CLARKE: DIETS OF FOURTEEN SPECIES OF MESOPELAGIC FISHES 



14 



20 25 30 35 40 45 50 55 60 65 70 75 80 



STANDARD LENGTH (mm) 



Figure 3. — Relationships between standard length and average space between gill rakers on the lower branch of the first gill arch for 

 12 species of mesopelagic fishes designated by initials of genus and species names. Lines for Lampanyctus nobilis, Triphoturus 

 nigrescens, Ceratoscopelus warmingi, Benthosema suborbitale, Bolinichthys longipes, Diaphus schmidti,D. perspicillatus, D. fragilis,D. 

 trachops, and Melamphaes danae and dashed line for Lampanyctus steinbecki are drawn from equations determined by least squares 

 regression on measurements from five or more specimens of each species over the size ranges plotted; coefficients of determination (r^) 

 exceeded 0.80 for all except M. danae ( r^ = 0.78). The equation for Diogenichthys atlanticus (r* = 0.60) was almost identical vdth that for 

 M. danae and was omitted for clarity. Notolychnus valdiviae ( r^ = 0.04) is represented by the area enclosed by points from five specimens. 



most similar species were Lampanyctus steinbecki, 

 L. nobilis, T. nigrescens, and Notolychnus val- 

 diviae. All ate relatively large and opaque or pig- 

 mented prey. Both within and between species, the 

 sizes of the most frequent and most preferred prey 

 were roughly correlated with standard length, i.e., 



the large L. nobilis favored euphausiids and large 

 copepods, while A^. valdiviae and the small L. 

 steinbecki and T. nigrescens preferred some types 

 as small as Oncaea. All four species had relatively 

 small eyes and relatively large gill raker gaps, and 

 three had relatively low gill raker "areas." The gill 



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