Species Spotlight: The Bull Shark

Guest Blog by Shark Stewards Team Member David Kronman

The bull shark is an iconic shark species with a fearsome reputation. With their blunt snouts, classic grey and white coloration, and a big attitude, bull sharks are widely known as a shark to respect. Found in tropical and subtropical waters around the world, these sharks are present in many different aquatic environments from marine to estuarine. They are also unique in their ability to survive for long periods in freshwater. As such a widespread species, their prey are diverse, mainly consisting of bony fish and smaller sharks.  However, they also prey on dolphins, turtles, crustaceans, squid, and sea birds.  When people think of the bull shark, they think of an aggressive, dangerous shark.  While there is some truth in this perspective, bull sharks are highly adapted marine predators.

Gary Rose

Bull sharks are considered to be a dangerous shark species, being responsible for over 100 attacks, and believed to be responsible for many attacks that weren’t attributed to a specific species.  They are considered in this way for a multitude of reasons.  First, bulls are undoubtedly aggressive, and they have to be in order to survive.  Bull sharks are cannibalistic, eating younger bull sharks as well as other shark species.  Being aggressive helps them survive before they become fully grown.  Another reason they have so many negative encounters with people is due to their habitat.  Bulls are globally distributed in tropical and subtropical shallow waters, as well as in freshwater including rivers, lakes and estuaries.  They are able to survive in freshwater due to a unique attribute their kidneys have that recycles salts in the bloodstream instead of removing them via urine. This allows bull sharks to swim in places other sharks simply can’t get to, putting them in more contact with swimmers.  In saltwater, they come into contact with people more frequently, as popular swimming destinations overlap with their home range.  Finally, bull sharks have relatively poor vision. They have small eyes, implying vision isn’t as important for hunting as with other shark species.  The combination of being naturally aggressive, habiting areas where people frequently swim, and having poor eyesight can lead to bites on people.  However, there are many locations and conditions in which swimming with bull sharks can be a very pleasant and life changing experience, giving divers a newfound appreciation for these animals.

There are many places on our planet where you can swim with bull sharks.  The more ideal locations have clear waters and sandy bottoms, including Costa Rica, Thailand, Fiji, and perhaps most notably in Playa Del Carmen, Mexico.  Female Bull sharks migrate to this part of Mexico between the months of November and March, to their breeding and pupping grounds and divers migrate to see them.  Divers have often described this migration as very moving and powerful.  In clear water a bull shark can show remarkable levels of grace as they swim by you.  Seeing such a strong animal passing by, just checking you out as they move on, can be a life changing experience.  Many divers come back from these dives with a different perspective on these stereotypical aggressive sharks, seeing them as much more majestic sharks than what bulls are traditionally thought of.

Bull sharks aren’t targeted specially by any large commercial fisheries, however they are often caught as bycatch and for sport. The largest threats include habitat loss, bycatch in nets and killing for their fins to supply the shark fin soup trade.

Currently listed as near threatened under the IUCN, bull sharks require protection in many regions of the world, and you can help these and other species.  Check to make sure you aren’t using products that contain sharks.  Many household items and makeup products contain shark and shark derived oils.  Familiarizing yourself with these products and avoiding them is a great way we can protect sharks.  More directly, you can contribute to shark conservation by donating or volunteering with Shark Stewards, an international shark conservation nonprofit dedicated to the protection of sharks worldwide. 

The most impactful way we can protect sharks is by using our voice.  Contact your representatives and let them know sharks are important to our oceans, and many species need protection from overfishing and the shark fin trade.

The author, David Kronman, has a lifelong love for sharks, and a passion for
conservation.  He is attending the Rosenstiel School of Marine and
Atmospheric Sciences at the University of Miami, studying marine
biology and ecology.  David is originally from Pittsburgh,
Pennsylvania, and he enjoys scuba diving and photography.  Along with
volunteering at Shark Stewards, David works at the Pittsburgh Zoo and
PPG Aquarium.