Center of Expertise in Marine Mammalogy

Scientific Research Report
2015-2017

Table of Contents

• Complete Text
• Introduction
• Using aerial infrared images to count ringed seals on ice
• The use of unmanned aerial vehicles (UAV)
• 2017: A Marine Mammal Odyssey, Eh!
• Mark-recapture analysis from long-term study on Sable Island identifies changes in demographic rates in northwest Atlantic Grey Seals
• OTN – Using grey seals (Halichoerus grypus) as bioprobes to estimate phytoplankton biomass
• Northwest Atlantic International Sightings Survey (NAISS) of Marine Megafauna on the Continental Shelf From Northern Labrador to the Bay of Fundy
• Monitoring Movements of Whelping Seals on Drifting Pack Ice
• Marine Mammal Genomics Research in the Central and Arctic Region
• OTN and predator-prey interactions
• Listening in on the Deep: Passive Acoustic Monitoring of Whales off Nova Scotia
• Sharing Meals Keeps Killer Whale Families Together: Provisioning relatives maintains long-term social bonds and helps pass on shared genes
• New developments in the use of fatty acids to determine marine mammal diets
• More than a mouthful – unlocking bowhead whale foraging and reproductive histories from baleen
• Observing walrus behaviour at haulout sites in quasi real-time
• Moving towards automated counting
• References

Monitoring Movements of Whelping Seals on Drifting Pack Ice

Garry Stenson

Harp, hooded and grey seals give birth on drifting pack ice off the coast of Newfoundland and Labrador or in the Gulf of St. Lawrence. In order to determine abundance of these populations, we estimate the number of pups born every four or five years. The first step is to search the ice in the historical whelping (pupping) areas to find the concentrations of seals which in the case of harp seals is an area larger than England and Wales combined. Once these concentrations are found, we carry out visual and/or photographic surveys to count the number of pups hauled out on the ice.

However, a major challenge facing us is to ensure that once we find the seals, we are able to monitor where they are as the pack ice drifts with the current and winds. This movement can be very extensive, particularly during a storm. Even under normal conditions, for example, the ice moves at a speed of one nautical mile per hour off the coast of Labrador. We need to account for this movement to ensure that we are able to find each pupping concentration again in order to survey it and that we do not unknowingly count the same animals twice. Historically, finding these groups each day using helicopters or planes was costly, and took a tremendous amount of effort and time.

Fortunately, new technologies have made it far easier to monitor ice movements. During the most recent harp seal survey, we tested the use of small, inexpensive GPS beacons. These units determine their location to within 10 meters and then send their position to a satellite where it can be uploaded to a website for researchers. The frequency of reporting can be set by the user; in our case we obtained beacon positions every 30 minutes in order to ensure that the batteries lasted for the entire project (in fact they lasted for over 2 months).

One or more beacons were deployed in each of the pupping concentrations and their movements tracked for over 3 weeks. The GPS beacon was place in a specially constructed tube to protect them from the weather and keep them upright (see photo). The tubes were then placed on the ice and marked with highly visible, non-toxic dye so that they could be retrieved after the survey.

The movements of the beacons (Fig. 7) illustrates how dynamic the ice is and the amount of drift that can take place. The average displacement for all beacons off Newfoundland and Labrador was over 210 km. While the general pattern of drift is southward, strong winds can drive the ice movements into quite complex patterns (Fig. 8). For example, in the northern Gulf of St. Lawrence, winter storms drove the ice and seals northward early in March while later in the month, the currents had greater influence and the ice drifted southward. After three weeks, this beacon ended up less than 10 km from where it started! Trying to follow each of the groups and keep them separate would be almost impossible and very expensive using traditional search methods

Carrying out surveys of seals pupping on drifting pack ice is a complex and difficult task. Thanks to the development of GPS beacons that can be deployed quickly and transmit information on their locations to us, it has made this survey a little easier.