Have you heard people talk about the El Niño this year?
El Niño is a natural cycle in the Pacific Ocean which generally occurs every 2-7 years and has the ability to drastically change our climate. An El Niño is caused when the normal trade winds weaken or even cease over the Pacific. This halts the flow of many ocean currents, such as the Humboldt Current, which are dependent on these trade winds for momentum. Fueled by the trade winds,The Humboldt Current is a cold water current that runs northward along the west coast of South America. As it nears the equator, it turns west into the Pacific and gradually warms. During El Niño, the Humboldt Current loses this fuel and slows down dramatically. The normally cold water in the current beings to warm, creating changes in our climate worldwide.
This change in the ocean’s climate in the South Pacific extends to different parts of the planet. El Niño affects San Diego in several different ways, mainly on our local wildlife because water temperature increases. Cold water has a high nutrient content; it can sustain more life - just think about how rich and diverse kelp forests are!
This change in water temperature happens can cause a collapse in the local ecosystem in tempererate seas. With the warmer waters that El Niño brings, we see a lack of growth in our kelp forests which are home to thousands of marine organisms. This wreaks havoc on our native wildlife causing much of it to move farther north to cooler waters which are more abundant in food. The National Oceanic and Atmospheric Administration (NOAA) said “A major consequence of an El Niño is the loss of commercially important species where they traditionally occur. A notable example is the movement of the market squid to cooler waters to the north, away from established fisheries in California” (Impacts).
Every summer, pregnant leopard sharks come to La Jolla shores and primarily feed off of California Market Squid. Market Squid have a key place in the food chain in La Jolla, as well as the entire west coast. Because of the warm water temperatures we see during El Niño, much of the local marine life may move north until the cold water returns. When the water off of California warms in result of El Niño, we see predatory game fish flush north along the west coast that are typically seen in more tropical areas. Fish like Dorado, Yellowfin Tuna, Bluefin Tuna, and even Wahoo can be seen far up the coast of Southern California. El Niño can often bring a whole parade of animals that live farther south, northward, in an attempt to feed off of the still very nutrient rich waters.
Last summer, the normal blue and mako sharks that we typically see during or pelagic shark diving trips disappeared. We couldn’t believe that we were chumming up smooth hammerheads and schools of mola and getting in the water with them!
As of April 9, 2015 NOAA has issued statements saying El Niño has arrived. However, because this is not a strong El Niño and it is coming at the end of California’s rainy season, we will not see the torrential rain that generally accompanies an El Niño. What we will see is the underwater effects of El Niño and unfortunately it does not look like the water in San Diego will be cooling off any time soon.
“We Need Your Help!” NOAA: Elusive El Niño Arrives. 04 May 2015.
“Impacts of El Niño on Fish Distribution from NOAA Fisheries.” NOAA Fisheries: El Niño Related Research. 04 May 2015.
“El Niño Information.” El Niño Information. 04 May 2015.
Written by Bryant Grady