Tag Archives: Marine Ecology

Top shelf bottom feeders

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If you are in Jervis Bay and see someone knee deep surrounded by rays or alternatively sitting staring at rays for hours on end then chances are you are looking at the “mother of rays”  otherwise known as  Joni  – the driving force behind the Stingray Diaries. She’s studying smooth stingrays throughout the Jervis Bay Marine park, in conjunction with Fisheries NSW and gives us a rundown on her research in her guest blog below…

Top shelf bottom feeders

Learning to swim by getting thrown off the end of a busy public wharf on the Hawkesbury River in nothing but a pair of hot pink floaties… Living in a swimsuit and covered in sand every single day of the year… Chucking tantrums when told to come inside after playing on the beach all day because it was dark… At the age of 4, saying with great certainty, “Mum, when I grow up I’m going to be a Marine Biologist.” Continue reading

Tagging along with the Coastal Carolina University Shark team

 

Caroline (from over at CCU Shark Research Team) stopped by the Fish Thinkers blog to give us a run down on where her research is headed and a sneak peak into the world of grad student shark research in the United States. Continue reading

Ocean Acidification – The Ocean’s other problem with CO2

This guest post is from Elliot Scanes, a PhD candidate from Western Sydney University who runs cool experiments to understand the impact of climate change on our molluscs. Elliot has a great Instagram research account with Dr Vicky Cole called seao2, so give them a follow to keep up to date with their work.


Ocean Acidification – The Ocean’s other problem with CO2 

by Elliot Scanes

Humans are currently emitting CO2 faster than has occurred on Earth for millions of years. Currently, atmospheric CO2 concentrations are at their highest point in 800,000 years and don’t look like slowing any time soon. Inevitable global warming as a consequence of the excess CO2 and other pollutants causing the “greenhouse effect” is well established among scientists (despite what politicians might say). This warming of the earth will eventually also cause warming of the oceans, most notably affecting species ranges. But this is not the only way excess CO2 is going to change the world’s oceans. The oceans have already absorbed 40% of the CO2 emitted by humans, and will keep continuing to do so. As CO2 dissolves in seawater, it forms carbonic acid, which, in turn causes the oceans to acidify. So far, oceanic pH (the measure of acidity) has fallen 0.1 units, and is predicted to fall 0.3 – 0.4 pH units by 2100 unless drastic global action is taken to curb emissions.

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Collecting Sydney rock oysters (Saccostrea glomerata) for experiments in Port Stephens.

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Opening flat oysters (Ostrea angasai).

 

 

 

 

 

 

 

 

This small decrease in pH may seem insignificant, however pH is measured on a natural logarithmic scale (for those mathematicians) which means that each unit is an order of magnitude larger than the previous. A 0.3 unit drop in pH means that calcium carbonate, the mineral that all shelled animals shells are composed of, is now soluble in seawater. Predictably, scientists are most concerned about the shelled animals of the ocean like molluscs, crustaceans and cnidarian (corals). Investigations by our lab at Western Sydney University have shown that under these scenarios Sydney rock oysters will have difficulty forming their shell, especially in their juvenile stages. These difficulties waste vital energy, which is especially important in an environment where you always need an edge on your competitor. Similar studies have found comparable effects in sea urchins, corals, scallops and almost every shelled animal in the ocean that you can think of. Continue reading

Dragging the chain – does anchoring by large ships impact our marine life?

I’m excited to announce that I’ll be joining a multidisciplinary team of researchers, supported by UOW’s Global Challenges program, to investigate the potential impact of large ships anchoring on our marine life and seafloor habitats.

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As an island nation, we are heavily dependent on shipping, with large ships transporting 99% of our trade by volume. Prior to entering our ports these large vessels may anchor in deep water, often for many days, waiting for their turn to exchange cargo.

Now when I say ‘large’ I mean freakin huge (see pic below). These ships are between 200-300 metres long and to anchor they require an anchor chain up to 250 metres long where each individual chain link can weigh up to 200 kilograms! Continue reading

Special underwater video session – ASFB conference

I’m very excited to be co-convening a special session on the use of video technology to better understand fish ecology and behaviour at the Australian Society of Fish Biology conference 2015!! See flyer below for details. Registration and abstract submission ARE NOW OPEN!!

Also check out ASFB’s Facebook page here for regular updates.

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Positive response of Giant Mud Crabs to protected areas

The giant mud crab (Scylla serrata) is a beast of a crustacean, capable of reaching 3kg in weight but often caught around the 0.5-1kg range. In Australia, they are distributed in sheltered waters from southern NSW, up through QLD, across the NT and over to Broome, WA.

Giant mud crabs have a short life cycle (3-4 years) and are reproductive machines. Females can carry between 2 – 5 million eggs and migrate up to 95km offshore to release their eggs. The young crabs hatch as tiny planktonic larvae, where they can remain in this stage for several weeks at the mercy of ocean currents. This aspect of their biology gives giant mud crabs substantial capabilities for dispersal.

A giant mud crab (Scylla serrata) chillin next to some mangroves on Mali Island. Photo by Jürgen Freund. Check out more of his amazing wildlife photos here and on facebook at Jurgen Freund Photography – Australia.

Their prized meat and high numbers within estuaries make them a highly targeted recreationally and commercially harvested species. In NSW, annual commercial landings are approximately 100-120t and the annual recreational catch is estimated between 30-60t. The main method of capture by both commercial and recreational fishers are crab pots, however rec fishers also use hoop nets or dillies.

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Surrogates for temperate reef biodiversity and their use in conservation

Earlier this year my co-authors and I published a paper in Diversity and Distributions that examined a cost-effective way of predicting reef biodiversity for conservation purposes. Here is some background on the issues surrounding the design of Marine Protected Areas (MPAs) and a brief summary of our research findings.

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Continue reading