Category Archives: research

Bull sharks – salinity tolerance little-studied despite river attacks

While putting together a presentation for a Marine Biology subject on lionfish (and throwing in the recent controversy over plagiarised lionfish research), I struggled to find much research on an equivalent marine creature that has developed the same low salinity tolerance.

There were papers on the more well-known euryhaline species (those that tolerate wide ranges of salinities) but surprisingly little on bull sharks (Carcharhinus leucas) and their emergence as key predators in northern Australian rivers and lakes. This is strange given the heavy reporting on shark attacks far upstream in the Brisbane Times, Courier Mail and ABC TV among others.

Juvenile bull sharks have even been found in golf course lakes and unconfirmed reports stated there have been sightings in the Wivenhoe Dam. From what I could find in my research, freshwater bull sharks had a less-developed rectal gland (along with kidnyes, responsible for salt excretion) than their marine cousins and adults were less likely to shift back into marine waters from their freshwater range.

As for competition with longer-term inhabitants of the region:

 
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Why sea cucumbers aren’t just another ‘delicacy’ for Asian buffets

20140316-112712.jpg
Prickly redfish, a type of sea cucumber. This one was near Opal Reef, part of the Great Barrier Reef an hour from Port Douglas.

io9 is generally a scifi website, full of short monologues on the current state of scifi cinema, but occasionally they run very good articles on real science. Like the one below on the issues with sea cucumber harvesting:

Sea cucumbers are in trouble. Everyone knows about the problems that elephants and rhinos face due to poaching, that dolphins face due to drive hunts, and that sharks face when overzealous governments try to convince their constituents that they’re helping them avoid shark attacks. Sea cucumbers may not be as charismatic as their megafaunal counterparts, but they actually provide an important service for reef ecosystems.

They help to keep the sand in reef lagoons and seagrass beds fresh by turning them over, and by feeding on the dead organic matter that’s mixed in with the sand, the nutrients they excrete can re-enter the biological web by algae and coral. Without the sea cucumbers, that sort of nutrient recycling could not occur. It’s also thought that sea cucumbers help to protect reefs from damage due to ocean acidification. Feeding on reef sand appears to increase the alkalinity of the surrounding seawater.

The problem, according to a study conducted by Steven Purcell and Beth Polidoro, is that sea cucumbers are considered a luxury snack. As they explain at The Conversation, dried-out versions of the tropical species retail between $10 and $600 per kilogram in Hong Kong and on mainland China.

There’s actually one species that is sold for $3000 per kilo, dried. Sea cucumbers are thought of as “culinary delicacies,” and often adorn the buffets of festival meals and are served at formal dinners.
There are 377 known species of sea cucumber. Percill and Polidoro’s study shows that the more prized a species is as a delicacy, the more likely the IUCN is to categorize it as vulnerable or threatened – at least for the species they investigated. It’s plain to see that the more expensive the critters are, the more likely they are to be plotted with orange or red dots.

It’s not just a correlation. In most cases, it’s the rarity of a species that drives up the value, leading to exploitation and eventually, extinction. It’s basic supply/demand economics. But the researchers say that for the sea cucumbers they looked at, the causal relationship is reversed. “High-value drives rarity in sea cucumbers, not vice versa,” they write. “None of the naturally rare species are particularly high value.”

Is there anything that can be done to protect these awkward, squishy creatures? “Species-specific bans have been placed on threatened sea cucumbers in a few instances,” the researchers note, “but these regulations do not prevent serial depletion of other species further down the value chain.” Instead, they recommend that a short list of allowable species be created, sort of like Monterey Bay Aquarium’s sustainable seafood card, but for cucumbers. It would exclude threatened species and those most critical for providing ecosystem services to reefs. If sea cucumber fishing can be controlled, the rarer species just might have a fighting chance to survive.

Predicting mining impacts on deep sea communities

Group shot at the 4th SPREP/SPC Deep Sea Minerals workshop

Group shot at the 4th SPREP/SPC Deep Sea Minerals workshop

 

The complex and little-understood nature of deep sea biological communities needs to be further researched before any deep sea mining licenses are granted in the Central and West Pacific.

