New-Zealand Shelf
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LME 46: New-Zealand Shelf

Bordering country:

New-Zealand

LME total area:

980,420 km²

LME overall risk:

This LME falls in the cluster of LMEs that exhibit medium numbers of collapsed and overexploited fish stocks, as well as very high proportions of catch from bottom impacting gear.
Based on a combined measure of the Human Development Index and the averaged indicators for fish & fisheries and pollution & ecosystem health modules, the overall risk factor is very low.

Productivity

Chlorophyll-A:

The annual Chlorophyll a concentration (CHL) cycle has a maximum peak (0.396 mg.m^-3) in October and a minimum (0.232 mg.m^-3) during February. The average CHL is 0.288 mg.m^-3. Maximum primary productivity (175 g.C.m^-2.y^-1) occurred during 1998 and minimum primary productivity (140 g.C.m^-2.y^-1) during 2012. There is a statistically insignificant decreasing trend in Chlorophyll of -5.54 % from 2003 through 2013. The average primary productivity is 155 g.C.m^-2.y^-1, which places this LME in Group 2 of 5 categories (with 1 = lowest and 5= highest).

Primary productivity:

Sea Surface Temperature:

From 1957 to 2012, the New Zealand Shelf LME #46 has warmed by 0.09°C, thus belonging to Category 4 (slow warming LME). The New Zealand Shelf features strong interannual variability, with a magnitude exceeding 1°C, superimposed over a slow-warming trend. Ocean currents link different parts of the New Zealand Shelf LME with different Australian LMEs. For example, the North Island is oceanographically linked to the Northeast Australian Shelf LME #40, whereas the South Island is oceanographically connected to the Southeast Australian Shelf LME #42. The 1971 all-time maximum off New Zealand occurred two years prior to the 1973 near-all-time maximum in the East-Central Australian Shelf LME #41. Therefore, these events are not oceanographically connected because the time lag is too long. Another warm peak, of 1974, occurred off New Zealand next year after the 1973 warm peak in LME #41, making ocean connection possible. The warm events of 1971-1974 were confined to these two LMEs connected by the East Australian Current and its eastward extensions, namely Tasman Front, North Cape Current Front, and East Tasman Sea Front.

Fish and Fisheries

About 750,000 t of seafood is harvested annually by New Zealand’s fisheries - 70% from deepwater and midwater fisheries, 11% pelagic, 10% farmed species, and 9% from their inshore fisheries. About 20% of the population engages in marine recreational fishing annually and expenditure made by recreational fishers to catch 5 key recreational species is nearly $1 billion NZD per year.

Annual catch:

Total reported landings show a sharp spike in 1977 of 230,000 t, likely associated with the declaration of the 200 nautical mile Exclusive Economic Zone around the LME by New Zealand, followed by a continuous increase through the 1980s and 1990s and a decline in the 2000s. The reported landing reached a peak at 440,000 t in 1998.

Catch value:

The value of the reported landings reached 1.6 billion US$ (in 2005 real US$) in 1990, followed by a decline to between 640 million US$ and 820 million US$ in recent years.

Marine Trophic Index and Fishing-in-Balance index:

The MTI has been on a rise since the mid-1970, as has the FiB index, suggesting the development of previously under-utilized, high trophic-level fisheries resources by local as well as foreign fleets.

Stock status:

The Stock-Catch Status Plots for the LME illustrate that more than half of the stocks in the region are currently either overexploited or have collapsed. And the majority of the reported landings (over 60%) are supplied by stocks classified as "overexploited".

Catch from bottom impacting gear:

The percentage of catch from the bottom gear type to the total catch fluctuated between 4 and 8% from 1950 to 2010. This percentage fluctuated around 6% in the recent decade.

Fishing effort:

The total effective effort continuously increased from around 1 million kW in the 1950s to its peak around 46 million kW in 2005.

Primary Production Required:

The primary production required (PPR) to sustain the reported landings is currently below 4% with New Zealand accounting for the great majority of the ecological footprint in the LME.

