Jellyfish on the menu

November 29, 2017, University of East Anglia
Jellyfish on the menu
Credit: University of East Anglia

Squid, sole, dogfish, herring and cod all feed on baby jellyfish – according to new research from the University of East Anglia and the Centre for Environment, Fisheries and Aquaculture Science (Cefas).

The is commonly found around the coastlines of Britain. They're known for their translucent white colour and gentle swimming movements.

Until now, they were thought to have very few predators. But new findings published today in the journal Royal Society Open Science reveal that they are a veritable feast for a number of fish species.

Lead researcher Philip Lamb, a PhD student in UEA's School of Biological Sciences, said: "Localised outbreaks of jellyfish cause a variety of ecological and economic problems such as overrunning fish farms and damaging revenues from tourism. But until now there has been little known about some fundamental aspects of their ecology – particularly their role in food webs.

"It is hard to identify jellyfish predators because they are digested very quickly due to their soft-bodies.

"The only known jellyfish predators, in the Irish Sea, were small populations of Leatherback turtles and Sunfish. However both of these are rare and not thought to play a significant role in controlling jellyfish populations."

Thanks to new technological advances, the research team were able to study DNA in the guts of 50 potential predators. They extracted genetic material known as mitochondrial DNA (mtDNA) from more than 2,500 fish caught in the Irish Sea and compared these genetic fragments against a DNA database.

"By studying tiny fragments of DNA present in fish gut samples, we have even been able to detect jellyfish which have been highly digested," said Lamb. "We were really surprised by the results."

The team found jellyfish mtDNA in nine of the 50 potential predators investigated – in whiting, herring, dragonet, Dover sole, dab, squid, sprat, poor cod, and lesser-spotted dogfish.

Herring and whiting were found to feast on jellyfish frequently, while the others appeared to be minor predators. Looking at the jellyfish life-cycle, the team suggested that the majority of eaten would have been juvenile.

'Jellyfish on the menu: mtDNA assay reveals scyphozoan predation in the Irish Sea' is published in the journal Royal Society Open Science on November 29, 2017.

Explore further: DNA tests on albatross poo reveal secret diet of top predator

More information: Jellyfish on the menu: mtDNA assay reveals scyphozoan predation in the Irish Sea, Royal Society Open Science, rsos.royalsocietypublishing.or … /10.1098/rsos.171421

Related Stories

UN warns of jellyfish 'vicious circle' in Med

May 30, 2013

The United Nations on Thursday warned overfishing in the Mediterranean was boosting jellyfish, which reduce stocks further and it called for jellyfish to be used in food, medicine and cosmetics.

Baby fish lose poisonous protectors in acidified oceans

June 28, 2016

A common close partnership which sees baby fish sheltering from predators among the poisonous tentacles of jellyfish will be harmed under predicted ocean acidification, a new University of Adelaide study has found.

Recommended for you

Chimpanzee calls differ according to context

May 23, 2018

An important question in the evolution of language is what caused animal calls to diversify and to encode different information. A team of scientists led by Catherine Crockford of the Max Planck Institute for Evolutionary ...

How a cell knows when to divide

May 23, 2018

How does a cell know when to divide? We know that hundreds of genes contribute to a wave of activity linked to cell division, but to generate that wave new research shows that cells must first grow large enough to produce ...

Revealing the mysteries of early development

May 23, 2018

Zebrafish embryos are transparent and develop outside the mother's body, enabling scientists to get a detailed view of early development. A research team led by Lila Solnica-Krezel, the Alan A. and Edith L. Wolff Distinguished ...

Study bolsters bats' reputation as mosquito devourers

May 23, 2018

It's a common assumption: Bats are important because they feast upon those pervasive warm-weather pests known as mosquitoes. You want to see bats flying above, cleaning up the night sky and ridding you of itchy bites and ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.