Bartlett (1949). This gave the relationship: 



R' = 2.2 W-"-'^- 

 or 



R = 2.2 f^»-«» 



Theoretically, the respiration rate is expected 

 to be proportional to the % power of weight. 

 Since our estimates are slightly above (0.68) and 

 slightly below (0.62) the expected value of 0.67, 

 we consider that the % power relationship is 

 the best estimate for Metanujsidopsis and that 

 the best estimate of respiration rate (/nl Oj/hr) 

 is given by the equation: 



/? = 2.1 1^"" 



Estimates of weight -specific respiration for 

 three other, somewhat larger, species of Mysidae 

 are compared with Metamysidopsis in Figure 

 11. The upper four points ("1" on Fig. 11) 

 represents results for Neomysis americana from 

 Ravmont and Conover (1961) that were ad- 

 justed from 4° C or 10° C to 16° C by using 

 a Q,o value of 1.6 that was estimated from their 

 data. The intermediate point is an estimate of 

 the median value oxygen consumption rate cal- 

 culated from 12 determinations on Neomysis 

 integer (Raymont, Austin, and Linford, 1966) 

 that had been adjusted to 16° C by using a Q,o 

 of 1.9 (Grainger, 1956). The lower point was 

 estimated from the results of Grainger (1956) 

 for Hemimysis lamomae. The ranges of values 

 for these three larger species are about the same 

 as the range (1-3 ^il/hr) calculated from the 

 seasonal change data of Raymont et al. (1966) 

 that had been adjusted to 16° C. The estimates 

 for Metamysidopsis and the other three Mysidae 



FISHERY BULLETIN: VOL. 69. NO. I 



all lie well above the relationships calculated for 

 marine planktonic Crustacea by Conover (1960) . 



BODY COMPOSITION AND 

 ENERGY CONTENT 



To estimate the amounts of energy used in 

 respiration, molting, and reproduction it was 

 necessary to determine the body composition of 

 the mysids, their molts, and their young. For 

 these analyses the animals were captured alive 

 and, within 2 hr, placed in a constant-flow hold- 

 ing tank at 15° to 17° C where they were kept 

 for a short time prior to analysis. 



BODY COMPOSITION 



The estimates of body composition of dried 

 animals and molts are summarized in Table 3. 

 The estimates for ash, protein, lipid, carbohy- 

 drate, and chitin are not considered to be accu- 

 rate past the first decimal point. The fractional 

 percentage values are entered so that the sums 

 will equal 100 ^/c. The methods by which these 

 values were determined will be explained item 

 by item. 



To determine dry weights, the animals were 

 washed very briefly with distilled water while 

 still alive, then were oven-dried to constant 

 weight at 60° C. Materials that were available 

 only in small quantities were weighed on a Cahn 

 electrobalance. 



Ash 



Ash content was estimated by incinerating 



Table 3. — Average composition and energy content of dry Metamysi- 

 dopsis bodies, molts, eggs, and larvae. Tabulated values for composition 

 are %, and for energy content are cal/mg. The sums of % ash, "pro- 

 tein", lipid, carbohydrate and chitin = 100 %. 



* "protein" may include free omino acids. 



104 



