JOHNSON and BARNETT: CORRELATION BETWEEN CHARACTERS AND FOOD SUPPLY 



possible relationship between meristic counts and 

 measures of food supply. We did not offer any 

 explanation for this relationship in the earlier 

 report. In the present paper we extend our infor- 

 mation on D. taenia to the Atlantic Ocean, present 

 corroborative evidence for the relationship 

 between meristic counts and food supply based on 

 four other species of mid-water fishes, and 

 attempt to show that the relationship for the 

 species and areas studied is with food supply and 

 not temperature, salinity, or dissolved oxygen. We 

 hypothesize that this relationship between meris- 

 tic counts and food supply reflects differences in 

 egg size, fecundity, size at hatching, and size at 

 comparable stages of larval development between 

 populations in different areas, and that these 

 differences represent adaptations to low food 

 densities in areas of low productivity and higher 

 predator densities in areas of higher productivity. 



METHODS 

 Collection and Analysis of Data 



Methods of taking counts follow those of Grey 

 (1964), Morrow (1964), and Johnson (1970). Pho- 

 tophore rows in a generalized stomiatoid fish are 

 illustrated in Morrow (1964: Figure 73), but our 

 nomenclature for segments of photophore rows 

 follows that of Johnson (1970). All vertebral centra 

 were counted including the compound element 

 supporting the parhypural and hypurals (Weitz- 

 man 1967). Standard statistical texts have been 

 used as reference material (especially Tate and 

 Clelland 1957; Sokal and Rohlf 1969). Agreement 

 between sets of ranks is assessed via the tau 

 coefficient of correlation or Kendall's coefficient of 

 concordance, W (see Tate and Clelland 1957). 



Localities Studied 



We have studied specimens from eight areas 

 (Figure 1): 1) the eastern tropical Pacific (ETP) off 

 Mexico; 2) the central North Pacific (CNP) off the 

 Hawaiian Islands; 3) the central equatorial Pacific 

 (CEP) at long. 145° to 150°W; 4) the western 

 equatorial Pacific (WEP) around long. 170°E; 5) 

 the Philippine Sea (PS); 6) the South China Sea 

 (SCS); 7) the Gulf of Guinea (GG); and 8) the cen- 

 tral North Atlantic (CNA) including the Sargasso 

 Sea. All of these areas are tropical oceanic habitats 

 and represent a wide range of physical and 

 biological features. 



Measures of Biological Productivity 



The measures used to assess relative richness of 

 food supply are phosphate-phosphorus concentra- 

 tion, net primary production, and zooplankton 

 standing stocks. These three \ariables are highly 

 intercorrelated (Gushing 1971). These measures 

 were chosen because there are published attempts 

 at contouring values of these variables on an 

 oceanwide basis and because values for them are 

 commonly reported in more regionally oriented 

 studies. 



Despite many problems in both sampling and 

 interpretation associated with attempts to con- 

 tour values of biological variables on an oceanwide 

 basis and to integrate values based on a limited 

 number of measurements over a full year, we were 

 forced to accept such attempts as the principal 

 basis for ranking our eight study areas with re- 

 spect to the three measures of food supply. Where 

 possible we relied on synoptic studies presenting 

 contours on an oceanwide basis: net primary 

 production (as mg-C/m^ per day, Koblentz-Mishke 

 et al. 1970; as g-C/m" per year, Ebeling 1962 based 

 on Fleming and Laevastu 1956), zooplankton con- 

 centration (as parts/ 10-' by volume in the upper 150 

 m of the Pacific Ocean, Reid 1962), and 

 phosphate-phosphorus concentration (asjug- 

 at/liter contoured at 100 m in the Pacific Ocean, 

 Reid 1962). Where these studies did not cover 

 several of our study areas, we used regional 

 studies (SCS: Angot, Steemann Nielsen in Wyrtki 

 1961; Sorokin 1973; GG: Raymont 1963, Corcoran 

 and Mahnken 1969, Kinzer 1969, Zeitschel 1969, 

 Riley 1972; CNA: Menzel and Ryther 1961, 

 Raymont 1963, Corcoran and Mahnken 1969, 

 Zeitschel 1969, Riley 1972). 



We compared the contours or values for each of 

 the three measures of productivity over all eight 

 study areas and then ranked the eight areas with 

 respect to each other for each measure (Table 1). 

 As expected (Gushing 1971), the ranks for the 

 three measures over the eight areas are highly 

 concordant (IFgg = 0.85, P <0.01, concordance 

 coefficient corrected for ties, see Tate and Clelland 

 1957). This highly significant concordance 

 increases our confidence in this approach to 

 ranking the eight areas with respect to produc- 

 tivity and allows summation of the ranks of the 

 three measures of food supply over each area, 

 yielding a rank-sum. We then ranked this rank- 

 sum and obtained the following rank-index order 

 of productivity, from highest to lowest: 1) eastern 



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