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DISPLAYING POSTS TAGGED: marine biology (30)

Marine app out now

Author
by Blair
Publish date
16 November 2012
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There’s something new and blue in the app stores called the Bunurong Marine National Park Field Guide. Jointly produced by Parks Victoria and the museum, the app is released to coincide with celebrations of the tenth anniversary of marine national parks in Victoria. Nearly 12% of the state’s waters are protected in parks, sanctuaries and reserves that are managed by Parks Victoria, including Bunurong Marine National Park, which  is located between Phillip Island and Wilsons Promontory.

Two fish swimming Meuschenia flavolineata, Yellowstripe Leatherjacket, Shack Bay, Bunurong Marine National Park.
Image: Mark Norman
Source: Museum Victoria

The Bunurong Marine National Park Field Guide is free to download and contains information on over 300 species of marine and coastal animals and plants, including stunning images, many of which were taken by Museum Victoria scientists whilst diving in the park. It also includes park information and activities that may interest visitors. Maps and a gallery of the location, marine life and habitats are provided.

Rocks and coastal ocean Eagles Nest intertidal rock platform, Bunurong Marine National Park.
Image: Mark Norman
Source: Museum Victoria

Bunurong Marine National Park covers more than 2,000 hectares and extends along six kilometres of coastline. Above the water magnificent rock formations form the shore, while below, seaweed reefs are so dense that the experience is like swimming over the top of a rainforest canopy. The park is popular for rock pooling, while its extensive underwater rocky reefs, seaweed beds and seagrass meadows are excellent for diving and snorkelling. People exploring the nearby coastline will also benefit from the app. Many of the species occur at places like San Remo, Cape Paterson, Andersons Inlet, Waratah Bay and Wilsons Promontory.

Seaweed growing on rock Seaweed Habitat At Eagle's Nest, Bunurong Marine National Park.
Image: Mark Norman
Source: Museum Victoria

If you’re lucky, your park experience may be as surprising as mine during the making of the app. Off Shack Bay I was head-butted by a Bluethroat Wrasse. Surely only in a marine park could a fish be so cheeky as if to say "nick off, this is my turf!"

a fish Notolabrus tetricus, Bluethroat Wrasse, Cape Paterson, Bunurong Marine National Park.
Image: Julian Finn
Source: Museum Victoria
 

We've reached another milestone with this app as it available for both iOS devices (iPhone, iPod Touch, iPad mini, iPad) and for Android devices (phones and tablets). For those who have been waiting on Museum Victoria’s Field Guide to Victorian Fauna app to be released for Android – that’s our next project, so watch this space. And enjoy the Bunurong app in the meantime!

Bunurong Marine National Park Field Guide is built on Museum Victoria’s open source Genera code for producing field guides. The app can be downloaded free from the iTunes App Store for iDevices and Google PlayTM Store for Android.


Bunurong Field guide

Bunurong Field guide

Links:

MV Bunurong app support page 

Parks Victoria: Bunurong Marine National Park 

The truth is in the tooth

Author
by Kate C
Publish date
30 October 2012
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Leopard seals have jagged, three-lobed postcanine teeth at the backs of their jaws that fit together closely, almost like pieces of a jigsaw. These teeth were long presumed to allow these seals to sieve krill from the water, but the exact mechanism remained a mystery until now.

Leopard seal with mouth open A leopard seal at Taronga Zoo showing its teeth. The leopard seal has large canine teeth at the front of its jaw, and sieve-like cheek teeth at the back.
Image: Erich Fitzgerald
Source: Museum Victoria
 

skull and tooth of leopard seal The skull and postcanine tooth of the leopard seal. This detail comes from a working drawing in pencil, watercolour and indian ink that Becker made in preparation for Prodromus of the Zoology of Victoria.
Image: Ludwig Becker
Source: Museum Victoria
 

David Hocking and Dr Alistair Evans of Monash University, and Dr Erich Fitzgerald of Museum Victoria, have shown for the first time exactly how leopard seals can eat large prey, like penguins and seal pups, as well as small prey like krill. By observing live leopard seals at Taronga Zoo, their ingenious study reports that leopard seals use suction to draw small prey items into their mouths, then expel seawater out through the 'sieves' of their peculiar cheek teeth.

