Buzzed by sharks!

We just finished day 8 since arriving in the study area.   It is Friday 11 December 2015. Today our focus was on the south-east of the study area (see map below).

Focus area for the RV Solander today. Yellow and orange lines show where we used the towed-video system and collected critters from the sea floor. The red X shows where we were buzzed by sharks.

One of the first tasks for the start of each day is to take measurements of the ocean water’s key properties: conductivity, temperature and depth. Both conductivity and temperature affect how quickly sounds move through water. Knowing their values is thus important for making sure our multi-beam instrument is set up to work correctly as we map the sea floor.

We measure these properties repeatedly each day using an instrument we lower into the water called a CTD, as shown in the picture below.

The CTD instrument being lowered into the water using one of the Solander’s strong winches.
The CTD instrument being lowered into the water using one of the Solander’s strong winches.

As you can see in the photo above, the sea today (as on several other days on this journey) is calm. Without a gasp of wind to stir the water, these quiet seas earn a 0 on the Beaufort sea state scale which measures how wavy the seas are. When the Solander is not moving (as in the picture), the seas are so still that you can look through them almost like a window to the deep – this is sometimes called ‘glass-out’ conditions.

The reflection of the sediment grab instrument is clearly visible in the very calm seas.
The reflection of the sediment grab instrument is clearly visible in the very calm seas.

Because of this, when our instruments in the water caught the attention of three sharks, I was able to see them clearly through the water!

Buzzed by sharks!

As we lowered and retrieved the CTD and the sediment grab, three sharks repeatedly circled around the boat (see picture below). Can you find all three of them? Two of them are harder to see because they are deeper underwater. But all three are below the sea surface.

Three sharks swimming around the RV Solander while we stopped to take water measurements.
Three sharks swimming around the RV Solander while we stopped to take water measurements.
Close-up view of two of the sharks through the water during ‘glass-out’ conditions.
Close-up view of two of the sharks through the water during ‘glass-out’ conditions.
Check out the black tips on the fins
Check out the black tips on the fins

What is a spinner shark?

AIMS scientist Marcus Stower is reasonably confident that these sharks are spinner sharks due to the distinctive black tips on all of their fins. It is possible that they are black tipped reef sharks  instead, but black tips usually don’t swim so close to the sea surface

Spinner sharks got their name because they often spin around at high speed towards the sea surface trying to catch fish. Sometimes they leap out of the water still spinning, as you can see in the video below.

AIMS have not been able to video or photograph spinner sharks leaping out of the water, but we’ll keep trying. Our tow-vid technician (Niall) has seen them leap out of the water repeatedly over the past few days. They sometimes chase the aluminium frame of the tow-vid system as it is winched to the sea surface. That gives me a good reason to put on my life vest, hard hat and steel toed boots so I can watch for them on the back deck!

Did you know…?

  • On average, spinner sharks are about the length of a typical adult human is tall (195 cm).
  • The longest spinner shark ever measured was 278 cm.
  • No human injuries or deaths have ever been reported from spinner sharks.
  • Mother spinner sharks carry their babies for 12 to 15 months instead of the 9 months for human mothers.
  • Spinner sharks prefer to eat fish that swarm. That may be why we are seeing them – remember from my last blog that we took underwater video through a fish swarm yesterday.


Thanks for reading – see you next time!

Who lives in a pineapple under the sea?


Welcome back! We are now on day 5 since arriving in the Bonaparte Archipelago (Tuesday 8 December) and this is where we are.

Solander location 10/12/2015
Today  we are working north of Maret Island, in much deeper water (45+ metres deep) than yesterday. We have photographed sea floor habitats and critters along eight different 1.5 km transects with the AIMS towed video system, and collected 2 sled loads of critters from the sea floor to study.


A highlight for the day was getting a close-up look at several large sponges (see below) before we headed northward. So, today’s blog is all about sponges!


Sponges collected from the sea floor by AIMS at north-west Maret Island in the Bonaparte Archipelago, Western Australia.
Yes, sponges do indeed live under the sea. But of course they do not live in a pineapple, and in fact, they are only sometimes yellow like SpongeBob SquarePants.

What is a sponge?

A sponge is an animal with no muscles, heart or lungs! A sponge’s body is basically a U-shape – often like a barrel or a glass (see below). Spongebob Squarepants (and other kitchen sponges you may have seen or used) are actually just small pieces of the real sponge they would have come from.




An diagram showing the main parts of a sponge’s body (left) compared to an example of a real sponge filmed by AIMS towed video system (right). It is easy to see the central cavity (2) but you have to look closely to see the pores.
Even though it has no bones, a sponge keeps its shape because it is filled with a jelly-like substance called mesohyl within a skeleton made of fibers rather than bones. Water comes in and out of the sponge’s body through holes in its body walls called pores (see above). The water brings food (tiny bits of debris and plankton) to every part of the sponge, and the water takes away wastes. All the pieces that fit together to make the sponge can work together to squirt water out quickly, such as to prevent burial under sand.

