Tag Archives: Australian

Yes, kangaroos are endangered – but not the species you think

The Conversation

Karl Vernes, University of New England

Do you know what kind of animal the mala, nabarlek, or boodie is? What about the monjon, northern bettong, or Gilbert’s potoroo?

If you answered that they are different species of kangaroo – the collective term for more than 50 species of Australian hopping marsupials – you’d be right. But you’d be in the minority.

Include nearby New Guinea, and the number of kangaroo species jumps to more than 70. Kangaroos are so diverse that they have been dubbed Australia’s most successful evolutionary product.

But sadly, not everyone is aware of this great diversity, so most kangaroo species remain obscure and unknown.


Read more:
Bans on kangaroo products are a case of emotion trumping science


This is brought into sharp relief by a new movie that premieres nationally this week called Kangaroo: A Love-Hate Story. The filmmakers set out to expose the kangaroo industry, painting a picture of gruesome animal cruelty, an industry cloaked in secrecy, and the wholesale slaughter of an Australian icon.

The film, which includes brutal footage, also includes the claim that Australia’s kangaroos may be heading down the path of extinction.

The film has already screened in the United States and Europe to sold-out premieres, opening first in those places because they are important markets for kangaroo products.

But foreign audiences also probably know less about Australia’s major kangaroo species or the complexities of the kangaroo industry, and may perhaps be more easily swayed towards the filmmakers’ point of view.

Many US reviews have been positive about the film, although one review described it as “frustratingly one-sided”.

Most Australians, whatever their view on the kangaroo industry, would surely agree that if kangaroos are to be harvested, it should be done with minimal suffering. But are Australia’s kangaroos really at risk of extinction?

The iconic red kangaroo. Large kangaroos are typically widespread and secure, unlike many of their smaller cousins. Karl Vernes

On mainland Australia, four species are sustainably harvested, largely for their meat or fur: the eastern grey, western grey, common wallaroo, and Australia’s most famous icon (and largest marsupial), the red kangaroo.

The best scientific survey data, based on millions of square kilometres surveyed by aircraft each year, puts the combined number of these four kangaroo species currently at around 46 million animals.

This is a conservative estimate, because only the rangelands where kangaroos are subject to government-sanctioned harvest are surveyed. There is almost as much kangaroo habitat again that is not surveyed.

Of the estimated population, a quota of roughly 15% is set for the following year, of which barely a quarter is usually filled. Quotas are set and enforced by state governments, with the aim of sustaining population numbers.

For example, of 47 million animals estimated in 2016, a quota of 7.8 million animals was set for the following year, but only 1.4 million of these animals (3.1% of the estimated population) were harvested.

The wildlife management community is pretty much unanimous that the four harvested species are widespread and abundant, and at no risk of extinction.

Are non-harvested species at risk?

But what of the other forgotten 95% of kangaroo species? The conservation prognosis for these – especially the smaller ones under about 5.5kg in weight – is far less rosy.

The nabarlek – a small endangered rock wallaby from Australia’s northwest – has become so rare that its mainland population in the Kimberley seems to have disappeared. It is now only found on a few islands off the coast.

The boodie – a small burrowing species of bettong – was one of Australia’s most widespread mammals at the time of European arrival, but is extinct on the mainland and now found on just a few islands.

Gilbert’s potoroo holds the title of Australia’s most endangered mammal, clinging precariously to existence in the heathlands around Albany on Western Australia’s south coast. One intense wildfire could wipe out the species in the wild.

Meanwhile, if the alarming increasing impact of cats on our northern Australian wildlife continues, recent modelling suggests that the northern bettong – a diminutive kangaroo that weighs barely a kilogram – will disappear.


Read more:
Australian endangered species: Gilbert’s Potoroo


The list goes on: mala, bridled nail-tail wallaby, parma wallaby, woylie, banded hare-wallaby, long-footed potoroo, Proserpine rock-wallaby – all of these and more could slip to extinction right under our noses.

The culprits are the usual suspects: cats, foxes, land-use change – and our collective apathy and ignorance. Australia holds the title for the worst record of mammal extinctions in modern times, and kangaroos, unfortunately, contribute many species to that list.

Population modelling paints a grim picture for the northern bettong. Karl Vernes, Author provided

The theatrical trailer for Kangaroo: A Love-Hate Story’ features a voiceover from a concerned kangaroo activist, who says:

If Australians really knew what happens out there in the dark, they would be horrified.

Indeed they might. But it’s not just the treatment of the abundant big four kangaroos that are harvested (yet secure) that should attract attention.

The ConversationIf we also look at the other 95% of kangaroo species that need our urgent attention, we might just be able to do something about their dwindling numbers – and the real kangaroo extinction crisis – before it’s too late.

Karl Vernes, Associate Professor, School of Environmental & Rural Science, University of New England

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

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FactCheck: do Australians with an average seafood diet ingest 11,000 pieces of plastic a year?

The Conversation

Britta Denise Hardesty, CSIRO

Well, if you’ve got an average seafood diet in Australia today, you’re probably ingesting about 11,000 pieces of plastic every year. – Dave West, National Policy Director and founder of environmental group, Boomerang Alliance, speaking with a Fairfax video journalist.

