Bull Sharks: Terror of the Sea?
By Ryan Benincase
Sharks are some of Earth’s oldest living species. Their ancestry draws back beyond 400 million years and the fossil records show limited change throughout that timespan. Sharks are typically cartilage-based rather than bone, and have gills that filter water for oxygen as they move, so they must be in constant motion. Shark attacks blow up in the media and people start to view sharks as monstrous killers due to these rare attacks; approximately 19 attacks annually in the United States. Aside from the true to life attacks, movies and television exploit fear of sharks to entertain. Movies like Sharknado, or the more realistic Jaws, create mass fear of sharks and an unprovoked hate for the oceans top hunters. The sharks most well known for their aggression are bull sharks, tiger sharks and great whites.
Bull Sharks (Carcharhinus ieucas) have short blunt snouts and they head-butt prey before attacking, which is where their name comes from. Like most sharks, they are carnivorous. Bull sharks can grow from 7 to almost 12 feet in length and weigh up to 500 lbs. They prefer shallow warm waters and frequently live in tropical shoreline area, or can travel far up rivers. It is rumored that they can jump up rivers against the current like salmon in order to reach inland lakes. Attacks by bull sharks are frequently not fatal, they are medium sized sharks and attack for two reasons, accidently (assuming the person is prey) or out of curiosity/fear. People fear this shark more than the others due to how adaptable it is, living in fresh, brackish and salt water of all kinds.
The close proximity of humans and bull sharks may cause fear in people, but the true danger is to the sharks. Sharks of all kinds are hunted by people for food, oils and their skin. Over 100 million sharks are hunted each year for various reasons, and while the bull shark may not be endangered, it is estimated that their population numbers are dropping rapidly as well as their average size, and they may be on the list in a few years if the trend continues.
Aside from the massive hunting of these animals, their habitats are also being destroyed by people. According to the National Geographic Society “Because of their coastal distribution, bull sharks are more at risk from pollution and habitat degradation than other species.” As toxins from runoff and dumping such as mercury enter the food-web of an ecosystem like the ocean, the toxicity is absorbed by all creatures and resulting in an increase in the concentration up the ladder as predators eat multiple prey with the toxin (biological magnification). Many sharks like the bull shark utilize estuaries to nurse their young, but because of pollution and urban development, they can no longer use the area.
Sharks are an extremely important part of the waters ecosystem as they maintain balance in the underwater world. The Earth is over 70% water and sharks are a major piece of making the ocean a place for humans to use for all kinds of resources. Bull sharks specifically have been a focus of fear and a symbol of death to human creatures, but in reality there are millions of dead sharks for every injury caused by them. People must change their polluting and destroying ways or the Earth will lose its biodiversity and we will likely not be able to survive much longer than that.
[photo,Bull shark, by Lelly Abranches licensed by CC BY-NC-SA 2.0]
By Ryan Benincase
Sharks are some of Earth’s oldest living species. Their ancestry draws back beyond 400 million years and the fossil records show limited change throughout that timespan. Sharks are typically cartilage-based rather than bone, and have gills that filter water for oxygen as they move, so they must be in constant motion. Shark attacks blow up in the media and people start to view sharks as monstrous killers due to these rare attacks; approximately 19 attacks annually in the United States. Aside from the true to life attacks, movies and television exploit fear of sharks to entertain. Movies like Sharknado, or the more realistic Jaws, create mass fear of sharks and an unprovoked hate for the oceans top hunters. The sharks most well known for their aggression are bull sharks, tiger sharks and great whites.
Bull Sharks (Carcharhinus ieucas) have short blunt snouts and they head-butt prey before attacking, which is where their name comes from. Like most sharks, they are carnivorous. Bull sharks can grow from 7 to almost 12 feet in length and weigh up to 500 lbs. They prefer shallow warm waters and frequently live in tropical shoreline area, or can travel far up rivers. It is rumored that they can jump up rivers against the current like salmon in order to reach inland lakes. Attacks by bull sharks are frequently not fatal, they are medium sized sharks and attack for two reasons, accidently (assuming the person is prey) or out of curiosity/fear. People fear this shark more than the others due to how adaptable it is, living in fresh, brackish and salt water of all kinds.
The close proximity of humans and bull sharks may cause fear in people, but the true danger is to the sharks. Sharks of all kinds are hunted by people for food, oils and their skin. Over 100 million sharks are hunted each year for various reasons, and while the bull shark may not be endangered, it is estimated that their population numbers are dropping rapidly as well as their average size, and they may be on the list in a few years if the trend continues.
Aside from the massive hunting of these animals, their habitats are also being destroyed by people. According to the National Geographic Society “Because of their coastal distribution, bull sharks are more at risk from pollution and habitat degradation than other species.” As toxins from runoff and dumping such as mercury enter the food-web of an ecosystem like the ocean, the toxicity is absorbed by all creatures and resulting in an increase in the concentration up the ladder as predators eat multiple prey with the toxin (biological magnification). Many sharks like the bull shark utilize estuaries to nurse their young, but because of pollution and urban development, they can no longer use the area.
Sharks are an extremely important part of the waters ecosystem as they maintain balance in the underwater world. The Earth is over 70% water and sharks are a major piece of making the ocean a place for humans to use for all kinds of resources. Bull sharks specifically have been a focus of fear and a symbol of death to human creatures, but in reality there are millions of dead sharks for every injury caused by them. People must change their polluting and destroying ways or the Earth will lose its biodiversity and we will likely not be able to survive much longer than that.
[photo,Bull shark, by Lelly Abranches licensed by CC BY-NC-SA 2.0]