Not all fisheries are created equal

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.

To get as much reliable data together for their assessment, Ray and Daniel made use of a number of stock assessments including a global database of fisheries stock assessment called the RAM Legacy database.  It’s not mandatory for fishery managers to put their stock assessments in here, but it does contain a large amount of data, and is widely utilized by fishery scientists.  If you are interested in learning more about the RAM Legacy database, head over to this open access paper.  

There is one big caveat to the database – by its very nature it only contains information on stocks that have been assessed.  Assessment costs money.  The database is growing all the time, but Ray reports that at the time of his research, just 35% of the total world catch were included in the database.  Of that 35% most assessments came from regional fishery management organisations, wealthy countries, and in both cases focusing on larger commercially fished stocks.  

Ray and Daniel note that although good stock assessment doesn’t necessarily mean that there is good (if any) fishery management present, you don’t tend to get one without the other.  This is an important point for Ray and Daniel’s argument.  They say that traditional fishery management requires stock assessment, so when other papers have argued that traditional fishery management is failing because “unassessed fish stocks “are in much worse shape than the relatively well-studied fisheries on which previous global status reviews have relied”, they have missed the point.  “The decline of many of the world’s unassessed stocks is not a failure of fisheries management” Ray and Daniel write “it is a failure to implement fisheries management techniques that we know can work well”.  The data in the stock assessment databases provide a numerous cases they say.  There’s lots of detail in the paper (which I highly encourage you to read) but here’s a couple of snapshot:

Focusing on the RAM database, out of 16 stocks in Alaska that where showing a decline in BMSY (a reference point to evaluate stock status), the most recent 5 years’ worth of data shows that 69% are increasing.  74% of EU stocks are showing an increase too.  In New Zealand, things aren’t so good with the BMSY of 13 stocks just 46% showing an increase - which means 54% of the stocks are continuing to show a decrease.  So lots of variability in the data, but taking a look at the global picture 64% of stocks that were previously in decline are now apparently on the up.  An assessment of large (average catches of more than 10,000 MT each year) versus small stocks (average catches of less than 10,000 MT each year) showed that larger stocks were on average in better shape that the small ones.  For example, FAO stock assessments showed that 24% of stocks are considered overexploited, whilst 51% of smaller stocks are overexploited.

Ray and Daniel conclude their paper with a few key arguments.  First if we want to improve the status of global fish stocks, we don’t need to shut down large numbers of fisheries.  Instead we need to make fishery management more widespread.  Crucially, this management needs to engage and empower local communities.  They remind us that there’s nothing new under the sun, that community based fishery management has been around long before the age of industrial fishing – and that it is still present in many parts of the world.  Continued development and refining of effective fishery assessment and management - particularly for data-poor fisheries - is vital for the continued evolution of sustainable fisheries.  They note that there is not one fishery management style to rule them all, and reiterate the importance of ecosystem-based approaches to fisheries management though remind us that application of the concept is very challenging (particularly in light of a lack of data).  With proper fisheries management, perhaps we can have our fish and eat them too.

The paper published in the journal ICES is open access.  Even if you don’t agree with Ray and Daniel’s assessment, the paper is very much worth a read.  They make a good argument - and as always raise some interesting points.  You can access the paper here

Image: Stilts fishermen near Unawatuna, Sri Lanka.  Credit Bernard Gagnon/Wikimedia (CC BY-SA 3.0)