However, the veliger
larvae of mollu scs may not use metatrochal arrest as a way of reducing captures during swimming.
4D), leading to umbonate veliger
(prodissoconch II), with a semi-curved bulging profile (umbo).
Its expression starts from the four-cell embryo stage, reaches a maximum at the Trochophore stage, and decreases during the veliger
Bryan et al., (2013) hypothesized a "veliger
shadow" occurred in association with the power plant, as evidenced by increasing numbers of live dreissenids as distance from the power plant increased (from a few meters to ~10 km).
Only Marion Reservoir exhibited statistically different veliger
densities among upper, middle, and lower sections (ANOVAR [F.sub.2,6] = 6.01, P = 0.07; Fig.
The mean shell length (APM) was plotted from veliger
until pediveliger stage.
Abundance and distribution of queen conch (Strombus gigas, Linne 1758) veligers
of Alacranes Reef, Yucatan, Mexico.
In contrast, more ephemeral aggregations were characterized by low or inconsistent veliger
densities (particularly late-stage larvae), and were generally outside primary tidal current pathways.
A typical bivalve usually discharges gametes into the water and externally fertilized eggs develop into free-swimming trochophore, then veliger
larvae (Barnes 1968).
(High or low extremes in water temperature discourage reproduction.) Within three weeks of hatching, the young mussels reach the free swimming microscopic larvae "veliger
float in the water an average of eight to 14 days and can be carried for great distances in water currents.
In some littorinids, egg capsules that are released into the water can take from 3 to 7 days to hatch in subtropical waters, whereas the following free-swimming veliger
stage can remain in the water column from a few days to several weeks in temperate areas (Fish & Fish 1977, Son & Hong 1998).