Blue sharks acquired their name from their vibrant blue coloring that’s incomparable to other shark species. Unlike most sharks that are usually grey or mottled in color, blue sharks boast a bright blue skin color that is easily recognizable. Understanding the behavior of this deep dweller isn’t always straightforward, but the information below is a helpful start on what humans know about blue sharks.

Species Information

Otherwise known as Prionace glauca, blue pointers or great blue sharks, the blue shark is found in temperate and tropical open waters worldwide. Most of these creatures reside in the Pacific, Atlantic and Indian oceans, but migration often takes them elsewhere. Socially, blue sharks are known to travel in schools of one gender, and their reason for this behavior is still not known. Blue sharks typically grow to be between five and seven feet, but larger individuals can measure as long as 13 feet. Between their tapered bodies and elongated tail fins, blue sharks are fast & elegant swimmers. These sleek sharks are able to jump out of the water with ease and put on quite a show!

Blue sharks feed on many types of fish depending on their mood, including herring, hakes, cod, haddock, anchovies, pollock, mackerel, butterfish, tuna, and swordfish. They are also known to chase down squid, seals or sea birds for their next meal. Structures called gill feeders, common in filter feeding species like whale sharks, are present in blue sharks as well. Gill feeders allow the blue shark to feed on small invertebrates like shrimp when larger prey isn’t available. Blue sharks are active hunters at night, though they’re not averse to hunting during the day when the occasion calls for it.

Since blue sharks aren’t normally very large, they have a few notable predators. Shortfin mako sharks and white sharks are known to prey upon blue sharks, especially because they tend to frequent similar ocean depths. It’s also common in countries like Brazil, France, Italy and Spain to seek out blue sharks for their meat, hides, fins and liver oil. These habits make humans a distinct predator of the blue shark as well, whether their capture is intentional or by accident.

Blue Sharks Predict the Weather

Scientists in 2021 are getting creative with ways to fill out their patchy ocean weather data. Neil Hammerschlag from the University of Miami is using his established satellite tracking shark methods for a new and interesting purpose. This study will assist colleague & meteorologist Ben Kirtman to study ocean temperatures in ways other methods fall short. The project, started in 2021, will give Kirtman a better idea of what drives oceanic weather patterns under the water’s surface.

Since buoys and satellites are stationery and surface-level respectively, blue sharks that traverse the depths will provide thorough temperature readings from where they swim in the ocean. This data will hopefully help to predict what comes next as climate change alters weather patterns worldwide. Since the Gulf Stream is responsible for weather along the eastern coast of the United States, it’s no surprise that this area is worth studying in depth.

Blue sharks and shortfin mako sharks are known as pelagic creatures, meaning they dwell primarily in the open ocean. These habits will give scientists a solid idea of happenings within the water column while also revealing more about blue shark’s behavior overall.

Scientists ultimately hope for this data to be used in advanced weather models like SubX that are aimed at yielding reliable data about weather conditions weeks in advance. While this study is only in the data collection phase, the chances for growth are great and it will be exciting to see the role that blue sharks can play in such a project.

What is Special About Blue Sharks?

Other than predicting weather, there are a few major features about blue sharks that stand out. The blue shark’s vivid skin color is the first outright feature that automatically distinguishes this creature from other shark species. This coloration fades to a dark grey when blue sharks are removed from water. The pristine, white underbelly of the blue shark provides a sharp contrast to this unique feature. Blue sharks feature long snouts and large eyes in contrast to other, flatter species like hammerheads or whale sharks.

Data in the last few decades has shed light on a new revelation about how sharks grow and mature over time. Blue shark vertebrae were originally sectioned to reveal growth bands that are believed to form yearly. Similar to trees, new layers of material are continually added as the blue sharks grow over time, and this means the age of a blue shark can be estimated from these layers. In their 2003 study, MacNeil and Campana successfully estimated shark age using this method, with a slight twist. Instead of physically sectioning shark vertebrae for the study, they used image analysis to yield the same result. Imaging methods are much less time consuming than physical sectioning, so this was a win for studying blue shark age.

