Edwards: Allometry of energetics parameters in Stenella attenuate 



431 



CL lp , CL d , and CL t , were estimated from the traced 

 figures, by measuring the length of the fin parallel to 

 the main axis of the body. 



Unavoidable passive heat loss [HL U ] Unavoidable 

 passive heat loss was denned as heat loss due to con- 

 duction through blubber, if one assumes no heat loss 

 from appendages or from the head anterior to the eyes 

 (e.g., Brodie, 1975). Two morphological measurements 

 contribute to this estimate of HL U ; metabolic surface 

 area of the body (MSA b ) and average blubber depth 

 (BD,). MSA h was estimated by the same method as 

 wetted surface area, except that the first anterior and 



last posterior sections of the body (Fig. 1) were omit- 

 ted from the assumed thermal core and the conic ra- 

 dius used in the estimate was the radius of the body 

 core beneath the blubber. This metabolic radius was 

 estimated by determining the radius to the outer sur- 

 face at each circumference and by subtracting the av- 

 erage blubber depth measured at that circumference. 

 Two or three measurements of blubber depth were 

 made along each circumference at the dorsal midline, 

 ventral midline, and mid-way between these two lines. 

 BD a for the entire animal was estimated as the 

 weighted sum of average blubber depths at each cir- 

 cumference. Weightings were the circumferences them- 

 selves, which gives more weight to the relatively sym- 

 metrical mid-body areas that comprise the majority of 

 the insulating area, and less weight to the thick aver- 

 age blubber depths related to the hydrodynamic keel 

 in the tail region. 



Energy density Eleven morphological measurements 

 contribute to estimating the overall energy density of 

 an individual spotted dolphin (ED an ): fractions of wet 

 mass due to muscle (F,„), blubber (F bl ), bone (F h ), vis- 

 cera (F„), and fins CF}); energy densities of blubber 

 (ED hl ), muscle (ED,„), and bone (ED bn ); and water con- 

 tents of blubber (%H 2 W ), muscle (%H 2 0J, and bone 

 (%H 2 6n ). Energy content of body fluids (blood, inter- 

 stitial fluids) were ignored. Fluid losses accounted for 

 about 10% of the difference between total weights of 

 undissected specimens and the sum of dissected body 

 fractions. 



F m , F bl , F h „, F v and F f were determined by measur- 

 ing the total wet weight of each specimen, and by 

 dissecting the specimen into component parts and 

 weighing each component. Skeletal weight was deter- 

 mined after carefully flensing and scraping all tissue 

 from each bone, including tissue between ribs, be- 

 tween spinal column processes, and within the skull 

 and jaw structures. ED hh ED m , and ED h „ were deter- 

 mined by bomb calorimetry (Cummins and Wuycheck, 

 1971). Data used in regressions are means of two or 

 four replicate energy density determinations. Dry 

 weights were determined after freeze-drying samples 

 to constant weight (48 hours) and storing in a desic- 

 cator for 24 hours. Ash-free dry weights were deter- 

 mined after ashing samples at 450° C for 4 hours and 

 cooling for 24 hours in a desiccator. Dry and ash-free 

 dry weight determinations were made on samples of 



1-20 g wet weight. %H 2 W , %H,0„, and 

 calculated as 



fHA,, were 



( 1.0 - (dry weight/wet weight)) * 100. 



Energy density (ED„ n ) of entire dolphins was esti- 

 mated as the weighted sum of predicted energy densi- 



