Eelpout
Otolith description
The general shape of the otolith is ovally pointed. The sulcus runs straight over of the total length of the otolith. The sulcus is open at the ostium. Ostium and cauda are clearly separated. The ostium is deep and wide. The cauda is bordered by a thickening of the ventral area of the otolith. The surface of the inside is irregular, while the outside is smooth. The margins are smooth. The dorsal and posterior margins are rounded, while the ventral margin is straight or just slightly rounded. The rostrum is long, narrow and rather fragile and pointed. In large otoliths the rostrum is longer and even less wide. The antirostrum is not as well-developed as the rostrum but clearly visible and rounded. The inside is flat, but the ventral part is thicker than the dorsal part. The outside is also flat. The otolith is thick. Otoliths do not exceed 5 mm in length.
When eroded the sulcus remains visible. The rostrum is rounded, but often broken off.
Eroded otoliths of eelpout can be difficult to distinguish from those of butterfish Pholis gunnellus. The rostrum of butterfish otoliths is less well-developed, but the sulcus is deeper than in eelpout otoliths. The otolith length-width ratio is smaller in butterfish otoliths. Otoliths of butterfish are thicker, but smaller than eelpout otoliths. Otoliths > 2.5 mm are always of eelpout.
Otoliths of juvenile eelpout are oval. The sulcus is indistinct, but the ostium and cauda are visible. There is no rostrum.
It is also important to note that the bones of eelpout have a distinct green colour, instead of being white like other in other fish species. This green colour however can also occur in garfish Belone belone, but these have very differently shaped, and much robuster otoliths.
Fish length and distribution
Eelpout can grow up to 50 cm. Eelpout is a bottom-living fish (ZOARVIVI.TIF) found in coastal waters, even in the tidal-zone. In the tidal zone it is found among rocks and algae. In deeper water it is found on muddy or sandy bottoms. Eelpout is a viviparous fish and young are born in December to February (Wheeler, 1978, Nijssen and De Groot, 1987, Witte et al., 1991, Knijn et al., 1993, Muus et al., 1999).
Eelpout is a common fish found in the coastal waters of the NE Atlantic, North Sea and Baltic.
Sample origin
Western Wadden Sea.