1. According to the National Oceanic and Atmospheric Administration (NOAA), there are over 500 shark species worldwide. Of these, about 40 species are known to inhabit the waters around the United States.
2. The Shark Research Institute (SRI), a non-profit organization dedicated to shark conservation, estimates that there are around 20 million sharks in the Atlantic Ocean and Gulf of Mexico combined. This includes both coastal and pelagic (open ocean) shark species.
3. The Monterey Bay Aquarium Research Institute (MBARI), a non-profit organization focused on marine research, conducted studies that provide insights into shark populations off the California coast. Their findings suggest that there could be anywhere from several hundred thousand to a few million sharks in this region alone.
4. The Pew Charitable Trusts, a non-profit organization working on environmental issues, estimates that the global shark population has declined by 70% over the past 50 years. This includes sharks in US waters, where overfishing, habitat loss, and bycatch (unintended capture of marine life in fishing gear) have contributed to population declines.
It's important to note that these estimates may vary based on factors such as the migratory patterns of sharks, the accuracy of data collection methods, and the challenges of studying marine populations in vast and dynamic ecosystems. Researchers and conservation organizations continue to conduct studies to better understand shark populations and their distribution in the waters surrounding the US.