Plankton seining basking sharks are enigmatic visitors to the Bay
Basking sharks are the largest fish found in Canadian waters. On the Atlantic coast, these 10 m giants spend the summer months in the Bay of Fundy feeding on microscopic zooplankton. Despite their large size we know very little about their basic biology, life history and conservation status. Since 2008 the GMWSRS has been actively engaged in studying these elusive fish. We are employing a variety of techniques to learn about their diving behaviour, habitat utilization and migration patterns as well the conservation risks they face. To date we have deployed small diving recorders on basking sharks and have learned that they live up to their name, spending up to 40% of their time at the surface, which means they are vulnerable to ship collisions for a greater period than previously believed. We have also discovered, through the use of archival data loggers, that basking sharks are not year round residents but instead engage in long distance migrations, leaving the Bay of Fundy in November and travelling as far south as the southern Caribbean Sea before returning to northern waters in late spring. We have also carried out the first ever abundance estimates for Bay of Fundy Basking sharks using aerial survey techniques and have found that about 800 basking sharks typically reside in the Bay during the summer. We are beginning to learn more about some of these individuals through the use of photo-identification techniques were individual sharks are re-identified year after year using specific marks and scar patterns on their dorsal fins.
We plan to continue with more short-term tagging to record behaviors in the Bay of Fundy as well as long-term deployments to record more details about their migration patterns. We will complete another aerial survey in 2012 as well as continue with our photo-ID program. With each passing year the GMWSRS continues to learn more about, and raise awareness of, these fascinating animals.
We are continuing to maintain our photo-ID catalogue and are in the process of developing a shark sighting database for the Bay of Fundy. You can help our research by contributing sightings and photographs to our catalogue and database here . For current updates on this effort in the Bay of Fundy, please visit our Photo ID blog.