Faraway fettered fish fluctuate frequently

27 06 2010

Hello! I am Little Fish

Swimming in the Sea.

I have lots of fishy friends.

Come along with me.

(apologies to Lucy Cousins and Walker Books)

I have to thank my 3-year old daughter and one of her favourite books for that intro. Now to the serious stuff.

I am very proud to announce a new Report in Ecology we’ve just had published online early about a new way of looking at the stability of coral reef fish populations. Driven by one of the hottest young up-and-coming researchers in coral reef ecology, Dr. Camille Mellin (employed through the CERF Marine Biodiversity Hub and co-supervised by me at the University of Adelaide and Julian Caley and Mark Meekan of the Australian Institute of Marine Science), this paper adds a new tool in the design of marine protected areas.

Entitled Reef size and isolation determine the temporal stability of coral reef fish populations, the paper applies a well-known, but little-used mathematical relationship between the logarithms of population abundance and its variance (spatial or temporal) – Taylor’s power law.

Taylor’s power law is pretty straightforward itself – as you raise the abundance of a population by 1 unit on the logarithmic scale, you can expect its associated variance (think variance over time in a fluctuating population to make it easier) to rise by 2 logarithmic units (thus, the slope = 2). Why does this happen? Because a log-log (power) relationship between a vector and its square (remember: variance = standard deviation2) will give a multiplier of 2 (i.e., if xy2, then log10x ~ 2log10y).

Well, thanks for the maths lesson, but what’s the application? It turns out that deviations from the mathematical expectation of a power-law slope = 2 reveal some very interesting ecological dynamics. Famously, Kilpatrick & Ives published a Letter in Nature in 2003 (Species interactions can explain Taylor’s power law for ecological time series) trying to explain why so many real populations have Taylor’s power law slopes < 2. As it turns out, the amount of competition occurring between species reduces the expected fluctuations for a given population size because of a kind of suppression by predators and competitors. Cool.

But that application was more a community-based examination and still largely theoretical. We decided to turn the power law a little on its ear and apply it to a different question – conservation biogeography. Read the rest of this entry »

Interview with a social (conservation) scientist

22 06 2010

I was contacted recently by Josh Cinner, a self-titled ‘social’ scientist (now working at the Centre of Excellence for Coral Reef Studies) who has published rather a lot in the conservation literature. He was recently highlighted in the journal Science for his work, and he thought CB readers would enjoy the coverage. He stated to me:

“…as a social scientist, I have spent the past decade or so working with ecologists and managers trying to integrate social science better in conservation. There are often calls for the importance of integrating social science in conservation and I thought your blog readers might appreciate some high-level recognition of the importance of this. Additionally, as far as I can tell, this is the first of these profiles that has focused on someone working in conservation.”

So, while fully crediting the source of this article and its author, Helen Fields, here is the entire text reproduced for your reading pleasure.

In the late 1980s, things were not going well for the coral reefs at Jamaica’s Montego Bay Marine Park. Overfishing had taken out a lot of the fish that eat algae, and algae were taking over the reef. “It was a classic case of ecosystem decline,” human geographer Joshua Cinner says. He arrived in Jamaica in 1996 as a Peace Corps volunteer after graduating from the University of Colorado, Boulder, with a double major in environmental conservation and geography. He was particularly interested in parks and preserves.

He’d landed in the middle of a war. Lobbying by tour operators and others got spearfishing, one of the main culprits in overfishing, banned in the park. The ban did not go over well with local people. “All the park equipment got vandalized. We had park rangers get threatened; their families got threatened at spear point,” Cinner says. Spearfishing equipment is cheap and you don’t need a boat; men who do it are generally poor and are fishing as a last resort. “The cultural lens through which the fishermen viewed this issue was of struggle in a post-slavery society, of the rich, predominantly white expatriates making a law that oppressed the poorest of the poor locals to benefit the wealthy.”

