The Red Tide is Upon Us

The Red Tide. Photo From:
The Red Tide.
Photo From:

Red tide: a name that strikes fear deep into the heart of any surfer or educated marine lover. Although it may sound like the name of a poorly done horror movie, it is actually the common name for a harmful algal bloom (HAB). It is a concentration of phytoplankton, specifically Karenia brevis, a kind of dinoflagellate. These microorganisms have a reddish-brown color that can cause the ocean to look mucky during an algal bloom. The cause of these blooms is debated, but it is often linked to natural coastal upwelling or increased nutrients due to human activities such as agricultural runoff and water pollution.

The toxins found in some red tides can cause people to get a variety of symptoms similar to pollen allergies such as eye and skin irritation, coughing, and nasal infection. Surfers commonly experience these maladies because they may accidently ingest this “dirty” water. To prevent becoming sick during one of these algal blooms, if you plan on being coming in contact with the ocean, try to avoid letting water get in your mouth and flush your sinuses. During an especially toxic red tide (some are not toxic at all) it also can be advisable to avoid eating shellfish, as they are filter eaters and may accumulate toxins.

There are other issues linked to red tide as well. Recently, there have been several occasions where the fish population in the bay has experienced exponential growth. Many marine animals were drawn to the area by the dense population of phytoplankton and their predators. Large numbers of these fish also died, possibly due to toxins from the plankton, as is sometimes known to happen. Huge numbers of birds also accumulated in dense areas to prey on the fish. Naturally, with all the eating they were doing, these animals produced equally large amounts of excrement, which contributed to low water quality.

This inflated amount of marine activity during the fall also draws the attention almost every surfer and beach goers worst nightmare, sharks. Know as “Sharktober” for this exact reason, the most shark activity is during June to November. John McCosker, a shark expert and chairman of aquatic biology at theCalifornia Academy of Sciences in San Francisco, said that “The reason is there are a lot of seals and sea lions in the area at this time of year. The salmon are returning to the Sacramento River, the sea lions are following them and the sharks are following them.” Although this may make surfing during this time of year absolutely insane, you have to look at the statistics. According to the Santa Cruz Sentinel, in Santa Cruz County, dating back there to 1851 there have been 7 attacks, none fatal.

A humpback whale, just one of the Animals that feed of the algae.
A humpback whale, one of the animals that feeds on the algae.
Photo From:

Despite the many negative aspects of the red tide, it is also an important phenomenon for marine life. Sea animals get a huge amount of easy food that can help them sustain life. People enjoy observing these beautiful creatures, especially the whales and dolphins. The Press Banner found that local whale watching charter boats where encountering up to 20 humpacks on any given day. These majestic creatures delight in the benefits of the red tide. We however, must use precaution during the red tide in order to stay healthy. Remember to avoid getting water in your mouth and to flush out your sinuses whenever you go in the water during an algal bloom. One site you can use to check the water quality before going to the beach is

-April Martin-Hansen

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