FISHERY BULLETIN: VOL. 80, NO. 3 



Table 4.— Summary of respiration experiments. Dry weights are of Formalin preserved 

 larvae, uncorrected for weight loss due to preservation. 



- 10 



50 



51 - I00 



uj 101 - 200 



Q 



20! - 300 



% k0 



<1> li-8 8-12 >12 



LARVAL SIZE CLASS(MM) 



Figure 7.— The vertical distribution of Pacific hake larvae off 

 the California coast shown as the percent of larvae within each 

 depth interval by size class. Sample numbers are 1174, LT 4 

 mm; 1051, 4-8 mm; 19, 8-12 mm; 5, GT 12 mm; total sample of 

 2,249 larvae. 



1979, large larvae were also caught in midwater 

 trawls near the surface in nighttime. 



In contrast to eggs and larvae off the Califor- 

 nia coast, which are found at midwater, Pacific 

 hake eggs and larvae in Puget Sound are located 

 near the bottom of the water column. This is 

 shown in Figure 8 for animals sampled at Port 

 Susan (maximum depth, 110 m). This trend was 

 also observed for animals collected at Dabob Bay 

 (maximum depth, 175 m); the majority of eggs 

 and larvae were found in the bottom 25 m of the 

 water column. The difference in vertical distri- 

 bution between eggs off California and eggs in 

 Puget Sound may be explained as follows. The 

 water at a reference level of 100 m is less saline 

 (29.3%o) and less dense (1.0228) in Puget Sound 

 than water off the California coast (33.6 %o 

 1.0258). Off California, eggs are spawned at 200- 

 500 m depth, are relatively buoyant compared 



< 0-1)0 



> 



20 - 1)0 



1)0 - 75 



75 - 110 



EARLY STAGE LATE STAGE YOLK-SAC 

 EGGS EGGS LARVAE 



LARVAE 

 < 5™ti 



LARVAE 

 > 5™n 



EGG/LARVAL STAGE 



Figure 8.— The vertical distribution of Pacific hake eggs and 

 larvae at Port Susan, Wash., shown as the percent of eggs or 

 larvae within each depth interval by developmental stage or 

 size class. Sample numbers: early stage eggs, 2,845; late stage 

 eggs, 1,147; yolk-sac larvae, 409; larvae LT 5 mm, 31 ; larvae GT 

 5 mm, 12; total sample of 4,444. 



with the surrounding water, and rise upward to 

 a level of equal buoyancy. Eggs in Puget Sound 

 are spawned near bottom (Thorne 1977). Assum- 

 ing that they are about the same density as the 

 California eggs, these eggs are relatively less 

 buoyant in the less dense water of Puget Sound, 

 and therefore remain near the bottom. 



DISCUSSION 



Compared with eggs and larvae of other fishes 

 in the California Current system, rates of devel- 

 opment, growth, and metabolism of Pacific hake 

 eggs and larvae are slow. These factors may be 

 indicative of survival tactics (Hunter 1980), and 

 differences could reflect the relative importance 

 of certain environmental conditions, such as food 

 abundance and predation pressure, in larval sur- 



594 



