chovies seems to exist off Oregon associated 

 with the warm, near surface waters of the 

 Columbia River plume. The spawning period 

 seems to be correlated with the time when warm 

 plume water is a dominant oceanographic 

 feature, before the rest of the ocean surface 

 water warms to >14°C. Additional sampling 

 for eggs as well as larve with even more exten- 

 sive coverage is needed to determine areal extent 

 of spawning and extent of yearly variation 

 caused by changing oceanographic conditions. 



Osmeridae (687 larvae in 2 1 samples) 



Larvae of osmerids were collected in June, 

 July-August, August, and October at the near- 

 shore stations shown in Figure 5. The near- 

 shore area was heavily sampled on the July- 

 August cruise, perhaps explaining why few or 

 no specimens were taken on other cruises. 

 Similarly, no samples were taken near shore 

 south of Newport (Figure 1). Distribution 

 appears to be restricted to near shore when 

 upwelling was prominent. 



All specimens have not yet been identified to 



Figure 5. — Distribution of osmerids collected from June 

 to October 1969. 



species, although some are known to be Thale- 

 ichthys pacificus. The trend in growth in Figure 

 2B might indicate all the larvae were products 

 of one major spawning and therefore one species. 



Mycthophidae (8,694 larvae in 152 samples) 



Larvae of S. leucopsarus (7,683 specimens) 

 were taken from May to September in moderate 

 numbers. Capture of 3 -mm individuals in May 

 (Figure 2C) indicated spawning may have 

 occurred recently, although early growth rates 

 have not yet been established. The occurrence of 

 4-mm larvae as late as July-August appears to 

 extend the spawning period off Oregon beyond 

 the December to March range estimated by 

 Smoker and Pearcy (1970). The smallest larvae 

 taken in September were 8 mm. No larvae were 

 taken in October which supports the idea that S. 

 leucopsarus does not spawn throughout the year 

 off Oregon. 



The I KMT generally captured larger larvae 

 than the bongos or MN (Figure 2C). An increase 

 in median length of larvae occurred from May 

 through August. Individuals about to undergo 

 metamorphosis, which occurs around 18 mm 

 (Smoker and Pearcy, 1970), were taken from 

 July-August to September. By October, all 

 larvae apparently had begun the process of 

 metamorphosis, which takes place at depths 

 greater than we sampled (Fast, 1960). 



Larvae of S. leucopsarus were more abun- 

 dant west of long. 124°30'W(about 20 nautical 

 miles off Newport, Oreg.) than closer to shore 

 (Table 8) although a few specimens did occur in 

 nearshore samples. North-south distribution 

 was scattered. Larvae were never taken around 

 the mouth of the Columbia River where lower 

 salinity water fans out into the ocean. Larvae 

 were more frequently taken in deep (200 m) 

 tows than in shallow tows (Table 4) during the 

 June and July-August cruises. 



Larvae of T. crenularis (714 specimens) were 

 collected on all cruises. Larval lengths ranged 

 from 5-7 mm to 19-20 mm on each cruise from 

 May to September (Figure 2D). From these 

 data, T. crenularis appears to spawn at least 

 throughout the period sampled, although collec- 

 tion of only one specimen in October cannot be 

 explained. 



709 



