Cannonball Jellyfish

(Stomolophus meleagris)

By: Lindsey Wilcox

https://www.thoughtco.com/cannonball-jellyfish-4770889

What's The Wonder About?

Living in Wilmington NC, I grew up going to our beaches and often saw the Cannonball jellyfish washed up on the shore. I often wondered if these creatures were alive once they were washed up. The weird anatomy of these creatures always boggled me, I wondered why jellyfish evolved this way. I have always wanted to learn more about this species and this seemed like a great opportunity.

Names and Classifications of Cannonball Jellyfish:

What Is This Species Called?

The Cannonball jellyfish got this common name from its appearance which resembles a cannonball. This species is often also referred to as the Cabbagehead jellyfish, based on its appearance as well.

The scientific name of this species is Stomolophus meleagris, which was assigned because of the taxonomy classification we will discuss in the Lesson Plan linked below.
- - - Taxonomy is represented in the image to the right.

https://en.wikipedia.org/wiki/Cannonball_jellyfish

https://www.slideshare.net/MarkCasabuena1/phylum-cnidaria-66086977

https://blogs.ubc.ca/mrpletsch/2019/01/23/phylum-cnidaria/

What Are Characteristic of

The Phylum Cnidaria:

The Cnidaria Phylum includes over 10,000 different species.
- - - Phylum is visually represented in the image to the left.
Included in this phylum are aquatic fauna like sea anemones and coral, which jellyfish are closely related to.

Cnidarian translates to “stinging nettles” in Greek, which is a common characteristic. All Cnidarians have nematocysts, stinging cells, which are believed to have derived from a common ancestor of all Cnidarians.
Other defining characteristics of this phylum are being radially symmetric and possessing tissues.
- - Radial Symmetry is shown in the image to the left.

What Makes Jellyfish So Cool?

Unique Characteristics of Jellyfish:

Jellyfish are composed of 95% water, causing them to be semi-translucent. They do not have a brain, heart, blood, bones, or eyes, but they do possess tissues that make up their bodies, and tentacles that contain stinging cells. They also have one cavity in the center of their bodies which they use to eat, excrete waste and pulse water out of for locomotion.

Jellyfish are believed to have existed even before dinosaurs, they are believed to be around 500 millions of years old!

https://www.youtube.com/watch?v=yQduHyiWe9o

https://www.youtube.com/watch?v=WpqPphTZmkM

Unique Charateristics of The Cannonball Jellyfish:

- - - Cannonball jellyfish have a bell that is dome-shaped and can grow up to 10 inches in diameter. The rim of this bell is often a brownish or copper color.
      - The Cannonball Jellyfish can be seen in the video to the left.

Where Do Cannonball Jellyfish Live?

Where Can You Find Cannonball Jellyfish?

The Cannonball jellyfish has been found all throughout the West coast of both Mexico and South America. This species is also present along the Southeastern coast of the United States and the eastern coast of South America down to Brazil.
- - During the summer months, 16% of the biomass of the Southeastern coast is comprised of Cannonball jellyfish.

https://sites.google.com/site/barrierislandecology2013/aquatic-fauna/cannonball-jellyfish

https://grist.org/food/what-do-you-catch-when-there-are-no-more-fish-jellyballs/

Why Can You Find It Within These Habitats?

The Cannonball jellyfish inhabit the areas shown in the distribution map above because they prefer warm temperature and high salinity waters, although this species of jellyfish can inhabit a wide range of salinity and temperatures.

The distribution of the Cannonball jellyfish is present along a shoreline because the ocean floor is not too far away and can be utilized for reproduction.

Evolution of Cannonball Jellyfish:

Simplicity Of Cannonball Jellyfish Evolution

Cannonball jellyfish do not have a very complex evolution, as they are low on the evolutionary scale due to their simple radial symmetric body structure. The lack of complex evolution of this species has given them the advantage of being able to inhibit a variety of environments and to reproduce at a high rate. The simple evolution of jellyfish has allowed them to be able to reproduce sexually as well as asexually.

