The benthic ecology and community structure in Lyttelton Harbour ...

48.
distribution, avoiding the very sandy areas and having
• I
its maximum density to the north Quail Island.
Nectocarcinus is a pre?atory and scavang.ing carnivore.
There was a migration from the upper harbour areas
during the winter months with a corresponding-increuse
in numbers Purau Bay. Local concentrations were
evident near reefso
3.8 The benthic fauna as fish food
The mosf common fish in the sampling area over
the investigation period were the puffer f
h, Uranos!:orna
rlchei; the sole, Peltorhamphus novaezealandiae; red
cod, Physiculus bachus; 'the gurnard, Lepidotrigle
brachyoptera; spotted stargazer, Geniagnus monopteryqius
the trevally, Caranax lutescens; and f19under Rhombosolea
plebia.
Most of these, with the exception of the puffer,
sole, and flounder, were juveniles and their food
preferences generally reflected their small size and
relatively undeveloped jaws.
Many stomachs contained
Mysis ~. and the small isopods and amphipods found in
the upper harbour, particularly where algal growth was
abundant.
Uranostoma has been shown by Habib (1971) to feed
almost exclusively on the crab Hemiplax hirtipes.
The puffer has very strong jaws with the teeth forming
a "beak" as in the parrot fishes. The very strong
const'ruction allows it to crush Chione shells and crab
carapaces with little effort. Also prominent in the
diet of the puffer, and of most other~rbour
when it is available, is the shrimp Ponto~hilus
fishes
Opened guts of Uranostoma, Physiculus, and Caranax
austr~lis.