Speakers at the 4th Regional Training Workshop: Environmental Perspectives of Deep Sea Mineral Activities in Nadi, Fiji, discussed the potential commercial value of deep sea minerals and the expensive but vital research that should be continued to determine the impacts of mining on abyssal plain, seamount and hydrothermal vent communities.

The four-day workshop, organised by the Secretariat of the Pacific Regional Environment Programme (SPREP) and the Secretariat of the Pacific Community (SPC), aims to build on the work undertaken by the SPC-EU Deep Sea Minerals Project to strengthen governance systems in Pacific Island countries and territories to manage and minimise environmental impacts from mining activities.

Mining companies have yet to start any mining operation in the deep sea but are exploring several zones in the Central and West Pacific, searching for rich deposits of manganese nodules, cobalt-rich crusts and seafloor massive sulphides.

Duke University Marine Laboratory director Professor Cindy Van Dover, who has piloted the Alvin submersible to assess deep sea environments, said mining operations could have potentially long-term impacts on the fish, molluscs, sponge and worm communities of the deep sea.

“A single mining event could have the same impact as a volcanic eruption and it would be no big deal. Multiple events would be different,” she said.

“Hydrothermal vents are likely to be more resilient than anything else … but there’s still potential for things to go wrong.”

Prof Dover said hydrothermal vents, a key target for seafloor massive sulphide mining, were also being utilised for their genetic resources to develop medical, pharmaceutical, cosmetic and therapeutic products.

Dr Malcolm Clark, Principal Scientist at New Zealand’s National Institute of Water and Atmospheric Research (NIWA), said the faunal communities in manganese nodule and cobalt-rich crust environments were very different and mining operations should build in large buffer zones to reduce impacts.

Professor Mike Petterson, director of SPC’s Applied Geoscience and Technology Division (SOPAC), also launched the SPC-UNEP/GRID-Arendal Pacific Marine Minerals Assessment Report and presented Mr Samuela Namosimalua, Permanent Secretary, Fijian Ministry of Local Government and Environment, with copies of the report.

More information on the SPC-EU Deep Sea Minerals Project is available at

http://www.sopac.org/dsm

 

 

 

Marine Spatial Planning – one of the daily session summaries

I was asked by a few people at the Marine Spatial Planning workshop in Suva over the past week to post a few updates on my blog (the original articles I wrote appear on the Secretariat of the Pacific Regional Environment Program website)

What is Marine Spatial Planning, you might ask? Many attendees did this week and among many complex definitions I heard this was the easiest to comprehend: “It is the process of analysing and making recommendations on the distribution of human activities affecting coastal and marine areas. A key goal is to balance ecological, economic, social and cultural objectives.”

Attendees at the Marine Spatial Planning workshop, Suva, Nov 2013

Attendees at the Marine Spatial Planning workshop, Suva, Nov 2013

26 November 2013, Steve Pogonowski, Marine Spatial Planning, Suva Fiji – Marine spatial planning will become ever more vital as the Pacific islands and territories deal with the impacts of rising sea levels, ocean acidification and ocean warming, attendees at a workshop at the University of the South Pacific in Suva, Fiji, heard yesterday.

The second day of the Marine Spatial Planning workshop looked at climate change and other challenges to central and west Pacific countries and territories, case studies of marine spatial planning across the region and new projects being brought in to assist cross-boundary planning.

Attendees on the second day represented organisations in countries and territories including Wallis and Futuna, Solomon Islands, Tuvalu, French Polynesia, Micronesia and Samoa.

Sangeeta Mangubhai, Senior Programme Officer for IUCN Oceania Regional Office, said she hoped participants would all gain a greater understanding of initiating and carrying out good marine spatial planning.

“One of the things I really liked was listening to the case studies and also hearing some of the regional efforts being made to support countries if they decide to implement marine spatial planning from coastal waters out to their EEZ (Exclusive Economic Zone),” she said.

“Especially for our Pacific Island participants – and there are some here representing their governments – I hope they can gain a real understanding of marine spatial planning is and the role it can play in managing the valuable resources in their countries to achieve the ecological, social and economic outcomes that they want.

