Question

Gonionemus vertens: Clinging Jellyfish were recently found in local waters; they are an very small, invasive, highly venomous species of cnidaria. Write fully and explain the topic above (Gonionemus Vertens) and integrates knowledge of the species.

Answer 1

Character and behavior

Gonionemus genus of small marine hydrozoans (order-Limnomedusae, phylum-Cnidaria). Found in coastal regions throughout giant components of the Northern Hemisphere.

The conspicuous jellyfish stage of Gonionemus species is bell-shaped and measures regarding 15 mm (0.6 inch) or more in diameter. From the centre of the bell hangs the manubrium ( a tubular/hollow structure that contains the mouth)and around the bell’s rim are hollow tentacles armed with stinging structures called nematocysts.

  The gonads are clearly  colored orange, red or violet for female, or yellow-brown for male. The gonads are arranged hanging from four radial canals so that when inspect/see from the  above, the gonads are lined perpendicularly.

The gonads hang down along the 4 radial canals and form a clearly visible X shape (see photo bellow ). The manubrium is colored tan and hangs down close to the bell margin, with 4 slightly frilly lips. The bell is also be clear or light green. (It is uncommon for a hydrozoan medusa to be colored).

The bell of the jellyfish (medusae) reproduce sexually and the tens of thousands of eggs and sperm are released into the sea.They become planula larvae that eventually attach themselves to the seabottom on algae, rocks or shells as tiny/small polyps.

Each member of the genus begins life as a planula larva, which develops into a solitary non -swimming polyp measuring less than 1 mm in height. Fertilized eggs develop into planula larvae.

The polyps can split into several by budding. The change from polyp to tiny medusae, happens when the water surpasses 17–18 °C (63–64 °F). Because of this, the medusae follow an annual pattern and first appear in the spring or later depending on temperature,sometimes causing sudden blooms where many show up at once. The medusae stage generally lasts no more than three months, but the species can live for years in the polyp stage.

During the day the medusae can  attach themselves with the adhesive patches on their tentacles to varied surfaces, especially seagrass, earning the species its common name clinging jellyfish.

Gonionemus vertens may catch prey once attaches to surfaces throughout the day, but they mostly feed at night in open water, eating zooplanktonic organisms like fish larvae and tiny/small crustaceans.

$Gonionemus_vertensDLC2007-04s.jpg$

Gonionemus vertens are unusually venomous, and has a strong sting, which can cause pain, a swollen throat, chest tightness, muscle cramps, neuropsychiatric changes and anaphylactic shock. This is the main danger for swimmer  .Also causes a burning sensation in the skin, Numbness sets in, along with pain in the joints of the arms and legs; breathing becomes laboured and can temporarily cease. Liver malfunction sometimes occurs, and also the acute symptoms last four to five days.

Most Gonionemus species are cosmopolitan within the hotter regions of the Atlantic and Indo-Pacific oceans.

note-Image source and content from encyclopedia britannica and wiki.