52 



Fishery Bulletin 94(1), 1996 



Results 



Metabolism 



The slope of these two regression lines did not differ 

 significantly. From a common slope (0.0547) that was 

 computed, a Q U) = 3.52 was derived. 



A total of 49 fishes (57-1,327 mg WW) were used for 

 the ETS assay. A scatter diagram showing the rela- 

 tionship between specific oxygen consumption rates 

 (R/WW: juL OgAmg WW-h)) and WW is presented in 

 Figure 1. The effect of WW on oxygen consumption 

 rates (R: fih 2 /(fish-h)) was examined by using a 

 GM regression model (Ricker, 1973), log 1() /? = v 

 \og 1Q WW + log 10 */, where v and u are constants. Esti- 

 mates were t; = 0.987 (95% CI: 0.917-1.053) and 

 log ]0 « = -0.609 for the data derived from the ETS 

 assay. The v did not differ significantly from unity 

 (v=l). On this basis, a mean specific oxygen consump- 

 tion rate (R/WW) was calculated as 0.225 (±0.038 SD). 

 The relationship between ETS activity (ETS: /iL 

 O^Amg WW-h)) and temperature (°C) was linear over 

 the temperature tested (0.5 to 20°C) on a semilog 

 graph (Fig. 2). The relationship was expressed as 



\og 10 ETS = 0.0541 (95% CI: 

 0.0472 - 0.06101T - 1.0440, for fish 1 



and 



\og lQ ETS = 0.0554 (95% CI: 

 0.0490 - 0.0618)7; - 1.0038, for fish 2. 



TL (mm) 



~ 0-5 



i 



3 



IT 



Condition factor index, body composition, 

 and caloric content 



Over all size groups (<10 to >60 mm TL), the ranges 

 recorded were 5.23 to 9.53 for CFI, 68.8 to 78.8 (% 

 WW) for water, 10.7 to 25.7 (% DW) for ash, 34.1 to 

 54.4 (% DW) for C, 7.2 to 12.2 (% DW) for N, 5.1 to 

 8.4 (% DW) for H, and 1.02 to 1.98 (Kcal/g WW) or 

 3.51 to 6.33 (Kcal/g DW) for caloric content (Table 2). 

 Changes in these variables with increasing TL 

 were examined by using three regression models: lin- 

 ear (Y = aX + b), power ( Y = aX h ) and exponential (Y 

 = ae bX ). In these analyses, X was represented by the 

 mid-range value for each size group except that 10 

 was used for the <10 mm TL group and 60 for the 

 >60 mm TL group. Among these three regression 

 models, the best was selected, as judged by the high- 

 est correlation coefficient. The analyses revealed two 

 opposite patterns, i.e. an increase (CFI, C, H, and 

 caloric contents) or a decrease (water, ash, and N) 

 with the growth of M. muelleri. All regressions were 

 significant (Table 2) except for N. The decrease of N 

 with an increase in TL, however, was significant if 

 data from the <10 mm TL group were removed 

 (r=-0.947, P<0.01). 



The results of analyses on gonads are 

 summarized in Table 3. Among mature 

 ovaries, oocytes, and testes, the oocytes 

 exhibited the highest caloric content (5.61 

 Kcal/g DW), followed by mature ovaries 

 (4.88 Kcal/g DW). The lowest caloric con- 

 tent (4.66 and 4.79 Kcal/g DW) was re- 

 corded on two testicular samples. 



inn 



WW (mg) 



Figure 1 



Relationship between specific oxygen consumption rates (R/WW, /jLO./ 

 ( mg WW-h ) at 12°C ) and wet weight ( mg WW ) obtained from ETS assay 

 (ETS activity x 0.5) for Maurolieus muelleri. Because statistical analy- 

 sis indicated no effect of WW, a mean was calculated and superimposed. 

 The broken line is the relationship expected when size-dependent me- 

 tabolism is assumed for ETS data (i.e. R«WW 085 or R/WW^WW" 015 , 

 see text for details). Top abscissa denotes body length (mm TL) equiva- 

 lent to mg WW of bottom abscissa. 



Energy budget 



The patterns of energy utilization for cu- 

 mulative growth (G) and cumulative meta- 

 bolic expenditure (Af ), and changes in age- 

 specific net growth efficiency (K 2 ) and age- 

 specific daily ration (F') of 0-yr-old through 

 1.8-yr-old M. muelleri are shown in Fig- 

 ure 3. K 2 and F' were the highest at the 

 beginning of life and decreased progres- 

 sively toward the end of life at 1.8 years. 

 Irregularities in the pattern, which are 

 most pronounced for K 2 , reflect the change 

 of multiplier (Kcal/g WW) to convert WW to 

 calories. The overall ranges of K 2 andF' were 

 7.6 to 61.6% (lifetime average: 16.7%) and 

 2.4 to 10.4% (2.9%), respectively. 



