NOTE Gilman: An energy budget for Ammodytes dubius 



651 



Table 5 



Predicted daily ration of adult northern sand lance, Ammodytes dubius, on Georges Bank based on monthly growth 

 (Table 1) and assimilation efficiency for Calanus finmarchicus (Equation 2). 



Month 



Assimilation 

 efficiency (%) 



Required energy 

 (kcal/month) 



Ration 

 (g/month) 



Daily ration 

 (%body wt) 



January 



February 



March 



April 



May 



June 



July 



August 



September 



October 



November 



December 



Annually 



87.07 

 85.70 

 85.01 

 85.01 

 88.29 

 90.74 

 92.34 

 93.41 

 93.34 

 92.49 

 90.81 

 89.13 



0.00 

 0.00 

 0.00 

 5.05 

 8.83 

 6.62 

 5.73 

 7.33 

 5.11 

 3.07 

 2.91 

 3.44 



48.09 



52.62 



0.00 

 0.00 

 0.00 

 0.95 

 1.61 

 1.18 

 1.01 

 1.28 

 0.89 

 0.54 

 0.52 

 0.62 



8.60 



0.00 

 0.00 

 0.00 

 2.26 

 3.72 

 2.82 

 2.33 

 2.95 

 2.12 

 1.24 

 1.24 

 1.44 



100C = 15G + 5R + TIM + 9W, 



(4) 



where C = consumption; 



G = growth; 



R = reproduction; 



M = metabolic requirement; 



W = waste (that portion of the predicted ra- 

 tion that is not assimilated based on Equation 2 above). 



For an individual adult northern sand lance on 

 Georges Bank, total production is 10.53 kcal-yr -1 

 (growth+reproduction), and total consumption is 

 52.62 kcalyr _1 ( Table 5); therefore, ecological effi- 

 ciency is 20.0%. 



Population energy budget 



Northern sand lance consumed a significant propor- 

 tion of total annual zooplankton production of Georges 

 Bank from 1977 through 1986. Population abundance 

 of northern sand lance from 1977 through 1986 was 

 negatively correlated with zooplankton abundances 

 during the same period (r 2 =0.683, P<0.05; Fig. 1). 

 Northern sand lance consumed 0.79-19.24% of the 

 annual zooplankton production from 1977 to 1986 

 (Table 6; Fig. 2). 



The trophic efficiency of the northern sand lance 

 is 20%, according to the present energy budget model. 

 Jones's ( 1984 1 Georges Bank energy model found that 



