9. Marlborough Sounds
Map ID Number: 9
Location: Cloudy Bay to Croiselles Harbour, Tasman Bay
Approximate area: 4,450km2
Description of area:
The Marlborough Sounds are a complex drowned valley system spanning strong gradients in depth, tidal mixture, temperature, and wave exposure. As a result of these physical influences there are a wide range of habitats, including stream mouths and large estuaries, sheltered rocky shores with low algal biomass, shallow sand and mud habitats, and exposed eastern shores subject to high wave exposure and strong tidal currents.
Biological attributes:
Small pelagic fishes, such as sprats (Sprattus spp.), anchovy (Engraulis australis), and pilchards (Sardinops neopilchardus) are abundant in the Marlborough Sounds. These are important prey for seabirds such as shearwaters and gannets, and for bottlenose, dusky, and Hector’s dolphins. Estuaries and streams in the area are important for diadromous fishes (fishes that migrate between fresh and salt waters). Bryozoan beds at Chetwode, Titi, Trio, and Rangitoto islands support diverse assemblages of small benthic fishes (including juvenile commercial species such as blue cod (Parapercis colias)). Large schools of planktivores (predominantly butterfly perch Caesioperca lepidoptera) also live among the bryozoan beds. Deepwater emergence is observed at Port Underwood where lantern fishes, rat tails, and dark ghost sharks (Hydrolagus novaezealandiae) are found shallower than in other regions. The inner Queen Charlotte and Pelorus Sounds are spawning grounds for elephant fish (Callorhinchus milii). The Marlborough Sounds are the southern range limit for pink brotula (Brosmodorsalis persicinus): Queen Charlotte Sound and Port Hardy are the only sites south of East Cape where this species has been recorded.
Criteria applied:
Dependency for other species; trophic/functional diversity; representation (i.e. across physical types); extremities of range and adaptation to environment; degree of disturbance; special conditions and specialised organisms; habitat complexity/diversity.
Status and management:
The Marlborough Sounds are major recreational fishing grounds, particularly for blue cod. However, rocky habitat is limited to a thin strip around the sides of most sounds, which means that overfishing is a problem. Allowable catches for both commercial and recreational fisheries have been reduced in response. In the outer sounds and Cook Strait there is an important commercial and recreational hapuku (Polyprion oxygeneios) fishery. There were historical fisheries for this species inside both sounds.
State of information:
Moderately well studied.
References and further reading:
C. Duffy (unpubl. data), Hurst et al. (2000b), Johnston (1983).