roundscale spearfish, once thought to be a rare visitor to the offshore waters
of Maryland, may be more common than originally thought. The roundscale
spearfish is extremely similar to the white marlin, which is where the
confusion begins. Both species are almost identical in size, coloration, and
fin shape. They are both caught using the same techniques and are known to eat
the same things.
how do you tell the two species apart? The most reliable identification method
is by determining the size of the anal fin and its distance from the anal vent.
First, measure the distance between the fish’s anal vent and the front of the
anal fin. Then, compare that distance to
the length of the anal fin. If the
distance between the anal vent and the anal fin is 50 to 75 percent of the
length of the anal fin, you probably have a roundscale spearfish. If it is less
than 50 percent of anal fin length, it is almost certainly a white marlin. The
easier, yet not as reliable method for determining the species of a
questionable fish is by comparing the measurement of anal vent to anal fin to
known averages. On average, the distance between the anal vent and anal fin on
a white marlin is three inches. On a roundscale spearfish, that average is much
greater, usually being about six inches (NOAA 2017).
little is known of this species. The
locations and times of year when spawning takes place are unknown. Distribution
is still being determined.
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