Jellyfish are gelatinous blobs that are armed with stinging tentacles, not your idea of a delicious meal. Some species of jellyfish are often considered the most venomous of all aquatic creatures, so ‘do sharks eat jellyfish?’ and the short answer is “YES”, let’s dig into why!
Some shark species are prolific jelly blob hunters. Pelagic sharks routinely snack on jellyfish, which previously were taken as a dead-end in the food chain because of their apparent low content of nutrition.
Pelagic means sharks that live out in the open waters, and these will eat large quantities of jellies for the few calories as they are 95% water.
While most jellyfish are small, posing no threat to sharks, many prefer to stay away from large ones in schools, especially of box jellyfish that pack a venom punch. Continue reading to find out what types of shark eats which jellyfish and why these low-fat blobs would constitute any self-respecting shark’s diet.
Can Sharks Eat Jellyfish?
Sharks do eat jellyfish, and this may be on the rise as other staples like krill and fish decline in many shark-infested waters. What scientists once thought was nothing but a nuisance turns out to play more important roles in the food chains and webs of the ocean.
For years, the explosive population of jellyfish has caused researchers much concern, and they’ve been sounding alarms on overfishing, habitat modification, climate change, and nutrient runoff.
What jellyfish lack in nutrition they make up for in ease of capture and availability. Sharks see jellies as a sort of mid-ocean snack, a filler-food and not to be eaten sorely for sustenance. These results emerged after analyzing footage from cameras planted in the shark’s habitats, as well as examining the stomach contents of dead sharks.
Can a Jellyfish Kill a Shark?
It’s not a big deal for pelagic sharks, which hunt and eat jellyfish, but they are not likely to approach bigger, more poisonous species of jellies. A jellyfish that can kill a person will also likewise dispatch an unlucky shark, especially if it comes in contact with more than 70 or 80 inches of the barbed tentacles.
An unfortunate shark that crosses a box jellyfish’s path, and is injected with enough neurotoxic venom, will suffer paralysis and then cardiac arrest before succumbing to the poison in a matter of minutes.
But since only a few of the 50 or so box jellyfish species can deliver a human killing sting, it’s safe to assume that fewer sharks than people are killed by jellies. The deadliest box, also considered to be the most venomous aquatic creature, is the Australian Chironex Fleckeri, the largest of this species.
What Do Sharks Eat?
Depending on their habitat and diet designation, sharks like to dine on other aquatic creatures. All sharks are omnivorous but also carnivorous to a certain degree, and they will eat;
- All manner of fish
- Mollusks like sea snails
- Seals and sea lions
- Tuna and large game fish like marlin
- Mackerel and other schooling species
- Smaller sharks
- Crustaceans such as crabs, squid, and prawns
Like most predators, sharks have very effective noses and ears that help them track down prey for capture. Great white sharks, for instance, use their keen eyesight to swim close to the seabed in search of seals and other prey, which they attack from a downward approach.
Armed with great speed, a shark will break the surface in seconds, cornering the seal and biting it. In an incredible and impressive strategy to protect itself from the thrashing, the shark will move away until the shark dies before consuming it.
Sharks have evolved into effective killing machines, smelling a drop of blood from two miles off and stalking to take prey by total surprise. Species like the great white feature over 300 triangular, sharp teeth arranged in 7 rows, making it incredibly difficult for prey to escape.
Why Would a Shark Be Wary of Eating a Box Jellyfish?
Box jellyfish, apart from their powerful venom, have other traits that set them above common jellyfish. One of these notable characteristics is that they can swim, unlike other species that float whichever way the current is flowing.
With a maximum speed of about 4 knots, box jellyfish control their swimming direction by pumping water in and out of their box-like frame.
It’s also been proven that box jellyfish can see using a cluster of eyes located on each side of their boxy bodies. Scientists have found out that some of the box’s eyes are quite sophisticated as they feature a cornea, lens, a retina, and an iris that contracts with bright light or expands in darkness.
Box jellyfish, unlike the species that sharks love to snack on, actively hunt their prey which includes any small fish or shrimp.
What Is the Natural Predator of Jellyfish?
Jellyfish is a name that represents the simplistic organisms made of gelatinous matter and comprising 95% water. In the sea, there are two major jellyfish consumers by reputation; ocean sunfish and leatherback turtles.
