Emerging Super El Nino to Raise Risk of Sharks Along California Coastline

Much has been said in recent weeks about the impact of a potential Super El Niño on hurricane season and the overall weather patterns this summer and fall. Now forecasters are warning that the emergence of this climate phase could also raise the threat of sharks off the coast of California. Here is what you need to know heading into the summer beach season.

How Super El Niño Could Change Shark Migration Along the California Coast

El Niño is a natural climate pattern that results from warmer-than-average surface water temperatures in the equatorial Pacific Ocean.  The pattern typically triggers a more active Eastern Pacific hurricane season while muting the action in the Atlantic basin. What most people do not know is that El Niño also allows for a different species of sharks to move closer to the West Coast during the summer months.

Chris Lowe, professor of Marine Biology at Cal State, Long Beach, and Director of the Shark Lab in the Department of Biological Sciences, said that he thinks that it is "going to be a sharky summer off California this year." Warmer surface waters mean that sharks that usually make their home in the waters of Baja California could migrate farther north, reaching Southern California and well beyond.

In a normal year, great white, thrasher, and mako sharks make their home off the coast of Southern California, taking care of their babies in this region. However, during stronger El Niño years, the warmer waters lower the nutrient upwelling and overall productivity of these species of sharks, sending them farther up the coast to find optimal conditions.

Along that same vein, the warmer waters also prompt other types of shark species that typically remain away from California to migrate closer to its coastline. This includes a higher incidence of bull sharks and tiger sharks. This is why Lowe warns that unusual weather patterns can result in different types of species migrating into areas not accustomed to this type of shark activity.

Sharks have been shown to have specific thermal ranges that drive where they will swim. For example, great white sharks generally move to the north or offshore looking for cooler waters when the coastal temperatures become too warm.

Lowe explained that places off Baja that are typically big white shark nurseries might see a shift away from the activity as the animals travel north to find more habitable waters. Likewise, some of the white sharks that usually reside off the coast of Southern California may move into the waters near Central California searching for cooler water temperatures.

Juvenile white sharks generally begin to appear in the spring off the coast of California. However, some of these sharks were noted as early as February this year. Scientists believe that the record-breaking heat wave that supported higher ocean water temperatures along much of the West Coast was to blame for the earlier appearance.

The warmer waters also mean that sharks are more likely to stay longer in these northern locations. Rather than migrating back south at the end of the summer, the sharks are expected to extend their stay into the fall season.

The East Coast could also see an influx of sharks in areas farther north, thanks to the impacts of El Niño. Sharks that typically spend the summer months off the coast of Florida could migrate up the Atlantic seaboard in the hopes of finding cooler waters.