Tag Archives: Overexploitation

How special is a ‘Special Area of Conservation?


This week it has been brought to my attention that there is a proposal to dredge for scallops inside a ‘Special Area of Conservation’ located in Cardigan Bay, Wales.  This proposal has divided opinions.  On Twitter this week Professor Callum Roberts, a marine conservation biologist at the University of York (UK) lamented that there was ”No hope for UK marine conservation if this mad proposal to scallop dredge in a protected area goes ahead” .  Dr Magnus Johnson, a Crustacean Fisheries and Ecologist researcher at the University of Hull (UK) quickly countered “It is worth reading the science by first!”, following with a couple of hashtags “#eatmorefish #eatmoreshellfish”.  Two scientists, with two opposing views… what is going on?


What is a Special Area of Conservation anyway?

These are something unique to the European Union.  They arise from the Habitats Directive, first adopted in 1992 in response to a European convention called the Berne Convention.  Special Areas of Conservation (SAC) are designed to protect a number of habitats and species (plants and animals) considered endangered, vulnerable, rare, or endemic.  Once a SAC has been formally designated, the establishment and implementation of management measures are largely left down to the individual Member State.  However, there are certain things that they must do.  Briefly, under Article 6 of the Habitats Directive, these include:

Continue reading How special is a ‘Special Area of Conservation?

How deep is too deep for commercial fishing?

Our ever-improving technology has allowed us to fish longer, catch more, and move further from land.  It has also allowed us to fish deeper.  EU statistics indicate that between 1950 and 2006 fishing depths increased from an average depth of 407 metres, to 535 metres.

Life in the deep is slow-paced.  Food is scarcer than in the sunlit surface waters.  Species grow slower and live longer.  Some deep-sea corals, like the one in the image, are thought to be over 4,000 years old. Traits like these are why organisations like Marine Conservation Institute that ” The deep-sea is the world’s worst place to catch fish” .  It’s not just the sustainability of targeted species that is causing concern, but of those caught as bycatch, as well as damage to the seabed and the flora and fauna living in and on it – like the coral in the photo.  So can deep-sea fishing ever be managed sustainably?    A recently published study from Joanne Clarke, a PhD student at the University of Glasgow, and colleagues suggests that there might be a way to make the practice less damaging. Continue reading How deep is too deep for commercial fishing?

The unique ecology of human predators

The human predator shares many similarities with other animal predators on this planet.  They are intelligent, they can work either independently or in groups.  They can be strategic, cunning, and postulate on possible future outcomes of actions and events.  Despite such similarities, the human predator is very different from any other currently living on Earth.  At a population of over 7.3 billion, humans can be found across the whole planet.  They have harnessed the power of other animals to help their survival.  A highly adaptable animal and a generalist feeder, they exploit a range of different prey.  They have gone beyond simple tool use, creating technology capable of killing thousands of animals in one go (and technology that can potentially wipe out a significant number of humans too).  They have developed fuel to allow them to travel vast distances, and societal systems to maximise the efficiency of exploitation.  We are not just predators, we are “super predators”.

Evolutionary biologist Thomas Reimchen (University of Victoria) has spent many years studying stickleback fish predation.  Many different species like to feed on stickleback but the work Thomas has done found that stickleback predators typically target juveniles, and never take more than 2% of the population in his study area on Haida Gwaii each year.  In contrast, Thomas noted that fishers on Haida Gwaii took much more than 2% of the salmon… and they took mostly adults.  It’s a pattern many of us will have seen.  We take lots, and we take a lot of big individuals.  In this new paper Thomas, alongside Chris Darimont – Hakai-Raincoast professor at the University of Victoria, and science director for the Raincoast Conservation Foundation and colleagues explore just how different our exploitation rates are from other predators. Continue reading The unique ecology of human predators

Not all fisheries are created equal

 And not all fisheries are as poorly managed as others.  But does fishery management mean that a fishery can achieve that hallowed if rather vague ‘sustainability’ goal?  Ray Hilborn from the University of Washington has written numerous papers saying – yes it can.  In his latest paper, written with Daniel Ovando from the University of California, Santa Barbara, he argues that many scientifically assessed stocks – particularly large stocks – are not only in better shape than we perceive, but in many cases actually rebuilding.  Ray is no stranger to controversy when it comes to his stance on fishery management, and the state of the world’s fisheries.  Just take a look at this summary of a debate with another eminent fisheries scientist Daniel Pauly that took place in Nature News & Comment last year  and if you have access to Nature have a read of this response too.  Let’s take a look at the argument Ray and Daniel has presented in this latest open access paper.

It doesn’t matter which country you look at, many fisheries have historically been heavily overexploited.  However, as to the state of fisheries now remains controversial.  Some argue that in many cases fisheries management is not only rebuilding overfished stocks but preventing others heading into a downward spiral.  Others argue that the same fisheries management is failing, particularly from the point of view of ecosystem protection.  This sort of debate is all well and good Ray and Daniel say, but something is being missed here – the “opportunity to objectively assess the successes and failures of fisheries management and identify successful strategies for achieving sustainable fisheries”.  There are a few issues here – like the issue of scale.  Take a too big a view to get an overall picture and you lose sight of the variability – including the successes.  On the opposite end of the scale, keep your focus too small then you miss what is happening around you.  As an example of how this issue of scale can have impacts on fisheries, we’ll just take a brief foray to my home Island.  Through the strange quirks of constitutional agreements, ownership and management rights, even though we are not part of the EU or the UK our fishers can be subject to EU legislation.  The undulate ray (Raja undulata) is considered Endangered, and consequently through EU legislation can no longer be fished.  In my local waters, fishers tell us that the ray is so abundant that they cannot help but catch these critters.  The undulate ray fishery, they claim, is sustainable here.  Before I digress too much as to whether the Island’s fishers should be subject to this fishery closure I’ll move back to the paper. Continue reading Not all fisheries are created equal

How to hunt a species to extinction

Overexploitation is regarded as one of the main threats to biodiversity, with a number of species extinctions directly linked to our ability to efficiently hunt and capture (or in the case of plants remove) a whole range of different taxa.

But wait a minute – surely if a species becomes too rare, it will eventually become uneconomical to hunt – even if they are worth a lot of money….so exploitation will stop?  Not so say the authors of a new paper published in TREE last month.  In a scenario which they have coined ‘opportunistic extinction’, species that are no longer targeted for exploitation can still be caught if we stumble across them in our search for something more common.  In this situation, the rare species is whisked up, providing a tidy profit.

The authors Trevor A Branch, Steven Purcell and Aaron Lobo have provided a great overview of their paper and crucially its implications.

If you have access to the journal Trends in Ecology and Evolution, you can have a look at the paper http://dx.doi.org/10.1016/j.tree.2013.03.003

Image: The sperm whale was heavily hunted from the 18th to 20th century, primarily for its  spermaceti which had many applications including soap, candles, lamp oil, and pencils.  Credit: Peter G. Allinson, M.D. 2009/Marine Photobank

Overfishing linked to increasing numbers of sponge

Check out the size of that sponge!

Seriously, its a sponge, aptly named the “Giant barrel”.  But as awesome as this sponge is to look at, its not so awesome if your a coral.  Research by Joe Pawlik and colleagues released this week suggests that overfishing of fish that love to tuck in to a bit of sponge means sponges are taking over on some coral reefs.  There’s a nice overview of the paper or alternatively if you fancy reading the paper yourself you can – it’s open access!

Image: The giant barrel sponge taken by the paper author Joe Pawlik, UNC