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Author: Linnaeus, 1758

Agonus cataphractus Linnaeus, 1758

Diagnosis: two dorsal fins. No barbels on snout tip. Nasal tube short, never reaching upper jaw; nasal bones attached to each other anteriorly; a nonspinous rostral plate; nasal bone projecting forward beyond upper jaw; two nasal spines, one directed forward, one recurved posterodorsally, no ethmoidal spine; absence of supraocular spine. One or two pairs of barbels on ventral surface of snout; two or three maxillary barbels, no barbel on lower jaw tip; numerous short barbels on gular and gill membranes. Gill membranes united, widely fused with isthmus. No occipital pit. Breast covered with enlarged bony plates, unpaired row absent. The first dorsal fin with (4)5-6 spines, the second with (5)6-8 soft finrays; pectoral large, with 15-17 finrays; anal short, with (5) 6-7 finrays. 32-39 lateral line plates (Kanayama, 1991). Colour: upper parts greyish-brown, with 4-5 darker saddles (indistinct); lower parts lighter, sometimes with greyish spots; fins yellowish, with dark dots and stripes. Mouth and gill cavities densely pigmented; peritoneum pale. Size: to 21 cm TL, usually 13 -15 cm.

Habitat: benthic in inshore waters, min. depth 35 m, deeper in winter, down to 270 m in Skaggerak, preferring sandy bottoms, rarely with stones, at temperatures always above 0°C (most often 4-12°C). Food: small bottom crustaceans and polychaetes. Reproduction: February-May in North Sea; mature at 3-4 years; eggs about 2,700 of up to 2.2 mm, yellowish or orange, laid in clumps among the branches of Laminaria or other brown seaweed holdfasts; fry planktonic in February-April.

Distribution: Atlantic coasts from English Channel to Finmarken and Murman coasts and White Sea, also the Shetlands, the Faroes and southern and south-western coasts of Iceland; southern part of Baltic.

Complementary iconography. Ehrenbaum, 1931, pl. | Andersson, 1942, pl. 22 (color photo) | Andriashev, 1954, fig. 245-246.

Eggs, larvae and young stages. Kröyer, 1838: 143 | McIntosh & Prince, 1890: 674, 862, pl. 1 (fig. 23), pl. XVIII (fig. 10-11) | Ehrenbaum, 1904: 141, pl. Ill (fig. 16-17); 1905-1909: 75, fig. 31 | Rass, 1941: 23.
Otoliths (sagitta). W. Schmidt, 1968: 57, pl. 12 (fig. 162).

Hooknose (Agonus cataphractus)