540 



Fishery Bulletin 100(3) 



Table 3 



Restriction fragment patterns of the mitochondrial ND4 

 region of istiophorid and xiphiid billfishes. Only diagnostic 

 bands are shown. 



(A) Digestions with Hae III. A = blue marlin; B = striped 

 marlin, white marlin, sailfish; C = white marlin, sail- 

 fish; D = black marlin; E = spearfish; F = white marlin; 

 G = spearfish; H = swordfish. 



(B) Digestions with Ba/i I. A = blue marlin. sailfish, black 

 marlin, spearfish; B = striped marlin, white marlin, 

 spearfish; C = swordfish. 



B 



C 



850 1500 700 

 650 400 650 

 400 400 



nation of Ban I and Hae III was found to be diagnostic and 

 to reveal a low level of intraspecific variation. 



After finding diagnostic enzymes for use with tlie ND4 

 region, a total of 540 billfish samples was screened (Table 

 1) to evaluate the accuracy of the marker. Samples from a 

 broad geographic range, including both the Atlantic and 

 Indo-Pacific, were used for each species whenever possible. 

 Of these, the white marlin, spearfishes and sailfish each 

 exhibited one alternative restriction pattern for Hae III at 

 low frequency (3.6%, 20.0% and 7.4% respectively) but in 

 no case was the alternate pattern the same as a pattern 

 seen in another species (Table 3). In addition, spearfishes 

 exhibited an alternate pattern for the enzyme Ban I at a 

 frequency of 40%; however, because Ban I was used only 

 to discriminate white and striped marlin from sailfish in 

 the ND4 identification key, this pattern did not affect the 

 results (Figs. 1 and 2). 



Nuclear marker 



Six nuclear markers were screened in the preliminary 

 analysis (Table 2). These included the short actin intron, 

 the internal transcribed spacer (ITS) region (Goggin, 

 1994), and four anonymous single copy nuclear (scnDNA) 

 markers. The scnDNA markers MN32-2, BM47, BM81, 

 and WM08 were originally developed for analyses of popu- 



