Megrim
Otolith description
Otolith shape is round to oval. The sulcus runs over more than half the length of the otolith. The sulcus is open at the ostium and narrow. Ostium and cauda are distinguishable and separated by narrowing of the sulcus. Ostium is longer and wider than cauda. The cauda is deeper than the ostium. The surface of the inside is smooth and irregular on the margins. The margins are lobate especially ventrally. The outside of the otolith is smooth. The rostrum of the otolith is rounded and an indistinct antirostrum is visible in fresh otoliths. The inside of the otolith is convex and the outside concave. The otolith is thin but thicker than in other bothidae.
Megrim otoliths are difficult to distinguish from other bothidae such as turbot Scophthalmus maximus and brill S. rhombus. Otoliths of turbot are not lobate at the ventral margin, but when otoliths are eroded the margins are smoothed in both megrim and turbot. The sulcus of turbot is longer and the ostium is deeper than the cauda whereas in megrim the cauda is deeper. Otoliths of megrim are generally rounder and thicker than both turbot and brill otoliths. The sulcus of megrim otoliths is not as deep as in turbot and brill, but when eroded the sulcus becomes less distinct in both species. Otoliths with lengths >5 mm are always from brill or turbot. .
Eroded otoliths have smooth margins. The sulcus and antirostrum become less distinct with progressed erosion.
Fish length and distribution
Megrim can grow up to 60 cm. Megrim is a bottom-living flatfish (LEPIWHIF.TIF) that is found on muddy bottoms along the continental shelf at depths up to 300 m. Both juveniles and adult live in deeper waters (Wheeler, 1978, Knijn et al., 1993, Muus et al., 1999). It spawns from March to May (Muus et al., 1999).
Megrim is found in the NE Atlantic and Northern North Sea.
Sample origin
Northern North Sea.