While ocean sunfish can weigh up to 5 000 pounds, leatherbacks tip the scale at 2,000 pounds, and these feed exclusively on jellyfish.
Ridley turtles and sharks will also eat any of the floating blobs they come across, while some crabs and sea snails will nibble at the tentacles of jellyfish. Some seabirds specifically target jellies, precariously pecking on the inner parts to avoid the poisonous tentacles.
To glean any nutrition, if at all, the natural predators of jellyfish have to consume large amounts, in addition to having thick skins to resist stings. While all jellies can sting, they don’t all pack equal deadliness, such as the cannonball and moon jellyfish whose stinging barbs can’t penetrate your skin.
The natural predators of jellyfish also have mucus-covered bodies or tough scales to prevent sting penetration, and some will tolerate the painful toxins as though they’ve built immunity.
Are There More Poisonous Fish than Jellyfish?
Jellyfish come in many sizes, types, and compositions, as some aren’t single individuals but composite organisms living in symbiosis, such as the Portuguese man-of-war. There are also minuscule jellyfish species, almost microscopic, and they provide bite-size snacking for small fish and crustaceans.
In terms of poison comparison to other fish, the box jellyfish emerges tops as the most venomous sea creature in the ocean. The box, also known as the sea wasp, is a transparent invertebrate that looks harmless, but over 6,000 human deaths have been attributed to it.
Close to the box jellyfish in deadliness is the stonefish, or scientific name Synanceia, a highly camouflaged fish that’s common in the indo-pacific regions.
As a defense and hunting mechanism, the stonefish uses a dorsal fin spine that’s endowed with powerful neurotoxins. The poison secreted causes paralysis, heart failure, and eventually tissue death, killing an adult human in less than one hour.
Stonefish prefer to conceal themselves on the seafloor, in coral reefs, and around rocks or other sunken bodies.
Which Jellyfish Can Kill People?
Jellies are considered a delicacy in some human cultures, and in Asia, they’re salted to remove water for a sustainable, low calorie but protein-rich food. But how do jellyfish perceive humans? Are they delicious prey or tall, gangly predators that should be repulsed with sting attacks?
Jellyfish use their stinging tentacles to subdue their prey, delivering the stings through myriad small nematocysts, small capsule-like structures.
Inadvertently, jellyfish tentacles do come in contact with swimming people, and there are thousands of reported stinging each year. Effects of a jellyfish sting, particularly the species that carry large amounts of venom, can range from mild discomfort, severe illness, and death.
One of the most poisonous jellies, the box jellyfish, is responsible for most of these fatalities, and stings will happen even when it’s stranded on the beach. Nematocysts are spring-loaded with barb-like lances that are triggered to fire in the instant the tentacles are slightly stimulated.
Frequently Asked Questions
Do sharks eat box jellyfish?
Sharks eat jellyfish, as these gelatinous creatures can provide them with 95% water and up to 5 calories. Only pelagic sharks or those living in open waters make a habit of including jellyfish on their menu itinerary.
Sharks are however very intelligent, and they will steer clear of large jellyfish species like the box jellyfish. Let’s assume that sharks can differentiate the jellyfish with more venom than the others, as they only hunt smaller, less poisonous jellies.
Can Jellyfish be eaten by humans?
There are species of jellyfish considered a delicacy by some human cultures, especially in Asia, where it’s associated with treating high blood pressure, bone pain, arthritis, ulcers, and other gastronomical issues.
After being caught, cleaned, and processed, jellyfish are desalted and then rehydrated in freshwater by soaking it overnight. Although desalting improves its taste and texture, a jellyfish snack has a crunchy to chewy texture, and its taste is dependent on the seasoning or ingredients that are used in its preparation.
Jellyfish can be sliced thin, shredded, tossed with soy sauce, sugar, or oil and vinegar as part of a salad. You can also cut up the jellies like noodles, boil them and serve with a dish of meat or vegetables.
Although jellyfish look innocent and even lovely to touch, some species have stings that can send you promptly to the watery locker of old Davy Jones. With their omnivorous nature of eating just about anything, sharks will gobble up several jellyfish, especially when there isn’t an abundance of prey fish or crustaceans.