Jellyfish By: Chelsey McIntosh

What are Jellyfish? Also known as jellies or sea jellies, jellyfish are free swimming marine invertebrates that are members of the phylum Cnidarian. They are jelly-like and almost transparent with a bell shaped body. Jellyfish generally have long stinging threads on the surface. They are among the largest planktonic animals, they feed mostly on zooplankton and small fish. Some jellyfish can grow as large as 2 meters in diameter, with tentacles much longer.

Characteristics of the Phylum Cnidarian They have radial symmetry blind sac gut (coelenteron or gastrovascular cavity) diploblastic with mesoglea polyp and medusa body forms nematocysts (specialized stinging capsules) nerve net lack excretory, circulatory & respiratory systems complex life cycle many colonial forms exhibiting polymorphism

Did You Know? The largest type of jellyfish can be up to 120 feet long. (Lion’s Mane Jellyfish) In Countries like Japan, China and Korea it is a considered a delicacy to eat Jellyfish.

Life Cycles Most jellyfish have at least two distinctly different body forms in their life cycles. Polyp-This is when they take the form of a stalk with feeding tentacles. Medusa-tiny jellyfish which then grow into a large jellyfish.

Anatomy

Who preys on Jellyfish? Jellyfish are preyed upon by; tuna, shark, pacific salmon and sea turtles. Some jellyfish are even preyed upon by larger jellyfish.

How do Jellyfish protect themselves? Jellyfish use their tentacles to protect themselves, barb like filaments found on the tentacles pierce their victim, once this occurs venom is released from the filaments into the victim.

How do Jellyfish move? Jellyfish move like an umbrella, their jelly like “skin” opens allowing water to enter, it then closes using the pressure created from the release of water to move. Jelly Cam

References Fisheries and Oceans Canada. (2010). Canadian Waters. Referred from: www.dfo-mpo.gc.ca/canwaters-eauxcan/bbb-lgb/library-bibliotheque/glossary-glossaire/index_e.asp Krupp, D. (2004). Cnidarians. Referred from: http://krupp.wcc.hawaii.edu/BIOL200/powerpnt/pdffiles/cnidarchar.pdf New World Encyclopedia. (2010). Plankton. Referred from: www.newworldencyclopedia.org/entry/Plankton Pattern Media. (2009). Facts about Jellyfish. Reffered from: http://www.jellyfishfacts.net/facts-about-jellyfish.html

Pattern Media. (2009). Jelly Fish Facts. Reffered from: http://www.jellyfishfacts.net/jellyfish-information.html Pattern Media. (2009). Turritopsis Nutricula. Referred from: http://www.jellyfishfacts.net/turritopsis-nutricula-immortal-jellyfish.html Wiktionary. (2010). Jellyfish. Referred from: en.wiktionary.org/wiki/jellyfish