Marine Data - Page 9

Seabed trawling is the practice of towing fishing nets near or along the ocean floor. The towing process can physically damage seabed (benthic) habitats and species. It can also stir up sediment from the seabed. This creates sediment plumes that change light conditions. This can affect marine species (for example by limiting their capacity to generate energy through photosynthesis) and smother sensitive species.
This dataset relates to the "Commercial seabed trawling and dredging" measure on the Environmental Indicators, Te taiao Aotearoa website.

Seabed trawling and dredging, when fishing nets or dredges are towed near and along the seabed, can physically damage seabed (benthic) habitats and species. It can also stir up sediment from the seabed, shading (in shallow waters) or smothering marine species. This measure focuses on coastal areas (waters shallower than 250m). Focusing on coastal benthic habitats is important as these face multiple threats (for example from land-based activities) in addition to fishing.

Along with sea lions, fur seals, and dolphins, seabirds are the protected species most directly affected by fisheries in New Zealand waters (exclusive economic zone and territorial sea). Estimating seabird deaths from bycatch in commercial fishing is one way of assessing the pressure some seabird species face from current fishing practices. About one-third of our 92 resident seabird species and subspecies are considered to be threatened with extinction. We report on the risk of death from commercial fishing for 70 seabird species and subspecies.
The estimated annual seabird bycatch in trawl and longline fisheries is reported for Salvin’s albatross to illustrate effects on a threatened bird species with a very high risk of fishing-related death.
This data has been significantly revised since that reported in Environment Aotearoa 2015, with the estimated total bycatch of seabirds increasing by nearly 1400 birds (30 %) on average across the comparable years 2002/3 – 2012/13. This revision is due to an updated and more unified modelling approach being applied by the data providers. For further information about this revision please see our Marine domain 2016 webpage or Abraham and Richard (unpublished).

Along with sea lions, fur seals, and dolphins, seabirds are the protected species most directly affected by fisheries in New Zealand waters. Estimating seabird deaths from bycatch is one way of assessing the pressure some seabird species face from current fishing practices.
This dataset relates to the "Bycatch of protected species: seabirds" measure on the Environmental Indicators, Te taiao Aotearoa website.

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)

Sea lions and fur seals are the protected species most directly affected by fisheries in New Zealand waters, along with seabirds and dolphins. Estimating the bycatch of sea lions and fur seals indicates the pressures they face from current fishing practices.
The New Zealand fur seal Arctocephalus forsteri is classified as not threatened. Its population appears to be increasing and extending back into its historical range (where they were commonly found) (Baker et al, 2010).
The Fisheries Act 1996 designates this species as protected and requires mitigation measures to reduce bycatch (Ministry for Primary Industries, 2014).
This dataset relates to the "Bycatch of protected species: sea lion and fur seal" measure on the Environmental Indicators, Te taiao Aotearoa website.

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 dataset relates to the average number of days wind speed exceeded storm force (Beaufort Scale 10) from 1979–2015.

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 dataset relates to the number of days when wind speed exceeded storm force (Beaufort Scale 10) in 2015.

The average concentration of chlorophyll-a (chl-a) in phytoplankton over the period 1997–2014.
Concentrations of chl-a in phytoplankton are used to assess primary productivity in our oceans. Phytoplankton are primary producers of biomass and form the basis of the oceans’ food chains.

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.