Australians are growing increasingly aware of the real danger posed by the vast amount of plastic dumped in our seas every year. It’s an important issue, so it’s crucial we get the facts right.

Ahead of a Senate committee hearing on the threat of marine plastic pollution in Australia, Dave West from the environmental group Boomerang Alliance told a Fairfax video journalist that an average seafood diet in Australia would result in ingesting about 11,000 pieces of plastic a year.

Is that accurate?

Checking the source

When asked for a source to support his assertion, West referred The Conversation to a BBC article published in October 2015 that said:

Prof Tamara Galloway of Exeter University quotes research estimating that anyone consuming an average amount of seafood would ingest about 11,000 plastic particles a year.

The Conversation asked Galloway, a professor of ecotoxicology, to clarify and provide sources. She said by email:

The stats came from another published paper, by [Belgium-based researchers] Van Cauwenberghe and Janssen in which the authors had made a Fermi estimate (or order of magnitude estimate) based on their field data for cultured shellfish.

Professor Galloway also said she had co-written a commentary article for the journal PNAS which

covers a similar topic, but includes some data from another paper too, in which the authors found even higher concentrations of microplastics in seafood. Clearly, there is going to be variation in the levels of contamination depending on location and local sources of pollution, ocean conditions, etc. This does suggest however, that the Van Cauwenberghe results are not just a one-off.

You can read Professor Galloway’s full reply here.

The 2014 Van Cauwenberghe and Janssen paper to which Galloway refers was published in the journal Environmental Pollution.

However, that paper does not show that anyone consuming an average amount of seafood would ingest about 11,000 plastic particles a year. The figure of 11,000 is an upper-end estimate for Europeans who eat quite a lot of molluscs. The paper estimates that:

European top consumers will ingest up to 11,000 microplastics per year, while minor mollusc consumers still have a dietary exposure of 1800 microplastics year.

In that paper, the researchers note that shellfish consumption differs greatly among countries.

In Europe, for instance, mollusc consumption can differ over a factor of 70 between consumers and non-consumers. European top consumers can be found in Belgium (elderly), with a per capita consumption of 72.1g day, while mollusc consumers in France (adolescents) and Ireland (adults) have the lowest per capita consumption: only 11.8g day for both countries.

The researchers also noted that

The presence of marine microplastics in seafood could pose a threat to food safety, however, due to the complexity of estimating microplastic toxicity, estimations of the potential risks for human health posed by microplastics in food stuffs is not (yet) possible.

What does this mean for the average Australian seafood consumer?

The 11,000 figure applies to an estimate for “European top consumers” of molluscs, not an average Australian seafood diet.

We don’t yet have all the data needed to make a good estimate of how much plastic an average Australian seafood consumer ingests per year.

The Boomerang Alliance’s Dave West acknowledged the limitations of applying the 11,000 figure to Australia, telling The Conversation by email that:

Only comment I’d make is that I agree the comment referring to Australia rather than a generic average seafood diet was clumsy.

Small plastic particles can be ingested by bivalves (such as mussels, cockles, oysters, pipi and scallops) and remain there for some time. And these bivalves can be eaten by larger predators, pushing the plastic up the food chain.

It’s worth noting the important difference between eating fish and shellfish. Unless you’re eating sardines and anchovies, humans don’t typically consume the digestive tract of a fish (where plastics would be found). But if you’re eating molluscs and shellfish, particularly from urban centres, you may be adding plastic to your diet.

Australians are not the world’s top shellfish consumers, trailing behind Belgium, most East Asian countries, the US and many European nations.

Verdict

There is insufficient published research to support the statement that a person with an average seafood diet in Australia today is probably ingesting about 11,000 pieces of plastic every year.

The 11,000 figure applies to an estimate for “European top consumers” of molluscs, not an average Australian seafood diet. This is an important issue that needs more attention. – Britta Denise Hardesty


Review

This article is factually correct and represents a sound analysis.

In fact, our own studies found levels of microplastics in mussels from the Dutch coast that are one order of magnitude higher than those reported in the 2014 Belgian study by Van Cauwenberghe and Janssen: 13.2 particles per gram of mussel.

However, it should be noted that microplastics are everywhere and that humans are broadly exposed to them through the food. For example, microplastics have been recently detected in a range of terrestrial products such as milk, beer, honey and sea salt. Therefore, an analysis and assessment of the potential health risk of microplastics for humans should comprise dietary exposure from a range of foods across the total diet, in order to assess the contributing risk of contaminated marine food items.

Although it is evident that humans are exposed to microplastics through their diet and the presence of microplastics in seafood could pose a threat to food safety, our understanding of the fate and toxicity of microplastics in humans constitutes a major knowledge gap that deserves special attention. – Dick Vethaak


Have you ever seen a “fact” worth checking? The Conversation’s FactCheck asks academic experts to test claims and see how true they are. We then ask a second academic to review an anonymous copy of the article. You can request a check at checkit@theconversation.edu.au. Please include the statement you would like us to check, the date it was made, and a link if possible.

The ConversationBritta Denise Hardesty, Senior Research Scientist, Oceans and Atmosphere Flagship, CSIRO

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

 

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