Marine Data

Coastal sea-surface temperature is influenced by solar heating and cooling, latitude, and local geography. It is hard for some marine species to survive when the sea temperature changes. This can affect marine ecosystems and processes. It can also affect fish-farming industries based in our coastal areas.
This dataset relates to the "Coastal sea-surface temperature" measure on the Environmental Indicators, Te taiao Aotearoa website.

The pH of New Zealand subantarctic waters is calculated from pCO2 (dissolved carbon dioxide) and alkalinity measurements using refitted Mehrbach constants (see Mehrbach et al, 1973; Dickson & Millero, 1987), and in-situ temperature taken from the Munida time-series transect off the Otago coast. Measurements of pCO2 are taken every two months.
The Munida transect, in the subantarctic waters off Otago, is the Southern Hemisphere’s longest-running record of pH measurements (NIWA, 2015).
More information on this dataset and how it relates to our Environmental reporting indicators and topics can be found in the attached data quality pdf.

Sea-level rise is a consequence of climate change. Increased global temperatures lead to rising sea-levels because warmer waters take up more space and glaciers and polar ice sheets melt into the ocean. Sea-level varies naturally from place to place due to local ocean circulation and temperatures and the movement of the land relative to the sea. For example, earthquakes can lift or drop the land.
Linear trends were provided by NIWA and Emeritus Professor John Hannah (previously University of Otago). Ideally, linear trends in sea level would be reported if there are at least 50 years of data to account for climate variability from climate oscillations such as the 20–30 year Interdecadal Pacific Oscillation (IPO) and the shorter ENSO cycle. Such climate variability can be seen in the increase in annual mean sea level in 1999–2000, when the IPO across the entire Pacific Ocean changed to a negative phase. While the Moturiki data cover 43 years, it was considered appropriate to apply a linear trend to further extend the number of reported sites. Further detail on the data processing (including adjustments for historic datum changes) and methods used for the trend analysis can be found in Hannah (1990), Hannah (2004), and Hannah and Bell (2012).
More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.

New Zealand has a diverse range of marine mammal species and subspecies, including whales, dolphins, seals, and sea lions. Marine mammals are indicator species for the state of our marine environment. The conservation status of a species relates to its risk of extinction.
Many of these species are endemic (only found in) to New Zealand. They are apex species (near the top of the food chain) and can thrive only if their ecosystems are healthy. A decreasing population can indicate that the ecosystem is degrading. Marine mammals played an important part in New Zealand history; in the past whales and seals were hunted in great numbers. Now we have a rapidly-growing whale- and dolphin-watching industry.

Ocean acidification is the long-term decrease in the pH of our coastal waters and oceans. This indicator measures the change in pH in subantarctic surface waters at a station east of Otago from 1998 to 2017, and also the pH at selected coastal sites via the New Zealand Ocean Acidification Observing Network (NZOA-ON) from 2015 to 2017.

More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.

These data provide a snap shot of beach litter surveys submitted by Citizen Scientist ‘Monitoring Groups’ up to April, 2019. As defined by the United Nations Environment Programme (UNEP, 2009), marine litter is any persistent, manufactured or processed solid material discarded, disposed of, abandoned or lost in the marine and coastal environment. Marine litter washed onto beaches is one of the most obvious signs of marine pollution, and can have either land or sea-based origins. Land-based sources of marine litter include input from rivers, sewage and storm water outflows, tourism and recreation, illegal dumping, and waste disposal sites. Sea-based sources include commercial shipping, fisheries and aquaculture activities, recreational boating and offshore installations.

UNEP, 2009. Marine Litter: A Global Challenge. Nairobi: UNEP. 232 pp.

More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.

Sea-level rise is a consequence of climate change. Increases in global temperature cause ocean waters to expand, and glaciers and ice sheets to melt into oceans. Sea-level rise affects estuaries, coastal wetlands, and intertidal and sub-tidal habitats and species. The increased likelihood of coastal erosion from sea-level rise presents a risk for seaside communities and their infrastructure, and for the marine environment itself, from increased suspended sediments.
This dataset relates to the "Coastal sea-level rise" measure on the Environmental Indicators, Te taiao Aotearoa website.

New Zealand waters have at least 117 species of chondrichthyans (sharks, rays, and other cartilaginous fish species). They are particularly vulnerable to overfishing because they are long-lived, mature slowly, and have a low reproductive rate. Chondrichthyans are important for healthy ocean ecosystems, and reporting their commercial catch and bycatch helps us understand the sustainability of our fisheries.

The Hector’s and Māui dolphins are subspecies of the small dolphin Cephalorhynchus hectori. These coastal dolphins are endemic to New Zealand (not found anywhere else). Māui dolphins are found on the west coast of the North Island, most often between Maunganui Bluff, north of Dargaville, and New Plymouth. Hector’s dolphins are mostly found around the South Island. Both subspecies are threatened with extinction. The Hector’s dolphin is classified as nationally endangered, while the Māui dolphin is nationally critical. Dolphins can become entangled in fishing gear used by both commercial and recreational fishers, with set nets posing a particularly high risk. Reporting the bycatch of protected species helps us understand the pressures our protected marine species face from fishing.
We report on two aspects of Hector’s and Māui dolphin deaths based on data extracted from the Department of Conservation (DOC) Incident Database for 1921–2015: the number of dolphin deaths by cause of death, including a comparison of deaths over 1996–2015; and the number of dolphin deaths from entanglement by type of fishing gear.

New Zealand has a diverse coastline, which spans 15,000 km. Reporting on our coastal seabed (benthic) habitats provides important contextual information on the state of the marine domain.
This dataset relates to the "Coastal habitats" measure on the Environmental Indicators, Te taiao Aotearoa website.