ABSTRACT
Gobiidae eggs are generally ovoid to ellipsoid, but some are round and others pear-shaped, and many contain filaments for attachment to a
hard substrate (Ruple, 1984; Leis and Carson-Ewart, 2000). Th eir colour varies from clear and transparent to yellow, or darker, depending on yolk colouration (Hildebrand and Cable, 1938; Russell, 1976; Ruple, 1984). Eggs range in size (maximum axis) from as little as 0.34 mm (range: 0.33 – 0.35 mm) in Awaous melanocephalus to 6.83 mm (range: 6.25 - 7.40 mm) in Sagamia geneionema (Table 3.4.1). Th e incubation period also varies widely, even within the same subfamily. For example, the Gobionellinae presented one of the shortest and the longest developmental periods (18 hours for Evorthodus lyricus and for Ctenogobius boleosoma and 27 days for Pterogobius zacalles) (Table 3.4.1). A typical sequence of embryonic development is described for some of the Gobiidae species our group has been studying. Th e main events of the embryonic stage might be found in Ballard (1969) Gil et al. (1997, 2002) and Borges et al. (2003) (Fig. 3.4.1). In these species of the genus Gobius (G. paganellus, G. cobitis and G. cruentatus) occurring in the western Portuguese shore, the eggs are elongated and fusiform, with egg sizes (long axis) ranging in our study area from 1.60 to 3.74 mm (Gil et al., 1997, 2002; Borges et al., 2003). Embryonic development lasted from 9 to 24 days (depending on the species and temperature). For details on developmental sequences of other genera see Sonoda and Imai (1971), Takita (1975), Sunobe and Nakazono (1987, 1989, 1995), Sunobe (1995), Privileggi et al. (1997), Arakawa et al. (1999) and Sunobe and Shinomiya (2002).
