Table 2. Temporal parameters of spawning of the sea urchins Strongylocentrotus intermedius and Mesocentrotus nudus participating in mass spawning events.
The data for 15 females (f) and 96 males (m) of S. intermedius and 24 females and 119 males of M. nudus are presented as the median and range (in parentheses). “n” is the number of measurements for each parameter. The Mann–Whitney test was used to reveal intersex and interspecies differences.
| Parameter | S. intermedius | M. nudus | Intersex comparison | Interspecies comparison | ||||
|---|---|---|---|---|---|---|---|---|
| Male | Female | Male | Female | S. intermedius | M. nudus | Males | Females | |
| Release duration of one gamete batch (min) | 3 (1–90) n = 390 |
4 (1–34) n = 38 |
2 (1–34) n = 379 |
6 (1–21) n = 50 |
m ≈ f U = 6238; p = 0.1040 |
m < f U = 6148; p = 0.0001 |
mint > mnud U = 66350; p = 0.0049 |
fint ≈ fnud U = 869; p = 0.4966 |
| Total duration of gamete release (min) | 13.5 (1–92) n = 96 |
14 (2–61) n = 15 |
9 (1–62) n = 119 |
14 (3–37) n =24 |
m ≈ f U = 683.5; p = 0.6567 |
m ≈ f U = 1611; p = 0.5833 |
mint > mnud U = 4847; p < 0.0067 |
fint ≈ fnud U = 181; p = 0.5804 |
| Time interval between gamete batches (min) | 4 (0–162) n = 292 |
1.5 (0–35) n = 28 |
4 (0–79) n = 282 |
1 (0–11) n = 37 |
m > f U = 2862; p = 0.0072 |
m > f U = 2657; p < 0.0001 |
mint ≈ mnud U = 40895; p = 0.8645 |
fint ≥ fnud U = 401.5; p = 0.1148 |
| Total duration of intervals between gamete batches (min) | 15 (0–162) n = 96 |
1 (0–50) n = 15 |
9 (0–113) n = 119 |
0 (0–11) n = 24 |
m > f U = 348.5; p = 0.001 |
m > f U = 871.5; p < 0.0001 |
mint > mnud U = 4760; p = 0.0037 |
fint ≥ fnud U = 162.5; p = 0.062 |
| Spawning duration (min) | 36 (1–188) n = 96 |
24 (2–111) n = 15 |
24 (1–140) n =119 |
15 (1–48) n = 24 |
m > f U = 482; p = 0.0398 |
m > f U = 1178; p = 0.0089 |
mint > mnud U = 4423; p = 0.0003 |
fint ≥ fnud U = 162.5; p = 0.1826 |