20 July 2023

This July, our Husbandry Crew led the 2nd BIAZA Jellyfish Focus Group field research trip.

BIAZA Jellyfish Research Trip

Chaired by The Deep, the Jellyfish Focus Group is a collection of professional jellyfish aquarists from zoos and aquariums across the UK; the overaching goal is to increase knowledge of jellyfish husbandry, share information and undertake research projects.

Husbandry supervisor, Tom, alongside aquarists from The National Marine Aquarium (NMA), Liverpool Museums, and Scarborough, London, Brighton and Hunstanton Sealife centres, spent two days off the coast of Pembrokeshire in the Celtic Sea. The aim was to find and take tissue samples from our native UK jellyfish species, allowing us in the future to study these species more closely.

We have 6 main jellyfish species around the coast of the UK, along with several other ‘jelly-like’ animals. From each collected jellyfish, a very small sample of reproductive tissue is taken; this is harmless to the jellyfish and after the sample is taken, they are released back into the sea.

The trip was incredibly successful and despite some poor sea conditions, we were lucky to find 3 of the 6 species!

This included Moon jellyfish (Aurelia aurita), Compass jellyfish (Chrysaora hysoscella) and Bluefire jellyfish (Cyanea lamarckii). Once back in the lab, each tissue sample was assessed to ascertain whether the jellyfish was male or female. The aim was to collect planula larva from each species (the 1st stage in the jellyfish lifecycle). 

In some cases, the planula are already present within the tissue and we can simple collect it as it is released (a naturally occurring procedure). In other cases, we use a technique called in-vitro fertilisation. This involves introducing small samples of female and male tissue under sterile conditions. Because jellyfish broadcast spawn, the eggs are able to be fertilised mid water, much like corals and other similar animals.

Once back at our home aquariums, the planula are settled into small containers where they will develop into jellyfish polyps (the jellyfish producing stage). A healthy population of polyps will live for many years and are able to reproduce asexually, which gives us the opportunity to culture these jellyfish behind the scenes at The Deep.