Pātiki (Flounder)

Pātiki (Flounder)
Native flatfish of Aotearoa New Zealand
What is Pātiki?
Pātiki is the Māori name for flounder, a group of native flatfish species in Aotearoa New Zealand, most commonly Rhombosolea plebeia (sand flounder), Rhombosolea leporina (greenback flounder), and Rhombosolea retiaria (black flounder). These fish typically grow between 250 and 400 millimetres in length.
Pātiki have distinctive flattened, oval-shaped bodies with both eyes located on one side of the head. Their upper surface is usually mottled brown, green, or grey, allowing them to blend seamlessly into sandy or muddy seabeds.
Habitat and Distribution
Pātiki are found in estuaries, harbours, coastal lagoons, and shallow inshore waters throughout New Zealand. They are especially common in sheltered, soft-sediment environments where they can bury themselves just beneath the surface.
Juveniles often inhabit estuaries and lower reaches of rivers, while adults may move between coastal and estuarine habitats. These environments provide rich feeding grounds and shelter from predators.
Life Cycle
The life cycle of pātiki begins when adults spawn in coastal waters, usually in spring and summer. Fertilised eggs develop into free-swimming larvae that initially resemble typical upright fish with one eye on each side of the head.
As they grow, a remarkable transformation occurs: one eye migrates across the head to the other side, and the body flattens. Juveniles then settle onto the seafloor and adopt their bottom-dwelling lifestyle, moving into estuaries and shallow coastal habitats to feed and grow.
Feeding Behaviour
Ambush Predators
Pātiki are excellent ambush predators. They lie camouflaged in the sediment with only their eyes exposed, waiting for prey to pass by.
Diverse Diet
Their diet includes small fish, crabs, worms, shrimps, and other invertebrates.
Effective Hunters
Their flattened shape and cryptic colouration provide effective protection from both predators and prey, making them highly efficient hunters in soft-sediment environments.
Ecological Importance
Ecologically, pātiki play an important role in estuarine and coastal food webs. As mid-level predators, they help regulate populations of small fish and invertebrates. They are also a key food source for larger fish, seabirds, and marine mammals.
Because they rely on healthy estuaries and shallow coastal ecosystems, pātiki are strong indicators of environmental condition in these habitats.
Environmental Pressures
Despite their adaptability, pātiki face a number of environmental pressures. Habitat degradation is a major threat, particularly from sedimentation, pollution, and modification of estuaries and river mouths.
Agricultural and Urban Runoff
Agricultural and urban runoff introduce excess nutrients and contaminants that degrade water quality and affect prey availability.
Coastal Development
Coastal development can alter tidal flows and smother important nursery habitats.
Additional Threats
Overfishing and Bycatch
Overfishing and bycatch in inshore fisheries place additional pressure on pātiki populations.
Climate Change
Climate change also poses risks through increasing sea temperatures, altered current patterns, and rising sea levels that threaten estuarine nursery habitats.
Conclusion
Protecting Our Native Flatfish
In conclusion, pātiki are an ecologically, culturally, and commercially important group of native fish in New Zealand. Their unique life cycle, reliance on estuarine habitats, and role in coastal food webs highlight the importance of protecting New Zealand's estuaries and inshore coastal environments to ensure the long-term survival of pātiki populations.