Guest column: the “why” of shark behavior
By Geoff “Big Kahuna” Geist, founder of Shark OFF
At Shark OFF, we tackle a lot of questions regarding some of the ocean’s fiercest predators. We are used to the “how” – How do sharks think? How to protect the ocean and its inhabitants? How does our proven shark repellent work?
Now let’s dive into the “why”.
To act and protect sharks effectively, you need to know what drives them! Why are they approaching the shore? Why do they bite (and don’t bite) humans? Why are they a vital part of the ocean ecosystem?
Let’s find out!
Why do sharks come to shallow water?
It is becoming evident that sharks hang out with humans in shallow water more often than we ever imagined! With the new use of drones flying over beaches, many videos are going viral with images of sharks within meters of swimmers and surfers.
“We have a lot of pictures and anecdotal evidence of sharks swimming where humans play, and as long as people don’t pester them sharks don’t care,” says Chris Lowe, professor of marine biology and director of the Shark Lab at California State University in Long Beach.
But why get so close to pesky humans? A recent to study speak State Division of Marine Fisheries, Conservation of Atlantic white sharks and Arizona State University researchers have found that sharks visiting Cape Cod spend almost half of their time in shallow water. They tracked eight great white sharks and found that 47% of their time was spent in water less than fifteen feet deep!
The biggest motivation being the seals that live near the shore. Sharks risk being stranded for the reward of a tasty and fatty meal. Bulldog sharks in particular prefer to hunt in shallow water. Thanks to their signature “bump and bite” technique, bulldog sharks take advantage of shallow and murky waters where their sense of smell takes precedence over their poor eyesight.
Another reason sharks swim in human-infested waters could be the temperature, as sharks (especially great whites) enjoy warm temperatures in the shallow end. The good news is that they are much more likely to approach the shore at dusk and dawn when they have the visual advantage of a superior view of the seals.
Your afternoon beach picnic shouldn’t be crowded with sharp-toothed friends, but be sure to wear Shark OFF just in case!
Why is it important to protect sharks?
With the help of hundreds of ocean conservation organizations around the world, the reputation of sharks is restored. Especially here at Shark OFF, we know that explaining why sharks matter is like preaching to the choir! But do you know exactly how vital these amazing creatures are? Oceana published a report in July 2008, “Predators as prey: why healthy oceans need sharks”, illustrating our need to protect sharks. In this report, Oceana goes from Alaska to Australia, explaining what healthy ocean ecosystems look like and how different sharks function in different oceans.
Sharks are top predators, which means they are at the top of the food chain and eat a broad diet. This allows both to control prey populations, but also to control the “spatial distribution” of prey through intimidation. Basically, species will adapt to shark populations by altering their habitat use and level of activity, leading to an equal distribution of resources and a more diverse species population.
As they move towards the Atlantic Ocean, large sharks (sharks over two meters in length) lose their predatory position at the top. As a result, the populations of rays, rays and small sharks have increased tenfold. This means that the entire ecosystem has started to decline, starting with the decimation of scallop, clam and oyster populations. As stingrays and small sharks move down the food chain, coastal fishermen suffer and local restaurants lose popular dishes, affecting both marine ecosystems and the economy.
Should we now be more concerned with getting our hands on clam chowder than the lives of millions of ocean species? Of course not. But it shows just how bad the effect of the decline of top predators turns out to be.
Now let’s talk about what a healthy ocean ecosystem looks like. Oceana takes us to the Northwestern Hawaiian Islands, which are not completely altered by fishing and human inhabitants, but are home to one of the most diverse and thriving marine ecosystems. After studying shark populations versus prey species in these waters, they found that there is a higher shark population than their prey. Sharks represent more than half of the biomass of fish. Not only that, but the sharks here are even bigger than in other areas around Hawaii!
“These studies illustrate that a trophic pyramid typical of an unfished coral reef is actually inverted, which means that most of the fish biomass is at the highest level. It also shows that typical overexploited ecosystems lack top predators. “
The more sharks there are in a given ecosystem, the healthier and more diverse it will be!
Why do negative interactions with human sharks occur?
The age-old question: why do sharks bite humans? Do we look like seals with our limbs hanging from a surfboard? Not enough! While many shark encounters can be summed up as sharks mistaking us for a fish dinner, recent studies have pointed us to a different explanation.
Sharks’ mouths function as complex sensory organs that they use to assess their surroundings. This means that they often “put in the mouth” different objects to examine and determine possible food value. That’s right, sharks can just make us want to decide if we’re worth eating! Don’t worry though, we don’t meet their standard for fat content, which is why many shark encounters end with a shark retreat flash.
Sharks are purpose-driven, intelligent, and purpose-driven creatures. Another reason a shark can bite a human is territory. The bigger sharks get the best hunting grounds, and they’ll kick out anything, and anyone, that invades their space. The very important distinction to make here is that sharks do NOT hunt humans. They might be curious and calculated creatures, but we are not in their food pyramid, and we will always be a greater threat to them than they are to us.
Why we shouldn’t be afraid of sharks:
Now for the most important questions of all! Why shouldn’t we be afraid of sharks? As previously stated, humans are an exponentially greater threat to sharks than they are to us. Humans are responsible for the deaths of over 100 million sharks each year from fishing and bycatch. In addition, widespread media fear that “shark attacks are on the increase” does not take into account the increase in human populations in these areas. The increasing number of shark bite cases is consistent with the number of tourists and other beach goers who have made it to the shores. If you are afraid of meeting a shark, think of it this way-
“We have to think of the risk of a shark attack like we would think of the risk of a car accident. For example, we do not rate our personal risk of having a car crash by national car crash statistics from year to year. We think about our specific car, the weather, road conditions and other very local factors. According to Stephen Midway, assistant professor in the Department of Oceanography and Coastal Sciences at LSU.
In short, the ocean belongs to sharks, not us. We must play in their garden with respect and do all we can to preserve and protect their home. If you really want to protect sharks by deterring them from human infested waters, be sure to wear the proven Shark OFF shark jewelry! Visit our website for free shipping throughout the United States, including Hawaii.
And as always, lose the fear and LOVE the ocean!