leidy comb jelly mnemiopsis leidyi n.
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Leidy Comb Jelly ( Mnemiopsis leidyi ). Physical Description. The body is laterally compressed, with large lobes arising near the stomodeum , generating 4 deep, noticeable furrows that characterize the genus.

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physical description
Physical Description
  • The body is laterally compressed, with large lobes arising near the stomodeum, generating 4 deep, noticeable furrows that characterize the genus.
  • It has four rows of small, but numerous, ciliated combs which are iridescent by day and may glow green by night.
  • The color is usually transparent or slightly milky, translucent
some definitions
Some Definitions

Transparent Green at Night

  • Stomodeum:A midline ectodermal depression ventral to the embryonic brain and surrounded by the mandibular arch. It becomes continuous with the foregut and forms the mouth.
  • Ciliated Comb: swimming plate of a ctenophore.
  • Ctenophore: transparent invertebrates i.e. Jelly Fish
it came from where
It Came From WHERE!!??
  • The native habitat of the ctenophore, is in temperate to subtropical estuaries along the Atlantic coast of North and South America
  • It is tolerant of a wide range of salinity, temperature and water quality conditions over a broad range of inshore habitats.
introduced habitat
Introduced Habitat
  • Since its unintentional introduction to the Black Sea, the Comb Jelly has spread to adjacent bodies of water.
  • It inhabits water of salinities ranging from 3% in the Sea of Azov to 39% in the eastern Mediterranean, and temperatures ranging from 4°C in winter to 31°C in summer.
  • According to results of population Mnemiopsis leidyi study in 2001 the main area of its distribution is the Southern Caspian, where the comb jelly spends winter and then in spring it begins to distribute to the northward. First, it appears in the Middle Caspian, than it spreads to the Northern Caspian in the areas where salinity it not less than 4 ‰ in late July-early August.
means of introduction to black sea
Means of Introduction to Black Sea
  • In the early 1980s, the comb jelly was accidentally introduced via the ballast water of ships to the Black Sea where it had a catastrophic effect on the entire ecosystem.
  • It was also introduced into the Caspian Sea via the ballast water of oil tankers.
physical characteristics of black sea
Physical Characteristics of Black Sea
  • The surface water has an average salinity of 18 to 18.5 parts per thousand (compared to 30 to 40 for the oceans) and contains oxygen and other nutrients required to sustain biotic activity.
  • The Black Sea has an area of 168,495 sq miles
  • A maximum depth of 7,200 ft.
  • Sea Surface Temperature of the surface waters varies seasonally from 46 °F to 86 °F.
black sea background
Black Sea Background
  • During the 1980s and early 1990s, the Black SEA ecosystem was in a catastrophic condition.
  • The deterioration of this ecosystem was the result of two principal factors: 1) eutrophication: (that is, nutrient enrichment due to domestic or agricultural waste) and 2) invasion by the Comb Jelly.
  • These factors were exacerbated by pollution and over-fishing.
comb jelly an ecological catastrophe
Comb Jelly: An Ecological Catastrophe
  • This voracious zooplanktonic predator reached enormous biomass levels (>1 kg m-2) in the summer of 1989, devastating the food chain of the entire Black Sea basin.
  • After the ctenophore bloom, there were sharp decreases in the anchovy catch and in the biomass of nongelatinous zooplankton in all Black Sea regions.
the catastrophe continues
The Catastrophe Continues
  • Nongelatinous zooplankton remained low for several years and then in 1994 showed a modest increase that was quickly followed by a secondary Mnemiopsis bloom a year later.
  • Before the untimely arrival of Mnemiopsis, the anchovy was the major consumer of nongelatinous zooplankton.
  • By feeding on the food supply of the anchovy as well as on its eggs and larvae, Mnemiopsis induced the collapse of the pelagic fish population leading to untold economic damage to the Turkish fishing industry.
  • By devouring herbivorous zooplankton, Mnemiopsis indirectly caused a further increase in phytoplankton biomass and primary productivity within the entire Black Sea basin.
ecological effect of comb jelly on black sea
Ecological Effect of Comb Jelly on Black Sea
  • Mnemiopsis ledyi is a major zooplankton predator and is associated with fishery crashes.
  • A carnivorous predator on edible zooplankton (including meroplankton), pelagic fish eggs and larvae, the comb jellycauses negative impacts right through the foodchain of the areas it has invaded.
  • In the Black Sea and the Sea of Azov, the zooplankton, ichthyoplankton and zooplanktivorous fish stocks all underwent profound changes.
  • The pelagic ecosystem of the Black Sea was degraded, manifesting as sharply decreased biodiversity, abundance, and biomass of the main components of the pelagic ecosystem-zooplankton.
economical impact on black sea
Economical Impact on Black Sea
  • Fish stocks in the Black Sea and Sea of Azov have suffered due to predation on eggs and larval stages of food supplies.
  • By feeding on the food supply of the anchovy as well as on its eggs and larvae, the comb jelly induced the collapse of the pelagic fish population leading to untold economic damage to the Turkish fishing industry.
bouncing back
Bouncing Back

The Beroe (The Comb Jelly Predator)

  • The eutrophication indices for all regions of the Black Sea peaked in 1992, 3 years after the primary Mnemiopsis bloom.
  • After 1992, several eutrophication indices also improved in the eastern and deep Black Sea, indicating recovery within the entire ecosystem despite the continued abundance of Mnemiopsis.
  • The appearance in 1997 of a predator of Mnemiopsis, the ctenophore Beroe, helped the ecosystem to recover further.
beroe the ecosystem savior
Beroe: The Ecosystem Savior

The Black Beautiful Sea

  • The appearance in 1997 of a predator of Mnemiopsis, the ctenophore Beroe, helped the ecosystem to recover further.
  • Perhaps also arriving in ballast waters of cargo ships from the northwestern Atlantic, Beroe feeds almost exclusively on Mnemiopsis.
  • With the arrival of Beroe, the year-round abundance (apart from a brief peak in late summer) of Mnemiopsis dropped precipitously.
ecosystem restored
Ecosystem Restored


  • After the decline in Mnemiopsis, Beroe itself almost disappeared from the water column, indicating its dependence on Mnemiopsis for its food supply.
  • The Mnemiopsis population crash led to increases in nongelatinous zooplankton, anchovy landings, egg densities of anchovy , as well as increases in the biomass of two native gelatinous cnidarians.


ecologoical effects in caspian sea
Ecologoical Effects in Caspian Sea
  • Effects on the ecosystem in the Caspian Sea were faster and stronger than in the Black Sea.
  • In 2001, repercussions were felt at all trophic levels, including that of the top predator, the Caspian seal

Caspian Seal

economical effects in caspian sea
Economical Effects in Caspian Sea

Caspian Fishermen

  • The invasion of Mnemiopsis leidyi, or Leidy's Comb Jelly, has caused the Caspian's fish stocks to plunge, affecting the livelihoods of many local fishermen.
  • The dropping fish stocks have forced many fishermen off the job. Many owners of fishing vessels have been forced to sell their boats in order to pay off their debts.
  • Sturgeon species and 90% of the world's caviar originates from the Caspian Sea & the introduction of the comb jelly immediately declined the export of caviar from the Caspian Sea.
control efforts
Control Efforts
  • All five Caspian states -- Russia, Kazakhstan, Turkmenistan, Azerbaijan, and Iran -- now have to endorse the introduction of the Beroe ovata to the sea.
  • It is an expensive and technically difficult process.
  • It is anticipated that the results of a Beroe ovata introduction in the Caspian will be similar to that of the Black Sea.