What shapes can a sponge be?

Sponges can form into many interesting shapes. Some common ones include:

  • Barrel

This type of sponge can grow up to 1.5 metres long – big enough for a person to stand inside it! The surface of these sponges often have deep ridges. 95% of all sponge species are of this type.


Examples of medium sized barrel sponges collected by AIMS near the Maret Islands in the Bonaparte Archipelago of Western Australia. They are upside down in the photo. See the ridges on the outside of the sponges?


  • Fan

This type of sponge can grow up to 1 meter long. They form a fan shape.

An example of a small fan sponge collected by AIMS near the Maret Islands in the Bonaparte Archipelago of Western Australia.
  • Tube

Tube sponges are made up of thick tube-like structures that join at the base. They can grow up to 1 metre in length. They can chase away predators by squirting out toxic chemicals.


An example of a small tube shaped sponge collected by AIMS near the Maret Islands in the Bonaparte Archipelago of Western Australia

Watch this video of sponges near Maret Island


  • How many barrel sponges do you see? Are they all the same kind? 
  • Look closely to find the tube sponge towards the end of the video.
  • Do you see any fish or other creatures near or on the sponges?


Sponges are home to many small critters

You most likely saw fish swimming near some of the sponges in the video. And if you looked very closely, you may have seen little animals crawling on them. In fact, sponges are a very important part of the sea floor as they provide food and homes to many different types of animals like fish, starfish, brittle stars, feather stars, crabs, and more. In fact, some microscopic organisms even live inside the tissues that make the sponge’s body walls and give the sponges their colour.

Look at the picture of a sponge below.  Can you see the crab living on it?  Can you see the pores?

A sponge collected by AIMS from the sea floor. Can you see the crab living on this sponge? Look closely to see the pores
Look at the sponge below closely.  This time can you see the pores? What about the central cavity? How many critters can you spot living on it?

A barrel sponge collected by AIMS from the sea floor. How many critters can you spot on this sponge? On this sponge, it is very easy to see the central cavity but hard to see the pores.

Did you know…

  • New medicines for treating HIV and breast cancer have been discovered from sponges.
  • Sponges are common in Western Australia. 275 species of sponges have been found in the Damper Archipelago and 500+ at Ningaloo ReefNingaloo Reef.  
  • This expedition is helping to figure out how many are found in the Kimberly region of Western Australia.
  • Many types of fish, nudibranchs, star fish, turtles and other animals depend on sponges for food and shelter.
  • Sponges are under threat from heavy fishing gear which drags along the sea floor and damages or kills them.


I hope you enjoyed this blog! See you next time.


Hawaii experiences its most severe recorded coral bleaching event

Coral bleaching, in Kaneohe Bay near Kaneohe, Hawaii. Photograph: Dan Dennison/AP (source
Coral bleaching, in Kaneohe Bay near Kaneohe, Hawaii. Photograph: Dan Dennison/AP (source

Hawaii is experiencing some abnormally warm ocean temperatures causing extensive coral bleaching which is most likely the worst bleaching event recorded.

When corals bleach they expel there symbiotic algae which they rely on for nutrient and loose there colour. If temperatures don’t drop down to normal levels after several weeks this leads to coral death due to thermal stress and nutritional depletion.

Researchers from the Hawaii institute of Marine Biology indicated that most corals recovered from a milder bleaching event last year but this year’s event where water temperature is has been elevated for extended periods by as much as 3 degrees above the normal summer range has resulted in  severe bleaching and  significant coral death.

Sources (

February-May 2016: An extended bleaching outlook showing the threat of bleaching expected in Kiribati, Galapagos Islands, the South Pacific, especially east of the dateline and perhaps affecting Polynesia, and most coral reef regions in the Indian Ocean. (Credit: NOAA

Seeking coral spawn at Scott Reef in the Timor Sea

A tenuis crop

Mass spawning of corals occurs annually on reefs worldwide, usually between spring and autumn, in tune with seasonal cycles of water temperature and sunlight. This extraordinary natural event remained part of the secret lives of corals until the early 1980s when scientists began to spend time underwater after dark on the Great Barrier Reef and to their astonishment observed more that 100 coral species spawning. Subsequently careful observations after dark by researchers and enthusiast divers has resulted in coral spawning being documented throughout the tropics, including at Scott Reef, where spawning was first recorded in 1995.

The timing of spawning is usually fine tuned around the lunar cycle and researchers have become accustomed to predicting spawning times based on particular months of each year and certain days of the lunar cycle. In Australia, on the Great Barrier Reef, the main spawning season occurs after full moons between October and December, with November the peak month when the many corals spawn on mid-shelf and offshore reefs. Key nights have proven to be 4-6 nights after the full moon, around the time of neap tides. At Scott Reef a subset of species also spawn during October and November, but the major spawning season fall between February and April. Corals on the western side of Australia are mostly likely to spawn following the March full moon, but 8-10 nights later when, once again the tides are entering their neap phase.

