Tub gurnard
Otolith description
The general otolith shape is triangular. The sulcus runs diagonally from the anterior up to the posterior over the length of the otolith. The sulcus is open at the ostium. Ostium and cauda are distinguishable and separated by a narrowing of the sulcus. The cauda is wider than the ostium. The surface of the inside and outside is smooth. The ventral margin is slightly rounded and lobate. The dorsal margin is rounded and a bit irregular. The rostrum is pointed as is the antirostrum which is of the same size as the rostrum. The anterior margin is indented at the ostium. The posterior margin is pointed and there is often a small indentation visible. The inside is convex and the outside concave. The otolith is thin.
Otoliths of tub gurnard are difficult to distinguish from other triglidae, such as grey gurnard Eutrigla gurnardus. The otoliths of grey gurnard, though also triangular in shape, are generally rounder compared to tub gurnard. In tub gurnard otoliths the rostrum and antirostrum tend to be of the same size, while in grey gurnard the antirostrum is smaller. However, in small tub gurnard the antirostrum is also smaller than the rostrum. The sulcus of grey gurnard otoliths is deeper than in tub gurnard. Otoliths >6 mm are always of tub gurnard.
When eroded the sulcus remains visible and the otolith is rounder.
Otoliths of juvenile tub gurnard already have the shape and look of bigger otoliths, except for the smoother and rounder margins, rostrum and antirostrum. The antirostrum is smaller than the rostrum.
Fish length and distribution
Tub gurnard can grow up to 75 cm. Tub gurnard is a bottom-living fish (TRIGLUCE.TIF) found in inshore waters on muddy grounds. It forms small schools at the bottom but is occasionally found solitary as a pelagic fish. It spawns from May to October in deeper water (Wheeler, 1978, Nijssen and De Groot, 1987, Knijn et al., 1993, Muus et al., 1999).
Tub gurnard is found in inshore waters of the Eastern Atlantic and penetrates the southern North Sea in spring and summer.
Sample origin
Southern North Sea.