The conflict got Cinner thinking about how conservation really works. “It wasn’t really about the ecology,” he says. “Making conservation work in Jamaica had a lot to do with understanding the local culture and people.” It also opened his eyes to the role oceans play. “The ocean is often viewed as an open-access resource. That extra layer of complexity interested me,” he says. “Land can often be private property,” but “the ocean is typically viewed as free for anyone to fish in, for anyone to swim in and use.” Read the rest of this entry »

New April Issue of Conservation Letters out now

22 04 2010

Low intensity fire in a longleaf pine-wiregrass system

Another great line up of papers has just come out in the April Issue of Conservation Letters:

CJA Bradshaw

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February Issue of Conservation Letters

13 02 2010

Diver at Great Barrier Reef, Australia

Hard to believe we’re already at Volume 3 – introducing the latest issue of Conservation Letters (Volume 3, Issue 1, February 2010). For full access, click here.

Note too we’ve jumped from 5 to 6 papers per issue. Congratulations to all our authors. Keep those submissions coming!

CJA Bradshaw

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How to make an effective marine protected area

22 09 2009

Here’s a nice little review from the increasingly impressive Frontiers in Ecology and the Environment which seems to be showcasing a lot of good conservation research lately.



As we know, the world’s oceans are under huge threat, with predictions of 70 % loss of coral reefs by 2050, decline in kelp forests, loss of seagrasses, over-fishing, pollution and a rapidly warming and acidifying physical environment. Given all these stressors, it is absolutely imperative we spend a good deal of time thinking about the right way to impose restrictions on damage to marine areas – the simplest way to do this is via marine protected areas (MPA).

The science of MPA network design has matured over the last 10-20 years such that there is a decent body of literature now on what we need to do (now the policy makers just have to listen – some  progress there too, but see also here). McLeod and colleagues in the latest issue of Frontiers in Ecology and the Environment have published a review outlining the best, at least for coral reefs, set of recommendations for MPA network design given available information (paper title: Designing marine protected area networks to address the impacts of climate change). Definitely one for the Potential list.

Here’s what they recommend:


  • bigger is always better
  • minimum diameter of an MPA should be 10-20 km to ensure exchange of propagules among protected benthic populations


  • simple shapes best (squares, rectangles)
  • avoid convoluted shapes to minimise edge effects


  • protect at least 20-30 % of each habitat


  • protect at least 3 examples of each marine habitat


  • select MPA in a variety of temperature regimes to avoid risk of all protected reefs succumbing to future climate changes

Critical Areas

  • protect nursery areas, spawning aggregations, and areas of high species diversity
  • protect areas demonstrating natural resilience or rapid recovery from previous disturbances


  • measure connectivity between MPA to ensure replenishment
  • space maximum distance of 15-20 km apart
  • include whole ecological units
  • buffer core areas
  • protect adjacent areas such as outlying reefs, seagrass beds, mangroves

Ecosystem Function

  • maintain key functional groups of species (e.g., herbivorous fishes)

Ecosystem Management

  • embed MPA in broader management frameworks addressing other threats
  • address and rectify sources of pollution
  • monitor changes

Of course, this is just a quick-and-dirty list as presented here – I highly recommend reading the review for specifics.

CJA Bradshaw

ResearchBlogging.orgMcLeod, E., Salm, R., Green, A., & Almany, J. (2009). Designing marine protected area networks to address the impacts of climate change Frontiers in Ecology and the Environment, 7 (7), 362-370 DOI: 10.1890/070211

Few people, many threats – Australia’s biodiversity shame

31 07 2009

bridled_nailtail_400I bang on a bit about human over-population and how it drives biodiversity extinctions. Yet, it isn’t always hordes of hungry humans descending on the hapless species of this planet  – Australia is a big place, but has few people (just over 20 million), yet it has one of the higher extinction rates in the world. Yes, most of the country is covered in some fairly hard-core desert and most people live in or near the areas containing the most species, but we have an appalling extinction record all the same.

A paper that came out recently in Conservation Biology and was covered a little in the media last week gives some telling figures for the Oceania region, and more importantly, explains that we have more than enough information now to implement sound, evidence-based policy to right the wrongs of the past and the present. Using IUCN Red List data, Michael Kingsford and colleagues (paper entitled Major conservation policy issues for biodiversity in Oceania), showed that of the 370 assessed species in Australia, 80 % of the threatened ones are listed because of habitat loss, 40 % from invasive species and 30 % from pollution. As we know well, it’s mainly habitat loss we have to control if we want to change things around for the better (see previous relevant posts here, here & here).

