Coastal EcologyHauropi Taha Moana

In 2016, the Hawke’s Bay Marine and Coast Advisory Group (HBMaC) was formed around concerns over the perceived localised depletion of inshore finfish stocks and environmental degradation in Hawke’s Bay coastal marine area (CMA).  The HBMaC’s purpose is to provide recommendations on improving the information and evidential base of decision-making in the management of Hawke’s Bay CMA.  The multi-stakeholder HBMaC group includes recreational and commercial fishing interests, tangata whenua, government agencies and the Regional Council. 

Sustainable Seas

The HBMaC is collaborating with the Sustainable Seas National Science Challenge as a regional case study.  The goal of the study is to enable ecosystem based management (EBM) by taking a holistic approach to managing the marine ecosystem.  You can find out more information at their website.

Our coastal ecological monitoring programme looks at inter-tidal reefs, sandy beaches and estuaries. 

We look at ecosystem health and the level of contaminants in the mud, sand or gravel, to measure the impacts of human activities on the crabs, snails, fish and other creatures that live there.

For more information on any of these programmes, please contact coastal@hbrc.govt.nz

Rocky inter-tidal reefs make up 35% of Hawke’s Bay's coastline and are some of the most biologically diverse habitats in Hawke’s Bay. School children enjoy rocky shore outings to study the fascinating wildlife living in these places - the migrating sea birds, and larger fish and mammal species that rely on these areas for food.

The inter-tidal areas are exposed at low tide and are underwater at high tide. They provide important feeding grounds, and nursery areas for young creatures.

The Regional Council’s Reef Ecology Programme has been running since 2008. Several reefs around Hawke’s Bay are used as long term indicators for this project – Kairakau - Central Hawke’s Bay; Hardinge Road - Napier; and Te Mahia - Mahia Peninsula.

Issues:  Human access - motor vehicles, trampling by people or stock animals, increased population, and housing at beach areas developments.

Land and water - Erosion of cliffs and steep hillsides, or flooding of nearby rivers can fill these areas with sediment and kill young species, destroy habitats and food change.  The example is the flood damage to the south coast due to the storm of April 2011,  Good land management and soil conservation practices by landowners have benefits for coastal areas far beyond the farm gate.

Sandy beaches are where we like to relax, swim and surf, but they are also a valuable and undervalued part of our coastal ecosystem.

These beaches are an extensive part of the Hawke’s Bay coastline (48%).  As well as protecting nearby land (also see Dunes) our beaches support a vast range of animal and plant life by cycling nutrients, filtering large volumes of seawater and provide crucial nesting and foraging habitats.

The Regional Council’s sandy beach monitoring programme has been designed to provide information on the types and numbers of species present at these beaches and we monitor the condition of the ecology. Each community is influenced by the environment at their beach.  For example, the ecological community at Opoutama Beach is dominated by marine worms; large amounts of organic material washes ashore at this beach and marine worms are particularly good at breaking this down.  At the southern beaches you will find more crabs and shellfish as there is less organic material.

Issues:  Sandy beach ecosystems are vulnerable to the effects of human activities on the beach (vehicles, over-fishing or harvesting), nearby activities (housing developments, sewage tank leaks) and activity further inland (soil erosion, flooding).  Many of the region’s coastal margins are being developed and therefore putting more pressure on parts of our beaches. 

Shingle beaches are actually rare in the world, and Hawke’s Bay has a long shingle beach stretching between Clifton and Whirinaki. Shingle comes from the mountains via Hawke’s Bay’s long braided rivers. Shingle is very mobile; therefore estuary areas and river mouths change shape frequently. In certain sea conditions some river mouths will close up completely until a high freshwater flow (often assisted by the Regional Council diggers when safe) can push through a new opening.

While the Regional Council doesn't monitor the ecology of the shingle beaches, we are aware of the species that use these special and mobile areas.  Species of gulls, terns and petrels (some of them threatened species) use the shingle banks for resting while others build nests in the gravel.  Some seabirds also nest inland in the river gravels. There are rare native plant species that find a foothold here.

