FISHERY BULLETIN: VOL. 86, NO. 3 



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Figure 2.— Light micrographs of Pacific saury sagittae. a) OtoHth nucleus composed of 5 or 6 separate dense bodies with surrounding 



cores, b) Assumed 4 embryonic and 1 hatching (arrow) rings. 



The daily periodicity of growth increment forma- 

 tion in the Pacific saury has not been verified. For 

 that reason we plotted the number of increments 

 versus knob length instead of age versus length. We 

 used the Laird-Gompertz equation to describe the 

 relations of increment number and length as growth 

 curves for both the eastern and western Pacific 

 saury. Hatching size of artificially fertilized and in- 

 cubated Pacific saury from the western Pacific was 

 reported to be 7.19 mm in average live total length 

 (Yusa 1960). From the drawing of a newly hatched 

 larva in Yusa's paper, we estimated live knob length 

 to be 6.60 mm. Shrinkage factors of northern an- 

 chovy in the size range from 6.00 to 7.99 mm were 

 0.90 for a 5-min net treatment and 0.85 for a 10-min 

 net treatment (Theilacker 1980). Using these values, 

 the capture size of a newly hatched larva of Pacific 

 saury after a 5-min net treatment was estimated to 

 be 5.95 mm and a 10-min treatment to be 5.61 mm. 

 We fixed the hatching size from 5.85 to 5.95 mm 

 in the growth curve, because the Pacific saury lar- 

 vae at this size are in a more advanced develop- 



mental stage and shrank less by net treatment than 

 northern anchovy. 



The resulting growth equation for the eastern 

 Pacific saury was 



KnL = 5.85 exp((0.0427/0.115)(l - e(-o.oii5(/-5)))) 



and the equation for the western Pacific saury was 

 KnL = 5.95 exp((0.0504/0.0128)(l - e(-ooi28(/-5)))) 



where KnL is a knob length in mm and / is the total 

 number of increments observed in an otolith. The 

 term, 7-5, indicates that five increments were pre- 

 sumed to have been present at hatching. Data from 

 the western Pacific saury appear to consist of two 

 curves separated around 100 mm in KnL. Two 

 Laird-Gompertz curves fit much better than one 

 curve. The intersection of the two curves was at 1 14 

 increments and 100 mm. The growth equation for 

 fish smaller than 100 mm was 



492 