Kingsford and colleagues proceed to give a good set of policy recommendations for each of the drivers identified:

Habitat loss and degradation

  • Implement legislation, education, and community outreach to stop or reduce land clearing, mining, and unsustainable logging through education, incentives, and compensation for landowners that will encourage private conservation
  • Establish new protected areas for habitats that are absent or poorly represented
  • In threatened ecosystems (e.g., wetlands), establish large-scale restoration projects with local communities that incorporate conservation and connectivity
  • Establish transparent and evidence-based state of environment reporting on biodiversity and manage threats within and outside protected areas.
  • Protect free-flowing river systems (largely unregulated by dams, levees, and diversions) within the framework of the entire river basin and increase environmental flows on regulated rivers

Invasive species

  • Avoid deliberate introduction of exotic species, unless suitable analyses of benefits outweigh risk-weighted costs
  • Implement control of invasive species by assessing effectiveness of control programs and determining invasion potential
  • Establish regulations and enforcement for exchange or treatment of ocean ballast and regularly implement antifouling procedures

Climate change

  • Reduce global greenhouse gas emissions
  • Identify, assess, and protect important climate refugia
  • Ameliorate the impacts of climate change through strategic management of other threatening processes
  • Develop strategic plans for priority translocations and implement when needed


  • Implement restrictions on harvest of overexploited species to maintain sustainability
  • Implement an ecosystem-based approach for fisheries, based on scientific data, that includes zoning the ocean; banning destructive fishing; adopting precautionary fishing principles that include size limits, quotas, and regulation with sufficient resources based on scientific assessments of stocks and; reducing bycatch through regulation and education
  • Implement international mechanisms to increase sustainability of fisheries by supporting international treaties for fisheries protection in the high seas; avoiding perverse subsidies and improve labelling of sustainable fisheries; and licensing exports of aquarium fish
  • Control unsustainable illegal logging and wildlife harvesting through local incentives and cessation of international trade


  • Decrease pollution through incentives and education; reduce and improve treatment of domestic, industrial, and agriculture waste; and rehabilitate polluted areas
  • Strengthen government regulations to stop generation of toxic material from mining efforts that affects freshwater and marine environments
  • Establish legislation and regulations and financial bonds (international) to reinforce polluter-pays principles
  • Establish regulations, education programs, clean ups, labelling, and use of biodegradable packaging to reduce discarded fishing gear and plastics


  • Establish early-detection programs for pathological diseases and biosecurity controls to reduce translocation
  • Identify causes, risk-assessment methods, and preventative methods for diseases
  • Establish remote communities of organisms (captive) not exposed to disease in severe outbreaks


  • Establish regional population policies based on ecologically sustainable human population levels and consumption
  • Ensure that all developments affecting the environment are adequately analysed for impacts over the long term
  • Promote economic and societal benefits from conservation through education
  • Determine biodiversity status and trends with indicators that diagnose and manage declines
  • Invest in taxonomic understanding and provision of resources (scientific and conservation) to increase capacity for conservation
  • Increase the capacity of government conservation agencies
  • Focus efforts of nongovernmental organisations on small island states on building indigenous capacity for conservation
  • Base conservation on risk assessment and decision support
  • Establish the effectiveness of conservation instruments (national and international) and their implementation

A very good set of recommendations that I hope we can continue to develop within our governments.

CJA Bradshaw

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Interview with… ConservationBytes

16 07 2009

CBlogoA few months ago I was asked to do an online interview about ConservationBytes at The Reef Tank. I previously made mention of the interview (see post), but I think it’s time I reproduce it here.

The effects of pollution, carbon build up in the ocean, extinction, loss of coral reefs, over-fishing, and global warming is increasingly becoming more detrimental to our marine life and marine world.

