With five successful Melbourne Sea Slug Census events to date, our records of sea slug species found in and around Port Phillip Bay and Western Port are continuing to grow. Collecting photos of sea slugs present at different times throughout the year will help us monitor these species and track any changes, but we’ll need your help!

The fifth Melbourne Sea Slug Census was held over Friday 4 to Monday 7 October 2019. We had a massive response from our nudi loving community- roughly 400 photos were submitted, and we had a record number of slugs for the Melbourne project. You can see the highlights and download the report below.

The next Melbourne Sea Slug Census will be in 2020, between Friday 17 and Monday 20 January. If you are out and about that weekend and you come across any Sea Slugs, we want to know what you find! Images of Sea Slugs found during these dates can be sent to [email protected]

Heavy rain can impact water quality on our coasts, especially after fires and periods of smoke haze. In general the EPA recommends avoiding swimming near stormwater or river outlets 24–48 hours after heavy rain. Within Port Phillip Bay, you can check your local beach conditions at the Yarra and Bay Beach Report- https://yarraandbay.vic.gov.au/

See Get Involved below for more details.


In Partnership:-

The Sea Slug Census is supported by the Victorian Government.

Caption: Tambja verconis, a nudibranch commonly spotted in Port Phillip Bay. Photo Liz Harper

What is a sea slug and how will you know if you’ve found one?

Sea slugs are actually snails i.e. they are sea snails (marine gastropod molluscs) that have seemingly lost their shells. Also known as nudibranchs, they are found in most marine habitats, occurring in shallow rock pools and in the deep sea. Knowing when you find one can be easy when they are the size of a football, or extremely difficult when they are smaller than the nail on your pinkie finger. Generally, if it is in saltwater and it moves like a slug it is most likely a ‘sea slug’. If you are unsure, take a photo and we will let you know.

Sea Slugs are one of the most popular and most photographed groups of marine invertebrates, with ~400 species known in Victoria. They are excellent indicators of environmental change because they have rapid life-cycles (less than 12 months), very specific food requirements, and respond to changing oceanographic conditions.

Yet there is very little basic knowledge on their diversity, distribution and ecology. To learn more about them we teamed up with Southern Cross University to have Victoriaís first Sea Slug Census in Port Phillip Bay, Westernport Bay and surrounds. The information gathered will help marine scientists to update knowledge about the diversity and distribution of this spectacular group of molluscs.

To learn more about sea slugs in Victoria, check out these links:

A Museum Victoria field guide – Nudibranchs and related molluscs

Port Phillip Bay Taxonomic Toolkit

Australian Geographic – Nudibranchs: indicators of climate change

Facebook group for nudi-nerds!

Everything you need to know about the sixth Melbourne Sea Slug Census, 17-20 January 2020!

Water quality

Heavy rain can impact water quality on our coasts, especially after fires and periods of smoke haze. In general the EPA recommends avoiding swimming near stormwater or river outlets 24–48 hours after heavy rain. Within Port Phillip Bay, you can check your local beach conditions at the Yarra and Bay Beach Report- https://yarraandbay.vic.gov.au/

Info for Melbourne Sea Slug Census VI

To help our experts with their identification, try to get a clear shot of the slug’s body from the side and/or include as many creature features (rhinophores, gills/cerata, oral tentacles) as possible. As always when out and about in nature, be mindful of limiting your impact on your subject and their surrounds.

October 2019

Between Friday 4 – Monday 7 October 2019 people all across Port Phillip Bay, Westernport Bay and surrounds submitted their photos of nudibranchs as part of the fifth Melbourne Sea Slug Census.

88 species of slug were seen this time, with submissions from 25 individuals or teams. We received photos from usual hotspots like Blairgowrie, added some western Victorian sites to our records and ReefWatch’s Nicole even managed to join forces with Parks Victoria’s Sea Searchers down at Point Lonsdale for some intertidal adventures.

We had some terrific entries to the Census for October and it’s great to see many new names adding to our records and understanding of Victorian sea slugs.  See below for a list of the awards for this Census!


Best Photo: Kim Bremner, Coryphellina sp. RB1

Voted by Tim Hochgrebe of Underwater Australasia, and a favourite in the VNPA office- we all loved the beautiful colours of this photo as well as the ecological information it contains. Those delicate egg ribbons also belong to this species, so in reality Kim has captured hundreds of Coryphellina in this shot! Well done Kim.

Runner up for the category was Chris Hurwood with his Phyllodesmium serratum– in Tim’s words, “such beautiful colour and a vibrant shot”.

