RICHARDSON and I'EARCY: COASTAL ANDOCEANIC FISH LARVAE 



every month (Table 1). Of the 287 station oc- 

 cupancies, 219 were made during daylight, 50 at 

 night, and 18 at dusk or dawn. In addition, a series 

 of replicate tows was made on 28-30 June 1971, 

 which included two daytime and two nighttime 

 hauls at stations 2, 6, and 9 and one daytime and 

 one nighttime haul at stations 46, 56, 65, and 74. 



Samples were collected with a 70-cm (mouth 

 diameter) bongo net without a closing mechanism. 

 The bongos had two cylindrical-conical nets of 

 0.571-mm mesh Nitex 11 which were 4.6 m long 

 and had a filtering area to mouth area ratio of 

 about 10:1. Tsurumi-Seiki Kosakusho (TSK) 

 flowmeters were positioned off center in the mouth 

 of each net. A 40-kg multiplane kite-otter depres- 

 sor (Colton 1959) was attached to the cable be- 

 neath the bongos which produced a 2:1 wire out to 

 depth fished ratio. A time-depth recorder 

 (bathykymograph) was attached to the cable 

 above the bongos to record depth and path of tow. 



The net was towed along depth contours parallel 

 to the coast at a vessel speed of 2-3 knots. Tows 

 were made obliquely through the water column in 

 equal stepped intervals from the bottom or 150 m 

 to the surface. Tow times ranged from 8 to 39 min 

 and were usually between 10 and 30 min. Volume 

 of water filtered ranged from 283 to 1,411 m 3 and 

 was usually between 500 and 1,000 m 3 . 



At each station a bathythermograph (BT) cast 

 was made to the bottom or 140 m, a surface bucket 



"Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



temperature was recorded, and surface and deep 

 (bottom or 140 m) salinity samples were taken. 



Plankton samples were preserved at sea in 10% 

 buffered Formalin. One sample from each bongo 

 pair ( 287 samples) was sorted for fish larvae except 

 for the replicate series where both samples of each 

 pair (7 of the 287 samples plus 33 additional 

 samples) were sorted. All fish larvae were re- 

 moved from each sample and were stored in 5% 

 buffered Formalin. Larvae were identified to the 

 lowest possible taxonomic group, enumerated, and 

 measured (standard length). Numbers of larvae 

 from each sample were standardized to number 

 under 10 m 2 of sea surface. This standardized 

 number was used in all analyses unless indicated 

 otherwise. 



In addition to the above samples, a 24-h station 

 was occupied 18 km offshore at a location 46 km 

 north of the Newport transect at lat. 45°04.0'N 

 (Figure 1 ) on 30-31 May 1972. Water depth ranged 

 from 158 to 164 m. Four depth strata (0-10, 11-50, 

 51-100, and 101-150 m) were sampled. Tows were 

 designed to filter approximately the same volume 

 of water in each stratum (x = 912 m 3 ± 142). The 

 nonclosing bongo gear was lowered rapidly to the 

 maximum depth of the zone to be sampled, towed 

 obliquely through the depth zone in equally 

 spaced steps, and then retrieved quickly to 

 minimize contamination. Two tows were made in 

 each depth stratum in daylight and again at night, 

 which yielded 32 ( 16 pairs) samples. All fish larvae 

 were sorted, identified, and enumerated. Numbers 



TABLE 1. — Summary of 287 station occupancies made on an east-west transect (lat. 

 44°39.1'N) off Yaquina Bay, Oreg., 1971-72. 



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