Temte: Hormonal assessment of porpoise maturity 



163 



Females 



— 30 



E 



0)25 



ID ' 

 O 



(30) 



(21) 



(23) 



lOn-pregnanl pregnanl lactaling 



Reproductive Status 



Figure 1 



Serum progesterone concentrations for non-pregnant/non- 

 lactating, pregnant, and lactating female Dall's porpoises. Ver- 

 tical bars indicate ranges of values. Horizontal bars indicate 

 means and standard errors. Sample sizes are in parentheses. 

 Animals were collected June-July 1982 in the western North 

 Pacific Ocean. 



Results 



Comparison of 1982 and 1980 

 progesterone data 



The results of the progesterone assays (1982 data: Fig. 

 1) were compared with results of Temte and Spiel vogel 

 (1985) (1980 data). No significant differences were 

 found between the mean progesterone concentrations 

 for pregnant females (1980: n = 24, x = 19.40; 1982: 

 n = 30, x = 18.09; P>0.5; Student's t-test), or for lac- 

 tating females (1980: n = 8, x = 2.63; 1982: n = 23, 

 5=2.17; P»0.05; Wilcoxson rank sum). Mean pro- 

 gesterone concentrations were significantly different 

 for the two groups of non-pregnant, non-lactating por- 

 poises (1980: n = 19, x= 1.91; 1982: n = 21, x = 2.92; 

 P<0.01; Wilcoxson rank sum). However, the mean 

 length of the 1982 sample was significantly greater 

 than that of the 1980 sample (1982: x = 171.2cm; 

 1980: x= 163.1cm; P<0.05; Student's i-test), and the 

 difference in mean progesterone could be due to a dif- 

 ference in the proportion of mature females. Therefore, 

 the results of progesterone analysis in pregnant, lac- 

 tating, and non-pregnant/non-lactating females from 

 the 1982 sample were pooled with the results from the 

 1980 sample of Temte and Spielvogel (1985). 



Females 



Serum progesterone is plotted against length for 124 

 female Dall's porpoises (Fig. 2). The results demon- 



Length (cm) 



Figure 2 



Serum progesterone concentration as a function of length in 

 non-pregnant (1980 O; 1982 •), pregnant (*), and lactating 

 ( + ) female Dall's porpoises. 



Females 



130 140 150 160 170 180 190 200 210 



Length (cm) 



Figure 3 



Summation technique for female Dall's porpoises based on pro- 

 gesterone values. Intersection of lines occurs when X(m,) = 

 X(l-m,). 



strate the incidence of high progesterone levels at 

 lengths greater than 165 cm. These elevated levels 

 were seen not only in pregnant females, but also in non- 

 pregnant, non-lactating females, indicating possible 

 ovulation. The summation technique provided an 

 estimated LSM of 169.0cm (Fig. 3). 



Males 



Serum testosterone displayed a marked increase with 

 an increase in length. A natural break in the testos- 

 terone data occurred between 175 and 180cm, when 



