Beel den Stormer Presents the Only Fishery Blog You Need

Fish, Fisheries and Queryomics

Fishlove and Overfishing: How Badly Overfished Are Our Fisheries?

 

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Fishlove, based in the United Kingdom, has made headlines in recent months with advertisements showing provocative photographs of naked fish posing with celebrities.

According to its website, “Fishlove is an ongoing photographic project that invites well-known personalities across the globe to make a bold stand to stop over-fishing.”  In the photograph above, Lizzie Jagger- Mick’s daughter- is shown with a yellowfin tuna.  Woo hoo,  says Beel, she’s a beauty.  Look at those fins, those big blue eyes.

Fishlove’s campaign is well intentioned and directed toward ending overfishing. 

Fishlove cites a number of common fishery statistics, including the famously pessimistic, “Scientists predict that all marine life will effectively disappear from our oceans by the middle of this century if nothing is done about over-fishing.”

The latter quote is derived from a paper by Boris Worm and colleagues that was published in 2006.  However, more a recent examination of the global status of fish stocks, while still sobering, offers a ray of hope. 

Please, friends, let Beel offer results from another, more recent (2009) paper by the same esteemed Dr. Worm and his colleagues.  This paper is very detailed, and nuanced.  Its argument is perhaps most readily summarized by this figure.

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Fishery statistics for 166 fish stocks from around the world (Figure 3b, from Worm and colleagues 2009)

There is a lot going on here and it hurts Beel’s brain.  But let’s walk through it.

X-axis:
Bcurrent is the fish biomass currently being harvested.  BMSY is the amount of fish biomass that can be maximally, sustainably harvested. If the ratio is less than 1.0, the stock has been over fished. 

Y-axis:
Ucurrent is the current exploitation rate for a fish stock. UMSY is the exploitation rate that gives a maximum, sustainable harvest. So, if the ratio is less than 1.0, the stock is not being fished as heavily as it might be. If the ratio is greater than 1.0, the stock is being fished too hard.

So, globally, it is a good news-bad news kind of thing.  Bad News:  clearly, most fish stocks (about 63%) are to the left of 1.0 on the X-axis indicating they have been overfished. Good News: exploitation of about half of these same stocks has been reduced to the point that rebuilding is possible (these are the stocks in the lower, left-hand corner of the graph). 

Another 37% of assessed stocks have either not fallen below BMSY or have recovered from previous overfishing (lower right-hand corner of the graph). 

So, many stocks have been overfished, but it appears that fishing effort (exploitation) has been reduced enough to allow them to recover.  Another 37% of stocks are in good shape at this time.  The real problems lie in the upper left-hand corner, where stocks are below desired levels and are fished too hard.  This is about a quarter of fish stocks.

Two conclusions:  The picture is not all bleak.  Overfishing is not a one-size fits all issue.  This is a difficult, but important point.

Now, friends, after all of this heavy stuff, please let Beel present something to make things better.

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Enjoy, says Beel!

Sources:

Boris Worm and colleagues.  2006.  Impacts of biodiversity loss on ocean ecosystem services.  Science, Volume 314, pages 787-790. 

Boris Worm and colleagues.  2009.  Rebuilding global fisheries.  Science, Volume 325, pages 578-585.

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This entry was posted on January 17, 2013 by in Conservation, Fishing and angling and tagged , .
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