Catch potential projections (under global warming):

Pollution and Ecosystem Health

Pollution

Nutrient ratio, Nitrogen load and Merged Indicator:

Human activities in watersheds are affecting nutrients transported by rivers into LMEs. Large amounts of nutrients (in particular nitrogen load) entering coastal waters of LMEs can result in high biomass algal blooms, leading to hypoxic or anoxic conditions, increased turbidity and changes in community composition, among other effects. In addition, changes in the ratio of nutrients entering LMEs can result in dominance by algal species that have deleterious effects (toxic, clog gills of shellfish, etc.) on ecosystems and humans.
An overall nutrient indicator (Merged Nutrient Indicator) based on 2 sub-indicators: Nitrogen Load and Nutrient Ratio (ratio of dissolved Silica to Nitrogen or Phosphorus - the Index of Coastal Eutrophication Potential or ICEP) was calculated.

Nitrogen load:

The Nitrogen Load risk level for contemporary (2000) conditions was moderate (level 3 of the five risk categories, where 1 = lowest risk; 5 = highest risk). Based on a “current trends” scenario (Global Orchestration), this remained the same in 2030 and 2050.

Nutrient ratio:

The Nutrient Ratio (ICEP) risk level for contemporary (2000) conditions was very low (1). According to the Global Orchestration scenario, this remained the same in 2030 and 2050.

Merged nutrient indicator:

The risk level for the Merged Nutrient Indicator for contemporary (2000) conditions was moderate (3). According to the Global Orchestration scenario, this remained the same in 2030 and 2050.

POPs:

The New Zealand Shelf LME has 4 samples from 4 locations. They show low, moderate, and high average concentrations (ng.g^-1 of pellets) of PCBs (16, range 0.3-65 ), DDTs (20.8, range 3-42), and HCHs (15.6, range 0.4-28.9), corresponding to categories 2, 3, and 4, respectively, of the five risk categories (1 = lowest risk; 5 = highest risk). The highest concentration of PCBs (65 ng.g^-1) was recorded in a sample from the city of Auckland. This can be explained by legacy pollution. Extremely high concentrations of HCHs, corresponding to risk category 4 and 5 were detected in this LME. The collection was made in 2012 and 2013, after the onset of regulation by the Stockholm Convention. Illegal usage is suspected. Source identification of HCHs is necessary. Moderate concentrations of DDTs were observed in this LME, and could be attributed to agricultural application. However, dominance of DDT over the degradation products was not observed for the locations with higher DDT concentrations, suggesting past inputs of DDTs.

Plastic debris:

Modelled estimates of floating plastic abundance (items km^-2), for both micro-plastic (<4.75 mm) and macro-plastic (>4.75 mm), indicate that this LME is in the group with relatively high levels of plastic concentration. Estimates are based on three proxy sources of litter: shipping density, coastal population density and the level of urbanisation within major watersheds, with enhanced run-off. The high values are due to the relative importance of these sources in this LME. The abundance of floating plastic in this category is estimated to be on average over 100 times higher that those LMEs with lowest values. There is limited evidence from sea-based direct observations and towed nets to support this conclusion.

Ecosystem Health

Mangrove and coral cover:

0.03% of this LME is covered by mangroves (US Geological Survey, 2011).

Reefs at risk:

Not applicable.

Marine Protected Area change:

The New Zealand Shelf LME experienced an increase in MPA coverage from 1,674 km² prior to 1983 to 50,036 km² by 2014. This represents an increase of 2,890%, within the medium category of MPA change.

Cumulative Human Impact:

The New Zealand Shelf LME experiences below average overall cumulative human impact (score 2.75; maximum LME score 5.22), but which is still well above the LME with the least cumulative impact. It falls in risk category 1 of the five risk categories (1 = lowest risk; 5 = highest risk). This LME is most vulnerable to climate change. Of the 19 individual stressors, three connected to climate change have the highest average impact on the LME: ocean acidification (1.00; maximum in other LMEs was 1.20), UV radiation (0.51; maximum in other LMEs was 0.76), and sea surface temperature (0.73; maximum in other LMEs was 2.16). Other key stressors include commercial shipping, sea level rise, ocean based pollution, and demersal destructive and demersal non-destructive high-bycatch commercial fishing.

Ocean Health Index:

The New Zealand Shelf LME has one of the highest scores on the Ocean Health Index compared to other LMEs (score 81 out of 100; range for other LMEs was 57 to 82), but still relatively low. This score indicates that the LME is below its optimal level of ocean health, although there are some aspects that are doing well. Its score in 2013 decreased 1 point compared to the previous year, due in large part to changes in the scores for clean waters and lasting special places. This LME scores lowest on fisheries and iconic species goals and highest on mariculture, artisanal fishing opportunities, natural products and coastal livelihoods & economies goals. It falls in risk category 1 of the five risk categories, which is the lowest level of risk (1 = lowest risk; 5 = highest risk).