The worldwide observations of coral spawning have stemmed from plenty of time watching out for spawning at night, but researchers have also used some clues to fast track the discovery when seeking to work out spawning times at a new location. Detailed studies of tissue samples collected form coral colonies each month throughout the year have revealed that the corals take several months to grow their gametes prior to each spawning event. Each month the average egg size increases until the final size typical for each species is reached. Commonly mature coral eggs are 350-600 um diameter, making them visible to the naked eye if you break a coral open. Throughout this development immature coral eggs are usually white, but in their final month of maturation they can become coloured, with pastel pinks, oranges and reds the typical hues, but white, blue and green sometimes seen. The size and pigmentation of mature eggs provides researchers with a rapid guide to which species are ready to spawn during any particular month. Divers can check a few corals by cutting a small fragment and looking inside for evidence of the coloured eggs that signifies they are waiting to be released. This sort of pre-spawn check can really help when first studying a new location, but the second aspect of coral biology that helps predicting key spawning months is the synchrony within and often between species. Each coral colony that spawns its gametes into the sea is likely to achieve successful fertilisation with gametes from the same species if they release their gametes at the same time. Consequently there is a very high degree of spawning synchrony between colonies of individual species, with gametes usually being shed into the water within minutes of each other. Furthermore, as the seasonal and monthly cues that regulate the timing of spawning are common to all corals on a reef, it is normal for more than one species to spawn during the key nights each year. Although each species may have a particular time after dark for spawning. As a result, once a spawning month has been determined for one species it provides the focal point for when other species could be spawning at the same location. If many species spawn they can also provide a further cue in the form of a strong smell coming off the water and the next morning the presence of pink slicks of coral eggs and embryos floating on the sea.

These discoveries of coral spawning around the world have nearly all involved shallow water reefs where corals are easily accessible, marine labs or aquariums may be nearby for the study of live specimens and divers can spend time in the sea at night to make direct observations.  However, nobody is sure what happens in deeper water coral communities, living below 30m where scientific divers rarely spend much time corals living in this deeper twilight zone, known as the mesophotic due to the modest to very low levels of light available, are poorly studied but increasing recognised as important  parts of reef ecosystems worldwide. They are very abundant in the deeper lagoon at South Scott Reef.  A few samples collected using a grab during past research have indicated that some species had pale but pigmented eggs at the same time of year as the shallow species were spawning, but nothing definitive could be determined.

This month divers aboard the AIMS research ship RV Solander have been looking at the shallow corals and providing information to the team on Falkor. While it looks like the main spawning may have occurred following the March full moon, around 20% of the shallow water corals look like they’ll spawn during Falkor’s visit. The Falkor has sophisticated positioning equipment and an ROV fitted with high definition cameras. The Falkor’s presence at Scott Reef during a potential shallow water coral spawning event provides a rare opportunity to study the mesophotic corals and hopefully catch the first ever observations of them spawning  on the nights of 12-13 April.


Mesophotic corals in 52m water depth at Scott Reef during preliminary observations using the Falkor’s ROV.


A downward looking view of mesophotic corals  in 40-50m depths at Scott Reef


Mesophotic branching Acropora coral showing pale pink mature eggs in March  from a sample collected at 51m depth using a grab in 2013


A coral spawn slick containing millions of coral embryos on the sea surface the morning after a massive shallow water spawning event at Scott Reef (photo James Gilmour, AIMS)

About the North West Atlas blog site.

The North West Atlas was created in response to the need for more comprehensive and accessible information on environmental and socio-economic data on the greater North West region.  As such, the North West Atlas is a web portal to not only access and share information, but to celebrate and promote the biodiversity, heritage, value, and way of life of the greater North West region.

To achieve these goals, the North West Atlas provides the infrastructure and tools to promote the free and open exchange of information to support science, policy making and public understanding of the greater North West region.

The North West Atlas project builds on the e-Atlas project for the Great Barrier Reef and the Ningaloo Atlas covering Ningaloo World Heritage Area.  It is a partnership between government organisations, non-government organisations, researchers, industry, and community groups to improve our understanding and raise awareness of the greater North West region.

Funding for the North West Atlas project has been provided by PTTEP Australasia (a wholly-owned subsidiary of PTTEP, the Thai national petroleum exploration and production company) and the Australian Institute of Marine Science (AIMS).

The North West Atlas Blog forms part of the North West Atlas communication strategy to share information on the greater region to a wider audience.   Please feel free to contact at any time should you have any comments/suggestions for this Blog or the Ningaloo Atlas, or whether you would like to share anything on this Blog site that is related to the Ningaloo Coast.  We look forward to hearing from and sharing information with you.