Jellyfish

Peter Williams
Reaktion Books, £12.95

Jellyfish is one of a series of 95 books by Reaktion focused on specific animals, from the albatross to the zebra, and the quality of this one has inspired me to investigate the others.

A creature that has inhabited our planet for more than 600 million years is given the respect it deserves in this book, which is interspersed with stunning images. We are introduced in seven chapters to the importance of jellyfish within art, fashion, design, fiction, poetry, drama, myth, legend, documentaries, food and science. The jellyfish was even at the centre of Nobel
Prize-winning research (the fluorescent protein used in biomedical research and anaphylaxis using jellyfish stings).
The author doesn’t just cover the jellyfish class Scyphozoa, which purists believe to be the ‘true’ jellyfish, but also Hydrozoa, Cubozoa and Ctenophora.

Jellyfish are renowned for their ability to sting – their nematocysts can discharge at a speed of two metres per second and their venom can break down tissue, excite nerves and cause cell contents to leak. Toxins produced by the box jellyfish are lethal to humans and are released when they come into contact with skin.

Not all jellyfish species are marine: a freshwater species, Craspedacusta sowerbii, was discovered in 1880 living in a water tank in Regent’s Park, London. Further, jellyfish aren’t just passive drifters: when pulsing they produce two vortices so they expend less energy when travelling, exhibit diurnal migration and also social behaviour when swimming in shoals.

Jellyfish forms vary from the ribbon-like Praya dubia (a giant siphonophore), at up to 50 metres long, to the globular, and their life cycles vary from the fixed polyp stage to the pelagic phase.

With a decline in the health of the oceans, these diploblastic organisms could become top predators and potentially a more common sight on dinner plates. As the author states: “Being ephemeral creatures they provide a reminder of our own impermanence on planet Earth”.

Jean Wilson MBE C.Biol FRSB