“If they undergo a marine spatial planning process, they now realise there are experts and experiences in this region that they can tap into to get support and assistance.”

Discussion topics included the success of Locally Managed Marine Areas in involving communities in conservation; how data collection on tuna fishing can track the effects of climate change; and the importance of local socioeconomic, governance and ecological issues in cross-boundary planning.

François Gauthiez from the French Marine Protected Areas Agency (AAMP) said the workshop had also generated interesting discussions on various software tools and how they can be used to present data simply to help island communities develop their fishing and conservation plans for the future.

A mild recovery: bluefin tuna stocks may be on the rise

After decades of falling stocks of northern (NBT) and southern bluefin tuna (SBT) in fisheries globally, some possible good news: stocks in certain areas appear to be on the rise, according to this Oceana report on a recent ICCAT Standing Committee on Research and Statistics meeting.

I feel like I should automatically qualify that by skipping to the third paragraph of Oceana’s post, which stated:

Scientists say that the models  (SCRS is) using are flawed and therefore have little confidence in them, so they will spend 2014 working with more recent data and improving their calculations.

Which makes me think of this piece of gold from 30 Rock:

Just like They Might Be Giants’ Dr Worm, Dr Leo Spaceman is not a ‘real’ doctor but he comes up with some very apt quotes that show how people can trust an academic or medical professional just because they “know science”.

Anyway, some fisheries managers and tuna fishers will be pretty excited about the possible stock rebound but hopefully they’ll err on the side of caution before making any changes to quotas. Here’s some research I put together for a uni report that might shed some light on the Antipodean situation:

“Australia’s SBT catch peaked at 21,500 tonnes in 1982 (Farley, J. H. et al. 2007) and quotas established in 1989 restricted the catch to 5265 tonnes annually.

Japanese long-lining catch peaked at 78,000 tonnes in 1961 and quotas were also introduced to restrict Japan to 6065 tonnes annually.

Illegal, unreported and unregulated fishing for the species is also a major concern with the Commission for the Conservation of Southern Bluefin Tuna finding that ‘substantial and continuous unreported catches of SBT had been taken by longline vessels since at least the early 1990s’ (Polacheck 2012).”

That’s just the Australian and Japanese reported data for SBT – areas of the New Zealand and South African coast are also key fishing grounds, as well as the international waters where self-reporting of catches is still a woefully inadequate system.

In my opinion, we need tougher quotas, not leniency for these ocean hunters.

1. Farley, JH, Davis, TLO, Gunn, JS, Clear, NP & Preece, AL 2007, ‘Demographic patterns of southern bluefin tuna, Thunnus maccoyii, as inferred from direct age data’, Fisheries Research, vol. 83, no. 2-3, pp. 151-61.

2. Polacheck, T 2012, ‘Assessment of IUU fishing for Southern Bluefin Tuna’, Marine Policy, vol. 36, no. 5, pp. 1150-65.

Cracking the code to farming rock lobster

One of the benefits of studying marine biology at Deakin University is the range of successful graduates Deakin can call on to give guest lectures during the semester.

David Francis, who completed the undergrad through to PhD route in aquaculture at Deakin, has been part of a team at the Australian Institute of Marine Science in Townsville, Queensland looking at developing a stable program of rearing farmed rock lobster (crayfish).

Photo: afma.gov.au

Tropical rock lobster. Photo: afma.gov.au

The growing and increasingly lucrative market in Australia (and for export) for rock lobster and its impact on wild stocks has understandably concerned crayfishers, fisheries bodies and marine scientists.

Many varieties of rock lobster have low fecundity, larval survival rates and long larval stages (the southern rock lobster Jasus edwardsii has an average larval (phyllosoma) stage of 450 days, while the tropical variety Panulirus ornatus has only 150 days as larvae). Illegal fishing – including licensed crayfishers flaunting size and catch restrictions – has further decimated wild stock numbers in several main fishing grounds.

