JOHNSON and BARNETT: CORRELATION BETWEEN CHARACTERS AND FOOD SUPPLY 



morphosis at an intermediate size in specimens 

 from lat. 25° to 27.5°N. Mean values of vertebral 

 and IPVALA counts are lowest in specimens 

 taken from areas where metamorphosis occurs at a 

 smaller size. A delay in vertebral ossification is 

 found in specimens from areas where meta- 

 morphosis occurs at a larger size. 4) Ahlstrom 

 and Counts (1958) report a north to south cline in 

 mean values for IPVALA photophore counts and 

 relate this to temperature. An east to west cline is 

 also suggested by their data (Figure 3), with mean 

 IPVALA counts lowest near the American con- 

 tinent and increasing with distance offshore. 

 Values for productivity measures in the eastern 

 tropical Pacific tend to fall off with increasing 

 distance from land (Reid 1962; Koblentz-Mishke et 

 al. 1970). If variation in photophore numbers in V. 

 lucetia is related to variation in productivity, we 

 would expect mean IPVALA counts at a given 

 latitude to be lower near the continent and higher 

 with increasing distance from land. Data from 

 Ahlstrom and Counts (1958) confirm this expecta- 

 tion (Figure 3) for all but two latitudinal transects. 

 Along these two transects, one just to the north of 

 the equator, the second centered at about lat. 

 12°N, mean values obtained for IPVALA counts 

 do not change or actually decrease to the 



130° 120° 110° 100° 90° 80' 



W 



westward, an apparent contradiction of our 

 hypothesis. However, these two zonal transects 

 fall along zonal areas of high or elevated produc- 

 tivity far to the westward of the American con- 

 tinent, and this is true for net primary production, 

 zooplankton standing stocks, or, as illustrated 

 (Figure 3), phosphate-phosphorus concentration. 

 Williams (1972) relates these zonal belts of elevat- 

 ed productivity to the divergence systems at the 

 equator and at the North Equatorial Counter- 

 current-North Equatorial Current boundary. 

 Williams (1972) states that the zonal band at lat. 

 10° to 12°N is best shown by data for zooplankton 

 stocks, but we note that this band is quite ap- 

 parent for phosphate-phosphorus concentration 

 (Reid 1962). Thus the apparently discrepant values 

 of mean IPVALA counts from specimens of V. 

 lucetia taken along these two zonal transects in 

 fact tend to further corroborate the hypothesized 

 inverse relationship between meristic counts and 

 productivity. 



Vinciguerria nimharia (Jordan 

 and Williams) 



Vinciguerria nimharia is nearly circumtropical 

 in distribution but does not occur in the Medi- 



PO4-P jjg at/I XIOO 



S>250 

 11200-250 

 P1 00 - 200 

 \S\ 50 - 1 00 

 []] 25-50 

 D <25 



Figure 2,.— Vinciguerria lucetia. Left: IPVALA photophores; values given are means based on five or more specimens taken at each 

 locality (see text for additional explanation, data from Ahlstrom and Counts 1958). Right: phosphate phosphorus data simplified from 

 Reid (1962). 



289 



