WALTERS: ECOLOGY OF HAWAIIAN SERGESTID SHRIMPS 



0.6 mm CL per month for up to one additional year. 

 Few males appeared to live beyond 18 mo, but a 

 few large females greater than 22 mm CL were 

 probably a full 2 yr old. The pattern of growth 

 appears clear cut, but the small sample size means 

 that the data should be treated cautiously. The 

 Kolmogorov-Smirnov test showed that only the 

 third and fourth quarter size-frequency curves for 

 the females were significantly different from each 

 other (0.05>P>0.01). 



Diet (Table 5) 



Seven of the eight 5. bisulcafa taken by DSB III 

 had food in their stomachs. Food items included 

 ostracods. an amphipod, foraminifera, bivalve 

 larva, and crustacean remains probably including 

 a euphausiid and a larval decapod. No copepods 

 were found, probably because of the small sample 

 size. 



Sergia maxima (Bur ken road 1940) 



Only two individuals of this species were cap- 

 tured, one on the March 1972 cruise in a 480- to 

 615-m daytime tow and the other on the December 

 1973 cruise in an open tow between 400 and 550 m. 

 Both individuals were immature males. 



Sergia tenuiremis (KreSyer 1855) 



Vertical Distribution (Figure 29) 



During the daytime most of the population was 

 below 800 m, although shrimp were sometimes 

 taken as shallow as 700-750 m. A single immature 

 individual was taken in June 1971 between 610 and 

 690 m. The deepest capture was in a tow between 

 1,220 and 1,500 m in August 1972. Tows below 1,500 

 m did not capture S. tenuiremis, but total trawling 

 time in this region was rather small. Immature 

 shrimp less than 15 mm CL were vertical migra- 

 tors, moving up to 300-500 m at night. The adult 

 population did not migrate as a whole, but part 

 spread upward at night as shallow at 550-600 m. 

 Moonlight had no effect on the nighttime vertical 

 distribution of S. tenuiremis. 



Population Size, Growth, and 

 Reproduction (Figure 30) 



Sergia tenuiremis is not abundant in Hawaiian 

 waters. The average population density estimated 



8 12 16 20 24 28 



8 12 16 20 2U 28 

 CflRflPfiCE LENGTH IMM) 



2 M 

 NO. PER 105 n3 



Figure 29.- Vertical distribution of Sergia tenuiremis. NIGHT 

 and MOON data combined. 



SERGIA TENUIREMIS 



6 



-I \ 1 r 



8 16 



la 



"T 1 1 ^ • — r— — 1 r 



8 16 24 32 



a„ 



M 



rh 



-I — I I I I 



8 16 24 32 



, r~i I 



m 



^ 



24 8 16 



CARAPACE LENGTH (mm) 



32 



Figure 30.-QuarterIy size-frequency distribution of Sergia 



tenuiremis. 



by all horizontal tows was 0.89 per 100 m^, day and 

 night values being similar. The two oblique series 

 produced slightly smaller values, 0.67 per 100 m- in 

 September 1972 and 0.70 in May 1978. Since these 



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