Million Dollar Fish Hurt By Lookalike

But are you really looking at a true white marlin? Examine the below photo. Does it show two of these fish, or two different species?

(Image: Guy Harvey Research Institute)

The image actually shows two different species: the white marlin and the roundscale spearfish.

What's troublesome about this lookalike situation, from a conservation perspective, is that the white marlin is heavily overfished, but it has never been listed under the U.S. Endangered Species Act. The issue was debated in 2002 and again in 2007. As it turns out, during such debates, the lookalike was counted in the white marlin's population! Lawrence Beerkircher of the NOAA Fisheries Service and study co-leader Mahmood Shivji, Director of the Guy Harvey Research Institute at Nova Southeastern University, determined that the roundscale spearfish makes up almost a third—27 percent—of the fish historically identified as white marlin.

"This proportion of roundscale spearfish along with its longstanding misidentification as white marlin for decades compromises the accuracy of current biological knowledge on white marlin," said Beerkircher. "These findings illustrate a need for the immediate collection of biological and fishery data such as age and growth, migratory patterns, and fishery catch statistics for both the real white marlin and the roundscale spearfish."

Shivji added, "It's remarkable how a simple case of mistaken identity can muddy what we thought we knew about a species from decades of study. This case points to the importance of making sure we know what species are out there in the first place."

Very little is known about the roundscale spearfish. It too may be on the decline, but scientists aren't sure.

And don't expect the debate on protecting the white marlin to end anytime soon. If the fish receives federal protection, the measures could halt white marlin fishing tournaments that pump millions of dollars into the recreational fishing industry as well as local economies.