Rock grenadier, Coryphaenoides rupestris.

Rock Grenadier, Coryphaenoides rupestris

This deep-sea fish has a distinctive triangular shape, with its elongate body ending in a sharp point at the tail. Its first dorsal and pelvic fins are in line with each other, imparting a symmetry to this fish's profile. Its second dorsal fin, and the anal fin, are long and extend to the tail, although the rays of the dorsal fin are markedly shorter than those of the anal. Its head is entirely scaled, unlike the allied smooth grenadier. The scales on its body are equipped with small spines, and the colour is brown with tinges of violet and black on the fins. A silver hue occurs on its sides, while its head is dark brown underneath. A relatively large fish, the rock grenadier can reach a length of 100 cm, and can live 30 years or more.

Found at depths of 350–2500 metres or more, this fish was once the target of commercial fisheries in the western Atlantic, but was overharvested. Its flesh is white, and similar in taste, texture and nutritional quality to that of Atlantic cod. It ranges from the Davis Strait south to North Carolina.

The rock grenadier feeds on crustaceans, as well as squid and some fishes, but the proportion of these items in the diet varies with location. Some of its diet consists of bottom-dwellers, as indicated by the presence in some specimens of parasites that are specific to bottom-dwelling prey! Most of the feeding is done in autumn and winter, when the fish migrate through the water column to eat.

Spawning seems to occur throughout the year, with some indication that Canadian populations migrate to areas south of Iceland to reproduce. A female produces up to 35,000 eggs, which measure 2.3–2.4 mm in diameter, and float about, being carried by the currents of the Atlantic.