A conundrum for management and conservation of one of the Atlantic’s most overfished oceanic species

Here’s an eye-opening tale of how little we really know about the diversity of life in our oceans. And why scientific information is so critical for sustaining our fisheries. A simple case of mistaken fish species identity has really messed up what we thought we knew about the magnificent, but severely overfished white marlin. Furthermore, this unrecognized mistake, which has occurred for decades, is raising serious questions about how we can better manage the white marlin to ensure its future survival.

So what’s this mistake? It turns out that for years, anglers thinking they were catching the prized white marlin may have caught an entirely different species instead! Just three years ago, a team of scientists from the Guy Harvey Research Institute (GHRI) at Nova Southeastern University and NOAA Fisheries in Florida made a startling discovery – they confirmed the existence of a previously unrecognized billfish species that looks very similar to a white marlin (see photo). Known as the roundscale spearfish, this new billfish species has now been found throughout the Atlantic Ocean, where its distribution overlaps that of the real white marlin.

Then in December 2009, the same scientific team reported that roundscale spearfish made up a significant portion (about 27%) of the commercial catch that was previously believed to be white marlin.

By now you may be asking, “what’s the fuss?” The problem is that because the existence of the roundscale spearfish was unrecognized until recently, its inadvertent misidentification as white marlin for decades makes past assessments of white marlin population sizes – which are based on fisheries catch data – inaccurate. Basically, what used to be called the “white marlin” was actually a mixture of two species!

What does this mean for the future of the threatened, real white marlin?  Given huge concerns about its depleted populations, two petitions (in 2002 and 2007) to list the white marlin under the U.S. Endangered Species Act were considered.  If such a listing had gone through, it would likely have put an end to white marlin fishing tournaments, which infuse millions of dollars into the recreational fishing industry as well as local economies. Now the discovery of a look-alike species, realization of it’s long-standing mix-up with  white marlin, and the fact that it makes up a substantial portion of past “white marlin” catch, raises considerable confusion regarding the accuracy of our biological knowledge about white marlin and its population sizes. Two issues are clear: First, it’s back to the drawing board to figure out what the white marlin population size really is and how to better manage this species before its populations completely crash. Second, it also means that there is another large billfish species out there (the roundscale spearfish) that we know nothing about and that could very well also be declining rapidly due to overfishing.

I find it remarkable that the existence of a large billfish species in U.S. waters went unnoticed until just three years ago! This “oops” moment points to the urgent need for more scientific research about our planet’s oceans before we lose even more biodiversity.

The good news is that the scientific team from the GHRI and NOAA Fisheries is making fast progress on developing the tools and providing the information needed to help fishery managers better conserve the white marlin and roundscale spearfish. Thank you for your continued support of such important scientific research through the purchase of Guy Harvey sportswear. It makes a statement that you care about the welfare of our fragile oceans!

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Related posts:

1. The Guy Harvey Research Institute and Marine Conservation Science

Tags: Billfish, Dr Mahmood Shivji, Guy Harvey Research Institute, Ocean Conservation

This entry was posted on Tuesday, March 9th, 2010 at 10:24 am and is filed under Fishing, News, Our Oceans. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.