Stalked jellyfish survey launched in Dorset

Stalked jellyfish in Kimmeridge Bay. Credit Steve Trewhella/UKcoastalwildlife.co.uk

A small group of divers and marine biologists, led by Steve Trewhella, have started a survey in Kimmeridge Bay to assess the stalked jellyfish population.

Stalked jellyfish are very small, measuring just 40 - 50mm (Researchers can just about ID them with the help of a magnifying glass.), and very strange animals; unlike other jellyfish they attach themselves to seaweed with a stalk, and move like a caterpillar. They feed on plankton which they catch with an umbrella like bell.

4 species in Kimmeridge Bay 
Kimmeridge Bay is lucky enough to have 4 species living amongst the seaweeds and algae. The projects aims to establish a 'ballpark' figure for the population, as very little is known about these fairly rare animals.

Putting quadrats down in a field and counting flowers is easy; being underwater with diving gear and magnifying glasses, is a different ball game. Credit S Trewhella/UKcoastalwildlife.co.uk.

Many of the UK species are of high conservation importance, listed as FOCI ( Features Of Conservation Interest ) under the proposed marine reserves. 3 of the UK species are UK BAP ( Biodiversity Action Plan ) Priority Species; all of these occur in Kimmeridge Bay. 

The Stalked jellyfish seem to favour certain types of seaweed, and Kimmeridge Bay is rich in seaweed, with more than 100 species, including some very rare ones. Like seahorse conservation, its all about protecting the habitat from damage.

Methodology
A GPS is towed across the bay by the divers, and quadrats are placed on the seabed within suitable habitat, If jellyfish are found, they are counted and identified, and the micro habitat (seaweed / substrate) is recorded. Using this system the research team will identify hotspots.

Putting quadrats down in a field and counting flowers is easy; being underwater with diving gear and magnifying glasses, is a different ball game.