Fortunately our marine ecosystems have Corey Bradshaw on their side. As a conservation ecologist, Corey studies these ecosystems with a passion, trying to understands the interactions between plants and animals that make up these ecosystems as well as what human activity is doing to them.

He has realised long ago that conservation and awareness is crucial to the survival of these living things and carries on the long tradition of studying and trying to understand these ecosystems at the School of Earth & Environmental Sciences at the University of Adelaide in South Australia.

He also avidly blogs about these pertinent issues at ConservationBytes.com, because he felt a need that these marine conservation issues needed to be heard. And he was more then right.

We were lucky enough to grab some time with Corey Bradshaw and he was kind enough to answer some important marine conservation questions, which are important in our desire: to make the marine world a better place.

What is your background in science and conservation?

I have a rather eclectic background in this area. I originally started my university education in general ecology, with a focus on plant ecology in particular (this was the strength of my undergraduate institution). There was no real emphasis on conservation per se until I started my postgraduate studies, although even then I was more interested in the empirical side of theoretical ecology than on conservation itself. It was more or less a gradual process that as I realised just how much we as a species have changed the planet in our (relatively) short time here, I became more and more dedicated to quantifying the links between species loss and how it affects human well-being.

After completing my MSc, PhD and first postdoctoral fellowship in New Zealand and Australia, I had the good fortune to work alongside a few excellent conservation ecologists specialising in extinction dynamics. This is where my mathematical bent and conservation interests really took off and eventually set the stage for most of my research today.

Your blog is ConservationBytes.com. Why the urge to start a blog on conservation only?

It may seem odd that I resisted blogging for many years because I thought it was a colossal time-waster that would take me away from my main scientific research. However, several things convinced me of its need and utility. First, it’s a wonderful vehicle to engage non-scientists about the research one does – let’s face it, most people don’t read scientific journals. Second, it’s interactive; people can ask questions or comment directly online. Third, it overcomes the strict language and technical rigour of most scientific publications and gets to the heart of the issue (it also allows me to express some opinions and speculations that are otherwise forbidden in scientific writing). Fourth, I realised there was a real lack of understanding about basic conservation science among the populace, so providing a vehicle for conservation science dissemination online appeared to be a good idea – there simply wasn’t anything like it when I started only a year ago. Finally, an effective, policy-changing scientist must advertise his/her research through the popular media to be recognised, so it obviously has career benefits.

Tell me about the conservation topics you cover?

ConservationBytes.com covers pretty much any topic that conforms to at least one of the following criteria:

  • It concerns research (previous, ongoing, planned) that is designed to improve the fate of biodiversity, whether locally, regionally or internationally

  • It concerns policy studies, actions or ideas that will have positive bearing on biodiversity conservation

  • It concerns demonstrations of the role biodiversity plays in providing humans with essential ecosystem services

I even have a section I call ‘Toothless’ that highlights ineffective conservation research or policy. Other areas include: exposés of well-known conservation scientists, a collection of links to conservation science journals, and my personal information (publications, CV, media attention).

What is your take on marine conservation? What does marine conservation include?

Given that I have worked in both marine and terrestrial realms from the tropics to the Antarctic, I really see little distinction in terms of conservation. True, the marine realm probably presents more challenges to conservation in some respects because it’s generally much more difficult and expensive to collect meaningful data, and it’s more difficult to control or mitigate people’s behaviour (especially in international waters), but the ecological patterns are the same (although I admit they may operate over different spatial and temporal scales).

Current ‘hot’ topics in marine conservation include the global degradation and loss of coral reef ecosystems (and what to do about it), terrestrial run-off of pollutants and nutrients affecting marine communities, over-fishing and better fishing management strategies, the design of effective marine protected areas, the socio-economic implications of moving people away from direct exploitation to behaviours and economic activities that promote longer-term biological community stability and resilience, and of course, how climate change (via acidification, hypercapnia, temperature change, storm intensification, seal level rise and modified current structure) might exacerbate the systems that are already stressed by the aforementioned problems.

Have you done any work, research in the area of marine conservation?

