Chrysaora fuscescens
Encyclopedia
Chrysaora fuscescens is a common free-floating scyphozoa
that lives in the Pacific Ocean
, and is commonly known as the Pacific Sea Nettle or West Coast Sea Nettle.
Sea nettle
s have a distinctive golden-brown bell with a reddish tint. The bell can grow to be larger than one meter (three feet) in diameter in the wild, though most are less than 50 cm across. The long, spiraling, white oral arms and the 24 undulating maroon tentacles may trail behind as far as 3.6 to 4.6m (12 to 15 feet). For humans, its sting is often irritating, but rarely dangerous.
Chrysaora fuscescens has proven to be very popular for display at public aquariums due to their bright colors and relatively easy maintenance. It is possible to establish polyps and culture Chrysaora in captivity. When provided appropriate aquarium conditions, the medusae do well under captive conditions.
, Chrysaora fuscescens are carnivorous animals. They catch their prey by means of cnidocyst (or nematocyst) -laden tentacles that hang down in the water. The toxins in their nematocysts are effective against both their prey and humans, though it is typically nonlethal to the latter. Because C. fuscescens cannot chase after their prey, they must eat as they drift. By spreading out their tentacles like a large net, the sea nettle is able to catch food as it passes by. When prey brushes up against the tentacles, thousands of nematocysts are released, launching barbed stingers which release a paralyzing toxin into the quarry. The oral arms begin digestion as they transport the prey into the sea nettle’s mouth.
C. fuscescens feeds on a wide variety of zooplankton
, crustaceans, salps, pelagic snails, small fish as well as their eggs and larvae, and other jellyfish
. Due to their growing numbers, they seem to be reducing fish populations and have become nuisances to the fisherman of Oregon by clogging up fishing nets. Their dense swarms have also become problematic for scientific trawls and water intake.
Despite having a potent sting, Chrysaora fuscescens is prey to many marine birds and large fish.
Although they cannot see distinct shapes or colors, C. fuscescens have rhopalia
located around the rim of the bell to help detect changes in light.
in the medusa
stage and asexual reproduction
in the polyp
stage. The life cycle of C. fuscescens begins when females catch sperm released by the males to fertilize the eggs she has produced and is holding in her mouth. These fertilized eggs remain attached to her oral arms, and there they grow into flat bean-shaped planula. Once they grow into flower-shaped polyps, they are released into the ocean where they attach themselves to a solid surface and undergo asexual reproduction. The polyp makes identical copies of itself this by means of budding, where the new polyp grows from its side. After the new polyp is fully formed, it too is released into the ocean and undergoes metamorphosis as it grows, developing a bell, arms, and tentacles until it is a fully formed medusa.
, brother of Pegasus
and son of Poseidon
and Medusa
. Translated, Chrysaor means “he who has a golden armament.”
Scyphozoa
Scyphozoa is a class within the phylum Cnidaria, sometimes referred to as the "true jellyfish".The class name Scyphozoa comes from the Greek word skyphos , denoting a kind of drinking cup and alluding to the cup shape of the organism....
that lives in the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, and is commonly known as the Pacific Sea Nettle or West Coast Sea Nettle.
Sea nettle
Sea nettle
Chrysaora quinquecirrha is a species of jellyfish that inhabits Atlantic estuaries, such as the Chesapeake Bay...
s have a distinctive golden-brown bell with a reddish tint. The bell can grow to be larger than one meter (three feet) in diameter in the wild, though most are less than 50 cm across. The long, spiraling, white oral arms and the 24 undulating maroon tentacles may trail behind as far as 3.6 to 4.6m (12 to 15 feet). For humans, its sting is often irritating, but rarely dangerous.
Chrysaora fuscescens has proven to be very popular for display at public aquariums due to their bright colors and relatively easy maintenance. It is possible to establish polyps and culture Chrysaora in captivity. When provided appropriate aquarium conditions, the medusae do well under captive conditions.
Distribution and habitat
Chrysaora fuscescens is commonly found along the coasts of California and Oregon, though some reside in the waters north to the Gulf of Alaska, west to the seas around Japan and south to the Baja Peninsula. The populations reach their peak during the late summer. In recent years, C. fuscescens has become overly abundant off the coast of Oregon, which is thought to be an indicator of climate change. However, others suspect that the population is increasing because of human influences to coastal regions, but little to no historical population data from which to compare current abundances exist.Feeding and Predators
In common with other cnidariaCnidaria
Cnidaria is a phylum containing over 9,000 species of animals found exclusively in aquatic and mostly marine environments. Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey. Their bodies consist of mesoglea, a non-living jelly-like substance,...
