Magnificent Ceratosoma magnificum!

The person who named Ceratosoma magnificum certainly had the right idea. Spotting this relatively large species at Terrigal Haven sent my excitement levels through the roof.

 

Ceratosoma magnificum is easily identifiable by the row of 3 upwards-facing pustules running along the centre of the mantle. The smallest slightly anterior to the rhinophores and the largest just in front of the brown-white gills.

The white margin with vivid blue and yellow is also a giveaway that you are viewing Ceratosoma magnificum. The foot of this individual was a deep purple with yellow spots.

Port Jackson shark project update #1

The project is looking great so far!

After a week or two of bad visibility I was finally able to get out into the water again to take some images. Pulling on the neoprene (my relatively new Neptune Dry Ice wetsuit!) is always a good feeling. Couple that with the amazing feeling of seeing 15+ Port Jackson sharks each dive on my last three research dives - yeah, it's good.

So the data gathering stage of my project is sailing along pretty smoothly at the moment. I haven't set myself a benchmark or limit on how many photographs I am looking to acquire (yet). I'm sure as the project develops I will get overwhelmed by shark images! Especially when every shot comprises the same orientation and subject matter (see below)!

Hopefully I'll be able to schedule a regular dive on Friday afternoons after uni has finished to increase my dataset of images. Finding a dive buddy for the Friday dives looks promising, with some of my uni mates becoming certified divers.

I'm really enjoying this project and depending on the results I may look at taking it further...

Check out http://nudibank.blogspot.com/2011/08/new-port-jackson-shark-project.html to read what this project is about.

Stay tuned for more information and results!

Peace,
Dave

New Port Jackson shark Project

I've recently started a project looking at the possible uses of natural markings to identify individual Port Jackson sharks - Heterodontus portusjacksonii.

From my preliminary results it looks as if the project will be quite successful.

I have played around with a program called StripeSpotter and had a little bit of success. I am now trialling some software that is used to analyse manta rays, whale sharks and great white sharks - I3S Manta.

Stay tuned for my results. Also, anyone who is doing similar research, I'd love to hear from you. Please get in contact and we can network and share experiences.

HMAS Adelaide

It's been a while since I posted a blog. Just so you loyal followers know (all 4 of you) I have not lost my interest in nudibranchs! I just haven't seen many recently...

I dived the HMAS Adelaide recently and I thought I'd share a few photos.

Also, if you are interested in an uplifting website. Check out my Bucket List website - www.crossitoff.net

South West Rocks - Grey Nurse Sharks and some new Nudibranchs!

South West Rocks is best known to the diving community for Fish Rock Cave and its population of beautiful endangered Grey Nurse Sharks. In my previous blog I mentioned that I was going to dive Solitary Island in Coffs Harbour. Well, that dive was canceled due to rough seas. Luckily the dive shop that we were diving with the next day, Fish Rock Dive Centre (awesome shop, I highly recommend checking them out if you are in SWR) told us we could dive with them on Saturday as well as Sunday.

So off we were to South West Rocks.

Our first dive was amazing!
The seas were doing their best to keep dive boats away from Fish Rock Cave, but that didn't phase our skipper or the 8 divers aboard our boat. Descending down the anchor rope into a channel filled with Grey Nurse Sharks is an awesome experience that should be scribbled in permanent marker on every divers 'to do' list, and then once it has been completed, it needs to be redone again and again!

Once you see these graceful giants just gliding past you gain a new respect for all sharks. More people need to experience the thrill of diving with sharks to stop this worrying new concept that "sharks and humans can't coexist". Over 100,000,000 sharks get killed by humans every year; around 4 humans get killed by sharks in an average year. Those numbers are ever increasing due to a menu item. Shark Fin Soup. Oops, see how easy I get sidetracked?

Sorry, back to the diving and nudibranchs!

We actually didn't see too many nudibranchs at South West Rocks. There were a few Hypselodoris bennetti present. But the Aphelodoris varia to the right was my most exciting find! Even though it is a relatively common branch on the East coast, it was the first time I had seen it. Colour variation between localities is common and can be strikingly different. Blue gills are a common feature, but the dark pattern can be bold (like the one pictured), blotchy or virtually absent. High sheaths around the base of the rhinophores is also a common feature of Aphelodoris varia.