Yes, quite a bit. Some salient areas include

  • The grey nurse shark Carcharias taurus was the world’s first shark species to receive legislative protection when the east Australian population was listed under the 1984 New South Wales Fisheries Management Act. It has since been listed as globally Vulnerable by the IUCN in 1996 and the east Australian population was declared Critically Endangered in 2003. Previously, we constructed deterministic, density-independent PVA models for the east Australian population that suggested dire prospects for its long-term persistence without direct and immediate intervention. However, deterministic models might be overly optimistic because they do not incorporate stochastic fluctuations that can drive small populations extinct, whereas failing to account for density feedback can predict overly pessimistic. We recently completed a study demonstrating that the most effective measure to reduce extinction risk was to legislate the mandatory use of offset circle hooks in both recreational and commercial fisheries. The increase in dedicated marine reserves and shift from bather protection nets to drumlines had much lower effectiveness.

  • The global extent of illegal, unreported and unregulated (IUU) fishing is valued from US$10-23.5 billion per year, representing between 11 and 26 million tonnes of fish killed annually beyond legal commercial catches. In northern Australia, IUU fishing has advanced as a ‘protein-mining’ wave starting in the South China Sea in the 1970s and now penetrates consistently into the nation’s Exclusive Economic Zone. We have documented the extent of this wave and the implications for higher-order predators such as sharks, demonstrating that IUU fishing has already depleted large predators in Australian territorial waters. Given the negative relationship between IUU fishing takes and governance quality, we propose that deterring invading fishers will need substantially greater investment in border protection, and international accords to improve governance in neighbouring nations, if the tide of extinction is to be effectively mitigated.

  • Determining the extinction risk of the world’s shark and ray species – some work I’ve done recently with colleagues is to examine the patterns of shark biodiversity globally and determine which groups are most at risk of extinction. Not a surprise, but it turns out that the largest species of shark that reproduce the slowest are the most endangered (including all those bitey ones that frighten people).

  • Finally, I’m doing a lot of work now examining how the structure of coral reefs affects fish biodiversity patterns and long-term resilience. It turns out that basic biogeographic predictors (e.g., reef size and relative isolation from other reefs) really do dictate how temporally stable fish populations remain. And as we know, the more variable a population in time and space, the more likely it will go extinct (on average). The practical implication is that we can identify those coral reefs most likely to maintain their fish communities simply by measuring their size and position.

You’re from Australia, correct? What kind of marine conservation is going on there?

I’m originally from Canada, but I’ve spent most of my adult life in Australia (mostly in Tasmania, the Northern Territory, and now, Adelaide in South Australia). I did my PhD in the deep south of New Zealand (Otago University, Dunedin). In Australia, all the aforementioned ‘hot’ areas of marine conservation are in full swing, with greater and greater emphasis on climate change research. I think this aspect is pre-occupying most serious marine ecologists in Australia these days. For example, the southeast of Australia has already experienced some of the fastest warming in the Southern Hemisphere, with massive regional shifts in many species of fish, invertebrates, macroalgae and plankton.

What’s your take on ocean acidification? Do you think people need to be aware of this issue?

I used to believe ocean acidification was THE principal marine conservation issue facing us today, but now I think it’s just another stressor in a cornucopia of stressors. The main issue here is that we still understand so little of its implications for marine biodiversity. Sure, you lower the pH and up the partial CO2 (pCO2) of seawater, and many organisms don’t do so well (in terms of survival, reproduction and growth). However, it’s considerably more complex than this. pH and pCO2 vary substantially in space and time, and we have yet to quantify these patterns or how they are changing for most of the marine realm. Therefore, it’s difficult to simulate ‘real’ and future conditions in the lab.

Another issue is that temperature is changing must faster and so far exposure experiments indicate that it generally has a much more pronounced effect on marine organisms than acidification per se. However, like many climate change issues, a so-called ‘tipping point’ could be just around the corner that makes many marine communities collapse. It’s a frightening prospect, but one that needs a lot more dedicated research.

Can a person own an aquarium and still be considered a marine conservationist in your opinion?