Apart from the difficulties and expense of farming a species with a long larval stage, Francis’ team also found that creating the right feed formulation was a tough task – larval lobster are notoriously picky and cannot survive on a standard fishmeal diet, so creating the perfect feed became the AIMS team’s key goal.

After investigating the gut contents of wild prey and chemical profiling the tropical lobster larvae, the AIMS scientists were able to formulate a growth-focused feed to take the larvae successfully into the juvenile stage.

Restrictions on funding meant the research has not yet been completed but Francis hopes an aquaculture company can continue to invest in the program and raise a commercial quantity of farmed lobster, helping in the long term to reduce the impact on wild fisheries.

Seaweed passion leads to crowd-funding research

Followers of education writing and/or interested in crowdfunding stories may have noticed this one pop up this week: a university academic, Dr Alecia Bellgrove, who is raising money to fund research into edible seaweeds growing along the Victorian southwest coast.

Photo: Warrnambool Standard

Photo: Warrnambool Standard

She happens to be one of my Deakin marine biology lecturers (who I plan to interview on this topic as it heads closer to its funding target) and here’s a brief explanation of the research:

At a time when over 60% of adults and 25% of children in Australia are obese or overweight and the world is experiencing an unprecedented increase in atmospheric CO2 and associated climate change, there is compelling evidence from both the health and sustainability literature that seaweeds should become a common part of global diets.

Seaweeds are incredibly nutritious and can significantly reduce obesity and associated illnesses. Regular consumption of seaweeds thus has the potential to enhance the health of societies now, and for generations to come.
Seaweeds are incredibly efficient at photosynthesising and have amongst the highest rates of carbon fixation per unit area of any plants on the globe. The production of seaweeds for food and other commercial applications thus represents part of a viable solution for climate-change mitigation without compromising the availability of agricultural land and water resources into the future.
Southern Australia has the highest diversity of seaweeds globally with approximately 70% endemic to this region. The unique diversity of seaweeds on our shores represents a treasure chest of potential health and pharmaceutical benefits waiting to be opened. “But seaweed? Does it really taste any good?” I hear you ask. Well, millions of people in Asia think so; but this is a great question, and really important to assess when we are talking about the potential for new food products from the Australian marine flora.

______________________________
Aims
With the $5250 requested we will be able to assess the taste preference of local (Victorian) seaweeds compared with seaweed from other parts of the world. We will do this by recruiting tasters and then cooking up a storm of local and imported seaweed delights to tempt their taste-buds. Funds will be used to lease a commercial kitchen, purchase ingredients and pay a research assistant to assist with the data collation.

______________________________
Future Possibilities
There are also other important aspects to consider such as the nutritional value of the seaweeds and ecological sustainability of harvesting.
With additional funding beyond that requested we can also
1) examine the nutritional quality of local seaweeds, with comparisons to commercially available species and
2) estimate the local biomass of high-value, edible seaweeds and prospects for sustainable harvesting of wild populations.

______________________________
Keep informed
You can follow us on Facebook : http://www.facebook.com/Wouldyoulikeseaweed
And on Twitter: @DeakinSeaweed and @Deakinsensory

More than a planktonic relationship: microbes digest double the carbon previously estimated

Microscopic plankton (of the plant and animal variety) drives global carbon dioxide absorption. While the Amazon rainforest is absorbing nearly 2 billion tonnes of carbon per year, scientists have calculated the global ocean currently absorbs about one-third of carbon emissions but both carbon sinks can also be producers of carbon dioxide.

Researchers at the University of California (Irvine) have compared their survey data to 18 other marine voyages to find that plankton digest double the carbon previously calculated and overturning a 1934 science marine principle in the process:

Models of carbon dioxide in the world’s oceans need to be revised, according to new work by UC Irvine and other scientists published online Sunday in Nature Geoscience. Trillions of plankton near the surface of warm waters are far more carbon-rich than has long been thought, they found. Global marine temperature fluctuations could mean that tiny Prochlorococcus and other microbes digest double the carbon previously calculated. Carbon dioxide is the leading driver of disruptive climate change.

