Importance of Bahia Sebastian Vizcaino as a nursery area for white sharks (Carcharodon carcharias) in the Northeastern Pacific: A fishery dependent analysis

Abstract

In the Northeastern Pacific, immature white sharks (Carcharodon carcharias) have been recorded in the nearshore waters of the Southern California Bight (SCB), USA, along the Mexican coast off Baja California and throughout the Gulf of California, which makes them susceptible to incidental capture by coastal fisheries. While the SCB is considered a nursery area for white sharks, records of young-of-the-year white sharks (YOY) in Bahia Sebastian Vizcaino (BSV) off central Baja California suggest that this region could also be an important white shark nursery area, but a formal evaluation of the region’s habitat function is lacking. We analyzed incidental catch records of white sharks from the US-Mexico border to BSV and evaluated whether Heupel et al.’s (2007) criteria for the identification of shark nursery areas were met for BSV. We compiled a total of 390 white shark incidental catch records between 1999 and 2013 and compared incidental catch records from the region north of Bahia Sebastian Vizcaino (NBSV; an area not considered to be a nursery ground) with those for BSV. There was a significantly higher abundance of newborns and YOY in BSV than NBSV. White shark were caught consistently throughout the year within BSV; however, the majority (70.1%) were caught between May and September. Our results are consistent with the shark nursery area criteria proposed by Heupel et al. (2007), and indicate the region between BSV to the SCB may be an important migration corridor for YOY and juvenile white sharks. Future management and conservation efforts ought to consider BSV’s nursery habitat function.