Fine scale, long-term tracking of adult whites sharks
- Michael Domeier
Marine Conservation Science Institute
Although much has been learned about white sharks over the last ten years, there is still much that we do not know about the life cycle of this species in the northeastern Pacific Ocean. The complete migration cycle of adult female white sharks is not known, due to the relatively short lifespan of satellite pop-up tags. Furthermore, without concurrent precision tracking of white sharks from central California and Baja California, Mexico, the level of mixing of individuals from these two regions is unknown. Theoretically, DNA studies could demonstrate that these two spatially distinct groupings of white sharks are in fact one population, when in fact it is the mixing (interbreeding) of just a few individuals per generation that produce the result. I propose to address these questions by capturing and affixing near real-time satellite transmitters to the dorsal fins of 5 male and 8 female white sharks from the Farallon Islands. The sharks will be captured via hook-and-line, raised from the water on a large hydraulic platform and tagged before being released. Data will be collected and monitored over the next 4-6 years, via the ARGOS satellite array. Results will be disseminated to the Sanctuary via reports, and to the scientific community via peer-reviewed publications.
Summary to DateIn 2009 two male white sharks were tagged at Southesast Farallon Island. Near real-time transmitters were attached to the dorsal fin of both sharks. Both of these sharks made their normal seasonal migration to a region in the middle of the Pacific Ocean centered between the Hawaiian Islands and Baja California Mexico. This is the same region that is frequented by white sharks from Guadalupe Island and so is termed the shared offshore foraging area (SOFA). The sharks remained in the SOFA until they returned to the central California region during the summer of 2010.
- Migration/movement patterns