Ocean acidification will lead to increased shark attacks.

We have all heard about coral reefs being destroyed by rising ocean acidity, but one thing hasn’t gotten a lot of publicity: sharks will be significantly affected by increases in atmospheric carbon. The ocean absorbs 25-30% of carbon emissions.

In a study conducted by the Center for Shark Research to determine how the sensory receptors of sharks respond under conditions of high acidity, the results had serious implications for the future of coastal communities and of sharks. Sharks rely on sensory receptors to interpret all stimuli in the water. They use these sensory receptors to detect and navigate in response to possible foods, predators, and mates. The study proved that sharks in high CO2 conditions use attack strikes instead of feeding strikes and confuse prey stimuli.

Does this mean surfers and swimmers are at a higher risk of being attacked?

The study also found that sharks avoided food indicators all together when they were exposed to extremely high levels of CO2. This suggests an ultimate species extinction as ocean acidity levels continue to arise.

Mr. Faust, Laguna Blanca’s AP Environmental Science teacher, remarks on the possible claim that sharks can evolve to compensate for their damaged receptors. He points out that we have not only directly caused a rise in acidity leading to the deterioration of shark’s ability to properly assess prey, but we have also overfished and depleted sharks’ food sources. If this weren’t enough, according to National Geographic, humans kill over 100 million sharks annually for fins, meat, or through trawling and longlining bycatch.

These conditions, when combined, have created effects we can already begin to see today. In cities all along the west coast, shark sightings have increased because of rising ocean temperatures. Juvenile sharks and their prey rely on warm temperatures for ocean habitats. According to The Tribune newspaper of San Luis Obispo, June was the 14th consecutive record-hot month. This heat trend is a result of the rising levels of carbon in the atmosphere.

The otter mystery of Morro Bay clearly demonstrates the fate awaiting surfers and swimmers as confused sharks migrate up the warming coast and move in towards shore.

In San Luis Obispo’s Morro Bay, otters are being found washed up on shore with evidence of lethal shark bites. The curious thing about the nature of these attacks isn’t necessarily that sharks are attacking prey they formerly didn’t (that could be explained by the increase in juvenile shark populations), it’s that the otters aren’t eaten, they are just bitten. Most human shark attacks are in fact shark bites; deaths are mostly because of blood loss and not from sharks eating humans.  Sharks explore possible prey by biting it — exactly what is happening to Morro Bay otters.

Could this be an example of sharks being confused with impaired receptors? Are we already seeing the effects of ocean acidification?

Escalating ocean acidity has ramifications far beyond what we can attempt to predict.

What implications will this have on the future of sharks, ocean food chains, tourism, local economies, and our coastal lifestyle?