FISHERY BULLETIN: VOL. 87, NO. 2, 1989 



Table 1 . — Collection data of juvenile Trachurus murphyi from tfie Subtropical Convergence Zone of the central Soutfi Pacific by 



RV Townsend Cromwell. 



Morphometric and meristic characters were deter- 

 mined using the procedures described by Hubbs and 

 Lagler (1957), and Berry (1968) with respect to the 

 lateral line. Measurements were made of fork length 

 (FL), standard length (SL), body depth (BD), head 

 length (HL), snout length (SnL), eye diameter (ED) 

 ( = orbit length), and pectoral fin length (PL). Addi- 

 tional measurements included the lengths of the 

 curved and straight sections of the lateral line (LL 

 Curv, LL Str), and the height of the largest scale 

 in the curved section (Ht Curv) and the largest scute 

 in the straight section (Ht Str). Measurements were 

 made to the nearest 0.1 mm using vernier calipers 

 and fine-point dividers where practical and a dissect- 

 ing microscope fitted with an eye piece graticule for 

 SnL, ED, Ht Curv, and Ht Str. Counts were made 

 of dorsal and anal fin softrays, gill rakers on the first 

 gill arch, and scales and scutes along the lateral line. 

 The end points of the dorsal accessory lateral line 

 (LL Ace) and the curved section of the lateral line 

 were measured with reference to the nearest dor- 

 sal softray. 



DESCRIPTION 



The morphometries and meristics of Trachurus 

 murphyi from the central South Pacific are shown 

 in Table 2. The color of live specimens is dark blue 

 dorsally to a line slightly above the lateral midline, 

 and silver-gray immediately below. The fins are 

 clear, with numerous black speckles on the dorsal 

 and caudal fins. In most specimens the operculum 

 has a black spot on the upper posterior margin. 



A total of 566 jack mackerel from the two Town- 

 send Cromwell cruises, including the 40 specimens 

 described here, was measured. Fork length ranged 

 from 17 to 96 mm (mean FL = 60.7 mm, SD = 12.9 

 mm). Jack mackerel measured from the 1987 sam- 



Table 2.— Morphometric and meristic characters of juvenile 

 Trachurus murphyi from the Subtropical Convergence Zone of the 

 central South Pacific. 



^See text page 274 regarding abbreviations 



pie (n = 335) differed from the 1986 sample in the 

 occurrence of 31 specimens between 17 and 40 mm 

 length. Although fins appeared completely formed 

 in this size range, specimens below about 35 mm 

 could not be identified beyond genus because scales 

 and scutes did not cover the entire length of the 



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