500 



FISHERY BULLETIN OF THE FISH ANI> WILDLIFE SERVICE 



I I I I I L 



2 



_i i_] lJ 



I I I I I I I I 

 METERS 



Figure 2. — The body proportions at 50 pounds of (a) Tet- 

 raplurus angustirosfris, (b) Makaira audai, and (c) Mak- 

 aira ampla; and at 200 pounds of (d) Isiiompax marlina, 

 (e) Makaira andax, and (f) Makaira ampla. 



ANALYSIS OF DIAGNOSTIC CHARACTERS 



It is obvious from an examination of the 

 literature on marlins and from study of a few 

 specimens that a proper designation of the species 

 can be made only after a suitable account of the 

 variation in diagnostic characters. All too fre- 



quently casts or photographs of single specimens 

 have been used to describe new species and sub- 

 species. The danger of such a practice has been 

 shown by Conrad and LaMonte (1937) and 

 Gregory and Conrad (1939), who measured 

 numerous specimens of three species from re- 

 stricted localities and found marked variation in 

 body proportions in each species. Furthermore, 

 since Shapiro (1938) and Morrow (1952a) demon- 

 strated marked changes in certain proportions due 

 to allometric growth, it is dangerous to use ratios 

 to describe the size of body parts. 



Of the spearfishes, the marlins are the species 

 of most concern, and the numerous authors who 

 have considered them have tried to recognize 

 their differences with a great variety of external 

 characters. These characters have included the 

 proportions of the head with its unique sword, 

 body proportions, length or height of certain fins, 

 character of the lateral line, color patterns, and 

 in a few instances, the number of rays in certain 

 fins. Also, it has been observed repeatedly that 

 the pectoral fin of certain marlins cannot be folded 

 against the body, whereas the pectorals of other 

 marlins fold readily. The work of Nakamura 

 (1938) has shown that considerable differences in 

 bone structure account for this variation in 

 flexibility. 



SOURCE OF THE DATA 



There is now available a considerable amount of 

 material for morphological comparison which 

 includes the 12 sets of measurements of IsHompax 

 marlina and the 30 of Makaira audax. from New 

 Zealand and Australian waters recorded by 

 Gregory and Conrad (1939); also the 23 sets of 

 measurements of the Atlantic blue marlin, Ma- 

 kaira ampla, obtained at Bimini, Bahama Islands, 

 in July 1937 and reported by Conrad and LaMonte 

 (1937). Morrow (1952a) gave a few measure- 

 ments for 49 audax from New Zealand. From our 

 POFI collection, we have measurements of 11 

 marlina, 68 ampla, 25 audax, 6 hliophorus orien- 

 talis, and 8 Teirapturus angustirostris (appendix 

 tables 1-A to I-E, p. 541). Almost all of these 

 spearfishes are from the central equatorial Pacific 

 waters. In addition, Vernon Brock of the Ha- 

 waiian Division of Fish and Game (DFG) has 

 made available to us certain measurements from 

 5 marlina, 27 ampla, 30 audax, and 2 angustirostris 

 (appendix tables 2-A to2-D, p. 548), obtained from 



