Population of Prize Fish Species May be 27% Smaller than Previously Estimated


Image credit: dominic sherony/Flickr

The white marlin, a prized trophy fish, is one of the most overfished marine species under international management. It has been nominated for inclusion on the United State's endangered species list multiple times and has been included in the National Oceanic and Atmospheric Administration's Species of Concern List.

Now, researchers believe that population data has been unrealistically inflated due to the marlin's similarities to another species, the roundscale spearfish.Discovered only three years ago, it is now thought that nearly a third—27 percent—of fish historically identified as marlin were in fact roundscale spearfish. Using computer models, researchers have attempted to estimate the current and historical ratio between the two species.

These models demonstrated that small changes in the ratio could have a serious effect on the actual populations, versus those perceived. "It's remarkable how a simple case of mistaken identity can muddy what we thought we knew about a species from decades of study," explained Mahmood Shivji, Director of the Guy Harvey Research Institute at Nova Southeastern University, then added that "this case points to the importance of making sure we know what species are out there in the first place."

Lawrence Beerkircher, lead author of the study and a scientist at the NOAA Fisheries Service commented that:

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...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.

If conservations are to be successful in rebuilding white marlin populations, Beerkircher added, they will have to implement "species-specific monitoring measures" and perform new population assessments.

Read more about overfishing:
80 Year-Old Bookkeeping Error Causes First Species to be Fished to Extinction
Global Fisheries Hit by Climate Change and Overfishing
How Overfishing Almost Got Capt. Phillips Killed by Pirates
Overfishing Means Marine Animals Are Starving: Report

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