Of course, provided one is cognisant of several important issues. First, most aquarists rely on the importation of non-native species. Lack of vigilance and carelessness has resulted in a suite of alien species being released into naïve ecosystems, resulting in the extinction or reduction of many native fish and invertebrates. Another issue is the transport cost – think how much carbon you are emitting by flying that tropical clownfish to your local pet shop in Norway. Third, do you know from which populations your displayed fish come? Were they harvested sustainably, or were they the last individuals plucked from a dying reef? A good knowledge of an animal’s origin is essential for the responsible aquarist. In my view one should play it safe. I think having aquaria filled with local species that are easily acquired, don’t cost the Earth to transport and pose no risk to native ecosystems is the most responsible way to go. You can also be a lot more certain of sustainable harvest if you live close by the source.

What is your take on climate change and its effect on marine life? Is being aware and educated on this particular topic and how it affects the marine world make someone a marine conservationist?

Awareness is only the first and most basic step. I’d say most of the world is ‘aware’ to some extent. It’s really the change in human behaviour that’s required before we make any true leaps forward. Some of the issues described above get to the heart of behavioural change. To use an analogy, it’s not enough to recognise that you’re an alcoholic, you have to stop drinking too to prevent the damage.

What can we do to raise awareness of the importance of marine conservation and conservation in general?

My personal take on this, and it applies to ALL biodiversity conservation (i.e., not just marine) is that people won’t take it seriously until they see how its loss affects their lives negatively. For example, let’s say we lose all commercially exploitable fish – not having access to delicious and healthy fish protein will mean people change the way fishing is done; that is, they’ll try to force fishers to fish sustainably and consumers to demand responsibly. The same can be said for more esoteric ecosystem services like carbon sequestration, oxygen production, water purification, pollination, waste detoxification, etc. if, and only if, we understand the economic and health benefits of keeping ecosystems intact. We need more research that makes the biodiversity-human benefit link so that people ultimately get the message. Destroying biodiversity means destroying yourself.

As I said before, awareness is only the first step.

Realising you’re a drunk is only the first step

11 05 2009

© A. Savchenko

© A. Savchenko

I recently did an interview for the Reef Tank blog about my research, ConservationBytes.com and various opinions about marine conservation in general. I’ve been on about ‘awareness’ raising in biodiversity conservation over the last few weeks (e.g., see last post), saying that it’s really only the first step. To use an analogy, alcoholics must first recognise and accept that they are indeed drunks with a problem before than can take the (infamous AA) steps to resolve it. It’s not unlike biodiversity conservation – I think much of the world is aware that our forests are disappearing, species are going extinct, our oceans are becoming polluted and devoid of fish, our air and soils are degraded to the point where they threaten our very lives, and climate change has and will continue to exacerbate all of these problems for the next few centuries at least (and probably for much longer).

We’ve admitted we have a disease, now let’s do something about it.

Read the full interview here.

CJA Bradshaw

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To market, to market, to buy a fat… fish

4 05 2009

An interesting new paper just appeared online (uncorrected proof stage) in Biological Conservation. Brewer and colleagues’ paper entitled Thresholds and multiple scale interaction of environment, resource use, and market proximity on reef fishery resources in the Solomon Islands describes how the proximity of fish markets explains some of the variation in fisheries takes on South Pacific coral reefs. Well, that may seem intuitive, you say – if you can’t access even a local market, chances are your fish will only feed you and your immediate family. Make an economic link to a larger pool of demanding consumers, and you have all the incentive you need to over-exploit your little patch of finned money.

Of course, the advent of better, more efficient transport (including refrigerated transport) and the development of local markets (i.e., tapping into larger ones in more populated areas) has inevitably caused fish depletions across the globe. Brewer and colleagues’ work provides a quantitative link between human demand and biodiversity decline (including ‘fishing down the web‘), and suggests that our best way to manage fisheries is to target the source of this demand – the markets and patterns of consumption. Ultimately, it’s the consumer that will dictate what does and what does not go extinct (see also previous post on consumer preferences for rare species). After all, if there’s a demand, someone will step in to provide the resource (provided it’s still there). Better education, smarter consumption and regulation along the entire chain will be far more effective in the long run than just attempting to control the fishers’ behaviour.

CJA Bradshaw

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