- - Radial symmetry branch of evolution can be observe in the image to the right.

https://sites.google.com/site/antijoanafieldguide/kingdom-animalia

Advantages of Cannonball Jellyfish Simplictic Evolution:

Despite being simple creatures in structure, the Cannonball jellyfish have many advanced features as well. For example, they have developed advanced defense stinging mechanisms from cells called nematocysts. They also have two different life stages, as they are born in a polyp stage and float through the ocean until they plant themselves and grow into a stalk-like structure, before they finally become the medusa structure we typically refer to as jellyfish. The medusa stage of jellyfish are the earliest fauna to evolve a primitive organization level of muscle tissues, which made them strong enough to swim through the ocean.
- - - The branch of tissue level of organization can be observed in the image below.
    - The reproduction cycle of jellyfish can be observed in the image to the below.

https://depositphotos.com/129294360/stock-illustration-jelly-fish-life-cycle.html

How The Environment Effects Cannonball Jellyfish:

The impact humans have on the ocean is astronomical. As humans release more CO2 the ocean becomes more acidic. This has a negative impact on many species of crustaceans and molluscs that live in the oceans. On the contrary, Jellyfish are actually thriving in the more acidic environment. Their numbers are increasing rather quickly and one day may overtake our seas.
- - A visual representation of the increase of acidity to the ocean can be seen in the image to the right.

As well as being positively benefited by the increase in acidity of oceans, jellyfish are also one of the few species that are positively affected by climate change. Temperature increases to the oceans can increase the reproductions and growth rates of the jellyfish.

https://www.climatecentral.org/gallery/graphics/ocean-acidification-process

How Cannonball Jellyfish Effect The Environment:

Cannonball Jellyfish play a crucial part in the aquatic food web, as they are both predators and prey. Jellyfish feed on zooplankton as their primary food source. On the other hand, jellyfish are consumed by sea turtles, sunfish and spadefish.

https://tybeeisland.com/discover-tybee/tybee-jellyfish/

Cannonball Jellyfish Friends:

A symbiotic relationship exists between the Cannonball jellyfish and the Longnose spider crab (Libinia dubia). The crab hitches a ride along the jellyfish bell or even goes up inside the bell, where it hides out from prey and may steal a bit of the jellyfishes food. It can sometimes even feed on some of the jellyfish's jelly, all without harming the jellyfish.
- - - This symbiotic relationship can be seen in the image to the left as well as in the YouTube video below.
Many different species of fish also swim beside Cannonball jellyfish for protection, some even swim in between the jellyfish tentacles dodging them in effort to avoid predators.

https://www.youtube.com/watch?v=SXCnLmy5Mxg

Cannonball Jellyfish Foes:

Leatherback sea turtles are the most common predator to the Cannonball jellyfish. Studies state that the number of Cannonball jellyfish is directly proportional to the number of Leatherback sea turtles.
- - This predator prey relationship can be explore in the article linked below:
    - http://167.7.158.9/cwcs/pdf/Cannonballjellyfish.pdf

Can You Identify Both The Friends and Foe In This Image?

https://www.dailymail.co.uk/news/article-4642814/Sea-turtle-takes-bite-lions-mane-jellyfish.html

Conservation Of Cannonball Jellyfish:

Even though increased ocean acidity and climate change do not have a negative effect on jellyfish species, other human impacts such as oil spills and pollution do. These effects can have a negative impact on the water quality of the ocean, killing off the jellyfish food source, zooplankton, causing jellyfish numbers to decline. This could have a negative effect on the entire aquatic ecosystem as jellyfish are an important aspect in maintaining healthy marine ecosystems.

We are aware that jellyfish populations are on the rise, but the Cannonball jellyfish populations should be closely monitored due to the importance Cannonball jellyfish have in maintaining healthy marine ecosystems. If Cannonball jellyfish remain abundant, this will play a crucial part in the conservation of the predators of Cannonball jellyfish, Leatherback sea turtles, which is a highly endangered species.