In making their findings, the researchers have upended a decades-old core principle of marine science known as the Redfield ratio, named for famed oceanographer Alfred Redfield. He concluded in 1934 that from the top of the world’s oceans to their cool, dark depths, both plankton and the materials they excrete contain the same ratio (106:16:1) of carbon, nitrogen and phosphorous.

But as any gardener who has done a soil test knows, amounts of those elements can vary widely. The new study’s authors found dramatically different ratios at a variety of marine locations. What matters more than depth, they concluded, is latitude. In particular, the researchers detected far higher levels of carbon in warm, nutrient-starved areas (195:28:1) near the equator than in cold, nutrient-rich polar zones (78:13:1).

“The Redfield concept remains a central tenet in ocean biology and chemistry. However, we clearly show that the nutrient content ratio in plankton is not constant and thus reject this longstanding central theory for ocean science,” said lead author Adam Martiny, associate professor of Earth system science and ecology & evolutionary biology at UC Irvine. “Instead, we show that plankton follow a strong latitudinal pattern.”

He and fellow investigators made seven expeditions to gather big jars of water from the frigid Bering Sea, the North Atlantic near Denmark, mild Caribbean waters and elsewhere. They used a sophisticated $1 million cell sorter aboard the research vessel to analyze samples at the molecular level. They also compared their data to published results from 18 other marine voyages.

Martiny noted that since Redfield first announced his findings, “there have been people over time putting out a flag, saying, ‘Hey, wait a minute.'” But for the most part, Redfield’s ratio of constant elements is a staple of textbooks and research. In recent years, Martiny said, “a couple of models have suggested otherwise, but they were purely models. This is really the first time it’s been shown with observation. That’s why it’s so important.”

 

 

Geelong Science Online Watch Party #scio13vic

Caffeine – no matter how many bad things can be written about its negative effect on sleep patterns, science conference attendees would have to be some of its biggest proponents.

After Science Online 2013, I’m sure many of the attendees and the thousands watching online and taped sessions worldwide were discussing their favourite roast-and-grind flavour as much as the session content.

Watch Party poster from Belgrade, Serbia

And when a targeted product arrives that helps focus the mind specifically on science concepts, Sci Online peeps will be lined up just behind CERN employees for their first taste.

I attended Science Online in North Carolina in 2010, as an employee in the marketing department of the little-known peer-reviewer Faculty of 1000. The level of science knowledge, passion and attendee prestige in each session scared me but also helped to plant the seed that would move me to ditch public relations for the life of a full-time student. In particular, presentations by the Science Cheerleader (Darlene Cavalier), Annie Crawley and session comments from Carl Zimmer and Lyndell Bade  inspired me to head into the marine biology field.

Being in Australia once again while the 2013 conference proceeded, I was determined to watch at least a few sessions online and was lucky to spot a message from George Aranda announcing watch parties would be held at Deakin Burwood and Waurn Ponds campuses.

So I signed up and joined medical PhD student Vanessa at Waurn Ponds (and 4-5 at Burwood) for two days of highlight sessions. Needless to say, the videos were mainly inspiring, intriguing and motivational and the number of coffees drunk increased as the days went on.

The whole conversation has been recorded on this Storify page and also under the #scio13vic tag on Twitter.

Numerous attendees have written blogs on it including Scicurious, Princess Ojiaku and many others – most of them are listed on ScienceSeeker.

The storify by Scicurious above is a great way to follow the discussion on Blogging for the Long Haul – many of the ideas are relevant whether you are a blogger, science writer, student with an interest in communications or professor scared of putting your work out there for the general public.

While I’m not in a communications job any more (apart from freelance writing and of course, this here blog), the conference helped inspire me to push for more writing workshops to be conducted at my university – in an effort to improve the writing level of science undergrads in my course for starters.

I’ve lost count of the number of papers I looked at as a favour to classmates last year, only that find that – while their science knowledge might be above mine – the low quality of essay and academic paper writing were harming their final marks. Deakin is only one of several universities that needs to lift its game in teaching science students good science writing.

In a month, I’ll be back at uni for first semester and keen to put some of the learnings into practice!

