Early development of the freshwater goby Orsinogobius croaticus endemic to Croatia and Bosnia-Herzegovina
Early development of the freshwater goby Orsinogobius croaticus (Mrakovčić, Kerovec, Mišetić & Schneider, 1996) endemic to Croatia and Bosnia-Herzegovina, reared under laboratory conditions, is described for the first time. Eggs were pear shaped, 1.4 × 1 mm in size. Hatching occurred 9 to 10 days after spawning, and larvae had a mean TL of 4.27 mm, with the caudal fin and all three pairs of otoliths developed and clearly visible at hatching. Hatched larvae showed positive phototaxis. The mouth opened on days 2-3 post-hatching (PH), with larvae feeding independently on the third day. The yolk sac was absorbed and notochord flexion began on days 6-8 PH. On day 31 PH, the larvae had a mean TL of 10.69 mm, and began to show negative phototaxic behaviour, moving towards the bottom of the tank to begin demersal life.