Grunion until the next tide series high enough reaches them 10 or more days later. Grunion eggs can extend incubation and delay hatching if tides do not reach them for an additional four weeks after this initial hatching time. Most of the eggs will hatch in 10 days if provided with seawater and the agitation of the rising surf. The mechanical action of the waves is the environmental trigger for hatching. The rapidity of hatching, which occurs in less than one minute, indicates it is probably not an enzymatic function of a softening of the chorion as in some other fishes.
USS Grunion the exact location indicated by the commander of the "Kano Maru". The sunken object had many characteristics typical of a submarine. In 2007, using a ROV, DSSI/Oceaneering returned to the site and took video recordings of the imploded remains of a submarine, which had markings in English, and propeller guards and limber holes identical to those of the "Grunion". The following year, the US Navy confirmed that the find was the "Grunion". Although it is not absolutely certain, the evidence strongly suggests that the "Grunion" was lost as a result of multiple torpedo failures during her encounter with the "Kano