buries itself in the estuary mud

Size
Length: 25-45 cm, Wt: up to 600 g
Lifespan
Unknown
Diet
Nocturnal feeder on amphipods small crabs shrimps and worms found in soft sediment. Forages by moving slowly across bottom detecting prey by touch and smell.
Habitat
Muddy and sandy bottoms of estuaries harbours and sheltered bays to about 100 m. Juveniles use estuarine mudflats as nursery habitat for up to two years.
Range
Endemic throughout New Zealand from Cape Rēinga to Stewart Island and Chatham Islands. Found in shallow coastal waters on both main islands and offshore.
Endemism
Endemic
Main Threats
Subject to commercial and recreational fishing. Taken as bycatch in some trawl fisheries. Population stable. Managed under the Quota Management System.
Population
Common throughout New Zealand in suitable soft-sediment habitat. Managed commercially. No specific population concerns. Not assessed separately by DOC.
Conservation Status
Not Threatened
Human Risk
harmless
Handling Note
native sole, harmless to humans, leave undisturbed
Conservation Note
Endemic marine fish; not assessed by NZTCS as marine fish are outside the scope of current threat classifications.
Te Ao Māori
To Māori the common sole is known as pātiki rori. This name distinguishes it from other flatfish species. Pātiki the general term for flatfish appears widely in place names. It features in oral traditions associated with estuaries and coastal waterways. This reflects the importance of these environments and the fish they contained as food sources. Common soles were taken in nets and traps in estuaries and harbours by coastal iwi. The estuary habitats where juvenile soles are reared fall within the rohe of coastal hapū. These groups maintain kaitiakitanga over these areas. The health of those estuaries is understood as directly connected to the abundance of species like pātiki rori.
A common sole resting on a harbour mudflat is one of the harder things to see in a New Zealand estuary. It is greenish-grey above with faint mottling. The body presses flat against the sediment. It is very close to invisible until it moves. When startled it produces a brief burst of speed. It relocates a metre or two away. It becomes invisible again almost immediately. This is the entire defensive strategy. It works well enough that the species has made a successful living in shallow coastal habitats throughout New Zealand for a very long time. Peltorhamphus novaezeelandiae is a flatfish. It is a righteye flounder in the family Rhombosoleidae. It is endemic to New Zealand. Like all flatfish it begins life as a bilaterally symmetrical larva. One eye sits on each side of the head. During metamorphosis the left eye migrates across the top of the skull to join the right. The fish settles permanently onto its left side. The upper surface carries both eyes. It develops cryptic pigmentation. The underside remains white. In the common sole this produces a fish that is oval thin and smooth-edged. It grows from 25 to 45 centimetres long. A long filamentous ray on the upper pectoral fin distinguishes it from other New Zealand sole species. The rostral hook covers the mouth on the eyed side. This is another useful identifying feature. The species is nocturnal. During daylight it rests on the bottom. It often buries partially in sediment by rippling the marginal fins. It shuffles gently downward until only the eyes and the top of the head remain visible. After dark it forages across soft substrate. It hunts amphipods crabs shrimps and worms. It moves slowly. It detects prey by contact and smell rather than vision. Juveniles spend up to two years in estuarine nursery habitats. These are shallow mudflats and sandflats in sheltered harbours. They move to deeper inshore waters as adults. This nursery dependence makes estuary condition a relevant factor in population health. The species is more abundant in the South Island than the North. This is consistent with its preference for cooler more productive soft-sediment environments. Common soles are taken commercially under the Quota Management System. They are regarded as good eating. They are also caught recreationally by net and line in estuaries and sheltered bays. The population is considered stable. The species carries no conservation concern. It simply gets on with being flat and invisible. That turns out to be a very effective long-term plan.