Aspects of the biology of the red cod, Pseudophycis bacchus
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Codfishes, of the order Gadiformes (Anacanthini), puborder Gadoidei, are moderate to deep water fishes which have a worldwide distribution. The group is best represented in temperate and cold waters, especially in the Northern Hemisphere, where it contains some of the most valuable commercial species found anywhere in the world. Predominantly bottom-dwelling omnivores, these fishes characteristically have moderately elongate bodies covered with small scales, a tail fin free from dorsal and anal fins, a dorsal fin divided into two, or three parts, pelvic fins jugular in position, all fins being without true spines. The mouth is large and terminal, the chin often has a sensory barbel. In New Zealand waters, codfishes are represented by six families, twelve genera, and fifteen species. Many of these are little known deep water species. Unexploited and seldom seen by New Zealand fishermen, their occurrence in our waters in any quantity has only recently become known through the reports of foreign fishing fleets. The best known of New Zealand's codfishes is the red cod Pseudophycis bacchus (Forster in Bloch and Schneider, 1801). Of all the cods, this species most closely resembles its northern hemisphere counterparts. Elongate with a stout body, it is distinguished from other southern species by its red-grey colour, square-cut tail, body proportions, the number of rays in its fins (first dorsal 9-12, second dorsal 39-48, anal 40-50, caudal 32-36, pectorals 22-26, pelvics 5-6), and by a black spot on the side of the body near the pectoral fins. Averaging 2 kg (to 6.3 kg) in weight and 55 cm (to 120 cm) in length, the red cod is an active wandering marine fish with a range which extends from the shore into depths of over 750 metres (Shuntov, pers. comm.). Fast growing and of relatively short lifespan, this primarily ground-dwelling predator moves throughout the levels of the sea at times, feeding on a wide range of marine animals.