FISHERY BULLETIN: VOL. 75, NO. 1 



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46 56 

 STATIONS 



65 



74 



FIGURE 2. — Day and night catches offish larvae on transect off 

 Yaquina Bay, Oreg., June 1971. 



daytime tows (4-16 mm). Decreased larval abun- 

 dances at night at station 74 were due mainly to 

 reduced numbers of S. leucopsarus (5-13 mm at 

 night, 5-16 mm in day). Thus avoidance of the net 

 by large larvae in daytime seemed to account for 

 much of the day-night variation at the coastal sta- 

 tions 2, 6, and 9. Differences at the offshore 

 stations may have been due to patchiness of small 

 larvae. 



Variability among repeated samples was 

 examined at the three inshore stations where four 

 day and four night replicate samples were taken at 

 each station. Coefficients of dispersion were 

 calculated for total larvae, osmerids, and total 

 larvae minus osmerids (Table 3). Values were 

 close to 1.0 for total larvae minus osmerids at 



200 r- 



100 



900 1- 



300- 



200- 



100- 



20 30 



STANDARD LENGTH (mm) 



FIGURE 3. — Day and night length frequencies of osmerid larvae 

 collected at 6 and 9 km off Yaquina Bay, Oreg., June 1971. 

 Numbers of larvae were combined for both nets from four day 

 and four night hauls. 



stations 6 and 9 and for total larvae at station 2 

 where osmerids were not abundant suggesting 

 that larvae were randomly distributed. Coeffi- 

 cients were large, however, for total larvae and for 

 osmerids at 6 and 9 where smelt larvae were 

 abundant, except at night at station 9. These 

 large coefficients of dispersion indicate high con- 

 tagion, possibly caused by schooling behavior of 

 large osmerid larvae. 



TABLE 3. — Coefficients of dispersion (s 2 /x) for total larvae, 

 osmerids, and total larvae minus osmerids in replicate tow series 

 made in June 1971 on the transect (lat. 44°39.1'N) off Yaquina 

 Bay, Oreg. 



VERTICAL DISTRIBUTION 



One attempt was made to study the vertical 

 distribution patterns of larvae in the coastal zone 

 18 km offshore north of the Newport transect 

 (Figure 1). Thirty-two samples were taken within 

 four depth strata (0-10, 11-50, 51-100, and 101-150 



130 



