Harvey: bffects of El Nino events on consumption and egg production of Sebastes spp 



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Figure 1 



Estimated allocation of energy consumption by northern California S. 

 mystinus from ages to 30 under baseline model conditions. Consumption 

 (C) is allocated as respiration (R), waste, and digestive costs (F+U+SDA), 

 growth (4B), and reproduction (G). (A) Females. (B) Males. 



also similar in all models and in both sexes, despite the 

 declines experienced by females. 



Repeated exposure to El Nino also affected reproduc- 

 tion by S. mystinus. Both sexes experienced delays in 

 maturation as a result of slowed growth rates during 

 El Nino events, and the delay was related to the num- 

 ber of El Nino years experienced at young ages. In the 

 baseline model, 50% maturity was reached at age 6 

 for both sexes. In cohort A, 50% maturity was reached 

 at age 6 by females, but at age 7 by males. Under the 

 more arduous conditions of cohort B, both sexes reached 

 50% maturity at age 7. The effect of delayed maturation 

 in terms of energy consumption should be greatest in 

 females because of their greater investments in repro- 

 duction, although this was not especially noticeable 

 at the scale of cumulative consumption per individual 



(Table 3). A further effect of El Nino events occurred 

 in female egg production. The dramatic reduction in 

 fecundity during El Nino years over the course of an 

 individual female's life caused cumulative egg produc- 

 tion in cohort A to be only 87.9%> of the baseline level, 

 and cohort B female egg production was only 81.3% of 

 the baseline level (Fig. 3C). 



More pronounced El Nino effects occurred at the per- 

 recruit scale. El Nino conditions reduced per-recruit en- 

 ergy consumption in both sexes in contrast to baseline 

 conditions (Fig. 4, A and B). Incorporating mortality 

 lowered the contribution of older age groups, where 

 individual consumption was highest (Fig. 3, A and B), 

 thereby magnifying the El Nino effects on young fish. 

 The negative effects on young age classes were exac- 

 erbated in females by slowed maturation and reduced 



