FISHERY BULLETIN: VOL. 84, Na 1 



Table 2.— Relationship between incubation time, egg size, and initial increment deposition: Determing whether species with long incuba- 

 tion and large eggs initiate increment deposition on or before hatch, while species with short incubation and small eggs initiate increments 

 at first feeding or yolk sac absorption, ysa = yolk sac absorption. 



'Grace McPhee, P.O. Box 210972, Auke Bay, AK 99821, per. commun. summer 1983. 



Table 3.— Otolith increment deposition for larval fish maintained in the laboratory over a known time span. 



of daily deposition (24L, 20°C) would be an anomaly 

 under this hypothesis. 



Ten studies have investigated deposition rates 

 under suboptimal, extreme or varying conditions 

 (Table 4). These studies are important to the under- 

 standing of the underlying mechanisms causing in- 

 crement deposition. Two studies, one by Radtke and 

 Dean (1982) and one by Taubert and Coble (1977), 

 demonstrated disruption of daily increment forma- 

 tion under extreme or abnormal changes in photo- 

 period. Taubert and Coble (1977) found that in 

 simulated winter conditions, cold temperature and 

 shorter photoperiod resulted in cessation of incre- 



ment formation in Lepomis cyanellus. At and below 

 temperatures of 10°C, growth and increment deposi- 

 tion ceased. If such changes occurred gradually, as 

 occurs in the normal lifetime of fish, acclimation to 

 these temperature changes might be expected 

 through most of the temperature range. Within nor- 

 mal physiological limits (especially where some 

 growth continued), increment deposition would be 

 assumed to continue regularly. However, Marshall 

 and Parker (1982) also found that temperatures 

 below 10°C resulted in cessation of increment deposi- 

 tion in sockeye salmon. Hence two studies have 

 shown that increment deposition is not maintained 



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