Aquatic Environment and Biodiversity Annual Review 2012

AEBAR 2012: Ecosystem effects: Land-based effects
• widespread and increased eutrophication;
• decline of fish stocks and other renewable resources; and
• changes in sediment flows due to hydrological changes
. Coastal development is projected to impact 91% of all inhabited coasts by 2050 and will contribute
to more than 80% of all marine pollution (Nellemann et al. 2008).
Aquaculture and land-based activities that may have impacts on seafood production are primarily
regulated under the Resource Management Act 1991 (and subsequent amendments). Fisheries are
controlled under the Fisheries Act 1996. Fisheries 2030 is a long-term policy strategy and direction
paper of the Ministry for Primary Industries. It was released in 2009 and states that improving the
Fisheries/Resource Management Act interface is a priority (objective 8). Strategic actions to achieve
this priority are listed as:
8.1 Improve fisheries sector input to processes that manage RMA-controlled effects on the
marine and freshwater environment.
8.2 Promote the development and use of RMA national policy statements, environmental
standards, and regional coastal and freshwater plans
The Government’s ‘Fresh Start for Freshwater Programme 26 ’ (lead by MfE and MPI) is addressing a
range of issues through a water reform strategy that includes governance, setting objectives and limits,
managing within limits (quality and quantity) and that better reflects Maori/Iwi rights and interests in
water management. The Coastal Policy Statement (2010) also has relevance to matters of fisheries
interest, e.g. Policy 20(1) (paraphrased) controls the use of vehicles on beaches where (b) harm to
shellfish beds may result. MPI also works with other agencies, principally DOC, MfE and regional
councils and through the Natural Resource Cluster to influence these processes to ensure
consideration of land-based impacts upon seafood production.
Land-based effects on seafood production and supporting biodiversity in this context are defined as
resulting either from the inputs of contaminants from terrestrial sources or through engineering
structures (e.g., breakwaters, causeways, bridges) that change the nature and characteristics of coastal
habitats and modify hydrodynamics. The major route for entry of land-based contaminants into the
marine environment is associated with freshwater flows (rivers, streams, direct runoff and ground
water), although contaminants may enter the marine environment via direct inputs (e.g., landslides) or
atmospheric transport processes.
The most important land-based effect in New Zealand is arguably increased sediment deposition
around our coasts (Morrison et al. 2009). This deposition has been accelerated due to increased
erosion from land-use, which causes gully and channel erosion and landslides (Glade 2003). Inputs of
sediments to our coastal zone, although naturally high in places due to our high rainfall and rates of
tectonic uplift (Carter 1975), have been accelerated by human activities (Goff 1997). Sediment inputs
are now high by world standards and make up ~1% of the estimated global detrital input to the oceans
(Carter et al. 1996). By contrast New Zealand represents only ~ 0.3% of the land area that drains into
the oceans (Griffiths and Glasby 1985, Milliman and Syvitski 1992).
Different land use effects act over different scales; for example localised effects act on small streams
and adjacent estuarine habitats, large scale effects extend to coastal embayments and shelf
ecosystems. Associated risks will vary according to location and depend on the relevant ecosystem
services (e.g. high value commercial fishery stocks) and their perceived sensitivities. The risk from
stormwater pollutants will be more important near urban areas and the effects of nutrient enrichment
will be more important near intensively farmed rural areas.
26 http://www.mfe.govt.nz/issues/water/freshwater/fresh-start-for-fresh-water/
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