At the Sightings Network, we are happy to get any report, whether the observer is seeing the animal(s) right at that moment or is recounting an encounter from many years ago. They all help us better understand the distribution and occurrence of cetaceans both spatially and temporally. If you’ve spotted a cetacean (whale, dolphin or porpoise) or sea turtle in B.C. waters any time, we want to hear about it!
However, while all reports are useful, we get particularly excited when we receive “real time” sightings – that is, a report of a sighting right as it is happening or directly after. Sometimes, when reports are close enough to our home base at the Vancouver Aquarium, we take out our trusty research vessel “Skana” to investigate. Such was the case earlier this week when a crew member aboard one of the BC Ferries called to report “the largest group of dolphins I’ve ever seen.” The report was from out in the Strait of Georgia, not far away, and with good weather on our side, we headed out for the afternoon. Thanks to some further assistance of the ferry crew, we easily located a group of approximately 300 Pacific white-sided dolphins.
When investigating a sighting report, our purpose can be varied. In the case of an unusual species or location, we may want to check species identification or assess the health of the animal, as was the case when a grey whale wandered into False Creek a few years ago. Other times, particularly with dolphins and killer whales, we want to collect additional information and data. With this week’s dolphin encounter, we spent our time collecting identification photos, looking for scales for diet sampling and recording acoustics.
Photo-identification is a helpful tool to determine movement patterns, seasonality and population estimates. By comparing photos taking during different encounters, researchers are able to assess how often, when and where individuals are re-sighted. In the case of dolphins, their use of the lower Strait of Georgia and Howe Sound is fairly recent. Using photo-identification, we hope to determine whether the same dolphins are using this area or if multiple groups are coming in and out at various times. Like many species, we photo-id dolphins primarily by taking pictures of the left side of their dorsal fins.
Additionally, when appropriate, we collect diet samples and acoustic recordings. Recording acoustics is dependent on whether the animals are vocalizing or not. With such a large group of dolphins, we were greeted with a cacophony of buzzing echolocation and squeaky calls as soon as we dropped the hydrophone. These recordings are added to a larger collection that can be used to better describe the vocal repertoire and behaviour of Pacific white-sided dolphins.
Collecting diet samples is dependent on whether the dolphins are feeding. Usually the only leftovers from a dolphin meal are a few floating scales on the surface. By scooping these scales out we can send them to colleagues who can determine what the animals were eating without having to see the entire fish! Unfortunately, no surface scales were spotted this time around and our scooping nets stayed empty.
All this information was collected thanks to a simple “real-time” report from a BC Ferries crew member. Unforunately, weather, distance or daylight hours sometimes impede our ability to respond to reports, but we are always thankful to get them and will respond when we can. The best way to alert us of your real-time report is to call us, toll free at 1 866 I SAW ONE (1 866 472 9663).