Marine Data - Page 5

New Zealand has 92 seabird and 14 shorebird species and subspecies (taxa). We have the highest number of endemic seabirds (found only in a particular area) in the world. Nearly 25 percent of the world’s seabird species breed in the New Zealand region, and almost 10 percent only breed here. Seabirds and shorebirds tend to be at or near the top of the food chain, and thrive only if the marine ecosystem is healthy. Decreasing bird populations can signal that the ecosystem is degrading.
This dataset relates to the "Conservation status of seabirds and shorebirds" measure on the Environmental Indicators, Te taiao Aotearoa website.

New Zealand’s four million km2 marine environment is diverse, with a range of coastal habitats and offshore seabed environments. We also have many marine species found only in New Zealand. Marine protected areas conserve or manage some of these unique habitats and species, while a range of other tools also provide marine protection. We report on the area covered by marine reserves as an indirect measure to understand the state of the marine environment.

The ocean storm index estimates the number of days in a year when wind speeds exceed gale and storm force on the Beaufort Scale. In a gale, sea conditions are rough and waves can be over six metres high. In a storm, waves can be over 10 metres high. To put this into context, on land a near gale would make walking difficult, and a storm would cause some damage to roofs, chimneys, and trees. Climate change could lead to changes in the frequency and intensity of storms. More frequent and intense storms will likely be a stressor for habitats and species.
The ocean storm index estimates the number of days that wind speeds exceed gale and storm force on the Beaufort Scale. The Beaufort Scale is a widely used international classification that rates sea conditions from 0 (calm) to 12 (hurricane). We report on estimated wind speeds broken down to:
- gales – measure 8 on the scale, have rough sea conditions with wind speeds of approximately 62–74 km per hour and wave heights of 5.5 metres
- storms – measure 10 on the scale, have wind speeds of approximately 89–102 km per hour and wave heights of 9–11.5 metres (McDonald & Parsons, 2016).
This data relates to the average number of days wind speed exceeded gale force (Beaufort Scale 8) from 1979–2015.

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.

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 average concentration of chlorophyll-a (chl-a) in phytoplankton over the period 1997 to February 2016.
Concentrations of chl-a in phytoplankton are used to assess primary productivity in our oceans. Phytoplankton are primary producers of biomass (mass of living organisms) and form the main basis of marine food chains. They use the chl-a pigment to capture the sun’s energy through the process of photosynthesis. Phytoplankton growth is affected by the availability of nutrients and light, which in turn are affected by the structure of the surface water column. The surface water column structure is affected by oceanographic and climate processes; large-scale changes to climate and oceanographic conditions can lead to changes in phytoplankton growth and chl-a concentrations.

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).
Trends were assessed using linear regression at the 95% confidence level.
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.

Our fish stocks are affected by commercial, customary, and recreational fishing, and environmental pressures (eg ocean temperature, acidity, and productivity). The Ministry for Primary Industries uses three performance measures to assess influences on fish stocks: a soft limit (below which a rebuilding plan is required), a hard limit (below which closing a fishery should be considered), and an overfishing threshold (where the rate of extraction is higher than the rate of replenishment).
This dataset relates to the "State of fish stocks" measure on the Environmental Indicators, Te taiao Aotearoa website.

Our fish stocks are affected by commercial, customary, and recreational fishing, and environmental pressures (eg ocean temperature, acidity, and productivity). The Ministry for Primary Industries uses three performance measures to assess influences on fish stocks: a soft limit (below which a rebuilding plan is required), a hard limit (below which closing a fishery should be considered), and an overfishing threshold (where the rate of extraction is higher than the rate of replenishment).

Ocean acidification, measured by the reduction in sea water pH, is mainly caused by oceans absorbing and storing carbon dioxide from the atmosphere. Ocean acidification affects marine species in various ways. The growth and survival rates of some shell-building species are affected because they struggle to build their shells. The behaviour and physiology of some fish is also affected. This could influence marine ecosystems and commercial, customary, and recreational fishing or harvesting.
This dataset relates to the "Ocean acidification" measure on the Environmental Indicators, Te taiao Aotearoa website.