Norway pout
Otolith description
The shape of the otoliths is ovally pointed. When viewed from the side the otolith is curved. The sulcus is well developed and wide. The sulcus is closed, but runs over almost the whole length of the otolith, pointing down at the posterior. The ostium and cauda are well developed and separated by a narrowing of the sulcus. The cauda is longer than the ostium. The surface of the inside is smooth, while the outside and margins are slightly lobate. The rostrum is not well developed and round lobate. The antirostrum is indistinct. The posterior margin is pointed. The inside of the otolith is convex and the outside concave. The otolith is thick at the anterior while thin at the posterior. Otoliths of gadidae, except rockling otoliths, are all very large and mostly robust otoliths.
Otoliths of all Trisopterus species that occur in the North Sea are thicker and shorter, and more lobate at the outside, compared to other gadidae. Norway pout otoliths are hard to distinguish from other Trisopterus species. Otoliths of norway pout are smooth on the outside and margins compared to poor cod T. minutus and bib T. luscus otoliths. The cauda is wider than the ostium on poor cod and bib otoliths, while on norway pout otoliths the ostium and cauda are of the same width. Trisopterus spp. are the smallest of the gadidae and otoliths are <12 mm in length. Otoliths of bib can be larger than 10 mm, while otoliths of poor cod and norway pout do not exceed 10 mm.
In eroded otoliths the sulcus is less clear. The outside and margins are smoothed.
On otoliths of juvenile norway pout the sulcus is indistinct. The margins and outside are already slightly lobate.
On otoliths of juvenile fish the sulcus is not well developed. The outside and margins are slightly lobate.
Fish length and distribution
Norway pout can grow up to 25 cm. Norway pout is a demersal fish (TRISESMA.TIF) that is mostly found offshore. It spawns from March to May (Wheeler, 1978, Nijssen and De Groot, 1987, Knijn et al., 1993, Muus et al., 1999). It forms huge schools that are targeted by industrial fisheries.
Norway pout is found in the NE Atlantic and North Sea.
Sample origin
Northern and central North Sea.