Jm. Lyle et Dc. Smith, ABUNDANCE AND BIOLOGY OF WARTY OREO (ALLOCYTTUS-VERRUCOSUS) AND SPIKYOREO (NEOCYTTUS-RHOMBOIDALIS) (OREOSOMATIDAE) OFF SOUTH-EASTERN AUSTRALIA, Marine and freshwater research, 48(2), 1997, pp. 91-102
The distribution, abundance, size structure, reproductive biology and
diet of warty oreo, Allocyttus verrucosus (Gilchrist), and spiky oreo,
Neocyttus rhomboidalis (Gilchrist), from the continental slope region
(400-1200 m depth) of south-eastern Australia are described. The dept
h distributions of the two species overlap, with spiky oreo being more
abundant in intermediate depths (600-800 m) and warty oreo abundance
peaking at greater depths (900-1200 m). There was evidence of size str
ucturing with depth. Warty oreo juveniles and subadults were comparati
vely more abundant in depths of less than 1000 m and adults dominated
at greater depths. In spiky oreo, juveniles were largely restricted to
the depth range of 700-900 m. Size at 50% maturity in females was 28
and 35 cm for warty and spiky oreos, respectively. Males mature at sli
ghtly smaller sizes. Spawning occurs in May-June for warty oreo and be
tween August and October for spiky oreo. Just prior to spawning in war
ty oreo the sexes appear to segregate by depth, with females becoming
progressively more dominant with depth. Both species are benthopelagic
feeders, consuming a range of prey items including crustaceans, fish
and squid. Salps were also an important component of the diet of spiky
oreo.