In this video, these scientists report their findings, as published last week in the journal Polar Biology.

 

Links:

David P. Hocking, Alistair R. Evans & Erich M. G. Fitzgerald. 'Leopard seals (Hydrurga leptonyx) use suction and filter feeding when hunting small prey underwater' in Polar Biology, published online 29 October 2012.

Caught and Coloured: Leopard seal

Blog about a blob

Author
by Blair
Publish date
24 September 2012
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Comments (12)

Under the marine lab microscope today was a curious specimen. It was so curious that everyone passing through the lab stopped to offer their 'expert' opinion to help identify it.

marine organism What is this? The mystery specimen has been cut in half; the left piece was originally on top of the right piece bit.
Image: Blair Patullo
Source: Museum Victoria
 

Here are some of the comments made by various non-expert 'expert' staff.

"Got no room for guts so it's not a sea cucumber." Followed by: "No longitudinal muscles either."

"Oh, it's not one of those things that squirts out water is it?" I think in reference to a sea squirt or cunjevoi.

"It's got no legs so I can't identify this."

"It's from Antarctica so could be anything. Who knows what stuff we haven't found there yet!"

"I've seen more radial symmetry in a horse than in that thing." Okay, so without radial symmetry it is not an echinoderm.

"Is that a small pink tongue poking out from the base of the tree stump?" Then pointing to the crack in the middle of the tree stump shaped half, "nah, it would need cirri in there." 

Dissected marine organism Half of the animal looked like a little tree stump when it was dissected.
Image: Blair Patullo
Source: Museum Victoria
 

And then with some promise and authority: "I reckon that's the anus and those are anal tentacles." Now we're getting somewhere.

"But where's the siphon?"

"Looks like a peduncle on the bottom of a goose barnacle." A what on the bottom of a what?

"It's not a mammal." I can also add with some conviction that it is not a whale or a penguin.

"It's marine." Yep, it says so on the label in the specimen bag.

"Pretty sure it's that rare species Toohard basketii."

"It must be a remnant of Cthulu."

"Maybe it's not even an animal, but it doesn't look planty either." So that only leaves mineral. If only one of the museum geologists were around to confirm it... my guess is they would say it is a mini volcano.

"Marine fungus. But I doubt that, it's too soft."

"You'd think it would have a big empty cavity inside."

"That might be its mouth, not its butt." And boom, there we go back to the start again. It's looking like these 'experts' may never resolve a name for this animal!

top of marine organism The top of the mystery organism: mouth, anus or volcano?
Image: Blair Patullo
Source: Museum Victoria
 

Later I summarised for the work experience student in the lab who overheard the comments. "That's what we do here, get excited about stuff that looks like a blob with tentacles."

"Aha," he said.

These non-expert comments are always fun to hear, but they rarely produce a conclusive identification of a specimen. That process is a meticulously careful one that will extend beyond this afternoon. The animal may be further dissected, examined at different magnifications and possibly sent to associates outside the museum. Keys, descriptions and pictures from various publications may also be consulted.

And now that all the 'experts' have returned to their desks, the real expert Michela can begin her investigation. The end point will be a name written on a label that is placed in the jar alongside this specimen. We'll let you know what it is as soon as she's worked it out!

First fossil of Pygmy Right Whale

Author
by Kate C
Publish date
10 August 2012
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The Pygmy Right Whale (Caperea marginata) is the oddball of the whale world. The bizarre anatomy of this species has confounded researchers for years – even its common name demonstrates our historical lack of understanding. Its arched upper jaw and skim-feeding behaviour is similar to the right whales however DNA analysis shows that Pygmy Right Whales are more closely related to the rorquals (family Balaenopteridae) than the true right whales (family Balaenidae).