Issues:  Human activity, predators and roaming dogs impacting on nesting birds, or tired migrating birds stopping to rest.  Vehicles are banned from the shingle bank between Waitangi and Tukituki Estuaries for this reason. People should take care walking along this bank and not disturb any birds.

Extensive dune systems are along the Hawke’s Bay coastline. The largest of these are at Porangahau, Ocean Beach, Rangaiika, Pukenui and Onenui (southeast Mahia Peninsula).  In their untouched state, dunes would have been prime breeding grounds for seabirds and a range of native reptiles and invertebrates. There were once diverse shrublands, native sand binders, Spinifex, pingao and sand tussock providing habitats and these are now sparse.  Dunes also provide protection from the sea for the land (and settlements) behind them.

Many of the dune systems along our coast are under severe threat. However only one of these dune systems has protective status - a small system between Cape Kidnappers and Black Reef.

Issues:All of the dunes systems have been modified to some extent by farming, weed invasion and animal pests (rabbits especially).  Dunes have also been modified by coastal settlement and development, a pressure which is accelerating.   Some efforts have been made by coast care groups in communities to fence off dunes to stop people and vehicles trampling them.  Boardwalks and steps provide beach access. However storms can destroy these structures.

Estuaries are distinctive and dynamic habitats.  They sit in the boundary between land and sea and have a mix of fresh and salt waters. 

Estuaries have many valuable functions:

• Bird roosting, feeding and breeding
• Fish spawning and nursery
• Habitat for shellfish, snails, worms
• Habitat for specialist plants
• Nutrient and sediment filter or sink
• Buffer the effects of the sea on the land and, vice versa, buffer the effects of land-based activities on the sea
• Recreation for people.

The Regional Council science staff monitor and research estuaries which involves mapping of the vegetation around the estuary (including weeds and rare species), monitoring what birdlife, fish, aquatic invertebrates or any other pest species that are there. Annual State of the Environment monitoring is currently conducted in the Wairoa,  Porangahau and Ahuriri estuaries.

Issues: People - Our expanding population and more urban development near the coast means that our estuaries and their fringing habitats are under constant threat.  Care must be taken when managing recreation in these areas to keep people and dogs away from sensitive habitats.

Pollution and Pest Organisms - Estuaries and harbours are particularly prone to pollution from stormwater (which is not treated and contains pollutants), sewage spills, and industrial spills. Harbours are at risk of pollution and introduction of new organisms through oil spills and discharges of effluents and ballast water from ships.

Ahuriri Estuary has been a particular focus in Hawke’s Bay as it is the only estuary within city boundaries. While this gives local people good access to the lagoons, ponds, tidal flats, salt marsh islets, and channels which make up the 275 ha (high tide) estuary, it also adds pressures. This estuary supports a rich diversity of bird and fish species and is a DOC Wildlife Refuge. A cycle route passes along stopbanks and trails within the estuary area. The estuary receives stormwater runoff from the majority of the Napier-Taradale urban and industrial areas, plus runoff from pasture lands near the upper estuary. Oil spills can occur at the Inner Harbour, which is the mooring for commercial and recreational boats, and the entrance to the harbour is periodically dredged.

Ahuriri Estuary was one of the six environmental hot spots identified by the Council in its annual plan 2017-18.

Te Angiangi Marine Reserve  is along the coast between Aramoana and Blackhead.  It represents a typical stretch of the central Hawke’s Bay coastline, approximately 30 km east of Waipukurau and Waipawa. The reserve is well used by the local community, and the inter-tidal reef platform is ideal for school ‘rocky shore’ studies. There are camping grounds at both ends of the reserve, and plentiful bach (holiday) accommodation.

Find out more about marine pests on this page.

Check out our 'pest hub' to search for specific marine pests.