Wildlife Wednesday: Blacktip Reef Shark

Although they’re definitely not as big as Jaws, the sight of one of these guys (or gals) near a sandy shoreline will probably still send swimmers and snorkelers back to their beach towels.

On this Wildlife Wednesday,let’s take a deep breath, lift our chins, and fish out some interesting facts about blacktip reef sharks.

Habitat

Good news! In Canada, we’re too far north to “enjoy” the company of these rather toothy fish.

These sharks can, however, be found swimming in most of the world’s warm and shallow coastal waters, including the seas around northern Australia, south-east Asia, north-eastern Africa ... and the southern United States (including Hawaii).

Trivia

• Unfortunately, Bruce from Finding Nemo was wrong—fish are food, not friends. They, predictably, make up most of a blacktip’s diet, which also includes crustaceans, molluscs, squids, and stingrays.
• Occasionally, blacktip reef sharks are spotted leaping above the water, twisting themselves around, and performing back-flops. One reason for these rather showy displays is to “sneak” up on unsuspecting schools of fish swimming near the water’s surface.
• You may think of them as cold-blooded fish-catchers, but even sharks have friends! In 2012, researchers discovered that reef-living sharks—including these blacktip ones—form long-term relationships with others, gathering together to hunt as a team and for protection from predators.
• Oddly enough, it turns out that female blacktips are capable of reproducing without the help of males, in a process known as “parthenogenesis.” This was first observed in 2008—much to the surprise of researchers.

Why are they threatened?

These miraculous cases of asexual reproduction, however, shouldn’t keep us from being concerned about this shark species’ declining population size.

Blacktip reef sharks, while not a target species for major fisheries, are regularly fished for their meat, liver oil, and fins. The development of coastal areas can also affect their habitat, keeping the sharks from using breeding grounds and other important areas.

A new concern, brought to light by a 2014 study, is caused by ocean acidification—when increasing levels of carbon dioxide is absorbed into the water. The study found that these increased levels of CO2 may impair the sharks’ ability to sniff out prey, which could affect how successful they are while on the prowl for a bite to eat.