Table 2 Plasma protein electrophoresis comparison between female and male undulate skates (Raja undulata) maintained under human care. No statistically significant differences were detected between sexes (p > 0.05; Mann-Whitney U test or *Student’s t-test)

Female (n = 21)

Male (n = 27)

Analyte (unit)

Mean

SD

Median

Min

Max

Mean

SD

Median

Min

Max

P

TP (g/l)

29.62

3.37

30.00

22.00

35.00

29.11

3.09

28.00

24.00

36.00

0.589*

Fraction 1 (%)

0.49

0.23

0.40

0.20

0.90

0.43

0.24

0.40

0.10

1.00

0.461

Fraction 2 (%)

12.63

4.70

11.40

5.20

21.30

13.61

5.34

13.40

4.40

24.20

0.338*

Fraction 3 (%)

43.03

2.85

43.30

37.20

47.20

42.37

3.43

42.10

36.10

48.90

0.483*

Fraction 4 (%)

32.80

3.43

32.10

26.70

38.90

33.65

4.04

33.70

24.30

42.30

0.550*

Fraction 5 (%)

4.97

1.76

4.60

2.30

8.40

4.53

1.21

4.50

2.30

7.60

0.228

Fraction 6 (%)

4.30

1.57

3.90

2.10

8.30

3.57

1.46

3.40

1.40

7.30

0.100

Fraction 7 (%)

1.79

0.43

1.90

0.90

2.40

1.84

0.64

1.90

0.80

3.10

0.917*

Fraction 1 (g/l)

0.15

0.08

0.13

0.05

0.32

0.13

0.07

0.11

0.03

0.26

0.448

Fraction 2 (g/l)

3.71

1.35

3.58

1.64

5.88

0.39

1.55

3.75

1.20

0.80

0.435*

Fraction 3 (g/l)

12.79

2.01

12.90

8.62

16.07

1.35

1.87

11.89

9.94

17.24

0.313

Fraction 4 (g/l)

9.69

1.34

9.60

7.31

12.75

9.85

1.92

9.60

5.83

14.81

0.987

Fraction 5 (g/l)

1.45

0.49

1.34

0.69

2.44

1.31

0.33

1.23

0.81

2.13

0.101

Fraction 6 (g/l)

1.30

0.58

1.09

0.63

2.74

1.03

0.38

0.96

0.39

1.82

0.146

Fraction 7 (g/l)

0.53

0.15

0.58

0.24

0.72

0.54

0.20

0.53

0.22

0.90

0.519