Concentrations of osmotically related constituents in plasma and urine of finless porpoise (Neophocaena asiaeorientalis): implications for osmoregulatory strategies for marine mammals living in freshwater

Zoological Studies

Table 2 Osmolality and other constituent values in urine of finless porpoise compared with other cetacean species

Constituents	Fin whale^a	Bottlenose dolphin^b	Freshwater^c	Seawater^d	Yangtze population		Bohai sea population
					N(n)	Mean ± SD	N(n)	Mean ± SD
Na⁺ mmol/L	303.0 ± 56.6	490.1 ± 87.9	0.35	470	3 (15)	20.07 ± 8.13	4 (4)	156.95 ± 77.33**
Cl^- mmol/L	306.0 ± 57.5	402.7 ± 79.6	0.23	548	3 (15)	13.0 ± 5.38	4 (4)	194.15 ± 76.92**
K⁺ mmol/L	60.9 ± 21.3	80.7 ± 25.8	0.08	10	3 (16)	65.5 ± 12.14	4 (4)	60.55 ± 12.49
Ca²⁺ mmol/L	-	-	0.75	10	3 (16)	2.4 ± 0.72	4 (4)	3.35 ± 2.16
Mg²⁺ mmol/L	19.4 ± 6.2	-	0.21	54	3 (16)	2.2 ± 0.62	4 (4)	2.21 ± 1.64
Creatinine mmol/L	4.3 ± 3.07	8.5 ± 5.0	-	-	3 (16)	2.6 ± 0.89	4 (4)	3.2 ± 1.79
Urea mmol/L	419.0 ± 186.0	703.5 ± 253.9	-	-	3 (4)	40.7 ± 15.78	4 (4)	74.96 ± 20.06*
Osmolality mosmol/kg	1040 ± 211.0	1715.7 ± 279.4	-	1,000^b	3 (14)	934.6 ± 149.99	4 (4)	1223.75 ± 341.84*

^aKjeld2001; ^bSuzuki et al.2008; ^cHill et al.1989; ^dKjeld2003. Significant differences between the finless porpoise are indicated by *P < 0.05 and **P < 0.01. N, individual number; n, sample number.