Hundreds of human-size jellyfish have been spotted lurking off the coast of the UK in the past few days.
According to marine experts, there have been more sightings of these gigantic creatures during the past week than over the past 15 years.
Lizzie Daly, a biologist* with Wild Ocean Week, said the animal she came into contact with during a dive in Falmouth was the same size as her.
Giant barrel jellyfish
Barrel jellyfish are the largest species of jellyfish found in that part of the world, with a diameter of up to 90cm and weighing up to 35kg.
This year, hundreds of barrel jellyfish have washed up on beaches across Cornwall and Devon, UK.
“Barrel jellyfish are so big that this is really quite a phenomenon*,” blogger* and kayaker Rupert Kirkwood wrote this week.
Mr Kirkwood, who is known as The Lone Kayaker, wrote on his blog earlier this year, “There are more barrel jellyfish around the coast of SW England than I have ever seen in 15-plus years of sea kayaking.
“A lot more. I have seen more in the last three days than all the other years added together … 91 on Tuesday, 120 plus on Wednesday and 40 plus today.
“This number of any other jellyfish is not unusual, but barrel jellyfish are so BIG that this is really quite a phenomenon. Their ‘bell’ can be two foot across and they can weigh in at over 30kg.
“Their appearance seems to have coincided* with a plankton* bloom* (upon which they feast) that has probably been caused by the sunny weather.”
Mr Kirkwood believed there could be “millions” in UK waters.
Despite being the size of a bin lid, the jellyfish are gentle giants and their sting is too weak to hurt humans.
They feed on plankton and are usually spotted along UK coasts through summer and autumn.
Collective nouns* are the handy words we use to describe a group of something.
Well-known examples are a school of fish or a flock of birds.
There are several collective nouns to describe a group of jellyfish.
Kids News’ favourite is FLUTHER, as in “A fluther of barrel jellyfish just floated past”.
Other jellyfish collective nouns are: SCHOOL, SMACK and SWARM
Their scientific name is Rhizostoma pulmo.
They are common off the southern and western coasts of the UK in summer and are attracted to the supplies of plankton.
They are also often seen in late spring and wash up on beaches in May or June — sometimes in their hundreds.
They live in the northeast Atlantic Ocean, and in the Adriatic, Mediterranean and Black seas and the Sea of Azov.
They are the size of bin lids (which some countries call dustbins), giving them their other name: dustbin-lid jellyfish.
The jellyfish have eight arms, which are frilly in appearance. These frills contain their small stinging tentacles that surround hundreds of mouths. The sting is too weak to cause any serious harm to humans.
Although barrel jellyfish are very large, they’re not as big as lion’s mane jellyfish, the largest in the world. The biggest lion’s mane jellyfish was one seen off the US east coast in 1870 that was 2.3m in diameter.
This article originally appeared on The Sun and was reproduced with permission
- biologist: plant and animal scientist
- phenomenon: something noticeable
- blogger: someone who writes online on a blog
- coincided: happened at the same time as
- plankton: tiny aquatic creatures that float in the ocean’s currents
- bloom: big, sudden population growth
- nouns: words we use to describe people, places or things
- How many centimetres across is a barrel jellyfish?
- How much can one weigh? Is that more than a lion’s mane jellyfish?
- Are you likely to see a barrel jellyfish in Australian waters?
- How many arms do barrel jellyfish have?
- Are they dangerous to humans?
LISTEN TO THIS STORY
1. Cause and Effect
Animal populations ebb and flow in accordance with environmental conditions. The article suggests some reasons that the barrel jellyfish’s population has increased significantly. Their natural predators, the leatherback turtles as well as other animals may also be in decline.
Draw up a cause and effect flowchart showing some things that may have caused this population explosion and make predictions about the impact this may have on environmental conditions into the future.
What happens when this massive population has eaten all the plankton? What may happen to the population of their predators?
Time: allow 20 minutes to complete this activity
Curriculum Links: English, Science
What have you learnt about barrel jellyfish from this article?
Create a slide show presentation that shows the following information:
- Physical features
- Population distribution (use a map to show where and when you might see them)
- Other interesting facts.
You may need to do some further research to find extra information about these jellyfish.
Time: allow 45 minutes to complete this activity
Curriculum Links: English, Science, Humanities and Social Sciences — Geography
After reading the article, with a partner, highlight as many connectives as you can find in pink. Discuss if these are being used as conjunctions, or to join ideas and create flow.
HAVE YOUR SAY: What is your favourite type of jellyfish? Which sorts have you seen? Describe what they looked like.
No one-word answers. Use full sentences to explain your thinking. No comments will be published until approved by editors.