The puzzle of the evolutionary history of this species was not helped by the fact that it appeared completely absent from the fossil record. Palaeontologist and whale expert Erich Fitzgerald was therefore extremely pleased to identify a lone fossil specimen in the Museum Victoria as a partial periotic (the bone that surrounds the inner ear) of an ancient relative of the Pygmy Right Whale.

One theory about this group, explains Erich, is that "the bizarre features of the Pygmy Right Whale evolved rapidly within the last three to four million years. But this fossil suggests that they're much older than that." The specimen, which Erich describes as "looking like a coconut," is larger than the periotic of the living Pygmy Right Whale and dates to the late Miocene. This makes it six million years old, which will help calibrate the whale phylogenies (evolutionary trees) that are based on DNA sequences.

four views from different angles of whale earbones. Comparison of the incomplete fossil specimen (left) with a complete earbone of a juvenile Pygmy Right Whale.
Image: Erich Fitzgerald
Source: Museum Victoria / Journal of Vertebrate Paleontology

 
It is the peculiar skeleton of the Pygmy Right Whale, particularly of its ear bones, that allowed Erich to identify such an odd and incomplete fossil. "Baleen whales in general have strange skulls but in Pygmy Right Whales the ear bones are particularly strange because the back end, of the periotic, is enormous and bulbous. This fossil has no features that would ally it with any other family."

The strangeness of this whale doesn't end with its skull. First up, there is its size; at just 6.5 metres long, it's the smallest living baleen whale. Compare this with its colossal distant relatives, such as the 33 metre Blue Whale. But there's more, says Erich. "If we look beyond the head, there are some really strange things. In particular, the Pygmy Right Whale has ribs that are flattened and expanded. It almost looks like the ribs have formed a shield over the organs." This may relate to their unusual way of swimming which requires a stiffer trunk. "A young animal filmed underwater in South Africa shows that they flex their entire body not just the tail. It's thought that the ribs may be expanded to help keep the body rigid during this movement."

Until this footage, almost all knowledge of the species came from stranded individuals. Recent aerial photographs of a pod of Pygmy Right Whales off the coast near Portland showed some kind of social behaviour but exactly what it is – feeding, reproducing or something else – is still unknown.

Museum of New Zealand Te Papa Tongarewa made this video with a dissection of a stranded whale which clearly shows the unusual ribs.

 

Links:

Erich M. G. Fitzgerald. 2012. Possible neobalaenid from the Miocene of Australia implies a long evolutionary history for the pygmy right whale Caperea marginata (Cetacea, Mysticeti). Journal of Vertebrate Paleontology 32(4): 976-980. DOI:10.1080/02724634.2012.669803

The Tetrapod Zoology blog has a series of three terrific posts about Pygmy Right Whales:
Caperea is really weird
More on little Caperea
Caperea alive

Fishes of Australia website

Author
by Di Bray
Publish date
8 August 2012
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Di is Senior Collections Manager in our Sciences Department and is absolutely passionate about all things sciency. She loves telling people about the amazing and unique fishes found in our waters.

After a prolonged gestation, we recently launched the beautiful Fishes of Australia website in Adelaide at the Annual Conference of the Australian Society for Fish Biology

Fishes of Australia website banner showing title and fish Fishes of Australia website banner.
Source: Museum Victoria
 

The website, funded by the Australian Biological Resources Study, is hosted by Museum Victoria on behalf of OzFishNet, a group of fish experts who work at, or are associated with, museums in Australia and the CSIRO. Senior curator Martin Gomon and I worked with the museum's in-house design and development team to build the site, which will appeal to everyone with an interest in Australian fishes, whether they be divers, anglers, aquarists, students, teachers, or researchers. 

