Dragonet
Otolith description
The shape of the otolith is triangular. The sulcus is well developed and open at the ostium. There is no cauda visible. The ostium is wedge shaped. The outer margin of the sulcus is thicker than the rest of the otolith. The surface of the inside, apart from the thickening around the sulcus, the outside and margins are smooth. The rostrum is small and pointed. The antirostrum is indistinct. The posterior margin is pointed and there is a slight indentation visible in the direction of the sulcus. The inside of the otolith is convex and the outside concave. The dorsal margin is rounded, while the ventral margin is almost straight. The otolith is thick. Otoliths of dragonet are small and do not exceed 4 mm in length.
Otoliths of dragonet are hard to distinguish from reticulated dragonet Callionymus reticulatus and four-bearded rockling Enchelyopus cimbrius. The sulcus of reticulated dragonet otoliths in less well-developed and the rostrum is rounded instead of pointed like in dragonet otoliths. Otoliths of reticulated dragonet are smaller and do not exceed 3 mm in length. Otoliths of four-bearded rockling are thinner than callionymidae otoliths and have not only a wedge shape ostium but also a wedge shaped cauda. Otoliths of four-bearded rockling can be larger than callionymidae otoliths; otoliths > 4 mm in length are always of four-bearded rockling.
When eroded the sulcus and rostrum become indistinct. The posterior end remains pointed.
Otoliths of juvenile dragonet already have the characteristics of larger otoliths, but the sulcus is hardly visible.
Otoliths of callionymidae are very small and are often not found in samples. All callionymidae species have strong spined preoperculae that remain in samples. These are also useful for distinguishing between species of callionymidae. The preoperculum of dragonet has four spines; one pointing forwards and three pointing backwards and/or upwards. The preoperculum of reticulated dragonet has only three spines that are all pointed back and upwards.
Fish length and distribution
Dragonet can grow up to 30 cm. Dragonet is a bottom-living fish (CALLLYRA.TIF) found in waters of 20 to 100 m in depth. It is found over sandy or muddy grounds. Spawning takes place in February and March and is preceded by a display of colourful fins of the male (Wheeler, 1978, Nijssen and De Groot, 1987, Witte et al., 1991, Muus et al., 1999).
Dragonet is a very common fish found in Eastern Atlantic, North Sea and Baltic.
Sample origin
Southern North Sea.