Best Photo: Kim Bremner, Coryphellina sp. RB1

Runner Up: Chris Hurwood, Phyllodesmium serratum


Most interesting species: Rebecca Lloyd, Eubranchus sp.

This unusual Eubranchus isn’t an entirely new find, but we were excited that Rebecca managed to uncover more specimens during a Census this time! Bob Burn judged this the most interesting species and it’s one that is on his (extensive) list to formally describe.

We also loved PT Hirschfield’s Melibe sp RB3, just for being such a weird and wonderful species of sea slug!

Photo: Rebecca Lloyd, Eubranchus sp.

Honourable mention: PT Hirschfield, Melibe sp. RB3

Best Group Shot: Naomi Strong and Steven Walsh

We loved this artistic shot of a gaggle of Kaloplocamus ramosus, submitted by Naomi and Steven.

Photo: Naomi Strong


Biodiversity Awards: Steven Kuiter, Sally Nankervis and Edward Lee

This award for capturing multiple species of slug in one shot jointly goes to Steven Kuiter for his trio of Trapania (brunnea bottom left and aureopunctata top right) feasting on nodding heads (kamptozoans), and to Sally Nankervis and Edward Lee for their shots of two common “expat” species Polycera hedgpethi and Thecacera pennigera congregating around their own shared food source of bryozoans.

Photo: Steven Kuiter

Photo: Sally Nankervis

Photo: Edward Lee


Photobomb Awards: Chris Hurwood and Steven Kuiter

Because nature doesn’t always behave, we wanted to mention those photographers whose “perfect” shot was thwarted by another critter who may not necessarily be a target for the Census records! Chris Hurwood had two worthy contenders for this award, with his gorgeous shot of Polycera janjukia being “invaded” by a Polycera hedgpethi in the bottom right corner, and for his Madrella sanguinea feat. one confused looking shrimp. Also getting a mention here is Steven Kuiter for his Goniobranchus meracula, with a shrimp and isopod generally getting in the way.

Photos: Chris Hurwood

Photo: Steven Kuiter


Ultimate Nudi Hunter Awards: Rebecca Lloyd and Chris Hurwood

Rebecca Lloyd led the pack having captured a whopping 60 different species on camera, followed up by Chris Hurwood with 50 species. They continue to set the bar for future Censuses.


Best Portfolio: Rebecca Lloyd and Nick Shaw

Both Rebecca Lloyd and Nick Shaw impressed us with the overall quality of their many submissions, with several photos each making the shortlist in a blind selection by VNPA staff.


Thanks again to everyone who contributed photos, keep up the great work. Our next Melbourne Sea Slug Census will be held between Friday 17 to Monday 20 January 2020. This will be our first true summer Census and we’re excited to see what’s out there!

October 2019

What can we say other than we were blown away by the number of nudis spotted this time! 88 species to be exact, some new additions to our records and a few entries that left our experts pleasantly surprised. October certainly seems like a busy time for both our nudis and the keen citizen scientists who search for them!

Download full report for October 2019

June 2019

Our winter wonderland edition of the Melbourne Sea Slug Census saw many people brave the cold water, but only 6 groups of nudi hunters managed to photograph slugs during that time. Still, 29 species of slug were sighted, with some really beautiful submissions and new species to add to the Melbourne census records. A commendable effort for a very chilly weekend!

Download full report for June 2019

March 2019 

Melbourne Sea Slug Census III was held over the 15-18 March. Many groups reported seeing far less slugs than expected, but all in all, over 100 nudi hunters that were out and about across the weekend recorded 48 individual species between them. Well done everyone!

Download full report for March 2019

October 2018 

The second Melbourne Sea Slug Census took place on the 12-15 October. Over four days, enthusiastic teams and individuals managed to find an incredible 75 species of sea slugs! It was a fantastic effort and the overall quality of images submitted impressed everyone involved in sorting and identification. Some of the species photographed during this Census have rarely been seen in Victoria, even by our leading experts!

Download full report for October 2018

April 2018

The first Melbourne Sea Slug Census was held on the on the weekend of 21-22 April. Thank you to the over 150 people who photographed different sea slugs (nudibranchs) in Port Phillip Bay, Western Port Bay and surrounds and submitted them to ReefWatch. Together, we found a total of 53 species of nudibranch!

Download full report for April 2018

Support the 2018 Sea Slug Census with your own t-shirt.

Cost: $25.00
Cotton machine washable t-shirt locally printed from an ethical accredited supplier. Available in sizes S-XXL while stocks last.

T-shirts can be collected from the office or at a Sea Slug Census event (by arrangement) at no cost. Alternatively, T-shirts can be delivered to you for $5 each.

Purchase from our online store

Nicole Mertens, ReefWatch Project Officer