engleski

Embryonic and larval development of the brown wrasse Labrus merula (Pisces: Labridae)

In March 1997 one male and one female brown wrasse spawned spontaneously in aquaria conditions. Eggs were incubated at ambinet temperature, salinity, oxygen and pH. The developmnet of the eggs, yolk-sac larvae and larvae is described and illustrated with particular emphasis on features of practical value for identification of specimens from plankton. The ripe egg of brown wrasse is a typical labrid egg with a mean diameter of 0.93 mm. The incubation period was 106 h 45 min at a mean temperature of 14.3C. Newly hatched yolk-sac larvae were 3.8 mm, while the yolk-sac was resorbed when larvae reached 4.68 mm in total length. Some characteristics which may be useful for identification are described and compared with some labrid yolk-sac larvae and larvae. The length of newly hatched yolk-sac larvae of brown wrasse was significantly larger (t-test, P<0.05) than those of other labrid species, but it is similar to that of Labrus berglyta. During the first 16d (after resorption of yolk-sac) brown wrasse larvae does not possess a double crsecent of melanophores on top of the head, but has a few melanophores on the anal fin which is very similar to the pigmentation of Symphodus melops larvae, although there is a difference in length between them. Larvae older than 16 d have a double crescent of melanophores on the top of the head with melanophores on the anal fin-fold identical to L. berglyta larvae, but the difference in larvae length also exists.

embryo; larva; development; brown wrasse

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