Leafy Seadragon fish Leafy Seadragon, Phycodurus eques
Image: Graham Short
Source: Fishes of Australia
 

Australia's amazingly rich and diverse fish fauna comprises about 5000 species. With so many fishes, the website is a work in progress, but photographs of over 800 species are already in the website's gallery. Eventually, we'll include detailed images and information on all Australian fishes – including tiny desert gobies from hot artesian springs in central Australia, weird and wonderful deep-sea critters found offshore, and all species on the Great Barrier Reef.

Green Moray Eel Green Moray Eel
Image: Steve Dreezer
Source: Steve Dreezer
 

We're also including fishes found in our territorial waters – those from our Antarctic and Subantarctic waters, plus the fishes of Ashmore, Cartier, Lord Howe, Norfolk, Christmas and Cocos Keeling islands.

Alison's Blue Devil fish Alison's Blue Devil, Paraplesiops alisonae
Image: Rudie Kuiter
Source: Aquatic Photographics
 

We've included a couple of user-friendly interactive keys – one to fish families, and the other to freshwater fishes (including the nasty introduced ones). Try them out on that weird fish you caught last summer, or put a name on your favourite aquarium species. We thank the many fantastic photographers who have allowed us to use their gorgeous images that illustrate the site.

Kiwi Hatchetfish Kiwi Hatchetfish, Polyipnus kiwiensis
Image: Robin McPhee & Mark McGrouther
Source: NORFANZ Founding parties
 

Threadfin Dragonfish Threadfin Dragonfish
Image: Julian Finn
Source: Museum Victoria
 

And finally, please 'Like' us on Facebook and tell us what you think.

Links:

www.fishesofaustralia.net.au

Orange army on the sea floor

Author
by Kate C
Publish date
23 May 2012
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Comments (1)

Every year, thousands of Giant Spider Crabs (Leptomithrax gaimardii) congregate in Port Phillip Bay ahead of their annual winter moult.

When solitary, these crabs are often hard to spot; algae, sponges and sea squirts set up shop on their shells and provide excellent camouflage. However when the crabs aggregate and march, this hungry army is easy to spot. They scavenge whatever food they can find, including the wildlife on the shells of one another. The spectacle of hundreds of large orange crabs against the bare, sandy sea floor is an amazing sight.


It’s still a bit of a mystery what the aggregations are all about but senior curator Dr Julian Finn has some ideas from several years of observation.

Like many crustaceans, Giant Spider Crabs are protected by their hard body shell, rather like a suit of armour. The trouble is that a hard shell doesn’t allow room for growth. Crabs must shed their old skin to get bigger; they can expand their size in the brief window before the new skin hardens. The process of moulting takes up to an hour and all the crabs in an aggregation moult almost simultaneously.

Spider crab emerging Spider crab emerging from its old shell. The new shell is a vivid orange colour.
Image: Julian Finn
Source: Museum Victoria
 

Newly-moulted Giant Spider Crab Newly-moulted Giant Spider Crab in its fresh orange shell.
Image: Julian Finn
Source: Museum Victoria
 

A soft, freshly-moulted crab is irresistible to predators such as rays, seals and birds. By aggregating in the thousands an individual crab reduces its chance of being eaten, much the same way as mammals in herds find protection in numbers. Movement into shallow waters may help the crabs, usually dispersed throughout Port Phillip Bay, aggregate in a single mass and gain refuge from the strong tidal currents that scour the deep channels.

An earlier explanation that the annual aggregations were related to mating has thus far proved unlikely, as following the moulting of tens of thousands of crabs, only the odd couple has been observed to mate. We still don’t know however what happens when they disperse back into deep water. Julian believes this sudden influx of tender crab meat is an important part of the Port Phillip Bay food chain.

Spider crab moults Hundreds of cast-off spider crab moults on the sandy seabed.
Image: Julian Finn
Source: Museum Victoria
 

If you'd like to see some Giant Spider Crabs without the need for SCUBA gear, have a look at the entrance of the Marine Life exhibition at Melbourne Museum.

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