. Gliders and fixed moorings—both equipped with acoustic listening devices—are being used to understand how the scientific monitoring platforms and environmental factors affect whale monitoring efforts in distinctively challenging areas. Transport Canada is assisting with deployment and recovery of two acoustic recorders and visual sightings to help validate acoustic recordings.

“The instruments deployed in early September have performed really well so far, and have detected fin and sei whales in the Honguedo Strait,” says Dr. Davies. “These data will allow us to measure the presence of endangered whales in and around the shipping corridor, and learn how best to use the technology to support ship strike mitigation efforts.”

The international team, which also includes scientists from OTN, Dalhousie University, Woods Hole Oceanographic Institute, JASCO Applied Sciences and Teledyne Webb Research, in addition to the University of New Brunswick, hopes that fine-tuning whale monitoring systems in the Honguedo Strait will help support dynamic management of these and other shipping lanes in Canada to reduce the harmful interactions between marine mammals and vessels.

North Atlantic right whale mother and calf.
Photo: courtesy of NOAA.

Transport Canada has already put speed restrictions of 10 knots on vessels above 13 meters in length  when right whales are present in the Gulf of St. Lawrence. Fisheries and Oceans Canada has also put several measures in place to protect right whales throughout the peak fishing season when there is the highest concentration of whales present, including season-long commercial fishery closures for most of the Gulf of St. Lawrence and two other critical habitats (Roseway Basin and Grand Manan Basin) with temporary closures in other areas when right whales are detected. In addition, concurrent efforts on the Northeast Coast of the United States also include seasonal speed limit restrictions implemented by NOAA.

The glider is currently on a two-month mission in the Gulf of St. Lawrence where it will complete 16-20 transects of a 65 kilometre section of the Strait. It is also sending real-time information on the presence of sei, fin, humpback and blue whales, which is shared with Transport Canada managers, research partners, and the public through WhaleMap (whalemap.ocean.dal.ca). WhaleMap is an online map that communicates the latest right whale observations.

The glider will be retrieved at the end of October and the team will begin gathering information  to analyze the findings, including environmental data and whale “up-calls” (vocalizations produced by right whales to communicate with one another) from archived moorings and the glider platform, correlations between acoustic detections and visuals captured by aerial surveillance along with oceanographic data (currents, temperature, salinity etc.). Following the analysis, researchers will use their findings to determine the optimal flight settings for the glider and improve its effectiveness for future monitoring. A report will be prepared for Transport Canada and the public in early next year to inform management planning for the 2020 season.

This research advances risk reduction efforts for minimizing the harmful impacts of human activities on right whale populations–vital step forward for ensuring the survival of one of the world’s most endangered species.

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