The blue shark is listed as near threatened by the International Union for Conservation of Nature’s Red List as of November 2018. Like other sharks, blue sharks are often either caught for sportfishing or accidentally brought in with commercial fishing nets. Even though sportfishing isn’t inherently dangerous, it’s somewhat common for blue sharks to not survive when released after capture. Luckily, blue sharks are still relatively abundant compared to some other shark species in the ocean, so this provides a short-term buffer from outright extinction.

Captivity is always an option as a result of overfishing and blue sharks becoming less common in the wild, but this comes with an inherent drawback. Blue sharks specifically will deal with a lifespan that is almost halved in captivity. Blue sharks average 15-to-20-year life spans in the wild, compared to captivity which brings estimated lifespan down to eight years.

Are Blue Sharks Aggressive?

Blue sharks are not usually known to be aggressive; however, they have been implicated in a handful of unprovoked attacks on humans. Some of these instances have been as a result of air and sea disasters. Since the blue shark is typically a curious creature by nature, it’s difficult to say whether attacks on humans are a normal attribute of these animals or whether the sharks were taking advantage of human vulnerability. It’s best to use caution around any predator in the open ocean in an attempt to stay safe.

Do Blue Sharks Attack Humans?

There have been 13 total unprovoked blue shark attacks on humans since the year 1580. Compared to hundreds of attacks between the big three shark species (great white sharks, tiger sharks and bull sharks), the incidence of being attacked by a blue shark is very low. Blue sharks are known to be inquisitive and will often approach humans on dives to make their presence known and assess these visitors. Considering this fact, the amount of blue shark attacks is most likely even lower in comparison to sharks investigating their environment.

Has a Blue Shark Ever Killed a Human?

Out of the 13 attacks over the last 430 years, only four of these blue shark attacks have been fatal to the victims. Anything is possible, but the likelihood of being attacked by a blue shark, let alone dying because of it, is extremely low. Just like any predator, blue sharks deserve space, respect and caution when exploring the area that surrounds them. Despite these attacks being unprovoked, it doesn’t hurt to stay vigilant if you’re going on a shark dive.

Although blue sharks are considered to be apex predators, they are relatively docile where humans are concerned. Blue sharks may be classified as near threatened, but they are abundant compared to some other shark species. These interesting creatures are well known for their unique appearance, and they’re worth saving in the wild while it’s still possible.

Works Cited

Rafferty, J. (August 12, 2021). Blue shark. Encyclopedia Britannica online. Retrieved December 28, 2021, from https://www.britannica.com/animal/blue-shark.

Collins, M. (December 27, 2021). Fastest sharks in ocean become climate data hunters. News4Jax. Retrieved December 29, 2021, from https://www.news4jax.com/weather/2021/12/27/fastest-sharks-in-ocean-become-climate-data-hunters/.

No author or date specified. Blue Sharks, Prionace glauca. MarineBio. Retrieved December 29, 2021, from https://www.marinebio.org/species/blue-sharks/prionace-glauca/.

No author specified. (November 23, 2018). Blue shark. Government of Canada. Retrieved December 29, 2021, from https://www.dfo-mpo.gc.ca/species-especes/profiles-profils/blueshark-requinbleu-eng.html.

Joseph, K. (September, 2018). The Blue Shark. Untamed Science. Retrieved December 29, 2021, from https://untamedscience.com/biodiversity/blue-shark/.

No author specified. (November 06, 2018). Blue shark. IUCN Red List. Retrieved December 29, 2021, from https://www.iucnredlist.org/species/39381/2915850.

No author specified. (January 24, 2019). Blue shark research. Government of Canada. Retrieved December 29, 2021, from https://www.dfo-mpo.gc.ca/species-especes/sharks/bio-research/blue-shark-eng.html.