Embryonic and larval development of the brown wrasse Labrus
merula (Pisces: Labridae)
Dulcic a1, V.
Kožul a2, M.
Kraljevic a1, B.
Skaramuca a2, B.
Glamuzina a2 and P.
a1 Institute of Oceanography and Fisheries-Split, POB 500, 21000 Split, Croatia
a2 Institute of Oceanography and Fisheries-Split, Biological Station Dubrovnik, POB 39, 20000 Dubrovnik, Croatia
a3 Faculdade de Ciências da Universidade de Lisboa, Laboratório Maritimo da Guia, Cascais, Portugal
In March 1997 one male and one female brown wrasse Labrus
merula spawned spontaneously in aquaria conditions. Eggs were incubated at ambient temperature, salinity, oxygen and pH. The development 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±0.05 mm. The incubation period was 106 h 45 min at a mean temperature of 14.3°C. Newly hatched yolk-sac larvae were 3.8±0.02 mm, while the yolk-sac was resorbed when larvae reached 4.68±0.15 mm in total length. Some characteristics which may be useful for identification are described and compared with some other 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 the other labrid species, but it is similar to that of Labrus
bergylta. During the first 16 d (after resorption of yolk-sac) brown wrasse larvae does not possess a double crescent 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 (Crenilabrus) 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.
larvae, but the difference in larvae length also exists.