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DISPLAYING POSTS TAGGED: marine biology (32)

Sponge love

Author
by Blair
Publish date
14 February 2013
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Love is in the ocean not in the air this Valentine’s Day. Just ask this romantic heart-shaped sponge.

red sponge Heart-shaped sponge just below the surface at Flinders. And yes, that shape is the live animal, no Photoshop, just a quirky growth form.
Image: © John Gaskell

Imagine spending Valentine's Day dinner sifting through a mouthful of muddy silt. You're joined by several friends nearby to hug or hold hands with, but the only kiss on offer is from a fish that tries to eat you. And sex after dinner? Not tonight, unless you happen to be skilful enough to catch a comrade's passing sperm in the water. That's the life for many a sponge.

The photographer at the heart of the sponge image is John Gaskell. He’s a local diver, consultant and author of the popular local marine guide Beneath Our Bay. He also collaborates with Reef Watch to spread word on our interesting marine life. He caught this one at Flinders last week truly romancing the reef as it grows.

“Maybe the sponges are trying to tell us something,” Gaskell told Reef Watch, “reduce effluent or love our underwater reefs more”.

Keeping in the spirit of sponge love, Museum Victoria is producing Sponges, the next book in the science field guide series. Written by local expert Lisa Goudie, it celebrates not only sexual and asexual reproduction in sponges (Phylum Porifera), but also the diversity of species in Victorian waters and their amazing shapes and colours.

6 different sponges Diversity of shape and colour of sponges in Victorian waters.
Image: Mark Norman and Julian Finn
 

The non-love sponge information:

Household sponges were once made of skeletal remains of true sponges from the ocean, although modern times replace the natural form with synthetic products. Not all sponges are soft; some are prickly, crumbly or slimy. Most species are marine, but a few live in freshwater. Sponges are not colonies of individual animals, but rather collections of cells that have specialised functions. Fossils indicate that this animal group has existed for at least 600 million years. They are some of the longest-lived animals in the world, with individuals of a tropical species being estimated at age of 2000 years. Other species are short lived and die back each year.

Links:

 Museum Victoria Science books 

 Sponges on the Port Phillip Bay Marine Life website

Redmap Australia launched

Author
by Di Bray
Publish date
13 December 2012
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Di is Senior Collections Manager in our Sciences Department and is absolutely passionate about the amazing and unique fishes found in our waters.

Museum Victoria staff are involved in a fantastic citizen science project that's taking a giant nationwide leap from its starting point in Tasmania. With today's launch of the Redmap Australia website, the community is being asked to look out for unusual occurrences of species in the seas around Australia. These community sightings will help reveal if fishes and other marine species are shifting their ranges with the changing climate.

Man holding a fish A Yellowtail Kingfish (Seriola lalandi) caught away from its usual range along Tasmania's east coast and logged on Redmap.
Image: Scott Johnston
Source: Redmap

The website, also known as the Range Extension Database and Mapping Project, began in Tasmania in 2009. Already Tasmanian fishers and divers have logged hundreds of unusual sightings including Eastern Rock Lobster, Southern Maori Wrasse and King George Whiting, all spotted further south than usual.

  Southern Maori Wrasse Southern Maori Wrasse (Ophthalmolepis lineolatus) are uncommon in Tasmanian waters but more and more are being reported to Redmap along the north and north-east coasts of Tasmania. This one was snapped by diver Emma Flukes off the coast of St Helens.
Image: Emma Flukes
Source: Redmap
 

Yellowtail Kingfish Large schools of Yellowtail Kingfish (Seriola lalandi) are being spotted in south-east Tasmanian seas, further south of their usual marine postcode.
Image: Mick Baron
Source: Redmap
 

Redmap founder, Dr Gretta Pecl, is a senior marine scientist at the Institute for Marine and Antarctic Studies (IMAS) at the University of Tasmania. She says Redmap "taps into the knowledge - and eyes - of thousands of fishers, divers and swimmers to track changes in fish distributions in Australia's vast coastal waters." Some three or four million Australians go fishing or diving at least once a year.

The Redmap website encourages members to share photos and anecdotes about turtles, octopus, lobsters, corals, seaweeds, urchins, prawns and marine mammals. A network of marine scientists around the country will review each photo to verify the species' identity and ensure high-quality data. Redmap aims to become not only a continental-scale range-shift monitoring program along Australia's vast coastline, but also engages Australians with marine issues using their own data.

Some seas along the Australian coast are warming at three to four times the global average. We're not sure how species will react to warmer waters - some may adapt, others may search for new habitats, while others may disappear. New arrivals of some species, especially recreational fishes, may actually benefit some communities. Understanding the movement of other species of marine pests may help minimise the risks to ecosystems or fisheries. In Victoria, fishers and divers have already been telling us about rare or uncommon fishes they've seen - including Blue Groper, Cobia, Rock Blackfish and Spotted Grubfish. Gathering sightings over time will show if these species are simply seasonal migrants, one-off visitors, or are here to stay.

Blue Groper Victorian diver and Redmap member Mary Malloy has been seeing more Western Blue Groper (Achoerodus gouldii) over the past decade around Queenscliff and Barwon Heads.
Image: Mary Malloy
Source: Mary Malloy
 

I'm the coordinator of Redmap VIC and the MV team includes Martin Gomon, Julian Finn, Erich Fitzgerald and Kate Charlton-Robb. Although we'll officially be tracking some 35 species in Victoria through the Redmap project - such as octopus, Greynurse Sharks, Harlequin Fish, Striped Marlin, whales and dolphins - we're very keen to hear of sightings of other rare or uncommon species seen along our coast. You can get involved by becoming a Redmap member, signing up for the quarterly newsletter, liking Redmap on Facebook, and logging unusual marine life at www.redmap.org.au.

Marine app out now

Author
by Blair
Publish date
16 November 2012
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Comments (1)

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
Comments
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

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Updates on what's happening at Melbourne Museum, the Immigration Museum, Scienceworks, the Royal Exhibition Building, and beyond.

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