“SHARK ATTACK!” NB: does not feature an actual shark attack

Marine biologists, social scientists and many shark conservation groups have been battling the stigma about sharks for decades, even before the Jaws films made going in the water a scarier prospect.

A Photoshopped image of a shark attack that fooled many viewers

A Photoshopped image of a shark attack that fooled many viewers

But despite the many graphs showing the minute number of attacks over hundreds of years, shark stories – like the crocodile yarns in the Northern Territory News – capture the imagination and are obviously relished by sub-editors who are usually responsible for the inaccurate headlines.

This article in the Guardian explores recent research on the reporting of ‘shark attacks (emphasis on last two paragraphs is my own):

Would a shark attack by another name would be any less terrifying? Researchers say it would, arguing that the current all-purpose “attack” label is unnecessarily scary, inaccurate, and is helping to drive sharks into extinction.

A study published this week in the Journal of Environmental Studies and Sciences makes the case that the use of the term “shark attack” is overly emotional, and steeped in Jaws-type lore about “man-eating” and “rogue” sharks preying on unsuspecting beachgoers.

Instead, they suggest a sliding scale of new descriptions, from “shark sightings” to “fatal shark bites”.

To support their case, the researches note that records from the two global shark “hotspots”, New South Wales and Florida, indicate the majority of encounters were sightings or, in cases where there was contact, involved small species of shark that pose no real danger to humans.

In the case of Florida, records kept since 1882 show only 11 of the 637 confirmed cases of shark attacks ended in death – fewer than 2%. About three-quarters of the 637 encounters involved shark species that were only capable of inflicting small wounds or scrapes, and were not associated with life-threatening injuries.

The proportion of fatal shark encounters was also in the single digits for New South Wales. And yet all those incidents were lumped together under the label “shark attack”.

The researchers, Christopher Neff, a social scientist at the University of Sydney, and Robert Hueter, a marine biologist who heads the shark research centre at the Mote Marine Laboratory in Sarasota, Florida, instead suggest such incidents should be re-classified according to severity.

“Until new scientific information appears that better explains the physical, chemical and biological triggers leading sharks to bite humans we recommend that the term ‘shark attack’ be avoided,” the paper said.

Future encounters should be categorised as shark sightings, where the animals are nearby but no contact takes place; shark encounters, such as a close call with a swimmer or a surfboard where there is no injury; shark bites, where there is only a single bite and only minor injury; and fatal shark bites for the small proportion of events that end in death.

The nomenclature is important because it feeds an irrational fear of sharks, the researchers said. The Jaws scenario of great white sharks belongs to the realm of fiction, Hueter said.

“When surfers hold a contest where 4ft or 5ft sharks are actively feeding and a few get bitten on their toes, and these all get reported as shark attacks, you present a wrong picture of what is going on,” he said.

The reality is very different; the sharks are the ones in peril. Shark populations have fallen drastically over the last few decades, with some populations in areas of the Pacific falling by 90%.

Conservation groups estimate that tens of millions of sharks are slaughtered each year for their fins, which are used as a thickener for shark fin soup. “When we try to argue for the need for shark conservation because of depletion of sharks, in the public mind and even in the minds of government officials, that is counteracted by this perception that these are man-eaters and that they attack people,” said Hueter.

“More than 90% of these incidents are not fatal. Most are very minor incidents and in many cases there is no injury at all, but when these things are reported and discussed as shark attacks you get a certain mindset about the behaviour of these animals. When you actually look at the outcomes, you get a very different picture.”

It’s an important argument that we should fight the notion of all sharks being human-eaters in order to make their slaughter for shark fin soup and other food products.

I know from experience seeing a shark in the water that it’s a scary prospect but much of that fear comes from watching the shark attack-focused movies, reading biased stories and listening to people who are too afraid to swim in the ocean.

My town of Warrnambool last had a serious shark attack in the 1980s but in telling a few friends about seeing a 1.5m gummy shark while spearfishing earlier this week, there was still the sense that the fear is ever-present in most people. I was able to quickly identify the shark under a ledge as a harmless gummy and saw no reason to be scared of it, so education about the different types of sharks could help more people get over their fear and start to care about shark conservation.

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