Jan 2019 Sea Slug Census: Preliminary Report

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Hypselodoris obscura , near Merimbula Bridge Photo: Matt Nimbs, Jan 12th

Hypselodoris obscura, near Merimbula Bridge Photo: Matt Nimbs, Jan 12th

This is the third year of Sea Slug Censuses on this coast and this year we were delighted to have Matt Nimbs down from Southern Cross University in Coffs Harbour to work with us on our Census and to share some of his deep knowledge of these amazing creatures. Matt works with Prof. Steve Smith and together they have helped start Sea Slug Censuses around Australian coasts and now abroad – we had a request from Hawaii to join in with us!

Elysia australis , near Merimbula Bridge Photo: Libby Hepburn, Jan 12th

Elysia australis, near Merimbula Bridge Photo: Libby Hepburn, Jan 12th

Sea slugs are incredibly diverse creatures, ranging from less than 10mm in length like Elysia australis to really big sea hares like Dolebella which can be 500mm long. They take all kinds of forms, from wonderful camouflage to the gaudiest of colours and shapes for example the cluster of Plocamopherus imperialis that we found under Narooma Wharf.

Plocamopherus imperialis, under Narooma Wharf Photo: Paul Tan

Mostly sea slugs seem to be solitary animals, except when they get together to mate and lay their clusters of eggs, but over time we have discovered a wide range of species in our area. Often they glow like jewels amongst the seaweeds and are really exciting to find. You can see them all on our NatureMapr database which shows where and when they have been found.

This year we looked in rockpools and along estuaries, some people snorkelled and some dived, from Green Cape in the south to Bawley Point in the north and we are just now gathering all the information and images together from participants. We will produce a report shortly where Matt and Steve will tell us what is particularly interesting about our finds this year.

Intrepid searchers in the rain at Merimbula

Intrepid searchers in the rain at Merimbula

And on a sunnier day, Alan Scrymgeour leading an estuary search

And on a sunnier day, Alan Scrymgeour leading an estuary search

At Lennards Island, the only location where we found not one Sea Slug

At Lennards Island, the only location where we found not one Sea Slug

These scientists want us to find and record what’s living in all the different coastal habitats and what we can find each year. Because of the strengthening of the East Australian Current, they are particularly looking for species which are moving south into new areas, because of warming sea conditions. Last year Robyn Wimbush found a Sea Slug in the Blue Pool which was 600km south of its previously recorded range. 

As well as being a lot of fun and a fascinating study, we are creating a more complete species list for our coastline and we will be able to see better over time how things are changing.

Matt gave presentations, about the natural history and diversity of Sea Slugs, in Eden at the Sapphire Coast Marine Discovery Centre and at the Bateman’s Marine Park Office in Narooma for the Nature Coast Marine Group.

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Matt Nimbs at Camel Rock

Matt Nimbs at Camel Rock

We organised group searches and snorkels and some people went hunting on their own. Altogether we estimate over 50 people took part in this early season census. 

We are hoping to organise another later in the year, probably in April, so keep an eye on our Atlas of Life website for details of what’s coming up.

Libby Hepburn (29 Jan, 2019)

Aplysia argus, Batemans Marine Park  Photos: Phil and Lyn B Jan 17th