Happy Shark Awareness Day
Written by Editor on 14th July 2022
Happy Shark Awareness Day – 14 June 2022
Shark Awareness Day is not about fear…
Many marine conservation groups celebrate this day every year in observance of sharks and the essential part they play in the marine ecosystem. This day is not about standing on the beach and shouting out warnings to panicked swimmers, although it could be entertaining. Rather, Shark Awareness Day is about educating others about the role of these majestic marine creatures.
How is Seychelles celebrating Shark Awareness Day?
A collaboration of conservation groups in Seychelles is hosting a virtual classroom today from 1 pm till 2:20 pm to learn more about sharks and their importance to our oceans.
Here is some exciting information that we have gathered about sharks.
Firstly, what are sharks? They are cartilaginous fish, which means their skeleton is made of cartilage rather than bone. Cartilage is lighter and more flexible, enabling sharks to swim faster, use less energy, and turn quicker – increasing their predatory skills.
Sharks are among the top predators of the oceans. They have inhabited our planet for over 400 million years and are drivers of natural selection. However, in recent years they have suffered sharp declines due to overfishing and increased demand for their fins.
Living in the ocean can be tough. Little light reaches the deep murky waters, so marine animals often end up relying on other senses to survive. Sharks are no different, they have an excellent sense of smell, and they can even sense vibrations and electrical signals.
- Sight – Whilst not their strongest sense, sight is still important to sharks and their eyes are specially adapted for low light conditions. Their eyes are positioned to the side of their head, which gives them a good view in all directions. But it isn’t until they are close to an object that sight becomes most significant.
- Smell – Sharks have an amazing sense of smell, using it to detect the smell of predators, prey and potential mates. Some shark noses are so sensitive that they can detect one part of blood in one million parts of seawater.
- Sound – Sound travels better underwater than in air, so the sound is one of the first ways a shark will detect prey; they are most sensitive to low-frequency sound. Their ears are internal with only a tiny hole visible on the outside of the body, but they also have a lateral line which runs down the side of their body and enables them to detect vibrations. The lateral line is a channel filled with a gel-like substance and tiny hairs, that relates to surrounding water through a series of pores. As vibrations spread through the water they disturb the hairs, altering the shark to sound and vibrations.
- Electroreception – Sharks have a jelly-filled organ, known as ampullae of Lorenzini, in their heads which is filled with electroreceptors that can detect electrical signals. This includes the earth’s geomagnetic field, which is used for orientation and navigation.
Sharks’ role in the ecosystem
As apex predators, sharks play an important role in the ecosystem by maintaining the species below them in the food chain and serving as an indicator for ocean health. They help remove the weak and the sick as well as keep the balance with competitors helping to ensure species diversity.
As predators, they shift their prey’s spatial habitat, which alters the feeding strategy and diets of other species. Through spatial controls and abundance, sharks indirectly maintain the seagrass and corals reef habitats. The loss of sharks has led to the decline in coral reefs, seagrass beds and the loss of commercial fisheries.
By taking sharks out of the coral reef ecosystem, the larger predatory fish, such as groupers, increase in abundance and feed on the herbivores. With fewer herbivores, macroalgae expand and coral can no longer compete, shifting the ecosystem to one of algae dominance, affecting the survival of the reef system.
Humans are not prey for sharks
Whilst sharks have been known to attack humans, it may surprise you to know that humans are not their natural prey choice. Only a handful of species are considered dangerous – the great white shark, hammerhead shark, tiger shark, mako shark and bull shark. And, often when sharks attack it is a case of mistaken identity. To a hunting shark, it is not always easy to tell the difference between a surfer or a seal, which they would prey on naturally. Bites are often explored to see if what they have found is food, or attacks could be a form of defence. Sharks are extremely territorial and will attack to defend or protect themselves and their territory. But, even so, far more sharks are killed by humans than humans killed by sharks.
Here are some famous sharks in Seychelles