Burr (1977) noted that the typical spawning period for the species throughout its range is from mid-April to early June.
It has a long spawning period which takes place from May to the end of August.
A female can release several thousand eggs every spawning period, which is several times every 8-10 days.
Once mature, an individual may spawn during successive spawning periods at about 15-day intervals.
This closure is still in effect to protect grunion during their peak spawning period.
In Bermuda the spawning period is short and seems to be related to the phase of the moon.
There can be as many as 5,000 fry from a single spawning period.
The female's genital papilla is also enlarged up to the spawning period, but her color and pattern changes very little.
Females compensate by spawning large numbers of eggs and extending their spawning periods.
Moore (1938a) considered the main spawning period to be winter and spring although egg capsules are to be found throughout the year.