Here is another image I took of Aphelodoris varia at South West Rocks, just outside of Fish Rock Cave, in an area our divemaster referred to as The Aquarium. The size of this specimen was approximately 50mm. The depth was around 18m.


So in regards to my zany nudibranch adventures at South West Rocks, I would have to say they actually weren't zany at all! Only a few sightings in an area I had heard was filled with nudibranchs was a little disappointing. However, the rest of the diving was amazing! Grey Nurse Sharks, Lionfish, Sponges, Bryozoans, Fusiliers and loads more exciting marine critters made the whole weekend cement a spot in my memory.

Keep that neoprene wet guys!

Just a quick one...

Just a quick entry today.

I am currently sitting in a cabin in South West Rocks with my regular dive buddy Keith. Waiting for tomorrow when we get to dive at Solitary Island in Coffs Harbour. But even keener for Sunday when we get to dive Fish Rock Cave in South West Rocks. Hopefully the Grey Nurses will put on a show for us!
Killing time in the dated cabin - we were just going through some images and I came across a branch that I hadn't posted here.












The image above is of Ceratosoma amoenum. A relatively common nudibranch on the Central Coast of NSW.

Ceratosoma amoenum can reach a maximum size of 60mm. Colour variations are common between different areas.


The image below shows another Ceratosoma amoenum that I found near the Skillion at Terrigal on the Central Coast of NSW.
You can see the spots are different with red being more dominant.

Cleaning out the vault

Reminiscing over diving trips by looking back through old photos can make you feel quite bad sometimes. You are working 9-5, it's raining outside, your local dive site has the visibility of a glass of soy milk, the mercury in your thermometer has frozen solid... You know, the things that make you wish you were back at that perfect spot. For me that was on the awesome island on the Great Barrier Reef known as Lady Elliot Island. This place has boasted the best diving I have ever done, big call, but those who have dived LEI will certainly have it in their top 10 dive locations.

So as I was going through my photos I stumbled across a few images of nudibranchs, a Spanish Dancer - Hexabranchus sanguineus, a Neodoris chrysoderma, and a Hydatina physis to be precise.

Technically Hydatina physis isn't a nudibranch. Scientifically it is categorised in a different Order, Cephalaspidea. The individual I spotted was at Swansea on the Central Coast. There is a great drift dive there under the Swansea Bridge that I recommend for all divers, especially recently certified divers. This guy was approximately 50mm. The image I took does no justice to the vibrancy of the blue edges on the foot.




I had a lot of trouble identifying this Neodoris chrysoderma. It took me a while, but I stumbled across a post on the Sea Slug Forums. According to other divers on the Sea Slug Forums this nudibranch is quite common, and it isn't rare to see a group in a cluster of 5-10 individuals. This is a small branch, 30mm maximum, that can be coloured light yellow to orange. Regardless of the body colour, it always has white pustules.




The final entry into this blog is an image I had forgotten I snapped whilst on holidays at Lady Elliot Island. As I mentioned before, LEI is so far the greatest place I have ever dived. Manta rays, sharks (tigers, black and white tipped reef sharks), whales, turtles, dolphins; Deep, shallow, drift dives. All round, an awesome place to dive!

I spotted this nudi whilst reef walking, rather than diving, which is a shame as the Hexabranchus sanguineus, commonly known as the Spanish Dancer, has the ability to use its large parapodia to propel itself through the water. As far as I know it is the only Opisthobranch that moves in this way (please correct me if I am wrong!). I spotted this Spanish Dancer before I caught "The Nudibranch Disease", originally I had the impression that nudibranchs were all tiny 'sea slugs', and when I found one that was over 200mm I initially thought it must have been something else. I had heard people speak of Spanish Dancers swimming past, but I was under the impression that it was some kind of fish, or a squid like creature.




I hate doing this, but I am going to leave you on a negative note.
A very large amount of dives in a row have resulted in me exiting the water with BCD pockets full of plastic bags, bait packets, fishing line, sinkers, hooks, and general boating rubbish. I know all of you divers reading this blog would have the same experiences in seeing the horrible state of shorelines and shallow dive sites. I suggest that every few dives (if not every dive) it is beneficial to take a rubbish bag with you and do some collecting. There are some great bags you can buy from online stores and your local dive shops.

Thanks for your continued interest!

Keep on branchin'.
Dave