Socio-economics

Indicators of demographic trends, economic dependence on ecosystem services, human wellbeing and vulnerability to present-day extreme climate events and projected sea level rise, are assessed for this LME. To compare and rank LMEs, they were classified into five categories of risk (from 1 to 5, corresponding to lowest, low, medium, high and highest risk, respectively) based on the values of the individual indicators. In the case of economic revenues, the LMEs were grouped to 5 classes of revenues from lowest, low, medium, high and highest, as revenues did not translate to risk.

Population:

The coastal area stretches over 255,265 km². A current population of 4 276 thousand in 2010 is projected to increase to 5 722 thousand in 2100, with a density of 17 persons per km² in 2010 increasing to 22 per km² by 2100. About 20% of coastal population lives in rural areas, and is projected to slightly decrease in share to 29% in 2100.

Coastal poor:

The indigent population makes up 11% of the LME’s coastal dwellers. This LME places in the very low-risk category based on percentage and in the medium-risk category using absolute number of coastal poor (present day estimate).

Revenues and Spatial Wealth Distribution:

Fishing and tourism depend on ecosystem services provided by LMEs. This LME ranks in the high-revenue category in fishing revenues based on yearly average total ex-vessel price of US 2013 $853 million for the period 2001-2010. Fish protein accounts for 11% of the total animal protein consumption of the coastal population. Its yearly average tourism revenue for 2004-2013 of US 2013 $24 640 million places it in the medium-revenue category. On average, LME-based tourism income contributes 16% to the national GDPs of the LME coastal states. Spatial distribution of economic activity (e.g. spatial wealth distribution) measured by night-light and population distribution as coarse proxies can range from 0.0000 (totally equal distribution and lowest risk) to 1.0000 (concentrated in 1 place and most inequitable and highest risk). The Night Light Development Index (NLDI) thus indicates the level of spatial economic development, and that for this LME falls in the category with medium risk.

Human Development Index:

Using the Human Development Index (HDI) that integrates measures of health, education and income, the present-day LME HDI belongs to the very high HDI and very low-risk category. Based on an HDI of 0.921, this LME has an HDI Gap of 0.079, the difference between present and highest possible HDI (1.000). The HDI Gap measures an overall vulnerability to external events such as disease or extreme climate related events, due to less than perfect health, education, and income levels, and is independent of the harshness of and exposure to specific external shocks.
HDI values are projected to the year 2100 in the contexts of shared socioeconomic development pathways (SSPs). This LME is projected to assume a place in the very low risk category (very high HDI) in 2100 under a sustainable development pathway. Under a fragmented world scenario, the LME is estimated to place in a high-risk category (low HDI) because of reduced income levels and increasing population values from those in a sustainable development pathway.

Climate-Related Threat Indices:

The Climate-Related Threat Indices utilize the HDI Gaps for present-day and projected 2100 scenarios. The contemporary climate index accounts for deaths and property losses due to storms, flooding and extreme temperatures incurred by coastal states during a 20-year period from 1994 to 2013 as hazard measures, the 2010 coastal population as proxy for exposure, and the present day HDI Gap as vulnerability measure.
The Contemporary Threat Index incorporates a Dependence Factor based on the fish protein contribution to dietary animal protein, and on the mean contribution of LME tourism to the national GDPs of LME coastal states. The HDI Gap and the degree of dependence on LME ecosystem services define the vulnerability of a coastal population. It also includes the average of risk related to extreme climate events, and the risk based on the degrading system states of an LME (e.g. overexploited fisheries, pollution levels, decrease in coastal ecosystem areas).
The 2100 sea level rise threat indices, each computed for the sustainable world and fragmented world development pathways, use the maximum projected sea level rise at the highest level of warming of 8.5 W/m² in 2100 as hazard measure, development pathway-specific 2100 populations in the 10 m × 10 km coast as exposure metrics, and development pathway-specific 2100 HDI Gaps as vulnerability estimates.
Present day climate threat index of this LME is within the very low-risk (very low threat) category. The combined contemporaneous risk due to extreme climate events, degrading LME states and the level of vulnerability of the coastal population, is low. In a sustainable development scenario, the risk index from sea level rise in 2100 is very low, and increases to low under a fragmented world development pathway.