On Wednesday I got to meet some very charismatic creatures, some wonderful jellyfish!
Little is known about jellyfish in UK waters, but we have around different 7 species.
Jellyfish are notoriously difficult (…expensive) to keep in captivity with very few people possessing the appropriate level of know-how to look after them left alone breed them. This is exactly what the lab I was in on Wednesday was interested in doing, research ways to propagate the more difficult species.
What is a Jellyfish?
Jellyfish are gelatinous free swimming marine invertebrates with no skeletal structure or specialised digestive, osmoregulatory, central nervous, respiratory or circulatory systems. Their bodies contain between 95 and 98% water depending on the species.
Jellyfish have very limited control over their movement and are dependent on currents to feed however they can navigate by expanding and contracting their bodies to propel themselves forward.
Most species possess light sensitive organs called ocelli which allow them to determine the direction of light.
Jellyfish development is governed by multiple phases: larval planulae, polyps, ephyrae, and adult medusae.
Most species of Jellyifsh are either Male or Female. Adults spawn periodically by releasing sperm and eggs where upon contact the eggs are fertilised and will develop into a cluster of cells known as planula that will eventually settle on a hard surface and develop asexually into a polyp. Polyps resemble Sea anemones. The Polyp gathers food using tentacles until it developed into a stack of ephyra to form a strobila. The ephyra are undeveloped jellyfish that will eventually split off from the strobila stack and grow into adult jellyish known, perhaps insidiously, as medusae.
The process might sound complication is rarely simple, albeit difficult to replicate in a laboratory environment. It requires careful technique and specialist equipment but with care and diligence the lad is hoping to be the first in the country to successfully breed a large number of different species.
Download your free identification guide: Jellyfishguide