, Chrysaora fuscescens are carnivorous animals. They catch their prey by means of cnidocyst (or nematocyst) -laden tentacles that hang down in the water. The toxins in their nematocysts are effective against both their prey and humans, though it is typically nonlethal to the latter. Because C. fuscescens cannot chase after their prey, they must eat as they drift. By spreading out their tentacles like a large net, the sea nettle is able to catch food as it passes by. When prey brushes up against the tentacles, thousands of nematocysts are released, launching barbed stingers which release a paralyzing toxin into the quarry. The oral arms begin digestion as they transport the prey into the sea nettle’s mouth.
C. fuscescens feeds on a wide variety of zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
, crustaceans, salps, pelagic snails, small fish as well as their eggs and larvae, and other jellyfish
Jellyfish
Jellyfish are free-swimming members of the phylum Cnidaria. Medusa is another word for jellyfish, and refers to any free-swimming jellyfish stages in the phylum Cnidaria...
. Due to their growing numbers, they seem to be reducing fish populations and have become nuisances to the fisherman of Oregon by clogging up fishing nets. Their dense swarms have also become problematic for scientific trawls and water intake.
Despite having a potent sting, Chrysaora fuscescens is prey to many marine birds and large fish.
Body Systems
Chrysaora fuscescens swim using jet propulsion by squeezing their bell and pushing water behind them, allowing them to swim against currents, although most of the time they prefer to simply float. Sometimes they pick up hitchhikers, including small fish and crabs, which hide inside the sea nettle’s bell and may feed on it.Although they cannot see distinct shapes or colors, C. fuscescens have rhopalia
Rhopalia
Rhopalia are small sensory structures of Scyphozoa and Cubozoa . In Aurelia they lie in marginal indententions around the bell and are flanked by rhopalial lappets. Specialized structures to sense light and perceive gravity are usually present...
located around the rim of the bell to help detect changes in light.
Reproduction
Chrysaora fuscescens is capable of both sexual reproductionSexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
in the medusa
Medusa
In Greek mythology Medusa , " guardian, protectress") was a Gorgon, a chthonic monster, and a daughter of Phorcys and Ceto. The author Hyginus, interposes a generation and gives Medusa another chthonic pair as parents. Gazing directly upon her would turn onlookers to stone...
stage and asexual reproduction
Asexual reproduction
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization. A more stringent definition is agamogenesis which is reproduction without...
in the polyp
Polyp
A polyp in zoology is one of two forms found in the phylum Cnidaria, the other being the medusa. Polyps are approximately cylindrical in shape and elongated at the axis of the body...
stage. The life cycle of C. fuscescens begins when females catch sperm released by the males to fertilize the eggs she has produced and is holding in her mouth. These fertilized eggs remain attached to her oral arms, and there they grow into flat bean-shaped planula. Once they grow into flower-shaped polyps, they are released into the ocean where they attach themselves to a solid surface and undergo asexual reproduction. The polyp makes identical copies of itself this by means of budding, where the new polyp grows from its side. After the new polyp is fully formed, it too is released into the ocean and undergoes metamorphosis as it grows, developing a bell, arms, and tentacles until it is a fully formed medusa.
Etymology
The origin of the genus name Chrysaora lies in Greek mythology with ChrysaorChrysaor
In Greek mythology, Chrysaor , the brother of Pegasus, was often depicted as a young man, the son of Poseidon and Medusa. However, Chrysaor is sometimes said to be a giant or a winged boar. Chrysaor and his brother, the winged horse Pegasus, were not born until Perseus chopped off Medusa's head...
, brother of Pegasus
Pegasus
Pegasus is one of the best known fantastical as well as mythological creatures in Greek mythology. He is a winged divine horse, usually white in color. He was sired by Poseidon, in his role as horse-god, and foaled by the Gorgon Medusa. He was the brother of Chrysaor, born at a single birthing...
and son of Poseidon
Poseidon
Poseidon was the god of the sea, and, as "Earth-Shaker," of the earthquakes in Greek mythology. The name of the sea-god Nethuns in Etruscan was adopted in Latin for Neptune in Roman mythology: both were sea gods analogous to Poseidon...
and Medusa
Medusa
In Greek mythology Medusa , " guardian, protectress") was a Gorgon, a chthonic monster, and a daughter of Phorcys and Ceto. The author Hyginus, interposes a generation and gives Medusa another chthonic pair as parents. Gazing directly upon her would turn onlookers to stone...
. Translated, Chrysaor means “he who has a golden armament.”